Author Topic: lost two cylinders. Help needed (Read 4805 times)

Angus1211 · « **on:** September 15, 2008, 08:36:00 AM »

So yesterday, after driving in heavy rains and some flooded areas, my motor lost almost all power while I was driving. Got it home and found out by pulling plug wires that cylinders 1 and 2 were not firing. Plugs are 3 weeks old and were fine. So then we swapped wires around and it's not the coils. My father (electrical engineer) did some testing and after switching stuff said it's not the spark plug wires either. I was shocked by the wires a couple of times though... So before the coils, is there anything that could've broke or something to have caused this? It's a 93 318is w/ 200k on it.

thanks in advance!

EN318isPDX · « **Reply #1 on:** September 15, 2008, 10:30:31 AM »

Quote from: Angus1211;56717

So yesterday, after driving in heavy rains and some flooded areas, my motor lost almost all power while I was driving. Got it home and found out by pulling plug wires that cylinders 1 and 2 were not firing. Plugs are 3 weeks old and were fine. So then we swapped wires around and it's not the coils. My father (electrical engineer) did some testing and after switching stuff said it's not the spark plug wires either. I was shocked by the wires a couple of times though... So before the coils, is there anything that could've broke or something to have caused this? It's a 93 318is w/ 200k on it.

thanks in advance!

My guess would be the coils. If not that than maybe your fuel injectors are clogged

Angus1211 · « **Reply #2 on:** September 15, 2008, 02:05:21 PM »

Quote from: EN318isPDX;56721

My guess would be the coils. If not that than maybe your fuel injectors are clogged

the coils are fine, we swapped in the plug wire and ecu wire (from the computer) to different coild and it would still do the same when we pull the other input connector out...

is there a wiring diagram for this?

TIA

ak96ss · « **Reply #3 on:** September 15, 2008, 06:44:01 PM »

Look here: http://www.m42club.com/forums/showthread.php?t=4220

EDIT: Although yours may be different, what with it being the wrong M42 and all...

Angus1211 · « **Reply #4 on:** September 15, 2008, 07:36:08 PM »

well after many hours of troubleshooting the igniting system, there is nothing wrong with that... and i need to correct myself, it's cylinder 2 and 4 that are not firing. I really suspect that one of those cylinders wasn't working before too as acceleration wasn't that great and stumbled a bit, but i never knew how the m42 was originally...
Then another cylinder gave up and now it was down to two cylinders... So we tore apart the intake manifold, upper and lower, to pull the injectors. one was physically broken as the plastic tip piece was disconnected from the injector and fell into the intake valve area... got it out and put a 12v source to it to open it and it barely clicked and let out the rest of the fuel compared to the other 3 injectors... so that was shot and i am now ordering new injectors (2) to put in for cylinders 2 and 4. So we'll see if that fixes this problem.

i got this car b/c I blew the motor in my chrysler and now im working on it more than my chrysler

well if anyone has any other suggest or words of wisdom, let me know!

thanks

christophbmw · « **Reply #5 on:** September 17, 2008, 11:21:32 PM »

....wait, how did the wires shock you? if you where holding them (just the wire not the connector) and they shocked you then its definetly the wires.

Angus1211 · « **Reply #6 on:** September 18, 2008, 03:07:55 PM »

Quote from: christophbmw;56913

....wait, how did the wires shock you? if you where holding them (just the wire not the connector) and they shocked you then its definetly the wires.

the was a slight crack in the boot that when i squeezed it open, i then got shocked. We fixed that crack.

I have mustang injectors on their way now...

Angus1211 · « **Reply #7 on:** October 01, 2008, 11:16:10 AM »

UPDATE:

I put everything back together and it was still not working...

tried some other stuff and then put a scope on the injector wires/connectors. no pulse for injectors 2 and 4, but strong, visible pulse for 1 and 3 as those are the only ones firing.... BUT thing is, right at start-up, all injectors fire, but then 2 and 4 instantly stop firing...

what's next guys?

thanks in advance!

Jimmy Lewis · « **Reply #8 on:** October 01, 2008, 11:32:31 AM »

I'm stumped. Could you get your hands on a spare ECU and see if that makes any difference? If the injectors fire initially there is no reason why they shouldn't continue to fire. I would look into having someone send you a spare ECU, because that may be the culprit.

romkasponka · « **Reply #9 on:** October 02, 2008, 04:50:05 AM »

As I know injectors #1 and #3 works together, #2 and #4 also.

Angus1211 · « **Reply #10 on:** October 07, 2008, 08:34:08 AM »

we pulled the ecm out and opened it and there's lots of water damage in there....

I tried cleaning it up and my pops is currently resoddering and cleaning up connections to hopefully fix it.

But in the meantime, anyone have a spare ecm I could by or try to use to see if my ecm is the culprit? OR does anyone know of a god bmw ecm rebuilder?

thanks

haledj · « **Reply #11 on:** October 28, 2008, 12:15:24 PM »

Check the solder joints in the ECU, especially the ones on the transistors and regulators. Many problems like this can be solved by reflowing the solder.

I picked up a spare ECU on eBay for $20