Starting Help

[asubimmer]

Well some of you know that my m42 has been acting funny lately. It acted like there was a "rev limit" at 2.5-5.5k range, and would change where it wanted the rev limit to be at. It was like a rev limit but not as smooth. Well I replaced the fuel filter which helped but did not solve the problem. I also changed the spark plugs b/c they looked old and it cant hurt to change them. There was oil on the #2 spark plug but that was b/c the screw that holds on the VC right next to it was missing. I replaced the missing screw. Last week the fuel pump went out, which was my first guess what was wrong w/ it in the first place. So I replaced the pump today to find out that was apparently not the only prob. The fule is getting past the fuel filter fine so maybe the spark isn't right? I am starting to think the coils may have gone out. The engine will turn over but not catch.

BTW when the fuel pump went out I was on my way to a friends house and the "rev limit" had been 5.5k and droped to 4k. Soo I downshifted into 2nd and the "rev limit" drops to 2.5k!! as most of you know we have no power down there so I downshift into 1st and the engine cuts out.

Has anyone experienced something like this?

[bmwman91]

Could be coil packs. There were 2 brands that BMW used. I think they were Bosch, and something else starting with an L. The latter were known to die (the L ones). Might be it.

[asubimmer]

cool thanks...is there a safe way to test them w/out shocking the crap out of me IF they work?

[kowalski]

me too

http://www.m42club.com/forums/showthread.php?t=76

edit: mines fixed:)

[Febi Guibo]

yeah, like kowalski's experience... maybe check the connections AND the ground wire on your alternator?

The alternator vibrates as the engine revs, and that ground wire tends to go bad where it bends coming off the back of the alternator. kind of a long shot, but hey....

[asubimmer]

yeah I will definately check that out. I am getting the feeling that its the coils so tommorro I am going to put her on a trailor and head off to Korman to hook her up to the machines to find out exactly what it is.

But I guess if I should check out the alternator wiring first.

[bmwman91]

Yeah, check the alternator wiring first. It is a lot easier than trying to troubleshoot the coils.

[asubimmer]

it looks like the wires are fine on the alternator. The car is having a harder and harder time trying to turn over now. The car has been siting for a little over a week it that matters at all.

[kowalski]

it looks like the wires are fine on the alternator. The car is having a harder and harder time trying to turn over now. The car has been siting for a little over a week it that matters at all.

sounds like you have a short somwhere and its draining the battery. did you check running voltage of the car? cause that could be the problem right there. either your alt's bad or your battery, or you have a short. if the alt. is bad you will have a rev limit because it would have the power to supply high rpms. just a thought.. thats what mine has done every time the alt. went, and did this time as well.

[asubimmer]

turns out it was a bad crank sensor

[Febi Guibo]

that was my next guess... I swear!! kidding lol...