[flexinator]

I may have an idea. I thought I read on one of these posts that occasionally the dme records misfires on the wrong cylinder. How about removing the coil from cylinder 5 and take a look to see what happens while the engine is running to be sure cyl 5 is truly cyl 5 in the dme. If this is useless, sorry... Just a thought

[JamesM3M5]

Originally Posted by flexinator

I may have an idea. I thought I read on one of these posts that occasionally the dme records misfires on the wrong cylinder. How about removing the coil from cylinder 5 and take a look to see what happens while the engine is running to be sure cyl 5 is truly cyl 5 in the dme. If this is useless, sorry... Just a thought

That's what I was suspecting when I found a bad injector on cylinder 1 of a car reporting misfires on cylinder 5 regardless of coil/plug/injector. That was an hypothesis that seems to be losing traction after testing.

[flexinator]

oh well. used to work on my 3 cylinder snowmobiles... damn thing always fouled one plug and you had to figure it out the old fashioned way...

[themyst]

Originally Posted by JamesM3M5

That's what I was suspecting when I found a bad injector on cylinder 1 of a car reporting misfires on cylinder 5 regardless of coil/plug/injector. That was an hypothesis that seems to be losing traction after testing.

Maybe the firing pattern of cylinder 1 adversely affected the firing of cylinder 5. When we drop timing post-shift, the massive corrections seem to happen in 1 and 5 simultaneously.

[saxon]

Number 5 plug was a little darker, but not wet, and number one looked perfect

[JamesM3M5]

Originally Posted by themyst

Maybe the firing pattern of cylinder 1 adversely affected the firing of cylinder 5. When we drop timing post-shift, the massive corrections seem to happen in 1 and 5 simultaneously.

That's exactly what I was thinking, too. Firing order is 1-5-3-6-2-4, so I figured maybe misfire in 1 was looking like 5 to the ECU? I dunno. Swapping parts and replacing the sooty injector from cyl 1 and all plugs, moving coils, etc, and the misfire persisted but then would never throw a code! The owner will bring it back sometime (been a couple weeks already) to have the carbon cleaned, and I told him that the VC gasket or whole VC might need to be done, too. I figure if there is a lot of liquid oil in individual intake ports, that points to some sort of PCV failure.

[saxon]

update

2aaf code, thermostat code popped up

anyone think the 2aaf code could have something to do with it?

dealer thinks its dme or valve springs

dme i would have to purchase and hope it fixed the problem to get reimbursed for it

valve springs id be talking $500 in labor to just check them out

[JamesM3M5]

Anyone ever stick an oscilloscope on the coil primary to see charging current and voltage? Watching the voltage on the coil ground and charging current under load at speed may show a defective waveform, and probably condemn the DME at that point. That transistor is less than $5, and there was a thread on replacing it just a few weeks ago.

Broken valve springs typically show up as a high-RPM misfire/false low rev limit. Also a possibility, but yeah, the VC R/R starts at $500 at a dealer.

How much do you like this car? As in: How much are you willing to spend to continue chasing this problem? Are you getting this done under an extended warranty?

[saxon]

was trying to get it covered under my third party warranty

at this point im about half tempted to trade it in and say F itsince i just got my car back with a $1000 bill and no fix

[cstavaru]

Originally Posted by saxon

was trying to get it covered under my third party warranty

at this point im about half tempted to trade it in and say F itsince i just got my car back with a $1000 bill and no fix

Wait...there is someone at another forum that pulled the cylinder head out of the car, and found the likely cause of the misfires. If seems to have to do with wear on the "cam bearing ledges" (don't even know what these means) and a "rectanring washer that was busted in half at the crankshaft between the hub and the timing chain sprocket". That rectanring may not be the problem on your car, but you should definitely check the cam bearing ledges for wear.

I would strongly recommend looking up that thread. I don't think I am allowed to put that link here, but here is a Google search:

https://www.google.ro/search?q=pulli...ing+ledges+n54

[saxon]

that was taken care of at 24000 miles on my vehicle according to the service records

[JamesM3M5]

The washer between the vibration damper hub and the crankshaft sprocket was also broken on DZ's engine. That might cause some funky issues, especially with cam timing, as would the worn bearing ledges and broken seal rings (rectangrings in Germenglish).

High RPM misfires are a little easier to pinpoint, esp with a stock-like tune. Something is failing in the coil driver or injector driver circuit. Unless there's a broken valve spring, I'd be inclined to say DME quite certainly.

[joec500]

anyone know of a good DME refurb service? Could be worth sending the DME for a checkup?

[JamesM3M5]

These guys:

http://www.autoecu.com/

[nitehawk]

Ask the dealer to swap the ECU with another compatible car to see if the problem persists...I know they may be hesitant but better than throwing money in the dark.

[saxon]

they said ecu's must be brand new and cant be reused from another car

i was asking if i bought a used msd81 if they could program it for me since they are online for 300-400

[JamesM3M5]

I don't think you can move ECUs anymore, even with programming. But call and talk to RPM Motorsport in BC, Canada - they do ALL kinds of BMW coding and trickery that dealers and regular shops just don't have access/programmers to do. I used them to program a cluster from an E46 M3 into a 330i w/ S54 swap.

http://www.rpmmotorsport.net/

[Xander]

I had a thermostat/waterpump failure and it made my car run like it was in an odd "limp" mode. No SES light, just a soft code, but once it got warm it drove like it was running pig rich (which I believe it was to cool the pistons). That being said, I don't think that Thermostat code is your issue.

X...

[saxon]

Thanks for the insight xander, I plan on replacing water pump and thermostat soon

[nitehawk]

Originally Posted by saxon

they said ecu's must be brand new and cant be reused from another car

i was asking if i bought a used msd81 if they could program it for me since they are online for 300-400

Hmm, I can see why they would say that. Basically, Engine ECUs have a serial number that are VIN matched from the factory for traceability and regulatory reasons. That's not to say it can't be done, just that they're "not allowed" to do it. I don't know specifically about BMW systems, but when dealers need to change a fried ECU, their diagnostic software can VIN write and immobilize a "fresh" ECU to the car. The same can be done with the used ECU, but they're not supposed to. I would take up James's suggestion and try a third party shop, if the problem does come down to your ECU/DME.

[nitehawk]

Oh, btw I totally forgot that the DME is covered under the emissions warranty for 8 years or 80k miles. It's in your service and warranty manual. Honestly, wait it out to see if the issue gets progressively worse, so you have some lead before your start emptying your wallet.

[tmo335tt]

Did you ever get your problem fixed?