Rough running after replacing upper timing case gaskets

[udm95]

Just completed some long-delayed maintenance items on my 2002 E39 540i 6-speed with just over 200k miles.
• Valley pan
• Knock sensors
• Upper timing case gaskets
• Cam solenoid gaskets
• Primary chain tensioner
• Valve cover gaskets
• Sucking jet pump
• Brake booster hose
• Water pump & thermostat
• All coolant and heater hoses
• AC & serpentine belts

When I started it after everything was back together, it runs rough with misfires and backfires. It will struggle to idle, but pressing the accelerator causes it to die.

Using a Foxwell NT530 I get:
• P0102 Mass or volume airflow sensor ‘A’ circuit low.
• P1344 Misfire during start cylinder 2
• P1346 Misfire during start cylinder 3
• P1352 Misfire during start cylinder 6

I checked all wires and electrical connectors and for proper seals on all ductwork/vacuum lines. I used a scope to verify that the chain tensioner was seated properly against the arm of the tensioner rail.

After clearing the codes, a second brief attempt at starting again produced the P0102 code. I didn’t let it run long enough to produce the other codes.

When I had the passenger-side upper timing case cover off, I found no play/slack in the timing chain on the deflection rail side. The only thing that surprised me during reinstallation was that, in order to get the passenger-side cover back on, I had to put some pressure on the tensioner rail against the chain so that it would clear the inside of the cover where the chain tensioner comes through. This was only some modest hand pressure and there were no other interactions with the timing chain. Even so, any possibility I could have caused the chain to jump a tooth and any way to easily determine that? Or maybe the VANOS solenoid – I did initially turn the part of the solenoid that’s outside of the timing case cover, mistakenly thinking it needed to be removed. I would appreciate any thoughts/suggestions/advice.

I’m waiting on a new HFM now – at only $102 from FCP for the OE Bosch version, it’s worth a shot and it won’t hurt to replace it at 200k miles anyway.
Thanks in advance!

[dtw]

That sounds like a massive vacuum leak. Easiest and first thing to check.

That said if fuel system was disconnected, it may just need to run a minute or two to purge all the air. I had similar issues/codes on a major M62 service. It sorted iteself right out after a minute. You could carefully engage the Schrader valve on the fuel rail and see if you get any air.

Also make sure your injector plugs are very firmly, positively seated. Check all grounds, especially on the coil harness. Double check that coils are properly seated and all coil harness connectors are correctly engaged.

[udm95]

Really appreciate the quick response!! I'll follow thru on your suggestions.

One thing I forgot to mention is that I managed to break the vacuum line that taps into the air duct just before the throttle body and runs to the regulator on the fuel filter. I brushed some electrical connectors out of the way during re-assembly and caught the end of the vacuum line which was so brittle that it broke. I used some rubber tubing to mend it for now.

[udm95]

I double-checked all of the items that you listed. Also, I replaced the HFM with a known working unit yielding the same results.
Regarding the vacuum leaks – are all of the following the appropriate areas to be checked?
• HFM-to-Throttle Body duct
• Line to fuel filter pressure regulator
• Line to sucking jet pump
• Intake manifold gaskets
Any possibility these could contribute?
• Valve cover gaskets
• Upper timing case gaskets
Am I simply doing a visual check or is there a way to apply a vacuum or air pressure?

[udm95]

After checking everything else, I pulled the intake manifold back off. The source of the leak was then obvious – the gaskets were not providing a good seal. The apparent cause was the fact that the rubber grommets on the sleeves that fit over the studs that the nuts go on were too compressed to allow the proper amount of pressure to be applied to the gaskets.
Unfortunately, the grommets do not appear to be available separately from part #11611736648. I’m thinking I could probably slip some o-rings under the upper flange of the sleeves to make up the difference, but I purchased some replacements which corrected the problem.
Thanks,
Allan

[jicaino]

I replaced all those grommets and guide tubes when I did timing. The thicker grommets aren't available separately and the valve covers grommets are thin for the application. Maybe somebody tried to use valve cover grommets there on your car? Anyway back to my case they were marginally OK but I got them all for 80 bucks and bought them from a seller in Greece on eBay.
Another potential headache might be injectors if you pulled them off the intake. Also refurbished them all with a 20 bucks set of filters, upper and lower o-rings and plastic washer.

[udm95]

This is the second time I've had the intake off and replaced the gaskets - first time in 2012 at about 90k miles and now at just over 200k. No problem last time. The grommets were all very hard - more like plastic than rubber. The upper timing case cover gaskets were as brittle as plastic. I've been dealing them leaking oil for some time - hopefully this will fix that.
I got the replacement guide tubes and grommets from Pelican Parts for $85.10. I don't know why they don't sell those grommets separately. I didn't pull the injectors off, so I seem to be OK there. Thanks for the heads-up!

[jicaino]

This is the second time I've had the intake off and replaced the gaskets - first time in 2012 at about 90k miles and now at just over 200k. No problem last time. The grommets were all very hard - more like plastic than rubber. The upper timing case cover gaskets were as brittle as plastic. I've been dealing them leaking oil for some time - hopefully this will fix that.
I got the replacement guide tubes and grommets from Pelican Parts for $85.10. I don't know why they don't sell those grommets separately. I didn't pull the injectors off, so I seem to be OK there. Thanks for the heads-up!

Kind of the same as I did. Resealed all in 2013 and this time it was all hard as plastic as you say. My engine ran good, but after replacing all of the timing covers and valve covers gaskets and grommets, everything in the intake system gaskets and all, it purrs like a kitten. Those "intake suspension" grommets should be available separately. I contemplated drawing the grommets in fusion 360 and print them in tpu or something like that, but in the end having too many side distractions and I just bit the bullet and replaced them too.