Please Help Do or Die Warm Issue or ending up on BaT

E28 technical advice asked and given! Troubleshooting, modifications and more.
harrypalmer
Posts: 586
Joined: Jul 25, 2012 12:10 AM
Location: Denver, Colorado

Please Help Do or Die Warm Issue or ending up on BaT

Post by harrypalmer »

Hello all,

I realize that I have never properly introduced myself although I have received quite a lot of help and invaluable advice from some of you over these previous years for which I am very thankful. Some may already know that my real name is Jack, and that I currently reside in gorgeous Denver, CO.

The reason for reaching out to this great community today, is because I have arrived at a crossroad between trying to fix fastidious little things on my '86 535 M30B34 girl pictured here that keep me away of spending more relevant quality time with my daughter.

So as a last resort, I want your advice please, in helping me find a solution to both, an on going "running hot situation" and a "all the time" fuel smelling condition. Therefore, I've determined that if I am going to hang on to this German girl any longer, she'd better run flawlessly once and for all or I will offer her for sale on BaT.

To that effect, I will continue to ask more questions for the next two to three weeks, requesting your help, to hopefully allow me to fix, and keep her, and in turn I will add more pictures and or videos documenting this diagnostics/remedy process if there's one to be found.

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She runs strong and trouble free like a Panzer, specially on the Colorado 'Autobahn' at highway speeds. But if I am caught in hot weather traffic or simply idling for far too long, as it happened last week awaiting to get my second COVID shot in a Colorado Springs parking lot; the resulting issue is the engine bay gets too hot, to the point of even trying to overwhelm the newly installed one in-tank fuel pump mod, as the fuel gets really warm. More on that (down the line) as I have some puzzling details that I need to share about it.

So far, already checked that the thermostat housing marked with an 'A' is correct to my model year and correspond with the entire collection (long story) :oops: of 80'F and 75F stats respectively all are within spec. Blue Coolant Temperature Sensor and brown Thermo-Timer Switch per Bentley, measured fine as well. Out of curiosity, does anyone knows what this adjustable screw on the side actually accomplishes? Please see pic.

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So right now I'm learning how-to test, and re-doing everything I can, as a last resort.

After overloading on mountains of useful info here, still cannot find a proper way to measure the continuity on the Coolant Temperature Switch (the one-spade little guy to the right)

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Can anyone please teach me how? Bentley stipulates what the readings ought to be but does no say how to actually measure it with the MM.
Any insight on this item will be very much appreciated.

Until, next time.

-Jack
adam_poll
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Joined: Jul 23, 2014 8:19 PM
Location: Kitchener, Ontario, Canada

Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by adam_poll »

A couple of things off the top of my head. The blue sensor is the input into the ECU and will definitely affect driveability if there is a problem with it (but should not affect how hot the car runs). The thermo time switch is just for the cold start injector hiding under the intake manifold and not worth spending time on here (If I had to guess maybe that little screw is so they can calibrate the switch when built?). The single spade temp sensor is just used for the temperature gauge in the cluster so if that is working I wouldn't spend anymore time on it. If you are in doubt of the engine temp and ir temp gun comes in handy so you can actually read temperatures coming from the engine and as it leaves the rad heading back to the engine.

With the thermostat working properly and being the right one then you need to look at other things that help actually cool the car down.

The rad cap - is it holding pressure in the system and sealing? If pressure builds to high it will bleed off coolant through the overflow tube. If the car is hot but the various hoses aren't firm this could be a cause

The water pump - if it's not leaking and the bearing feels good with the belt removed I'd cross it off the list

The rad - is this a quality rad like oem with the flattened and finned aluminum tubes or is it round tubes with fins attached? If they are round tubes I'd encourage you to change it for the other style - see this thread https://www.mye28.com/viewtopic.php?t=154621

The mechanical fan and fan clutch - Is the fan engaging at idle and pulling air? Is the fan engaged when the car is hot? It will be pretty obvious if this is working as you can really hear it moving air when it is or feel it (like air blowing, not sticking your hand in it!) with the hood open.

The auxiliary electric fans - is the car getting too hot with the AC on? If so I believe these fans in front of the rad should be coming on with the AC (I'm a bit rusty on this as my car doesn't have AC or the fans), they should also come on when the outlet temp from the rad gets too high (there is a switch on the passenger side of the rad, short these wires to each other and the fan should come on).

Any other system leaks (hose connections, gasketed surfaces like the water pump or thermostat housing, block coolant drain at the back under exhaust manifold, heat valve etc.)? These will lead to lower system pressure and a lower boiling point for the coolant, not good for cooling!

Have you bled the system properly after checking the thermostats or replacing the coolant? I think it helps have the nose in the air to do this, make sure you turn the heat on in the car as well to get coolant flowing through the heater core. Air pockets are bad for cooling.

The cooling system on these cars is pretty good, I track mine in hot weather and the needle is pretty much the same on track as if I was cruising down the highway so there is definitely an issue here. Good luck!
harrypalmer
Posts: 586
Joined: Jul 25, 2012 12:10 AM
Location: Denver, Colorado

Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by harrypalmer »

adam_poll wrote: May 12, 2021 4:54 PM A couple of things off the top of my head. The blue sensor is the input into the ECU and will definitely affect driveability if there is a problem with it (but should not affect how hot the car runs). The thermo time switch is just for the cold start injector hiding under the intake manifold and not worth spending time on here (If I had to guess maybe that little screw is so they can calibrate the switch when built?). The single spade temp sensor is just used for the temperature gauge in the cluster so if that is working I wouldn't spend anymore time on it. If you are in doubt of the engine temp and ir temp gun comes in handy so you can actually read temperatures coming from the engine and as it leaves the rad heading back to the engine.

With the thermostat working properly and being the right one then you need to look at other things that help actually cool the car down.
Adam, thank you for taking the time.
The rad cap - is it holding pressure in the system and sealing? If pressure builds to high it will bleed off coolant through the overflow tube. If the car is hot but the various hoses aren't firm this could be a cause
Yes, the rad cap is holding pressure. Not a single drop of coolant fluid has been lost in since I replaced the radiator less than a year ago. And there are no visual clues of any present or past leaks anywhere to be found in the entire engine bay: switches, sensors, hoses, clamps, or the overflow tube that exits underneath the car included.
The water pump - if it's not leaking and the bearing feels good with the belt removed I'd cross it off the list
This pump is a GMP I believe, the propeller or impeller is metal and has proven to be a great performer. Other than disassembling it for a visual inspection I would bet my money on it as there are no leaks. Cannot hear any impeller (weird) noises. But I could do a dreaded R/R service.
The rad - is this a quality rad like oem with the flattened and finned aluminum tubes or is it round tubes with fins attached? If they are round tubes I'd encourage you to change it for the other style - see this thread https://www.mye28.com/viewtopic.php?t=154621
Curiously, the last person posting on that thread above is me, as I replaced mine with a good quality, that in turn replaced the 2 year old Behr made in ZA.
The mechanical fan and fan clutch - Is the fan engaging at idle and pulling air? Is the fan engaged when the car is hot? It will be pretty obvious if this is working as you can really hear it moving air when it is or feel it (like air blowing, not sticking your hand in it!) with the hood open.
Both, the mechanical fan and the fan clutch engage at idle and pull air. Also the fan engages when the car is hot or cold as it really never stops (other diminishing its speed when I'm on the highway) and is noisy as ever.
The auxiliary electric fans - is the car getting too hot with the AC on? If so I believe these fans in front of the rad should be coming on with the AC (I'm a bit rusty on this as my car doesn't have AC or the fans), they should also come on when the outlet temp from the rad gets too high (there is a switch on the passenger side of the rad, short these wires to each other and the fan should come on).
The car gets too hot with the AC on. The aux fan works at both high and low speeds. I am currently going to test the actually present 82F and 91F switches individually out of the car, for good measure. No pun intended. I actually shortened the high fan and wired it from the cockpit while I was waiting for the COVID vaccine turn and it did turn on but didn't do a thing. The engine bay was soaked in heat even after I left the site and driving all the way back to Denver.

BTW, while in gear, the car stuttered at 70 miles per hour between 3,500 and 4,500 RPM when floored the accelerator pedal.
But when I momentarily disengaged the shifter and kept going in neutral, the engine would happily rev up to 6,600 RPM without hesitation, so I know the previously in-tank fuel pump modification is working.
Something to do with the vacuum in my car that makes it hot? What do you think?
Any other system leaks (hose connections, gasketed surfaces like the water pump or thermostat housing, block coolant drain at the back under exhaust manifold, heat valve etc.)? These will lead to lower system pressure and a lower boiling point for the coolant, not good for cooling!
I need to understand better your above question to give you a coherent reply. However, what do you think I should look for if nothing is externally visually leaking and even the translucent water reservoir is always at the same appropriate fluid level?
Have you bled the system properly after checking the thermostats or replacing the coolant? I think it helps have the nose in the air to do this, make sure you turn the heat on in the car as well to get coolant flowing through the heater core. Air pockets are bad for cooling.
Yes, I have done this bled properly in the past, as per advice in this board. I will do it again after I test and install all the sensors and switches.
The cooling system on these cars is pretty good, I track mine in hot weather and the needle is pretty much the same on track as if I was cruising down the highway so there is definitely an issue here. Good luck!

Couldn't agree more with you about an issue somewhere. Adam, Thank you once more, and good luck to you as well.
Mike W.
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Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by Mike W. »

Warm or hot at idle is classic fan clutch problem. Test it by getting it hot and trying to stop it by sticking a newspaper in there. Slowly. Visual is not a test, the newspaper is. Next Aux fan. Does it come on with the A/C? It should be running if the A/C compressor is running. Low speed should kick in just over halfway on the gauge. Speaking of the gauge and sending unit, you test the sending unit by disconnecting the wire to it, then measuring resistance from the sensor terminal, not the wire, to ground at a given temp. Speaking of, a cheap infrared temp gun is a good idea too, doesn't have to be instrument grade, but it will tell you if it's about 180 or about 200. Fan switches can get cranky and not always seem to work even if they pass the test in a pan of water. Does the Aux fan work at all? Bad resistors are common in which case it will not run on low speed, which would include A/C, just high which is about 3/4 on the gauge, +/-. There are two different thermostats depending on the year. I think it relates to the housing, but search a bit on that. Longshot, but maybe.

The gauge is super sensitive to any bad grounds. E28s aren't as suspectable to them as earlier BMWs, but not immune either. Is the gauge ever jumpy? That's a sign of a bad ground. Lastly where does the needle go with the ignition off? I had an E24 one time that was almost out of the blue at dead cold that I thought ran hot.

Fuel smell. Where? Front or back? And we'll go from there.
kojo96
Posts: 386
Joined: Mar 31, 2019 7:39 PM
Location: Pleasanton CA

Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by kojo96 »

Invest in a Bentley manual, it'll help you get through most or all of your issues.
adam_poll
Posts: 97
Joined: Jul 23, 2014 8:19 PM
Location: Kitchener, Ontario, Canada

Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by adam_poll »

From your responses it sounds like the cooling system should be in good shape without any leaks or issues. Go through Mike's suggestions as well though as he is always on the money with good advice.

I think at this point you need to stop by Harbour Freight (or amazon or wherever) and grab a cheap infrared temperature gun to see what is going on. You can easily take temps all around the engine bay with it. Hit the thermostat housing by the sensors so you can see what temp it is at and how that registers on your cluster so you have a good idea of what is going on when you have problems. You can also check temps at your aux fan switches to see what temp the fans are actually kicking on at. Does the needle steadily increase on you towards or into the red or does it just move up a bit more than typical and hold steady there? The first scenario is bad, the second pretty normal I'd say unless it is getting too high.

From what you have said it almost sounds like you are having other issues related to heat and heat soak but the car actually overheating may not be the issue. Take the temps above and let us know what they are so we can hopefully cross the cooling system off the list.

The hesitation is interesting but the fact that it doesn't do it in neutral doesn't cross the fuel pump off the list. Under load the demand is a lot higher compared to unloaded in neutral. If you are suspecting it might be a fuel issue then getting a fuel pressure gauge teed into the feed would be a good idea. While you are at Harbour freight grabbing an IR temp gun also grab some fittings and install it under the hood, if you aren't getting steady pressure all the time that is an issue that needs to be resolved.
harrypalmer
Posts: 586
Joined: Jul 25, 2012 12:10 AM
Location: Denver, Colorado

Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by harrypalmer »

Mike W. wrote: May 12, 2021 8:19 PM Warm or hot at idle is classic fan clutch problem. Test it by getting it hot and trying to stop it by sticking a newspaper in there. Slowly. Visual is not a test, the newspaper is.

Hi Mike, I'm laughing at myself because it is about time for me to follow your advice and run the newspaper test. I'll do it even thought mine is six years old.
Next Aux fan. Does it come on with the A/C? It should be running if the A/C compressor is running. Low speed should kick in just over halfway on the gauge.
Yes it does come on with the A/C, and halfway it kicks in as well.
Speaking of the gauge and sending unit, you test the sending unit by disconnecting the wire to it, then measuring resistance from the sensor terminal, not the wire, to ground at a given temp.

This is where I get lost :dunno: (in electric/electronic tech translation) Do you mean the terminal but where can I find it and what is known as ground?
Speaking of, a cheap infrared temp gun is a good idea too, doesn't have to be instrument grade, but it will tell you if it's about 180 or about 200.
Been taking temp readings with the infrared gun for the past four years, and will post some pics in sequence to the present.
Fan switches can get cranky and not always seem to work even if they pass the test in a pan of water. Does the Aux fan work at all?
Yes sir, the Aux fan works.
Bad resistors are common in which case it will not run on low speed, which would include A/C, just high which is about 3/4 on the gauge, +/-.
Resistor is also five years old and will test it.
There are two different thermostats depending on the year. I think it relates to the housing, but search a bit on that. Longshot, but maybe.
Of all the 4 thermostats I've got, I am going to install the Wahler 80F instead of the BMW branded Wahler 80F that until recently was in my car, as it seems to open a bit effortless and should I dare to say sooner at the same temp. Have read the cons on the 75F so I won't install that one.
The gauge is super sensitive to any bad grounds. E28s aren't as suspectable to them as earlier BMWs, but not immune either. Is the gauge ever jumpy?
Actually the gauge remains steady. It did go a bit to the middle once I replaced the old Beru German made one spade sensor for a similar but new Irish made Beru unit.
That's a sign of a bad ground. Lastly where does the needle go with the ignition off? I had an E24 one time that was almost out of the blue at dead cold that I thought ran hot.
All needles, (except for the fuel gauge needle, as I'm having an issue with the fuel sender unit here: https://www.mye28.com/viewtopic.php?t=155298) return to the normal far left position when turned off.
Fuel smell. Where? Front or back? And we'll go from there.
Back in 2017 replaced the evap canister at the front, vent pipe and big connecting hoses. Also the plastic evap tank in the back (have one extra doing nothing in storage. Replaced as well, the vent metal pipe that runs out of the rear back seat in the trunk to the underside. And also replaced for the second time, all of the rubber hoses with BMW grade and correct clamps. The CSV was also replaced in 2019, rubber hose along with new fuel injectors. Now, to be fair, the car does not smell like fuel when running. It has a faint fuel odor at the exit of the fuel pressure regulator when parked. But mostly it comes from the tank area, sometime from within the trunk.

Shawn D. The Beamter, suggested the gas cap might be the culprit so I did get another (have three different BMW branded of those, including the original to the car) and ultimately, I added a second gasket to the current gas cap to make it tighter in there, harder to refuel but this trick worked for a while. However, when I go into the garage, the smell of gas is ever present nonetheless.

You haven't asked yet, but I have tested two fuel pressure regulators Bosch and Piersburg and both were good. mind you, not impressive but within spec. And for good measure, after 11,000 driven miles I am on my second fuel filter as well correctly installed.
Have a question for you. Would the car run at all if the return and the rail fuel lines where switched? I have replaced all rubber hoses on them as I saw them previously installed by the OP. I am the second owner but I am wondering.
Lastly, my car is the one that gargles fuel when hot remember? https://www.mye28.com/viewtopic.php?f=3 ... 2#p1444522

Mike, thank you for taking the time and will follow your suggestions, and report back.
harrypalmer
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Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by harrypalmer »

kojo96 wrote: May 12, 2021 8:41 PM Invest in a Bentley manual, it'll help you get through most or all of your issues.
Hi Kojo, I actually do own one. I just really have a hard time understanding how and where to measure parts/connections with a MM (electronic/electric diagrams are just very difficult personally) but thanks for the suggestion.
harrypalmer
Posts: 586
Joined: Jul 25, 2012 12:10 AM
Location: Denver, Colorado

Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by harrypalmer »

adam_poll wrote: May 12, 2021 10:25 PM From your responses it sounds like the cooling system should be in good shape without any leaks or issues. Go through Mike's suggestions as well though as he is always on the money with good advice.
Yes I will, and couldn't agree with you more.
I think at this point you need to stop by Harbour Freight (or amazon or wherever) and grab a cheap infrared temperature gun to see what is going on. You can easily take temps all around the engine bay with it. Hit the thermostat housing by the sensors so you can see what temp it is at and how that registers on your cluster so you have a good idea of what is going on when you have problems. You can also check temps at your aux fan switches to see what temp the fans are actually kicking on at. Does the needle steadily increase on you towards or into the red or does it just move up a bit more than typical and hold steady there? The first scenario is bad, the second pretty normal I'd say unless it is getting too high.
Have been doing that for about a couple of years actually. Will post some pics of said parts later on for comparison/analysis and feedback.
From what you have said it almost sounds like you are having other issues related to heat and heat soak but the car actually overheating may not be the issue. Take the temps above and let us know what they are so we can hopefully cross the cooling system off the list.
Image

Interestingly, this morning I was reading in Bentley's about the ThermoValve Switch (the closest to the thermostat) and the plastic vacuum actuated Purge Valve and how it affects drive-ability while warm. Both items where replaced in around 2018 along with a new Fuel canister and respective hoses at the front so I would not suspect them but I guess I can be wrong. Not sure about the canister itself as to how to test it or even do this test below:

Image
The hesitation is interesting but the fact that it doesn't do it in neutral doesn't cross the fuel pump off the list. Under load the demand is a lot higher compared to unloaded in neutral. If you are suspecting it might be a fuel issue then getting a fuel pressure gauge teed into the feed would be a good idea. While you are at Harbour freight grabbing an IR temp gun also grab some fittings and install it under the hood, if you aren't getting steady pressure all the time that is an issue that needs to be resolved.
Fuel pressure test was done twice in 2019 with two FPR and passed with both. Have videos and photos of these.
jayjaya29
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Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by jayjaya29 »

Regarding you gas smell all the time. Is there any signs of leaking on the bottom of the tank or any of the lines connected to the lift pump bracket in the trunk?

I have an occasional gas smell, particularly after I fill it up. I'm planning on following this thread to track it down, I have a sneaking suspicion its the hard line and/or the lines going from the tank to the vapor canister in the trunk.

https://www.mye28.com/viewtopic.php?f=3&t=156207
Mike W.
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Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by Mike W. »

Yes it does come on with the A/C, and halfway it kicks in as well.
Then the resistor is good.
Speaking of the gauge and sending unit, you test the sending unit by disconnecting the wire to it, then measuring resistance from the sensor terminal, not the wire, to ground at a given temp.


This is where I get lost :dunno: (in electric/electronic tech translation) Do you mean the terminal but where can I find it and what is known as ground?
Test between the prong on top of the sending unit and ground. The engine, the intake, what it screws into, any of those.
Of all the 4 thermostats I've got, I am going to install the Wahler 80F instead of the BMW branded Wahler 80F that until recently was in my car, as it seems to open a bit effortless and should I dare to say sooner at the same temp. Have read the cons on the 75F so I won't install that one.
There is a physical difference, not temp rating difference. I think it has to do with how the plate on the back fits with the water manifold, which would affect flow, which would affect temp. Compare them visually and search a bit.
Actually the gauge remains steady. It did go a bit to the middle once I replaced the old Beru German made one spade sensor for a similar but new Irish made Beru unit.
Then the sending unit is slightly suspect. I believe it will have some numbers on it, if you have the old one compare them. It relates to calibration, which would affect the gauge.
But mostly it comes from the tank area, sometime from within the trunk.
Have you done the vapor hoses? Those are a huge problem with age. There's 4 of them, a bit of a pita to do, but not complicated or technical, mostly laying on your back with crap falling in your face.

Would the car run at all if the return and the rail fuel lines where switched?
No.

Yes I do remember the gurgling but don't recall the resolution.
harrypalmer
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Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by harrypalmer »

Mike W. wrote: May 13, 2021 3:44 PM
Yes it does come on with the A/C, and halfway it kicks in as well.
Then the resistor is good.
Excellent!
Speaking of the gauge and sending unit, you test the sending unit by disconnecting the wire to it, then measuring resistance from the sensor terminal, not the wire, to ground at a given temp.
This is where I get lost :dunno: (in electric/electronic tech translation) Do you mean the terminal but where can I find it and what is known as ground?
Test between the prong on top of the sending unit and ground. The engine, the intake, what it screws into, any of those.
Of all the 4 thermostats I've got, I am going to install the Wahler 80F instead of the BMW branded Wahler 80F that until recently was in my car, as it seems to open a bit effortless and should I dare to say sooner at the same temp. Have read the cons on the 75F so I won't install that one. There is a physical difference, not temp rating difference. I think it has to do with how the plate on the back fits with the water manifold, which would affect flow, which would affect temp. Compare them visually and search a bit.
They all look the same back and front as were ordered for the newer version 86 model car.
Actually the gauge remains steady. It did go a bit to the middle once I replaced the old Beru German made one spade sensor for a similar but new Irish made Beru unit.
Image

Do you mean these two above as the sending unit for the coolant gauge? They have the same part number as you can see.
So by installing one at a time in the car and fill it with coolant, and hook the sensor's spade to the MM while the other cable of the MM touches ground, correct? "
Test between the prong on top of the sending unit and ground. The engine, the intake, what it screws into, any of those.
Just double checking.
Then the sending unit is slightly suspect. I believe it will have some numbers on it, if you have the old one compare them. It relates to calibration, which would affect the gauge.
But mostly it comes from the tank area, sometime from within the trunk.
Have you done the vapor hoses? Those are a huge problem with age. There's 4 of them, a bit of a pita to do, but not complicated or technical, mostly laying on your back with crap falling in your face.
Yes, tell me about it (twice).
Would the car run at all if the return and the rail fuel lines where switched?
No.
Awesome, thanks.
Yes I do remember the gurgling but don't recall the resolution.
None so far.
harrypalmer
Posts: 586
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Location: Denver, Colorado

Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by harrypalmer »

jayjaya29 wrote: May 13, 2021 3:41 PM Regarding you gas smell all the time. Is there any signs of leaking on the bottom of the tank or any of the lines connected to the lift pump bracket in the trunk?

I have an occasional gas smell, particularly after I fill it up. I'm planning on following this thread to track it down, I have a sneaking suspicion its the hard line and/or the lines going from the tank to the vapor canister in the trunk.

https://www.mye28.com/viewtopic.php?f=3&t=156207
Jay, thanks for the link I will follow too as well with interest.

As per your question, I have replaced all evaporative fuel related hoses, large and small diameter, front and rear twice. Evap tank in the trunk also twice. Except for the actual hard (metal) lines below the car and these I have blown them from the front to the rear with compressed air.

Last thing would be to buy a new fuel tank. Mine does not leak but I suspect there's some issue around the gas cap. Has been coated with POR-15 inside and outside.
adam_poll
Posts: 97
Joined: Jul 23, 2014 8:19 PM
Location: Kitchener, Ontario, Canada

Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by adam_poll »

Last thing would be to buy a new fuel tank. Mine does not leak but I suspect there's some issue around the gas cap. Has been coated with POR-15 inside and outside.
I wonder if some of the gas tank vent lines are plugged with POR 15? I don't think testing that theory will be fun or what the consequences would be if they were. Is there suction when you remove the gas cap? There shouldn't be.

When you are experiencing your hesitations you could pop the hood, pull the rubber line from the charcoal canister to the valve on the rubber intake tube, cap them both and see if your problems go away.
harrypalmer
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Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by harrypalmer »

Last thing would be to buy a new fuel tank. Mine does not leak but I suspect there's some issue around the gas cap. Has been coated with POR-15 inside and outside.
adam_poll wrote: May 13, 2021 9:40 PMI wonder if some of the gas tank vent lines are plugged with POR 15? I don't think testing that theory will be fun or what the consequences would be if they were. Is there suction when you remove the gas cap? There shouldn't be.
Ha. Funny you say that, as I have been considering uninstalling the fuel tank with this heat soaking situation, and actually remove the POR-15 inside and out. The manufacturer told me that only urethane paint remover will do the trick. Now how good I will find out, but I bet it will real fun. Already have different brand removers lined up. And to your question, no. There's no suction from the gas cap, but most of the time, the inside of the gas cap seal is soaked wet in fuel. This happens whether the tank is filled up, half empty, cold or hot. I will include some photos next.
When you are experiencing your hesitations you could pop the hood, pull the rubber line from the charcoal canister to the valve on the rubber intake tube, cap them both and see if your problems go away.
Oh that is a great idea. Wouldn't that be fantastic if it did? After I re-assemble the coolant system back, I definitively will try it next time its hot.

Your suggestion brought me back many years back on a trip I took to a hot weather climate place, in my rear engined Simca 1300 four door sedan (a true brick against aerodynamics and auto design). Anyway, it had a larger displacement motor so it was still a very fast car, but from time to time it would stutter, and unbeknown to me it also had a distributor of yet, another different car entirely. I don't remember how or why, but I decided then, to remove the whole rear engine lid (the trunk) and placed in the rear seats and suddenly the it felt and drove even faster than before, just like if it had a turbo. I guess all that air rushing in at speed in the engine bay and the experience was fantastic even on a 90F plus weather.
Ibmotoren
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Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by Ibmotoren »

I’m sorry if this is obvious to everyone, and maybe I’ll get flamed, but I haven’t heard mention of it. Have you been looking at this from the perspective of running at high altitude? Your thin air can cause these issues. I know the e28 528e, and M5 came with (or was it an option?) an altitude sensor. 535’s did not. But thin air can cause a rich condition which can lead to higher engine temps. There’s a compounding problem where thin air is also less capable of pulling heat. You have a lower boiling point too. Warm/hot fuel at elevation can cause vapor lock as well. Has this e28 always been at elevation? I live less than 50’ above sea level, and am way out over my skis here, but thought I’d at least bring it up. Obviously yours isn’t the first 535 to run at high altitude, but maybe your car hasn’t been set up for it properly if it came from a lower altitude.
harrypalmer
Posts: 586
Joined: Jul 25, 2012 12:10 AM
Location: Denver, Colorado

Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by harrypalmer »

Ibmotoren wrote: May 14, 2021 11:11 AM I’m sorry if this is obvious to everyone, and maybe I’ll get flamed, but I haven’t heard mention of it. Have you been looking at this from the perspective of running at high altitude? Your thin air can cause these issues. I know the e28 528e, and M5 came with (or was it an option?) an altitude sensor. 535’s did not. But thin air can cause a rich condition which can lead to higher engine temps. There’s a compounding problem where thin air is also less capable of pulling heat. You have a lower boiling point too. Warm/hot fuel at elevation can cause vapor lock as well. Has this e28 always been at elevation? I live less than 50’ above sea level, and am way out over my skis here, but thought I’d at least bring it up. Obviously yours isn’t the first 535 to run at high altitude, but maybe your car hasn’t been set up for it properly if it came from a lower altitude.

Thank you and please no fear of being flamed out. My car was initially sold in Tennessee or Kentucky, and lived the next 26 years in Maine or Mass,. Where it was practically bought sight unseen from her first owner by me. Subsequently, she spent the next four years in Miami Fl, until I moved her to Denver in 2016. Point being is, that even under the South Florida heat and humidity it would still get warm and act 'silly' frequently stalling at red lights (until I learned to gas it and rev it up a bit). But always and thankfully it would start right away like nothing ever happened. She starts on demand, cold or warm no matter what, so I don't know if that would be a symptom of vapor lock up. I really cannot tell.

At the time, both, moisture present inside the distributor cap due to a lacking rear seal, along with an exhaust system riddled with holes made it succumb to heat. Those items in turn, have been addressed and properly replaced, as well as a new in-tank OEM fuel pump and all the other parts mentioned in this post.

So, one would think (I know I did) these items could have made a difference and quite honestly, they have to a degree. However, once my car gets warmed up in traffic with the A/C on, she starts to behave erroneously; with a mild and lightly back fire, showing a tendency to stall, and the fuel gets really hot, you can hear it gargling at the front canister and hissing when the gas cap is opened. Will include videos from 2019, same thing happens today.

Can you please tell me more about how-to properly set it up for high altitude, I'd like to give it a try. My parts folder stacked mostly with replaced OEM parts receipts is almost five inches tall, but I'm about two inches short of calling it quits. So obviously I am grateful and open to any suggestions, that's for sure. Thank you again, Ib.
gadget73
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Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by gadget73 »

first disclaimer, I know practically nothing about BMWs so feel free to screen out any of this that doesn't apply or make sense

this really sounds to me like poor airflow through the radiator and other coolers on the front of the car. Getting hot when not moving, but running at a reasonable temp when moving down the road is a classic sign of that. With my own stuff, every single time its been a bad fan clutch.

If the clutch is good, the other stuff that comes to mind are restrictions from dirt / tree fuzz, some extra thing between the grille and radiator that blocks airflow, a missing fan shroud, the wrong fan, or maybe either the electric or mechanical fan running backwards. I realize the engine spins the way it spins, but if there exists a reverse-rotation fan that physically fits, maybe someone put that on at one point in the past? Electric fan is easier to get wrong if the wiring has been apart. If the electric and mech fan are trying to move air in opposite directions, the net flow ends up near zero and things get hot.
Ibmotoren
Posts: 25
Joined: Apr 26, 2019 9:38 PM
Location: Bay Area, CA

Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by Ibmotoren »

harrypalmer wrote: May 14, 2021 12:58 PM
Ibmotoren wrote: May 14, 2021 11:11 AM I’m sorry if this is obvious to everyone, and maybe I’ll get flamed, but I haven’t heard mention of it. Have you been looking at this from the perspective of running at high altitude? Your thin air can cause these issues. I know the e28 528e, and M5 came with (or was it an option?) an altitude sensor. 535’s did not. But thin air can cause a rich condition which can lead to higher engine temps. There’s a compounding problem where thin air is also less capable of pulling heat. You have a lower boiling point too. Warm/hot fuel at elevation can cause vapor lock as well. Has this e28 always been at elevation? I live less than 50’ above sea level, and am way out over my skis here, but thought I’d at least bring it up. Obviously yours isn’t the first 535 to run at high altitude, but maybe your car hasn’t been set up for it properly if it came from a lower altitude.

Thank you and please no fear of being flamed out. My car was initially sold in Tennessee or Kentucky, and lived the next 26 years in Maine or Mass,. Where it was practically bought sight unseen from her first owner by me. Subsequently, she spent the next four years in Miami Fl, until I moved her to Denver in 2016. Point being is, that even under the South Florida heat and humidity it would still get warm and act 'silly' frequently stalling at red lights (until I learned to gas it and rev it up a bit). But always and thankfully it would start right away like nothing ever happened. She starts on demand, cold or warm no matter what, so I don't know if that would be a symptom of vapor lock up. I really cannot tell.

At the time, both, moisture present inside the distributor cap due to a lacking rear seal, along with an exhaust system riddled with holes made it succumb to heat. Those items in turn, have been addressed and properly replaced, as well as a new in-tank OEM fuel pump and all the other parts mentioned in this post.

So, one would think (I know I did) these items could have made a difference and quite honestly, they have to a degree. However, once my car gets warmed up in traffic with the A/C on, she starts to behave erroneously; with a mild and lightly back fire, showing a tendency to stall, and the fuel gets really hot, you can hear it gargling at the front canister and hissing when the gas cap is opened. Will include videos from 2019, same thing happens today.

Can you please tell me more about how-to properly set it up for high altitude, I'd like to give it a try. My parts folder stacked mostly with replaced OEM parts receipts is almost five inches tall, but I'm about two inches short of calling it quits. So obviously I am grateful and open to any suggestions, that's for sure. Thank you again, Ib.
Lol, I was afraid you’d ask me that! Hence my out over the skis comment. I just read everything you’ve tried/ replaced and was hoping it might spur someone with better knowledge on altitude issues to chime in. I realize that a fuel injected car should compensate for the air to fuel mix, but why then did the 528e and M5 have a need for an altitude sensor? With all the attention on the cooling system, I thought to look elsewhere, like the possibility of running too rich in thin air. But then, like you said, you had this issue in FL too.
Mike W.
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Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by Mike W. »

I wouldn't worry about the high altitude. I had my '85 up over 12K feet in Rocky Mountain NP and it ran fine. Down on power of course, but it ran fine. Also in Yellowstone over at least 8K, probably 9K and other passes over 10K. I'd go so far as to say it ran remarkably well at those altitudes.
demetk
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Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by demetk »

Hi Jack, Show us the thermostat you're going to install? Have you tried running without the stat? That way you could rule out the stat.
harrypalmer
Posts: 586
Joined: Jul 25, 2012 12:10 AM
Location: Denver, Colorado

Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by harrypalmer »

demetk wrote: May 15, 2021 1:21 PM Hi Jack, Show us the thermostat you're going to install? Have you tried running without the stat? That way you could rule out the stat.
Hi Jim,

Thinking in re-installing # 2 in the pictures, as it seems (to me) to open up a wee bit faster, than the BMW branded (#1) that is/was currently installed in my car. They all work as they should when recently tested. Your opinions are awaiting and appreciated. Thank you sir. Image
harrypalmer
Posts: 586
Joined: Jul 25, 2012 12:10 AM
Location: Denver, Colorado

Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by harrypalmer »

gadget73 wrote: May 14, 2021 1:17 PM first disclaimer, I know practically nothing about BMWs so feel free to screen out any of this that doesn't apply or make sense

this really sounds to me like poor airflow through the radiator and other coolers on the front of the car. Getting hot when not moving, but running at a reasonable temp when moving down the road is a classic sign of that. With my own stuff, every single time its been a bad fan clutch.

If the clutch is good, the other stuff that comes to mind are restrictions from dirt / tree fuzz, some extra thing between the grille and radiator that blocks airflow, a missing fan shroud, the wrong fan, or maybe either the electric or mechanical fan running backwards. I realize the engine spins the way it spins, but if there exists a reverse-rotation fan that physically fits, maybe someone put that on at one point in the past? Electric fan is easier to get wrong if the wiring has been apart. If the electric and mech fan are trying to move air in opposite directions, the net flow ends up near zero and things get hot.
Hello gadget,

All shrouds are in place, and fans are working. Your comment made me think about a possible (unseen) obstruction between the rad and condenser but found nothing major aside from the typical super tiny little debris rocks (rocky mountain terrain here) that accumulate between the fins. The Euro grills on my car are a Tropical version (two fins at each end, that act as a funnel venting perhaps a bit more air towards the condenser. However, I completely ignore how they affect the overall radiator performance. Thanks. Image Image Image
harrypalmer
Posts: 586
Joined: Jul 25, 2012 12:10 AM
Location: Denver, Colorado

Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by harrypalmer »

Ibmotoren wrote: May 14, 2021 2:15 PM
Lol, I was afraid you’d ask me that! Hence my out over the skis comment. I just read everything you’ve tried/ replaced and was hoping it might spur someone with better knowledge on altitude issues to chime in. I realize that a fuel injected car should compensate for the air to fuel mix, but why then did the 528e and M5 have a need for an altitude sensor? With all the attention on the cooling system, I thought to look elsewhere, like the possibility of running too rich in thin air. But then, like you said, you had this issue in FL too.
No worries. I thought there may be some trick. As previously mentioned, the two FPR tested good and the present one is working (so far) below

Image

However, the unnerving warm behavior its been going on forever. Notice how LOW (to me) the temp needle is at almost 180°F in this 2019 video, compared to the actual warm engine condition. And how the ECU or whatever is in recovery mode trying to keep the engine running. Sorry don't know how to make the video play within the forum, other than copying the link but it is worth while watching. Mind boggling for sure. https://www.flickr.com/video_download.g ... 1185949628

Fortunately, temps have never past the 200°F mark

Image

In reviewing my own images, I can forward that my present ECU is a Programma (reconditioned by the OP). The current D'Sylva chip, as well as the fuel pump in-tank mod that I installed have not made the car's behavior or temperature rise. If anything, have improved the performance of the car.

And talking about temps, please see below some taken from different dates and also from last May 1st included. Any ideas please? Thanks.

Image
Image
Image
Image
Image
adam_poll
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Location: Kitchener, Ontario, Canada

Re: Please Help Do or Die Warm Issue or ending up on BaT

Post by adam_poll »

Those temps all look good to me, I wouldn't waste anymore time on the cooling system unless there are times when it gets quite a bit hotter than that.
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