Firstfives.org

A community of missing cars!!!

Here's my story, yet unresolved.

Coming across your thread gives me, hopefully enough, motivation to get out there and see if I can find mine.
Maybe this weekend???

Good luck with it Brian.

I saw the car yesterday and fiddled with it a bit.
It's definitely electrical. It's a misfire. The telltale is that the tach drops when the miss occurs.
Another significant piece of data is that the car runs perfectly when cold. As soon as it starts to warm up, it starts to miss. And it gets worse quickly as the car warms up.
It does it at idle, off idle, in gear (it's an auto) or in neutral.
Please correct my logic if you see a flaw in it.
I think it's in the primary ignition circuit. Otherwise the tach would not act up.
Distributor, ignition box, coil, and ECU have been swapped. (Along with numerous non ignition-related components.)

A bad ground maybe?

I spent some more time working on my patience skills with the E12 yesterday.

Replacing the ballast resistors did not make any difference, so after conversing with Pierre (and him fiddling with the car per his post above) I cleaned all the grounds I could find, including the three or four that are part of the negative battery cable. There is a mass of brown wires that screw in to the negative post that look a bit iffy, but cleaning them up didn't make much difference.

So, I followed the wires off the tach and checked all those connections (under the ICM, across the engine to the bottom of the fuse box, and where the black wire goes into the ECU). They all seemed OK, but I did notice that the tach was acting up "less" (sorta like being "kinda" pregnant), but I still have that darn miss. Grounding the AFM to the engine didn't do any good. Running a ground wire from the engine to the chassis didn't do any good.

Warner Phelps mentioned that he had a problem like this and it turned out to be a hole in his airbox. Fixing the hole solved the problem. I've argued that the airbox shouldn't matter - it's Pre-AFM, and he agreed, but it solved his problem.

I did notice that it looked like someone had removed the sheath around the mass of wires that plug into the ECU. I wonder if the next step should be to remove that sheath and see what the wires look like.

Thoughts? I appreciate everyone's help and suggestions with this ongoing saga. Otherwise I think I would have despaired entirely.

Brian

P.S. - the previous owner installed a big honkin' stereo (something like 3000 watts worth of Amplifier power) with big thick stereo cables all over the place. I'm beginning to wonder if that's wreaking havoc with things.

Now that brought up the stereo, I would start by diconnecting the main power wire from the battery.
A second suggestion would be to disconnect the cluster. The tach gets its signal from the coil, but if the tach is the culprit (I don't know why it would only act up when warm) it could be grounding the coil out.
The car should run without a tach attached.

Another update - I am going to try and remove the instrument cluster today and see what's wrong with the tach in the remote hope that this has something to do with the misfiring/cutting out/whatever when warm.

I was poking around under the hood today and noticed a couple of unusual things:

There is a random connector that comes out of the wiring harness along with the wires that attach to the starter. It appears to disappear into the fuse box on the other end, but is not connected to anything else. Attempt at posting a link to an image is here:

http://picasaweb.google.com/lh/photo/pn ... directlink

Also, i wonder if my alternator ground is not stout enough - it looks to have been replaced. Another attempt at a link to that image is here:

http://picasaweb.google.com/lh/photo/mZ ... directlink

Any more insight is greatly appreciated. If I can't get this sorted out by looking at the wiring in the cluster, I'm throwing in the towel and taking it to an actual mechanic. Grrr!

Thanks all,
Brian

The alternator and engine ground straps are cheaply replaced for about $4 apiece with braided ones from your local parts house.

Don't know if that'll solve your problem, but it'll certainly beat the continuity provided by the homemade one in the picture.

grumpsjr wrote: If I can't get this sorted out by looking at the wiring in the cluster, I'm throwing in the towel and taking it to an actual mechanic. Grrr!

Thanks all,
Brian

Hello again everyone,

I took the car this week to Bruce Barthel at Barthel Motor Works on recommendation of John Savage and Warner Hall. He called me on Thursday and indicated the car was fixed. The distributor that Pierre and I had swapped in a while back was most likely damaged on installation (we had a little trouble getting it in place correctly - oops!) and the springs that control the advance/retard mechanism were not doing what they should, thus no spark at the proper time.

Fortunately, John had provided me with another used distributor that tested OK, so Bruce swapped that in. He indicated the car is running a bit lean across the board and could use a new AFM (which may have been the original problem after all) but that in solving the initial problem we most likely created the distributor problem. I put about 75 miles on the car last night from Bruce's shop in the San Fernando Valley to my work in Malibu, to Pierre's in Camarillo, back home to my place, and it ran fine. It is running a little warmer than I would like (always at half while moving, close to 5/8-3/4 idling) and Bruce indicated the radiator has a slight leak, so I figure it may be time to pull the radiator and re-core. But on the whole, I am super pleased!

Thanks everyone for your advice and help in troubleshooting and listening to we rant and whine about the car. I am, as always, most appreciative of this board and everyone on it.

On to the 5-speed swap now!
Brian

I think I read somewhere that running lean runs hotter.

Great news on the distributor.

So, at the suggestion of Bruce, I swapped AFMs to see if that helped the lean running condition, and dang it if the car didn't start misfiring again.

After I got through contemplating the easiest way to slit my wrists, whether or not I should just sell the car, and trying to decide if this was justification for going out and buying a new M3, I swapped the old AFM back on hoping against hope that it would miraculously solve the problem.

Nope.

Given that the ONLY thing I switched was the AFM, which means one plug and one intake bellows, I am re-reading Lenny's post about connectors, and wonder if there's something going on with the AFM electrical connector, or if, even though I have done this a million times, I am somehow miraculously not getting the plug well-seated on the AFM.

I will call Bruce in the morning and see what he thinks, and of course, keep you all posted.

Sherman, you are correct, a lean condition does tend to cause warmer running.

When it comes to my E12, razor blades are kept locked up in the medicine cabinet.

Was it a new AFM?
Did you go through the adjustment process?

Looking forward to a happy ending.

So Pierre came over today to do some parting out on his M3 parts car and we tinkered with the E12 a bit. I have spent some time over the last few days fiddling with the AFM plug to see if I could get it to work better, and had moderate success.

We checked everything again today and decided to go for a drive. I didn't even get the car out of the driveway (literally) when it started acting worse than it ever has - it would hardly idle, and sounded like it was running on two cylinders. Pierre jumped out and started fiddling with the AFM connector, again with moderate success.

Randomly, he placed his hand on the airbox while fiddling with the AFM and the car smoothed out immediately. Lifting his hand from the airbox caused the car to run poorly. John Savage, does this sound familiar???

I noticed that Pierre was leaning against the fender, so he tried the same thing without touching any part of the car - no improvement in the misfire, but when he touched the fender AND the AFM, car runs smooth.

So, we ran a ground wire from one of the airbox mounting bolts to the body. After 50 miles, no misfire, period.

Here's what I think happened: Shortly after I bought the car, I replaced the intake bellows between AFM and throttle body. When removing the airbox/AFM assembly, I forgot to unplug the AFM connector; I distinctly remember that it got a pretty good tug. Shortly after that I began to notice the misfire. I believe that I managed to short out or break the ground wire in the AFM plug/loom, and with heat, the short or break would get to the point where the AFM would have issues. Pierre and I, hopefully, have re-grounded the AFM with this new wire, and all will now be as it should be, knock on wood.

Will keep you all posted if this turns out to not be the case; and of course the board has my genuine thanks for your thoughts and advice, and just plain listening to me whine.

Pierre is my hero for putting his hand on the airbox.

Brian

grumpsjr wrote:
Here's what I think happened: Shortly after I bought the car, I replaced the intake bellows between AFM and throttle body. When removing the airbox/AFM assembly, I forgot to unplug the AFM connector; I distinctly remember that it got a pretty good tug. Shortly after that I began to notice the misfire.


Brian

Oh!!! ....and now the truth comes out....

So if you would have said that, oh way back when, like 2 pages ago, well maybe we could have pinpointed your problem a little sooner.

Connectors.....hmmm........well.......


So.... do this........carefully peel back the rubber grommet thingy on the AFM connector. You must 'peel' it back, don't try to pull it back onto the harness - and carefully look at each of the white wires that are inside the harness. See that a) they are attached to the connectors (they are just crimped - did you know these little female connectors are available from the dealer? And cost about oh, $.80?) and b), most importantly, they are not touching anything else particularly each other because of the tug and c) that they are secure inside the black plastic housing so that when you plug it onto the AFM the wires actually connect onto the male counterpart in the AFM housing. That was my problem, two wires (the connector) would slide back out when trying to plug in the AFM. They are very small and very close together, take plenty of time to ensure it is absolutely correct. As the book says, installation is the reverse of disassembly.
So while you are there fiddling around with the AFM, open it up. I would make absolutely sure the wiper track is not worn (well it is, after all these years, but you have to make a new track that it wipes) as the 'idle' section (where it wears most and first) has a good contact. A later misfire was indeed just that, and Mike's suggestion regarding moving the whole board solved that problem.
Keep us posted...

Lenny D. wrote: Oh!!! ....and now the truth comes out....

So if you would have said that, oh way back when, like 2 pages ago, well maybe we could have pinpointed your problem a little sooner.

Connectors.....hmmm........well.......

C'mon Lenny... Hindsight is alwys 20/20.

The realization that the tug may have caused the problem came out after we figured it was a bad ground and the connector was probably the culprit. That is when Brian had an "aha' moment and remembered the tug over a year ago. We must have done 600 different little things, each of which would have been the reason, from adjusting the valves, to replacing a distributor, to replacing the module, and the ECU. Each event may have inadvertently caused a problem.
Keep in mind that the car did not start misbehaving right away after the tug. It crept up slowly some time later. The correlation between the connector and the misfire was not obvious. And the fact that is was starting to act after it had warmed up was even more of a distraction. To complicate things even more, the miss was always accompanied by a drop in the tach which seem to indicate an ignition problem. We stumbled upon the source of the problem by pure coincidence. And we lucked out that I acted as a ground for the AFM to actually work. And against a painted surface through my clothes nonetheless. Who could have thunk?

You input regarding a fix for the connector is appreciated.

Greater news on the "ground" discovery, through the clothes and paint at that...

Lenny,

Thanks for the input on the connector - I had previously peeled back the rubber boot to look at the wiring - but didn't know you could check to make sure the female connectors were secure in the hard plastic portion of the connector.

I seem to recall that you may have mentioned this in another post (or earlier in this thread - I'll go back and look) but I'm unclear on how to get the individual female prongs out of the hard plastic portion of the connector.

Thanks again for the tip.
Brian