Fuel injector Thoughts?

E28 technical advice asked and given! Troubleshooting, modifications and more.
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JustStartingOut
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Fuel injector Thoughts?

Post by JustStartingOut »

I have a faint gas smell in my garage intermittently after driving my car (I haven't identified a pattern yet, but I'm being mindful moving forward and remembering if it's connected at all to short drives, highway driving, filling the tank, etc). I'm keeping an eye on the lines in the engine bay and have never seen any leaks or moisture. The hoses are pretty old, so I'm thinking that's a project I need to tackle, but I've also had fuel injectors on my radar as a potential thing to refresh/replace anyway. So I was thinking that maybe I just get a new, refreshed set that I can plug and play so that my car is down as short a time as possible compared to pulling them and sending them off to be cleaned up.

I have a 1982 528e, and I believe these are the proper fit for the ETA models:

https://www.ebay.com/itm/111491849916?f ... R7T12sG1YQ


Can I get some feedback on this set from Atlanta Auto on eBay?

Also, this 8 x 13 braided hosing is what I should be using to replace the lines in the engine bay, right?
https://www.pelicanparts.com/More_Info/ ... VSVSI=0235
turbodan
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Re: Fuel injector Thoughts?

Post by turbodan »

If it runs well I wouldn't touch the injectors. Would be hard to match the quality of the ones you already have. Your fuel smell is likely from the evap system.

Does this thing have a charcoal canister? I would expect to find it in the passenger side front corner of the engine compartment. Check the lines going to it, check to see if the smell is originating from the canister. They can only absorb so much stink, after 40 years it probably isn't doing much anymore.
Shawn D.
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Re: Fuel injector Thoughts?

Post by Shawn D. »

The evap tank in the trunk and its lines that run to the tank filler neck are common culprits. Replace all those lines, and also inspect the top of the tank via the access panel in the trunk floor to see if there's fuel leaking out when full.
turbodan wrote: Jan 13, 2023 10:03 PM They can only absorb so much stink, after 40 years it probably isn't doing much anymore.
LOL, they're purged when the car is running. The material could break down, though.
Mike W.
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Re: Fuel injector Thoughts?

Post by Mike W. »

I agree with turbodan, but different. The evap lines around the tank and trunk are notorious for getting porous as they age. And causing odor, and in very extreme examples even leaking with a full tank. Since they come off the top of the tank, really the neck, they're more of a problem with a full tank. Sniff around a bit, sniff in the trunk, under the hood, try to get a general idea of where it's coming from.
JustStartingOut
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Re: Fuel injector Thoughts?

Post by JustStartingOut »

Thanks for the feedback guys - I’m (hopefully) coming to the end of getting over some kind of sickness right now, but I will get to work on this info when I’m feeling up to it and will report back what I find.
Blue Shadow
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Re: Fuel injector Thoughts?

Post by Blue Shadow »

On a 535 the stock injectors allowed an instant start at the bump of the key. Aftermaket bosch from the mustang, new pulls from motors being upgraded required a bit of cranking. Not bad but not instant cold start. The warm start was bad with tired injectors (dirty probably) but the new ones provided the same kind of cranking needed when the motor was cold to get a start. An improvement overall but just saying this so you might identify that your injectors are fine.

As to fuel smell, this is from small leaks, I guess. These leaks can be from old, tired, cracked fuel lines at their connections to hard parts.
Fuel pipe to and from the engine compartment
Fuel rail
Fuel pressure regulator
Cold start injector
all the connections at the tank fill nozzle (if you fill up too far, especially), vapor cannister and such
and all the stuff at the tank and fuel pump/filter.

It seems you do not have any of the pulse dampeners that BMW used on some cars in the fuel lines. I believe I have one that might be starting to leak. We throw these away, a cad coated 2½" round, 1" thick wide spot in the line with fuel line in and out. I have one just before the fuel rail. I think there is another one back with the pump. They are coming out when I do the fuel lines.
Mike W.
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Re: Fuel injector Thoughts?

Post by Mike W. »

Blue Shadow wrote: Jan 14, 2023 10:47 PM On a 535 the stock injectors allowed an instant start at the bump of the key. Aftermaket bosch from the mustang, new pulls from motors being upgraded required a bit of cranking. Not bad but not instant cold start. The warm start was bad with tired injectors (dirty probably) but the new ones provided the same kind of cranking needed when the motor was cold to get a start. An improvement overall but just saying this so you might identify that your injectors are fine.

As to fuel smell, this is from small leaks, I guess. These leaks can be from old, tired, cracked fuel lines at their connections to hard parts.
Fuel pipe to and from the engine compartment
Fuel rail
Fuel pressure regulator
Cold start injector
all the connections at the tank fill nozzle (if you fill up too far, especially), vapor cannister and such
and all the stuff at the tank and fuel pump/filter.

It seems you do not have any of the pulse dampeners that BMW used on some cars in the fuel lines. I believe I have one that might be starting to leak. We throw these away, a cad coated 2½" round, 1" thick wide spot in the line with fuel line in and out. I have one just before the fuel rail. I think there is another one back with the pump. They are coming out when I do the fuel lines.
No experience with the Mustang injectors, but I'll throw this out.

On my L jet cars, which is pretty much motronic, but without ignition control, they tended to start after 6 compression cycles, or two revolutions of the engine. My 535 seemed to start after 3 compression cycles, or one revolution. I've got to think it relates to when the FI sees everything and says it's ok to pulse the injectors. So unless the injectors are leaking, (which is a whole different problem and a real problem) or the check valve in the fuel pump decided to start leaking at the same time as the Mustang injectors were installed, there shouldn't be any difference between stock Bosch injectors and "Mustang" injectors in terms of starting. The system should hold pressure, spray when they're told to and not before.

Slightly OT. Newer BMWs, my E36/E39 cars seem to light off even quicker than the E28. Not instant, but real quick and I can't count the compression cycles like I could on earlier cars. Other cars of post 2000 model year, rentals and the '03 Datsun, seem to start somewhat slower. Not like I'm going crank, crank, crank sputter sputter fire, just not as quickly. Kind of like I have to hold it instead of just an instant past flicking it.
JustStartingOut
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Re: Fuel injector Thoughts?

Post by JustStartingOut »

Okay, I'm finally getting over this sickness and drove the car today for the first time since I made the first post. I did about a 20 minute "around town" drive and that gave me no fuel smell - neither right away or checking the garage an hour later. I smelled around the fuel tank / back wheel well, the back seat (haven't pulled the seat out yet though), and around the fuel lines / injectors / evap system in the engine bay. I'll continue to monitor, but i'm guessing it's better that it's not a constant, every time I drive issue? That will make it harder to identify, but I assume it's a better situation...

Despite there being no smell from the charcoal canister (at least today), I'm assuming this one is on or past its last leg, just based on wear and rust alone:

ImageIMG_4083

I have a nice looking charcoal canister I pulled from an e34 at the junkyard. It's not the exact same size, but I think I should be able to fit it in there somewhere, so I'm thinking I'll swap that in and replace the rubber hoses while I'm at it. Am I right in thinking that I don't need the "fuel injector rated" hose for the evap system? That I could just grab some 5/16th fuel hose from Autozone and replace the line headed to the trunk and the line that goes into the manifold?

ImageIMG_4084



Blue Shadow, I do have two of those pulse dampers. One by the fuel rail and one by the charcoal canister. I don't know what they are or what they do, but you're suggesting I take them out and leave them out when I replace any lines?
Panici
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Re: Fuel injector Thoughts?

Post by Panici »

JustStartingOut wrote: Jan 25, 2023 5:39 PM Am I right in thinking that I don't need the "fuel injector rated" hose for the evap system? That I could just grab some 5/16th fuel hose from Autozone and replace the line headed to the trunk and the line that goes into the manifold?
Yep they sell evap specific hose, or you can use the carburetor (low pressure) rated stuff.

Generally it's more flexible then the fuel injection rated hose.
JustStartingOut
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Re: Fuel injector Thoughts?

Post by JustStartingOut »

Panici wrote: Jan 26, 2023 9:28 AM
JustStartingOut wrote: Jan 25, 2023 5:39 PM Am I right in thinking that I don't need the "fuel injector rated" hose for the evap system? That I could just grab some 5/16th fuel hose from Autozone and replace the line headed to the trunk and the line that goes into the manifold?
Yep they sell evap specific hose, or you can use the carburetor (low pressure) rated stuff.

Generally it's more flexible then the fuel injection rated hose.
Perfect - thanks!
gadget73
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Re: Fuel injector Thoughts?

Post by gadget73 »

some other thoughts on injectors, based on what I've learned in the Ford tuning world

just because the flow rates are the same don't mean they are a drop-in. Besides the different possible spray patterns, the slope on the injectors can be very different. Not sure what other makers call this, but basically its a relationship of pulse width to flow rate. The 19 lb/hr that a Mustang injector flows is just what you can cram through the thing at a given pressure with it wide open. Where it gets tricky is knowing how much fuel you have going in for say a 10% duty cycle. Its not linear, so 10% duty doesn't mean 10% of the flow rate.
Mike W.
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Re: Fuel injector Thoughts?

Post by Mike W. »

gadget73 wrote: Jan 27, 2023 2:06 PM some other thoughts on injectors, based on what I've learned in the Ford tuning world

just because the flow rates are the same don't mean they are a drop-in. Besides the different possible spray patterns, the slope on the injectors can be very different. Not sure what other makers call this, but basically its a relationship of pulse width to flow rate. The 19 lb/hr that a Mustang injector flows is just what you can cram through the thing at a given pressure with it wide open. Where it gets tricky is knowing how much fuel you have going in for say a 10% duty cycle. Its not linear, so 10% duty doesn't mean 10% of the flow rate.
Interesting, I hadn't thought about that. But I'll expound on it a bit, new engines with 4 valves per cylinder sometimes have injectors with a split spray to direct fuel to each valve separately. Even if the flow rate is correct, you really don't want those.
gadget73
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Re: Fuel injector Thoughts?

Post by gadget73 »

yeah those are funky. definitely not what you want for an old style 2 valve engine.

The old EV1 type that I believe BMW use are more of a cone spray pattern using a single pintle in the end of the injector. Mustangs ran the same style through the 90s on the 5.0. There are different cone widths on those though. No clue what it happens to be for either the Ford or BMW honestly but with the actual Bosch part number you can probably find that info.
JustStartingOut
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Re: Fuel injector Thoughts?

Post by JustStartingOut »

Hey all, I’m replacing the evap lines now and as I was removing the line that goes from the manifold to the canister, that little white connector you see pictured above cracked. I looked in my Haynes manual and there is very, very little about this whole system. Can somebody tell me what that white part is? Is it just a hose connector or is it serving a purpose?


Figured out it’s the check valve. Trying to find one locally now!
JustStartingOut
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Re: Fuel injector Thoughts?

Post by JustStartingOut »

I found this cracked (adaptor?) on the underside of the hose as I took it off of the charcoal canister. Hopefully that was the cause of the intermittent fuel smell. Unfortunately, since I cracked the check valve during this process, I'm stuck with the car in the garage until the new one comes from FCP Euro. But still, progress!

ImageIMG-4096
Mike W.
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Re: Fuel injector Thoughts?

Post by Mike W. »

JustStartingOut wrote: Jan 31, 2023 4:10 PM I found this cracked (adaptor?) on the underside of the hose as I took it off of the charcoal canister. Hopefully that was the cause of the intermittent fuel smell. Unfortunately, since I cracked the check valve during this process, I'm stuck with the car in the garage until the new one comes from FCP Euro. But still, progress!

ImageIMG-4096
That's stock and they always look like that. Always, I swear every one I've seen.
JustStartingOut
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Re: Fuel injector Thoughts?

Post by JustStartingOut »

Mike W. wrote: Jan 31, 2023 5:32 PM
JustStartingOut wrote: Jan 31, 2023 4:10 PM I found this cracked (adaptor?) on the underside of the hose as I took it off of the charcoal canister. Hopefully that was the cause of the intermittent fuel smell. Unfortunately, since I cracked the check valve during this process, I'm stuck with the car in the garage until the new one comes from FCP Euro. But still, progress!
That's stock and they always look like that. Always, I swear every one I've seen.
Oh, crazy. I really thought I found my problem!
JustStartingOut
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Re: Fuel injector Thoughts?

Post by JustStartingOut »

Alright, I got my check Valve in and I’m trying to finish up this project and get back on the road. But the orientation on my old Valve is throwing me off.

I’m blowing through it and it’s allowing air to flow FROM the charcoal canister TO the exhaust manifold. And I was expecting it to be the other way around. Do I just have it wrong in my head, or was the old one on there backwards and essentially not doing anything?
Mike W.
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Re: Fuel injector Thoughts?

Post by Mike W. »

JustStartingOut wrote: Feb 03, 2023 4:19 PM Alright, I got my check Valve in and I’m trying to finish up this project and get back on the road. But the orientation on my old Valve is throwing me off.

I’m blowing through it and it’s allowing air to flow FROM the charcoal canister TO the exhaust manifold. And I was expecting it to be the other way around. Do I just have it wrong in my head, or was the old one on there backwards and essentially not doing anything?
Might you mean to the intake manifold? That would be correct, the path is from the gas tank, to the liquid vapor separator back in the trunk, up to the charcoal canister to the intake manifold. The charcoal canister is supposed to absorb the fuel vapors when the car is off, then really thru a controlled vacuum leak, into the intake when running to be burned off.
JustStartingOut
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Re: Fuel injector Thoughts?

Post by JustStartingOut »

Mike W. wrote: Feb 03, 2023 7:46 PM
JustStartingOut wrote: Feb 03, 2023 4:19 PM Alright, I got my check Valve in and I’m trying to finish up this project and get back on the road. But the orientation on my old Valve is throwing me off.

I’m blowing through it and it’s allowing air to flow FROM the charcoal canister TO the exhaust manifold. And I was expecting it to be the other way around. Do I just have it wrong in my head, or was the old one on there backwards and essentially not doing anything?
Might you mean to the intake manifold? That would be correct, the path is from the gas tank, to the liquid vapor separator back in the trunk, up to the charcoal canister to the intake manifold. The charcoal canister is supposed to absorb the fuel vapors when the car is off, then really thru a controlled vacuum leak, into the intake when running to be burned off.
Yes, the intake manifold! I’m definitely still working on figuring out names of everything, haha.

Wow, I watched a few videos on how the evap system worked and I had that exactly backward in my head. So, I’m following you in that I need to replace it just like it was - so i have the air flowing from the charcoal canister into the intake manifold?

I know I’m asking for re-confirmation…I just want to make sure I’m getting my head around it since I had completely been convinced of the other way about an hour ago.
Mike W.
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Re: Fuel injector Thoughts?

Post by Mike W. »

JustStartingOut wrote: Feb 03, 2023 8:06 PM So, I’m following you in that I need to replace it just like it was - so i have the air flowing from the charcoal canister into the intake manifold?
Yes.

No worries about needing reassurance, when something doesn't make sense sometimes we want to reconfirm.
JustStartingOut
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Re: Fuel injector Thoughts?

Post by JustStartingOut »

Mike W. wrote: Feb 04, 2023 12:41 AM
JustStartingOut wrote: Feb 03, 2023 8:06 PM So, I’m following you in that I need to replace it just like it was - so i have the air flowing from the charcoal canister into the intake manifold?
Yes.

No worries about needing reassurance, when something doesn't make sense sometimes we want to reconfirm.
You’ve helped me so much with this car - thank you again Mike!
JustStartingOut
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Re: Fuel injector Thoughts?

Post by JustStartingOut »

Alright, I have some new info and i think it’s pointing me in the direction of the problem, but wanted to get some input to make sure I’m heading in the right direction. The fuel smell never repeated since I changed the charcoal canister…until today. After a long joyride, I had $23 in my wallet, so I only put that much gas in the tank, leaving me about half full. When I got home and checked the smell a while later, I smelled fuel by the back passenger wheel /fuel fill area.

Since it was less than 3/4 of a tank, from what I’m seeing from a forum search it’s not the expansion tank / evap stuff, right? From what I’m seeing, it seems like I’m most likely looking for fuel filler neck issues?

If so, I’ve tried checking for a good YouTube tutorial and i think i have a decent idea of how to do it. But can I pull that fuel neck part off while I have fuel in the tank?
Mike W.
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Re: Fuel injector Thoughts?

Post by Mike W. »

Well there is that thing called rust, which while to me is only a rumor, is an actual thing back in Mi. So, given location, I can't rule out rust at the neck, but I've had a bunch of 70's-80's E's 12, 24 and 28 with the exact same tank, and E23s with a similar evap setup, and I swear I've had to replace evap hoses on every single one of them. Fill them up and they stunk of gas. How full? I dunno, for the most part I just fill them up.

By all means, listen to others, but my money is on those evap hoses, replace all 4, 2 are 6MM, 2 are 8MM, or get 6 feet of 1/4" and 6 feet of 5/16". Low pressure carb hose is fine, it's not under pressure. It's a medium PITA job, dirt and crap falling on your face, not difficult, just unpleasant. You need to lower, but not drop the tank and do it when it's low, the lower the better, if it's full it'll be raining gas as on you.
JustStartingOut
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Re: Fuel injector Thoughts?

Post by JustStartingOut »

Mike W. wrote: Feb 20, 2023 1:11 AM …I swear I've had to replace evap hoses on every single one of them. Fill them up and they stunk of gas. How full? I dunno, for the most part I just fill them up.

By all means, listen to others, but my money is on those evap hoses, replace all 4, 2 are 6MM, 2 are 8MM, or get 6 feet of 1/4" and 6 feet of 5/16”.
Oh, interesting. The sticky in the tech FAQ talked about below 3/4 tank, the expansion tank wasn’t involved. So I had hoped I could rule that out as I’m trying to identify the problem.

Either way, I’m thinking that this area being the origin of the smell makes it less urgent of an issue than if it was a fuel line weeping or something right? It’s still really cold by me, so I’m trying to put off some of the “it can wait” repairs until it’s warm enough to be pleasant to be outside for a few hours, haha!
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