Vanos Rebuild Start Hesitation

[jamesfoley]

Just to follow this up with a bit of data, here is a log of Inlet and Exhaust commanded vs actual positions. Pretty sure the Exhaust graph just looks bad due to scaling but the Exhaust position swings half a degree above and below the commanded, and Inlet swings up to a degree below commanded. TestO is pretty decent when it doesn't crash.

My only question is what are the "banks" it is referring to here?

[jamesfoley]

If the DME doesn't issue error code for the EX cam then it's acceptable. If the cam timing is bad enough to cause issue, then DME should have popped the codes.

I guess the only issue I have is that the DME doesn't seem to like throwing codes for anything 😅

Other than timing, is there anything else hidden in the VANOS that could cause issues and not present a code? I've read a couple of posts now of people who have had issues after a rebuild and mention wear on VANOS internals as a potential. There is also oil pressure at the VANOS which I could probably check? Suppose there is also the potential that there was an issue with the seal install

[sapote]

Intake cam actual position compared to requested are exactly the same, but my exhaust cam actual vs requested are out by a degree. Exhaust values jump around all over the place and are never in sync.

Can 1 degree on the exhaust cam be the cause of the issues?

This was picked up by another specialist after confirming fuel pressure was good.

If the DME doesn't issue error code for the EX cam then it's acceptable. If the cam timing is bad enough to cause issue, then DME should have popped the codes.

[oceansize]

Are mismatches expected at idle though? Inlet cam was rock solid 60 degrees with no variance, exhaust was flickering around a couple of degrees constantly almost like it was trying to adapt for the difference between commanded and actual but never being able to get them equal.

Is TestO the only tool I can graph the cam positions? Pretty sure the guys I saw used an Autel scanner which could graph stuff, but they're expensive it seems

Been a while but it seems like it is fine for the exhaust to fluctuate a bit while intake hangs steady, but perhaps someone else can confirm as it has been a year or two since I last data logged and took note. I have AutoEnginuity but it isn't cheap.

[jamesfoley]

Variances are common even after adaptations and the command vs actual is fine to mismatch while driving. 98% of the time the variances are within two degrees on my car. Get spikes where they can be greater.

The commanded values at idle should be:

intake: 60
exhaust: 0

Are mismatches expected at idle though? Inlet cam was rock solid 60 degrees with no variance, exhaust was flickering around a couple of degrees constantly almost like it was trying to adapt for the difference between commanded and actual but never being able to get them equal.

Is TestO the only tool I can graph the cam positions? Pretty sure the guys I saw used an Autel scanner which could graph stuff, but they're expensive it seems

[oceansize]

I think they were more saying that even after adaptation, the DME requested position never matched the actual position. So even though it it was requesting 0 degrees, actual position was coming back as 1 degree. I thought the adaptation values were meant to correct errors in requested vs actual to make them match?

Both intake requested and actual positions are exactly the same to the decimal place, so kind of assumed exhaust would be the same too. Wondered if it was this that was confusing the DME where the exhaust side of the VANOS is not left in the position it is expecting it to be when the engine is turned off, giving me the extremely random start hesitation depending on where the cam position is.

Variances are common even after adaptations and the command vs actual is fine to mismatch while driving. 98% of the time the variances are within two degrees on my car. Get spikes where they can be greater.

The commanded values at idle should be:

intake: 60
exhaust: 0

[jamesfoley]

No issues, can be off by as much as eight degrees so you are fine.

I think they were more saying that even after adaptation, the DME requested position never matched the actual position. So even though it it was requesting 0 degrees, actual position was coming back as 1 degree. I thought the adaptation values were meant to correct errors in requested vs actual to make them match?

Both intake requested and actual positions are exactly the same to the decimal place, so kind of assumed exhaust would be the same too. Wondered if it was this that was confusing the DME where the exhaust side of the VANOS is not left in the position it is expecting it to be when the engine is turned off, giving me the extremely random start hesitation depending on where the cam position is.

[oceansize]

Intake cam actual position compared to requested are exactly the same, but my exhaust cam actual vs requested are out by a degree. Exhaust values jump around all over the place and are never in sync.

Can 1 degree on the exhaust cam be the cause of the issues?

This was picked up by another specialist after confirming fuel pressure was good.

No issues, can be off by as much as eight degrees so you are fine.

[jamesfoley]

Intake cam actual position compared to requested are exactly the same, but my exhaust cam actual vs requested are out by a degree. Exhaust values jump around all over the place and are never in sync.

Can 1 degree on the exhaust cam be the cause of the issues?

This was picked up by another specialist after confirming fuel pressure was good.

[jamesfoley]

these could be the key to the mystery -- DME program code is corrupted. Try to reflash the code or change to another working DME.

For what it’s worth these codes only appear together with no other codes present, and P.A.Soft BMW Scanner is the only tool that shows me these. I get nothing in INPA or DIS/GT1.

[sapote]

63 [099] Internal fault
59 [089] Internal fault

these could be the key to the mystery -- DME program code is corrupted. Try to reflash the code or change to another working DME.

[jamesfoley]

E6	DME: Electric throttle: setpoint/actual value deviation

This should cause the limp mode, and you didn't see the engine light turning on?

"Codes cleared and have been replaced with two Internal Fault codes that do not clear 🤷♂️"
What does this mean?

Shadow codes could be just a momentary.

Nope, no limp mode or lights on the dash, figured it was just because I removed the plug for the throttle position sensor at the front of the engine.

As for faults I’m always left with:

63 [099] Internal fault
59 [089] Internal fault

Went for a 70 mile drive and have the log: https://datazap.me/u/jamesfoley/e46-...0&data=1-2-3-4

Looks the same as all the others. It didn’t throw any other codes after that other than the two internal faults.

[sapote]

E6	DME: Electric throttle: setpoint/actual value deviation

This should cause the limp mode, and you didn't see the engine light turning on?

"Codes cleared and have been replaced with two Internal Fault codes that do not clear 🤷♂️"
What does this mean?

Shadow codes could be just a momentary.

[jamesfoley]

Can confirm injectors did not change anything, still the same intermittent crank no start, or intermittent hesitation starting.

Pulled these codes:



I can understand injector and throttle position sensor codes as I had to unplug them to remove the injector harness.

The crankshaft sensor code however seems to have come back? I replaced the crankshaft sensor already so not sure why I am seeing this again...

Codes cleared and have been replaced with two Internal Fault codes that do not clear 🤷♂️

Looking at the OBD graph, are the O2 sensor readings and fuel system faults actually misfires?

[jamesfoley]

Bit of a boring update.

Got hold of a second hand set of injectors and had them cleaned. Fitted them today (which was a royal pain in the arse), reset all adaptations, and the car seems to run well. So far it has started first time every time with zero hesitation.

However, looking at a log I still have a butt load of points where fuel system status hits "8", and the fuel trims are creeping back into the negative again. I really hoped that this would have fixed it 😞

Here is a new log with clean injectors: https://datazap.me/u/jamesfoley/e46-...0&data=1-2-6-8

Still zero reported faults through generic OBD reader and INPA.

What was weird is that when I fitted the injectors, I removed the fuel pump fuse and cranked the engine to remove residual pressure. However it didn't start leading me to think it had zero pressure after sitting?