new to me, 98 M3

[B C]

Just out of curiosity:

Move injectors 1-2-3 to cylinders 4-5-6 and see if the Bank 1 deviation becomes Bank 2 deviation. If so you know its injector related (even though the injectors are assumed good)

If its still a Bank 1 deviation after that, move bank 1 o2 sensor to bank 2. If the deviation moves to bank 2 you know the sensor is bad even though it is assumed to be good. If it stays on bank 1 then there is excessive electrical resistance in the injector wiring, o2 wiring, or an air leak on the intake or exhaust side of cylinders 1,2, or 3

[jc43089]

^ Good steps, check those things out.

[cpandrewschmidt]

I had some time to noodle around with this over the weekend.  Here are a few observations.  Before moving injectors in addition to the codes above I would get a misfire on cylinder 5.  Wouldn't happen all the time, but somewhat consistent.  I've replaced all spark plugs and new coil packs but code persists.  

So, I removed plugs and rotated them around.  1 to 4, 2 to 5, 3 to 6 and then 6 to 3, 5 to 2, 4 to 1. 

New codes come up as:  Misfire cylinder 2 and 6.  (2 makes some sense since I moved 5 to that spot.  6 makes no sense)  I have mixture deviation on Bank 2 now vs bank 1.  Also, both Cat Efficiency Bank 1,2 still.  After moving them and starting the car I could feel the misfires right away.  However, after car warms up it appears to run perfectly fine.  

Anyway to test injectors besides sending them in to get cleaned and tested?  Seems weird for 6 to go bad.  That would have been in slot 1 before and I've never had a code there.  I wonder if there's something up with my electrical signal to them?  I probably stretching here.

Appreciate any thoughts.

[jc43089]

Did you move the injectors or just the plugs?  Did the plugs all look a similar color?

[cpandrewschmidt]

Just moved injectors.  Plugs are also new.  Looked fine when i pulled them for vanos job before.  I didn't put them back in the same spots so the misfire staying on 5 wouldn't have been plug related.  In the past i've moved those and coil packs.  Code stayed on 5.  So, plugs and packs should be good.

[B C]

Misfire makes sense as your bank 1 and bank 2 fuel trims dont "match" the injectors that they adapted to.

Reset the ecu/adaptations and check the codes again just to be sure.

[jc43089]

Ok, I misunderstood.  I think you have identified an injector problem if your misfire code moved with the injector.  Did you happen to look for an injector dripping while you had them out of the manifold?  

I think if you had a wiring harness problem the issue would have stayed at cylinder 5.

[cpandrewschmidt]

thanks guys.  Will do tonight and report back.  I found it strange that cylinder 6 now had a misfire as well.  I didn't check for a dripping injector unfortunately.

[B C]

There are a lot of variables in play so dont think too much of it until you clear adaptations and try again. Cyl 6 may have a good plug, good injector, but may be misfiring because of the extra lean/extra rich fuel trim on bank 2.

It would be best to send the injectors out for rebuild for peace of mind. I had a good experience and turnaround with Injector Rehab.

[Jdesign]

Not sure what style injectors you have, but you can always check them quickly yourself with a battery and some carb/injector cleaner.

[cpandrewschmidt]

Cleared codes and reset DME this AM.  Took to work today.  Start up was rough again, smoothed out after normal driving.  Although I feel even after warm up the sound of the exhaust is a little sputtery.  Pulled the same misfire codes on 2 and 6 and cat efficiency codes.  No mixture deviation yet, but that might come on with more driving I suspect.  

[B C]

Going to send the injectors off for rebuild then?

[cpandrewschmidt]

Yeah.  I'll start there for piece of mind.  Still think it could be my vanos job.  I've been reading about more steps on that and some people swear by having to test is with air for correct chain movement before buttoning up.  But, not too expensive to ship off the injectors so taking those off tonight.  Using this guy.  I've emailed with him.  http://injectorrepair.com/flow-testing-process/

[B C]

Did you use a dummy chain tensioner tool when you did your cam timing?

The fun part about my build is its OBD1 with no check engine light so if my engine runs funny then I don't get too many hints as to what it may be. Here is to hoping I fire mine up within the next month and it is perfect, and that yours is just some crummy injectors.

[cpandrewschmidt]

Snap said:

Did you use a dummy chain tensioner tool when you did your cam timing?

The fun part about my build is its OBD1 with no check engine light so if my engine runs funny then I don't get too many hints as to what it may be. Here is to hoping I fire mine up within the next month and it is perfect, and that yours is just some crummy injectors.

all i used for the tensioner tool was pressed down on the upper tensioner and then inserted a small nail into the hole to hold it down so the chain had slack.  That's what the beisan instructions lead me to believe is all i had to do.     http://www.beisansystems.com/procedures/vanos_single_procedure.htm

[B C]

Aha, okay. I replaced my cams and therefore had to remove the primary exhaust sprocket. You wouldn't have had to mess with the chain tensioner on the passenger side of the head.  disregard.

[cpandrewschmidt]

Got to do some fun stuff while waiting for my injectors to come back from testing.  Painted the spoilerless trunk i found at the junk yard.  Still need to wet-sand clear coat tonight.  Hopefully it comes out OK and matches well.  

[Jdesign]

Looks good to me!

[cpandrewschmidt]

well damn.  Injector guy just called back after testing.  Said they're 100% fine.  Figured since they really only have about 27k miles on them.  

Looks like I'll be trying my vanos job one more time.  Really isn't anything else I can test at this point.  Gotta track down that air tool to test chain movement that I'm reading about online.  Can't find it anywhere.

[Jdesign]

Damn thats a bummer.