fladventurerob

I took out the injectors and had them ultrasonically cleaned and rebuilt. Got all new plugs and coil packs (the engine has 115k on it). Reassembled and relearned the valvetronic limits, but have been having random misfires and rough running to the point I can't drive it, nor do I think I should lest I damage something. Here's what I've tried so far:

1) I reinstalled the original plugs and coils...problem still exists.
2) I did a smoke test and a low pressure test for vacuum leaks and found a very small one in the eccentric shaft seal, repaired...problem still exists.
3) I tried unplugging and even tested a new MAF sensor...problem still exists.
4) I decided to drive it for 5 minutes after clearing all the codes again, and it says random misfires, but misfires on cylinder 2 & 6. I tested the injector signal with noid lights on both injectors cables and they are good.
5) After running the engine for 30 seconds, I was able to feel the exhaust manifold on #6, and it was hot. I was also able to reach #5, and it was neither hot nor cool. (EDIT for anyone that sees this -- The cylinder numbers in the book, are not the cylinder numbers in the computer. The computer shows cylinders by firing order! So the #2 in the firing order is actually cylinder #5 which was the cool manifold pipe)
6) I unplugged both #2 & #6 injectors during noid testing, and the engine didnt run any worse or better.
7) With everything hooked back up, I unplugged the cable from the driver side eccentric shaft sensor which is the side I had to disconnect when removing the fuel injectors, and the engine didn't really noticeably run any worse but I almost want to say it ran slightly better (but that could just be me)

I am at my wits end and my wife is pissed that the car has been sitting in the garage for 3 weeks after what was supposed to be a quick weekend job...but now with no end in sight. I'd actually like to drive it again and stay married . I have an ICOM and all the software, if anyone has any helpful suggestions, PLEASE PLEAAASSSEE helppppp! I would be forever grateful! (Also, if you really know what you are doing and are in the Orlando, FL area, please shoot me a PM)

scottalexander

Before you took out the injectors and had them ultrasonically cleaned and rebuilt, did the engine have the misfires back then, that you are experiencing today?

fladventurerob

No, this issue did not exist then. I had symptoms of a leaky injector, which was why I went down the ultrasonic cleaning path. I do have 2 injectors arriving tomorrow, so I am going to swap out the #2 & #6 with the new ones.

The roughness chart in INPA shows that #2 & #6 are both extremely high.

scottalexander

If the two new injectors arrive, are installed, and the misfire goes away, the logical question is what happened at the shop when they were doing the ultrasound?

Something went south during the injector rebuild process?

When the two new injectors arrive, set them down next to the old #2 and #6 injectors and see if you can learn anything.

Reefin Dude

i am not sure if your DME is the same as the one in the 535, but if it is, than it could be one of your MOSFETs have gone bad on one of the ones going to the injectors to that bank.

i used this video to determine which MOSFET was bad.


i ended up buying a hot-air rework station to get the job done as finding a TV repair place in my area was proving difficult, and cost would have been close to the same.

i had the same problems. all of the cylinders in a bank were showing misfire. moving injectors, coils, and plugs around would not change anything. i stumbled on this while looking for solutions and it was the problem. my #5 cylinder MOSFET was bad. i bought a 10 pack of MOSFETS. replaced the bad one and have been running trouble free for several months now.

HTH,

G~