84 325e intermittent miss once warmed up

[Buckeye325is]

e30 electronic troubleshooting manual.
I ain't so literate when it comes to these complex schematics, but here it is.
Any interpretive help, in relation to my malicious misfire, would be appreciated or an interpretive dance, equally appreciated.

http://wedophones.com/Manuals/BMW/1984%20BMW%20318i%20-%20325e%20%20Electrical%20Troubleshooting%20Manual .pdf

I have disconnected the O2 but not for any prolonged period, usually <1min.
I'll try that.

Thanks,

[Buckeye325is]

Ok, now out to work, couldn't tear myself away from this. Definitely one of the best reads in years. I would've paid to crew on this adventure.
How A $500 Craigslist Car Beat $400K Rally Racers - Rallying - Jalopnik

[Buckeye325is]

I was able to wire up an splice to test the O2 sensor. Numbers bouncing from 0.28 to 0.73, I believe this is what is to be expected. It's a 3-wire lead the other wire didn't show any voltage. When the car started missing after a few minutes and was revved to approx. 2000rpm the O2 voltage went and stayed really high, in the 0.82 to 0.88 range. I believe this indicates that she is running really rich.
This pic is while she's still cold and not missing. 0.32 was just the random voltage the pic caught while the numbers were jumping around.

This one is at 2000rpm, warm and missing, voltage stayed in the 0.8 range.

Handywork of malicious mouse

Distributor, looks practically new, no carbon tracks...

FPR and replacement, O-rings look fine...

Testing the new injectors(on the trunk of my 87 325is), ghetto setup but it worked, installed them about 2 weeks ago, just late on uploading the pics.

[stephers]

I just thought of something, these engines are completly sealed, I mean that they cannot have any air leaks. I had one once that had a small air leak at the valve cover gasket and rubber end plugs. It may be way off base but worth a quick look. Try pulling out the dipstick just a bit while the car is idling and warm and see how it runs, if the miss gets worse. This will not give you a problem with starting but can cause the engine to run rough. Easy check

[Wapiennik]

Could you all teach me something new and explain to me what he's doing with the fuel injectors? That looks interesting.

[Buckeye325is]

Stephers,

Yup, checked the engine for any air leaks, literally hosed it down with starting fluid at all locations that there might be/could be an air leak. Did the old "Think with your dipstick Jimmy" pull trick and she really started running erratic, took of the oil filler cap on the valve cover and she almost died. I believe a vacuum leak would result in a overly lean running condition, O2 sensor is showing her to be rich.
I appreciate the input though, I'm willing to try just about anything at this point, I've even retested a number of possibles multiple times, second guessing myself, ect...

Wapiennik,

Can't claim this as my original idea, I saw it on another site, where the guy had a very elaborate setup with six 2-liter bottles and was able to run a semi-precise flow test.
My setup is just for functionality, and spray pattern. Air pressure reg. low on compressor outlet, gas in the tubing, wires hooked to battery with in-line bump switch (simulates short electrical pulse to injector). Bottle catches fuel and allows to observe spray pattern. Very simplistic setup, functioned surprisingly well and easy to operate. Tested 12 injectors in about 15min. Wasn't really going for time.

This evening, I'm going to test the cold start valve, and try to test the thermo timer. Those things cost over $100, crikey
I'm going to try to rule it out or something before spending that kind of money.
I have a

[Buckeye325is]

Making some progress I think.
Tested the cold start valve and thermo timer switch today effectively ruling them out.
Finally in an act of pure frustration I began moving the main wiring harness up and down, to put in nicely.
I noticed when it was pushed down the miss became significantly worse, to the point the car would almost die. When pulled up, the miss would almost disappear???
I took a zip tie, pulled the harness up and went out for a drive. Much improved, still misses over 3500rpm. But I think the bimmer gods finally threw me a bone.
Tomorrow is Sat. and I got all day to dissect, separate and find the wire or connection that has been causing me so much grief. Hopefully this is it and not some other problem I induced by trying to strangle her by the wiring harness.
Any thoughts on what wires running through it would or could cause these symptoms?

[Buckeye325is]

Issue resolved. Long story short I isolated it down to a black wire running to the front of the started. Connection was corroded and barely making contact. Cleaned terminal and plug really well, smeared it with dielectric grease and now no more miss.

What in the world does a wire on the starter have to do with causing a miss when the engine is running.
Anyway, took her out and "WOW" what a difference, I had forgotten how this little "eta" will run, --like a scalded dog-- maybe it's the 19lb Mustang GT injectors or the tuning up of everything else. Whatever it is she really scoots now. So much so that I blew the brake line (under the drivers side going to the rear) trying to slow her down tonight.
No worries, hand brake and gearing down got me the rest of the way home. Glad it gave out on me rather than my daughter, need to teach her how to stop when there are no brakes in case it ever happens to her.

So now just to replace that l-o-n-g brake line tomorrow.

Thanks for all the help and support.

[stephers]

Great news. Glad to see that the car is fixed. By the way, I have some miontenance items and other stuff left over from a long time ago. It is all new parts. PM if there is anything that you are looking for

Thanks, Rick

[JhwShark]

Great news!

A connection issue causing an Open circuit.

fyi...From the schematic (Start section): the wires on the starter go to two terminals.
1st is the big one that has a big red wire from the charging system, an almost as big black wire to the battery circuit, and a small red wire to the diagnostic connector.
2nd is a single wire that should be thin black with a yellow stripe that goes to a connection for: fuel injection/Motronic, cold start valve, thermo switch, and power distribution relays.
The terminal you cleaned up must have been the 2nd; if this would open intermittently the engine would definitely miss and have poor A/F mixture.

Man...in doing an electrical diag. using the manual this one would be at the later areas of an evaluation.
Jon