Author Topic: I need some Serious $#%@#$in Help seriously (Read 26729 times)

doitover · « **Reply #60 on:** February 25, 2011, 07:05:02 AM »

I don't know if you will have any luck getting the air out of the cooling system that way. I think you pretty much have to follow the BMW instructions. I won't butcher them by typing them from memory, they are easy to find.

fiftytakedowns · « **Reply #61 on:** February 25, 2011, 12:06:52 PM »

Ive got a bit of an update for today.

Drove the car around today after bleeding the system the proper way (from the bentley), and to my surprise the problem is almost gone. I think it is more of an ECU issue at this point because I have three ECU's:

mine stock:
Would Drive and pull normal, but for some reason if you downshifted or started cruising at 3.5 RPMs and then punched it it would misfire or hesitate etc. but it would Drive through it completely normal, and would pull through it as well.

mine chipped
same symptoms, except it would be at 4k RPms, and had more difficulty pulling through it. (still pulling a 1244)

Ryans stock: couldnt get problems to arise.

mine Mark D
Ryans Stock

DesktopDave · « **Reply #62 on:** February 25, 2011, 03:30:47 PM »

I found this recently, checking out some unrelated DIY FI stuff:
http://www.diyautotune.com/tech_articles/using_bosch_bip373s_with_megasquirt.htm

Along with this test, it'll give you a good idea if you have a bad MOSFET coil driver transistor in one or more of your DMEs. I have one with a known bad driver that I'm going to try this test on. Problem is that I don't quite have the tester yet, but I've been wondering what to get for my birthday...so it might as well be that with some nice leads too, eh?

But you swapped the coils, so my whole theory might be nonsense. Since you've pretty much isolated it to the DME, maybe that low impedance coil is overheating the driver & causing some interference when it goes above a certain timing advance? From what I'm thinking...the different chips all set different spark advance curves to maximize power, right? So your overheating DME causes hesitation at different times when it sweeps through a certain range. I know, it sounds far-fetched, but you've tried everything else it seems.

fiftytakedowns · « **Reply #63 on:** February 26, 2011, 03:59:13 AM »

So should I replace the coils and the dme?

DesktopDave · « **Reply #64 on:** February 26, 2011, 10:18:15 AM »

I'd just get them tested. I'm not sure how to do it yet, but if I tear my spare apart I'll let you know what the procedure looks like.

fiftytakedowns · « **Reply #65 on:** February 27, 2011, 12:12:08 PM »

I tseted the coils again and kept on getting inconsistent readings for .003 to .007 set on 2k Ohms. every now and then I would get a .002

longtallsally · « **Reply #66 on:** February 27, 2011, 12:13:34 PM »

I gotta say, you are turning me against going to the COP conversion...

fiftytakedowns · « **Reply #67 on:** February 27, 2011, 12:52:39 PM »

Quote from: longtallsally;101803

I gotta say, you are turning me against going to the COP conversion...

the m42 coils are just as bad perhaps. I dont even know if it is the coils.

I think Ive narrowed down the problem of the mid RPM misfire and bucking to be an ECU issue, however, The Cold Start Bogging Is still driving me crazy. I have to wait 15 minutes just for the car to warm up in order to drive it.

I pulled the plugs and replaced them with some champion plugs. not the best brand, but I dont want to throw money on a second set of plugs when my old NGKS have less than 10K on them.

anyone think the thermostat would cause the problem of cold starting?

fiftytakedowns · « **Reply #68 on:** March 01, 2011, 08:27:37 PM »

What would cause my two previous ECU's to go bad? and causing me to need a new one?

Still can't figure out the cold start issue:

why would injectors turn off or spark be cut?

DesktopDave · « **Reply #69 on:** March 01, 2011, 09:53:20 PM »

Check out the other thread...I think it's a throttle overrun issue. Maybe the DME thinks you're coasting down a hill and it's killing the injectors momentarily.

I'm also still thinking that the DMEs were damaged by a bad coil pack. I know, I'm like a broken record here... I'd be sure it was that except it's really odd that it changes with the different DMEs. It's not an easy one to isolate.

Did you get the radiator fan stat three-prong fixed? Here's a pic just in case:

It's not connected to the DME, just a thermostatic switch that click on the aux fan low or high speed based on coolant temp. Same for the thermostat itself, not related IMHO.

fiftytakedowns · « **Reply #70 on:** March 02, 2011, 12:00:40 AM »

Thanks a lot dave your a huge help for me in this trouble shooting process. that being said, I ordered two good known working coils off of another member here, so I will switch them out and see if that prevents ECU destruction. I also responded to that thread about hte inejctors switching off.. I am wondering what I should do to tackle it at this point.

DesktopDave · « **Reply #71 on:** March 02, 2011, 06:34:49 AM »

I'm honestly not sure what to do next. You've already done everything I'd do. Hopefully the coils will help with your problem.

inarticulate is · « **Reply #72 on:** March 02, 2011, 09:56:02 AM »

Had a similar issue with a Mercedes, turned out to be a bad afm, running issues were similar plus they were changed by disconnecting the battery which caused a reset of mapping. Your changing ecus may have done same thing.Might also explain onset after timing chain work. Also was not throwing codes for afm on standard diagnostic reader had to get a guy who had actual Mercedes computer.

rob_e30 · « **Reply #73 on:** March 02, 2011, 12:40:11 PM »

We chased a problem like this for a long time. Turned out to be fuel injectors were clogged. The only coil failure we've had is when we rested one on the downpipe from the turbo and almost set the car on fire. It melted that coil but all the others worked great. We've shipped hundreds of these coils and never had a problem.

fiftytakedowns · « **Reply #74 on:** March 03, 2011, 02:58:20 AM »

Quote from: rob_e30;101934

We chased a problem like this for a long time. Turned out to be fuel injectors were clogged. The only coil failure we've had is when we rested one on the downpipe from the turbo and almost set the car on fire. It melted that coil but all the others worked great. We've shipped hundreds of these coils and never had a problem.

That's bizarre, why would fuel injectors get clogged only when the engine is cold? I tried swithing out the injectors with four pintle ones, and then back to the old style.