533i manifold vacuum
Re: 533i manifold vacuum
I've used one of those cheap-O timing lights with a knob in the back to adjust timing, there is only one way to look at it, you need to position yourself a bit towards the driver's side from the engine and try getting a look at it without the upper rad hose in the way.
I had to do it to sync what the megasquirt thought TDC was vs what it actually was in the engine.
I had to do it to sync what the megasquirt thought TDC was vs what it actually was in the engine.
Re: 533i manifold vacuum
Thanks Mike and Juan. I'll look into both these items next.
Re: 533i manifold vacuum
Ok, I bought a timing light that has the dial (used to set the advance).
First, I can confirm it's difficult to aim through the water pump area and actually see the 0|T mark and notch on the timing cover, but it's possible.
Need help interpreting what I saw...
At idle, the 0|T mark was basically lining up with the timing cover notch at 0 degrees of advance on the timing light dial. Sometimes it jumped to the left of the notch (retarded, as I understand it).
I then set the dial to 20-22 degrees of advance, and revved the motor to somewhere in 1500-2000rpm range. (I'll need to retest and get exact rpm). I watched the 0|T mark draw over and align with the timing cover notch, which I think confirms that timing advance value.
Does anyone have any expected values? Does a properly functioning DME advance the timing at idle by any amount? In other words, IS my timing retarded a small amount at idle?
First, I can confirm it's difficult to aim through the water pump area and actually see the 0|T mark and notch on the timing cover, but it's possible.
Need help interpreting what I saw...
At idle, the 0|T mark was basically lining up with the timing cover notch at 0 degrees of advance on the timing light dial. Sometimes it jumped to the left of the notch (retarded, as I understand it).
I then set the dial to 20-22 degrees of advance, and revved the motor to somewhere in 1500-2000rpm range. (I'll need to retest and get exact rpm). I watched the 0|T mark draw over and align with the timing cover notch, which I think confirms that timing advance value.
Does anyone have any expected values? Does a properly functioning DME advance the timing at idle by any amount? In other words, IS my timing retarded a small amount at idle?
Re: 533i manifold vacuum
If you say that the ot mark was before (to the left) of the mark in the timing cover then that's advanced.
I can't speak for the map in a 533 ecu, but for sure it doesn't idle at 0 degrees in a 059, i don't have the idle spark row handy, but it was near 10 degrees.
In particular I idle at around 20 degrees, and can confirm that it has a big effect on vacuum
I can't speak for the map in a 533 ecu, but for sure it doesn't idle at 0 degrees in a 059, i don't have the idle spark row handy, but it was near 10 degrees.
In particular I idle at around 20 degrees, and can confirm that it has a big effect on vacuum
Re: 533i manifold vacuum
I was mistaken. You're right, LEFT of the timing cover notch is advanced. The engine rotates clockwise.
Retested tonight to confirm...
At idle, the 0|T aligns with the notch or slightly to the right (retarded) at 0 degrees advance.
At 2000rpm, I was only getting about 18 degrees of advance.
Juan, as you suggest, I think I should be seeing more advance in both conditions.
I now have 2 spare 008 DME's to test. I'll post anything learned, hopefully tomorrow.
Can anyone educate me on the fuel quality switch? I opened up one of the DME's but didn't see anything that resembled what I've read is a rotary style switch? I just see a circuit board on either side.
Retested tonight to confirm...
At idle, the 0|T aligns with the notch or slightly to the right (retarded) at 0 degrees advance.
At 2000rpm, I was only getting about 18 degrees of advance.
Juan, as you suggest, I think I should be seeing more advance in both conditions.
I now have 2 spare 008 DME's to test. I'll post anything learned, hopefully tomorrow.
Can anyone educate me on the fuel quality switch? I opened up one of the DME's but didn't see anything that resembled what I've read is a rotary style switch? I just see a circuit board on either side.
Re: 533i manifold vacuum
The switch (if present) should look something like this.
Something that would be interesting is to get the xdf and bin dump of that ECU to know if the ECU actually wants that spark timing or not.
Re: 533i manifold vacuum
Thanks Juan... sorry, you did post that picture earlier in the thread.
Anyway, I've now tried the 2 spare 008 ECU's and the basic results are the same as my original. Idle vacuum unchanged. Spark timing checked and basically the same (the 0|T aligns to the timing cover mark at 0 degrees advance). While I had the DME unplugged, I also checked the pins in the harness connector per Bentley. All good there, so DME power/ground/sensor inputs are satisfactory.
Still stumped on the fuel quality switch. Your picture seems to show a 944 Motronic unit, where the cover slides off, exposing the internals. With the 008 (and maybe others?) there's a top and bottom cover that unscrew and reveals a circuit board on each side. It looks like I'd have to unscrew the board from whatever is underneath, but this seems risky.
Anyway, I've now tried the 2 spare 008 ECU's and the basic results are the same as my original. Idle vacuum unchanged. Spark timing checked and basically the same (the 0|T aligns to the timing cover mark at 0 degrees advance). While I had the DME unplugged, I also checked the pins in the harness connector per Bentley. All good there, so DME power/ground/sensor inputs are satisfactory.
Still stumped on the fuel quality switch. Your picture seems to show a 944 Motronic unit, where the cover slides off, exposing the internals. With the 008 (and maybe others?) there's a top and bottom cover that unscrew and reveals a circuit board on each side. It looks like I'd have to unscrew the board from whatever is underneath, but this seems risky.
Re: 533i manifold vacuum
Ahh my bad, that does look a bit more vintage.
I tried searching a bit for someone who had measured ignition timing in a 533/633/733, but couldn't find any data on that. I can try next time I go to the car with the computer 0 degrees of timing at idle and let you know how the vacuum looks
I tried searching a bit for someone who had measured ignition timing in a 533/633/733, but couldn't find any data on that. I can try next time I go to the car with the computer 0 degrees of timing at idle and let you know how the vacuum looks
Re: 533i manifold vacuum
I can't say I've been into a 008 ECU, but a friend did tweak the switch in one long ago to pass smog, so I'm confident it's in there somewhere.
Re: 533i manifold vacuum
Continued focus on ignition timing...I think that if I can solve the ignition timing, then it might well solve the manifold vacuum issue as a result.
So, I decided to investigate one of the primary inputs to the ECU for ignition timing - the crankshaft sensors. The Bentley Manual shows the x, y axis for the timing map are Engine Speed and Load.
Both sensors were a little dirty, but I noticed the Speed Sensor has a pretty deep gouge in the head. See picture. (Note: Both sensors were new 6 years ago when I installed the rebuilt motor.)
Is this concerning, how could it have happened, and might it influence anything?
So, I decided to investigate one of the primary inputs to the ECU for ignition timing - the crankshaft sensors. The Bentley Manual shows the x, y axis for the timing map are Engine Speed and Load.
Both sensors were a little dirty, but I noticed the Speed Sensor has a pretty deep gouge in the head. See picture. (Note: Both sensors were new 6 years ago when I installed the rebuilt motor.)
Is this concerning, how could it have happened, and might it influence anything?
Re: 533i manifold vacuum
That doesn't look healthy, still, those sensors either work or not usually. Try swapping them around (also change the plugs on top)
Re: 533i manifold vacuum
Ok, you were right. Swapped the plugs and connectors - no change. Another item ruled out.
Next up:
1. I'd still like to check cam timing with upper timing cover removed. I want definitive proof that it's either correct or not.
2. Could the reference pin on the flywheel have been oriented wrong or mis-located during the engine rebuild?
- The pin works with the reference sensor to signal crankshaft position so that initial baseline ignition point can be determined for engine start. My theory is that if the baseline is wrong, then everything would be off from there.
- It does feel like a reach, but it turned out to be the issue with this person: https://www.mye28.com/viewtopic.php?f=3 ... g&start=50
Re: 533i manifold vacuum
If you want definite proof that the cam is correct, you'll need a comparator, a degree wheel, and the specs for your cam (and some time )
If not, you can use the method defined in the bentleys, which uses your eyes to confirm that the line that is formed by 2 of the bolts of the sprocket on the cam is parallel to the head.
As for the pin yes, don't remember that exact thread, but I do remember one where a semi-broken reference pin was causing issues. You can check your reference pin is correct if you know how many degrees before TDC it's supposed to be at (and the degree wheel for the previous test).
You are going into a mostly unknown realm though
Keep up updated
If not, you can use the method defined in the bentleys, which uses your eyes to confirm that the line that is formed by 2 of the bolts of the sprocket on the cam is parallel to the head.
As for the pin yes, don't remember that exact thread, but I do remember one where a semi-broken reference pin was causing issues. You can check your reference pin is correct if you know how many degrees before TDC it's supposed to be at (and the degree wheel for the previous test).
You are going into a mostly unknown realm though
Keep up updated
Re: 533i manifold vacuum
No, it could not have been moved without serious work, as in the link you posted. If you're really suspicious you could pull the stiffener pan that connects the engine and tranny. NOT the oil pan, the stiffener pan and that would give you a good look at the flywheel. But it's not something that could have been done by accident, it would be a very deliberate action. Not that people haven't done stranger things, but it would be beyond unusual.MattC wrote: ↑Sep 27, 2021 10:17 AM
2. Could the reference pin on the flywheel have been oriented wrong or mis-located during the engine rebuild?
- The pin works with the reference sensor to signal crankshaft position so that initial baseline ignition point can be determined for engine start. My theory is that if the baseline is wrong, then everything would be off from there.
- It does feel like a reach, but it turned out to be the issue with this person: https://www.mye28.com/viewtopic.php?f=3 ... g&start=50
Re: 533i manifold vacuum
Mike, thanks for the reply about the flywheel...I agree, unlikely scenario.
Today I pulled the upper timing cover to check cam position. Here's what I found in 2 pictures:
Picture 1: timing marks on crank are lined up, dowel on cam sprocket at 7 O'clock. I do not believe these bolts are lining up correctly.
Picture 2: lining up the bolts with the mark on timing cover and the 0|T mark does not reach TDC.
Thoughts? Do we think my timing is off 1 tooth?
Today I pulled the upper timing cover to check cam position. Here's what I found in 2 pictures:
Picture 1: timing marks on crank are lined up, dowel on cam sprocket at 7 O'clock. I do not believe these bolts are lining up correctly.
Picture 2: lining up the bolts with the mark on timing cover and the 0|T mark does not reach TDC.
Thoughts? Do we think my timing is off 1 tooth?
Re: 533i manifold vacuum
You've already got the upper timing cover off so it wouldn't be hard to check, and would do no harm, as long as you're careful and don't move the cam too far and bump valves against the pistons.
A FWIW, I've done a bunch of these and it never seems quite right when I do it. But it always is. Which means nothing except there might be room for confusion.
A FWIW, I've done a bunch of these and it never seems quite right when I do it. But it always is. Which means nothing except there might be room for confusion.
Re: 533i manifold vacuum
After further review... it does not seem to be off by one full tooth. Rather, it's more like a half tooth.Mike W. wrote: ↑Oct 02, 2021 3:30 PM You've already got the upper timing cover off so it wouldn't be hard to check, and would do no harm, as long as you're careful and don't move the cam too far and bump valves against the pistons.
A FWIW, I've done a bunch of these and it never seems quite right when I do it. But it always is. Which means nothing except there might be room for confusion.
Could this be the result of the chain slacked in wrong position when the engine builder engaged the tensioner? Wondering if this scenario would pull the chain tight and move the cam sprocket a smidge relative to crankshaft?
Re: 533i manifold vacuum
Are you checking it with the chain tensioned or not? That could make a difference. Installing of course it's not tensioned.
Re: 533i manifold vacuum
If you are going by the position of the vertical cam bolts, keep in mind that one of them is offset towards the dowel pin. They won't both line up with each other vertically. The recommendation is to only go by the position of the horizontal bolts in your picture.
In this pic, you can see how the bottom bolt is offset towards the dowel pin.
In this pic, you can see how the bottom bolt is offset towards the dowel pin.
MattC wrote: ↑Oct 02, 2021 1:54 PM Mike, thanks for the reply about the flywheel...I agree, unlikely scenario.
Today I pulled the upper timing cover to check cam position. Here's what I found in 2 pictures:
Picture 1: timing marks on crank are lined up, dowel on cam sprocket at 7 O'clock. I do not believe these bolts are lining up correctly.
Thoughts? Do we think my timing is off 1 tooth?
Re: 533i manifold vacuum
Oh wow this was very helpful, thank you! Strange that they offset that bottom bolt and then Bentley Manual describes alignment as "straight up and down." Anyway, per your horizontal reference, I'd say mine looks correct, right? (I have the level on the upper flat surface of lower timing cover).Thecar wrote: ↑Oct 03, 2021 4:18 AM If you are going by the position of the vertical cam bolts, keep in mind that one of them is offset towards the dowel pin. They won't both line up with each other vertically. The recommendation is to only go by the position of the horizontal bolts in your picture.
In this pic, you can see how the bottom bolt is offset towards the dowel pin.
Re: 533i manifold vacuum
Just glad I could help, I have gotten way more info from this site than I have added.
MattC wrote: ↑Oct 03, 2021 8:18 PM
Oh wow this was very helpful, thank you! Strange that they offset that bottom bolt and then Bentley Manual describes alignment as "straight up and down." Anyway, per your horizontal reference, I'd say mine looks correct, right? (I have the level on the upper flat surface of lower timing cover).
Re: 533i manifold vacuum
Still ruling out problems, but no solution yet.
I was able to measure the cylinder head height with the upper timing cover removed.
Bentley specifies:
129.0 mm +/-0.1mm head height new.
128.6 mm minimum head height allowed after milling
They say: do not shave more than 0.3mm, otherwise a new head is needed.
Using a set of calipers, I measured values in range of 128.8 to 128.9 mm on mine.
It's tough to get it exact, but I never came close to the 128.6 number, so feeling confident it was NOT shaved too far.
I was able to measure the cylinder head height with the upper timing cover removed.
Bentley specifies:
129.0 mm +/-0.1mm head height new.
128.6 mm minimum head height allowed after milling
They say: do not shave more than 0.3mm, otherwise a new head is needed.
Using a set of calipers, I measured values in range of 128.8 to 128.9 mm on mine.
It's tough to get it exact, but I never came close to the 128.6 number, so feeling confident it was NOT shaved too far.