Vanos Rebuild Start Hesitation

[sapote]

JI had the VANOS re-timed and the intake was a spline out which I guess was enough to put it out of spec.

If it was off by a spline then there should be an error code as one spline is more than 10 degrees error.

[jamesfoley]

Just as an update, I had the VANOS re-timed and the intake was a spline out which I guess was enough to put it out of spec. Car pulls so much better now that the VANOS is actually doing something.

Unfortunately still have issues with it starting. I realise that I put in the OP that I had the fuel regulator replaced, I have the part but it just hasn't been fitted yet. I think this is the last potential piece that could be causing me issues, either the fuel regulator itself, or the vacuum line between the regulator and the air rail.

[sapote]

1. Still haven't got around to getting the VANOS timing looked at, but pulled these graphs using TestO. Both graphs plotted at the same time and taken during engine start, and the wobble in the "Actual" graph is the engine starting and struggling to idle. As soon as it flattens out past the 15 second mark the car runs fine.

2. Not sure why the "Expected" graph starts at 52.5, but this was the DME value in DIS for the inlet cam to get an actual reading of 60 degrees, so I'm assuming when the engine is off 52.5 degrees is the position its being left in and then it does some hunting of the correct timing when it starts next?

1. The graph shows the cam wobbling during starting; I think this was due to the engine rpm unstable (DME reads the crank angle in order to come up with this cam angle value), and not the vanos itself struggled.
2. I think you're right about the initila 52.5* at start up. The working spread angle for intake is [70 to 130*] relative to 0* at TDC, where 70 is advanced and 130 is retarded; at start, the intake should be retarded at 130 which is 60* in VANOS speaking (0* is most advanced at real 70* spread angle).

[jamesfoley]

Still haven't got around to getting the VANOS timing looked at, but pulled these graphs using TestO. Both graphs plotted at the same time and taken during engine start, and the wobble in the "Actual" graph is the engine starting and struggling to idle. As soon as it flattens out past the 15 second mark the car runs fine.

Not sure why the "Expected" graph starts at 52.5, but this was the DME value in DIS for the inlet cam to get an actual reading of 60 degrees, so I'm assuming when the engine is off 52.5 degrees is the position its being left in and then it does some hunting of the correct timing when it starts next?

No idea if it actually shows / proves anything, but figured it might be worth just keeping it documented in the thread.

[jamesfoley]

Is it possible to pull up live VANOS data in INPA for the MSS54?

I can't seem to find anything related to VANOS in my copy of INPA.

[sapote]

On the VANOS test, does it pass the pressure test?

If you meant the leakage test - or timing holding test in x seconds -- then this test only performed after the command test which is failed right at the start. The DME can't tell the vanos oil pressure.

[jamesfoley]

Ah, it sounded like all the work, VANOS and fuel parts, was done at the same time (typically would not recommend this). The only thing I can guess is that they damaged the Beisan intake piston seal during installation. On the VANOS test, does it pass the pressure test?

The VANOS test fails at the first step almost instantly after getting the car to 1500rpm so I don’t have any other test results unfortunately.

[Slideways]

VANOS was done at a well recommended shop that does them frequently which is what makes this a bit fuzzy. They've also taken the car back and checked timing and told me everything is fine, however DIS is saying the inlet cam is out, so I'm not really sure who to trust at this point.

Fuel issues wouldn't cause the VANOS to not adapt though right? The car behaves exactly the same as it did before having the fuel pump and regulator changed so I have no real reason to suspect them, unless I'm honestly that unlucky to get a new genuine equally failing pressure regulator. I have zero issues while the car is running also, I can take the car through the entire rev range and not suffer misfires etc, apart from the car being obviously down on power.

Ah, it sounded like all the work, VANOS and fuel parts, was done at the same time (typically would not recommend this). The only thing I can guess is that they damaged the Beisan intake piston seal during installation. On the VANOS test, does it pass the pressure test?

[jamesfoley]

Never guessed that someone shimmed the holes with less than 0.5mm thick sleeves -- a bad idea.
The shop rebuilt the vanos should check the pressure after their works. It is like checking the engine compression after a rebuild.

As soon as I found that out I felt like I was driving a ticking time bomb, turns out finding an M3 with a VANOS rebuild invoice doesn't mean it was actually done well, but at least it was working at that point...

I have zero idea if the shop checked the pressure if I'm honest. The car is booked to go to my local BMW main dealer just because I was going around in circles with local garages trying to find the start hesitation, but now I've found this I'm tempted to find a specialist for a second opinion on the VANOS.

[sapote]

The original disc had the holes shimmed to reduce the play in the holes from a previous vanos rebuild, these thin shims were backing out of the holes on the oil pump disc. Had no broken hub tabs, but you could see the shims coming out of the holes with the valve cover off. As far as I know it was a redrilled disc from elsewhere, so not my original disc, just another pre-drilled S54 VANOS disc.

I've not taken pressure readings no as honestly I already feel like this is a little over my head at this point. Not really mechanically inclined, just putting together VANOS knowledge I've picked up from the hours of crawling the web trying to find a solution 😅

Never guessed that someone shimmed the holes with less than 0.5mm thick sleeves -- a bad idea.
The shop rebuilt the vanos should check the pressure after their works. It is like checking the engine compression after a rebuild.

[jamesfoley]

1) re-drill your original disc or something else? Oil pump disc has no shims so I don't understand this. Disc cannot back out unless the pistons jumped off the larger OD roller bearing when hub tabs broke.
2) Yes, the pressure at the metal pipe on top of vanos.

The original disc had the holes shimmed to reduce the play in the holes from a previous vanos rebuild, these thin shims were backing out of the holes on the oil pump disc. Had no broken hub tabs, but you could see the shims coming out of the holes with the valve cover off. As far as I know it was a redrilled disc from elsewhere, so not my original disc, just another pre-drilled S54 VANOS disc.

I've not taken pressure readings no as honestly I already feel like this is a little over my head at this point. Not really mechanically inclined, just putting together VANOS knowledge I've picked up from the hours of crawling the web trying to find a solution 😅

[sapote]

1) As far as I know it was the seals, anti rattle kit, and a re-drilled oil pump disc. Rebuild was done as it was done previously using shims on the oil pump disc that were backing out.
2) I'm assuming you mean oil pressure taken directly from the top of the VANOS itself?

1) re-drill your original disc or something else? Oil pump disc has no shims so I don't understand this. Disc cannot back out unless the pistons jumped off the larger OD roller bearing when hub tabs broke.
2) Yes, the pressure at the metal pipe on top of vanos.

[jamesfoley]

which parts they replaced?

As far as I know it was the seals, anti rattle kit, and a re-drilled oil pump disc. Rebuild was done as it was done previously using shims on the oil pump disc that were backing out.

Invoice lists timing chain tensioner pad, uprated cam bolts, uprated diaphragm springs, seal kit, anti-rattle kit, and re-drilled oil pump disc.

what valve body/coil pack? Do you mean the vanos solenoid plate or the ignition coils again?

No where I see report of the vanos measured oil pressure. The new Beisan pump disc/pistons can caused low pressure with parts not in tolerance. With low pressure dynamic cam timing will be wrong.

Sorry I meant valve body and solenoid pack, part number 11367839180 specifically brand new from BMW.

I'm assuming you mean oil pressure taken directly from the top of the VANOS itself?

[sapote]

I've had my VANOS rebuilt by a local shop using the usual Beisan parts.

which parts they replaced?

all ignition coils (Delphi)
After being reassured the timing was good I figured it was going to be the valve body / coil pack, so threw a new genuine valve body and coil pack
.

what valve body/coil pack? Do you mean the vanos solenoid plate or the ignition coils again?

No where I see report of the vanos measured oil pressure. The new Beisan pump disc/pistons can caused low pressure with parts not in tolerance. With low pressure dynamic cam timing will be wrong.

[jamesfoley]

A friend of mine recently had issues with VANOS failing to adapt. When they undo it, found the hub spring washers were installed incorrectly. You seem to have a hardware issue.

in his case the cup washer was flipped so the cam was stock. Similar to what you are experiencing

Fair, sounds like I either need to go back to the shop again and get them to pull it apart, or cough up some more cash and have another shop re-build it again.

Going to assume that if DIS says the timing is out, then its likely the timing is actually out rather than something else being faulty?