Author Topic: ECU?, fusible link? idk (Read 5131 times)

ScreamerBeemer · « **on:** January 17, 2009, 11:40:26 AM »

I read some similar occurrences to my recent experience. I was coming home from work and right as I got to my drive way the car died. I thought "weird", but it fired right up and I never thought twice. So, the next morning came and it was -5 outside so I went and decided to warm up the car. I started up fine and idled for about five minutes. I started to drive I made it about 300 ft and she died. Just shut off. Since then, I'm sure its safe to say that there isn't any spark. I gave it a shot of ether and all it would do is crank but not start, on top of that there is no CEL and I don't here any of the usual clicking from the relays. :confused: So I did some searching and found a thread on bimmerforums mentioning a fusible link. So, I checked for voltage at the little wire next to the main positive cable under the cover on the pass side under the hood. I have power there. Any ideas, bad ECU?

ScreamerBeemer · « **Reply #1 on:** January 19, 2009, 01:03:43 PM »

After some checking, I found that power is getting to the ECU. No power to the fuel pump. Fed the fuel pump power and it ran like hell. No Check Engine light at all. I gave it another shot of ether and it fired a little bit. If that's from spark or compression idk. I tried checking resistance on the crank sensor on pins 1 and 2 and I don't get anything. I've tried this with two different multimeters. I'm getting power at all three main relays. I didn't feel any clicking on the long relay in the fuse box when I turned the key to run.

Any Ideas?:confused:

Cobra Jet · « **Reply #2 on:** January 20, 2009, 02:46:30 PM »

Try this link:

http://www.m42club.com/forums/showthread.php?t=5462

Sounds like the same problem I encountered (which is why I had to start that above link for a non-start issue)...

My bet is it is going to be your crank positioning sensor ($160 part). Do read the above thread, there are MANY diagnosis procedures you should follow in that thread before finally determining it is the CPS...

For whatever reason, when the CPS takes a dump on these 318 M42's, it will NOT throw a code... I don't know why this is the case, but there's been many others (including myself) who experienced a CPS failure and there is never a CEL illuminated w/ the CPS failure code.

You must test the CPS w/ a multimeter and ohm it out. I forget the specs at the moment, however, they are in the above thread. If your CPS is reading either higher OR lower than the Bentley specs, replace it. Check it while it's on the engine, then remove it and check it again.

Sounds like you are on the right track for diagnosing your non-start issue - if you jumped the fuel pump directly at the fuel tank and it turns on, the fuel pump is GOOD. Did you check the fuel pump relay, if not, check that also w/ a multimeter. Have you tried jumping the fuel pump relay socket to see if the pump will prime that way too?

Like I said above, my bet is the CPS - same exact scenario I and others have ecountered - car was running fine, then go to start it later or after a stall and you get absolutely NOTHING (crank but no start and no fuel pump prime), it ends up being the CPS.

DO READ THE ABOVE LINKED THREAD...

roundel318 · « **Reply #3 on:** January 24, 2009, 10:01:03 AM »

The CPS definately is very important for the motor to run correctly

ScreamerBeemer · « **Reply #4 on:** January 25, 2009, 04:20:47 PM »

I checked the resistance between pin 1 and 2 on the crank sensor. I got nothing....on three different multimeters. So, I decided to take it off. It sucks ass to take off. Why did they have to route the sensor between the block and AC bracket? It makes sense as far as trying to keep it away from the belts, but it sucks to remove. Anyway, when I had it off, I checked the pins again this time I would wiggle the end and bingo. The readings jumped everywhere. Its odd though, I don't have any CEL, not even when I turn on the ignition.

ScreamerBeemer · « **Reply #5 on:** January 25, 2009, 04:26:18 PM »

Thanks Cobra Jet
I was going through bimmer withdrawals. I've been stuck with driving the wife's Focus.

Cobra Jet · « **Reply #6 on:** January 26, 2009, 03:45:43 PM »

Quote from: ScreamerBeemer;65340

Its odd though, I don't have any CEL, not even when I turn on the ignition.

Exactly what many of us M42 owner's experience w/ a CPS failure. I'm really not sure why we don't get a CEL or code when the CPS fails ... ?!? I don't know if it's a fault in the DME programming logic or what - a code does exist, but for whatever reasons unknown, a code is never thrown for a bad CPS. This CPS issue has been discussed on multiple BMW forums regarding the M42 engine and how a code is not thrown.

Glad you found your problem and are able to get it back on the road!

If you have not purchased a CPS yet - the best price I was able to get was from bimmerparts.com (you can contact him via phone # or email off his site - the part is not listed on his site, but he can get it. He sent me one out, genuine BMW part and way cheaper than the local BMW Dealers and some other online vendors).

Jimmy Lewis · « **Reply #7 on:** January 27, 2009, 12:42:41 PM »

Well this sounds a lot like my issue, I will have to get my hands on a spare and see. I sure hope it works, as I've been driving my sister's Scion xA for a week now and it is getting old.