86 eta weird start/idling issues MIND BOGGLER

[scabzzzz]

All right well it looks like from what you're saying, the only thing left i have not replaced is the reference sensor. ive had a few afm's in and 2 different dme's with and without a MarkD chip. The idle adjustment screw on the throttle body has never been touched. Still has cap on it and paint mark. Adjusting idle again is not a problem. I'll try that tonight.

Would o2 reading play into the situation at all? Seems like it would do the opposite if it did. I believe the one on my car to be the OEM issue with 220k+ miles on it.

thanks again Mr. Levie for chiming in.. Every forum I go on you help me out, with all my cars. :)

[scabzzzz]

After researching limp home mode for a bit on google, it does seem like when i start it up sometimes it goes into it. The exhaust note changes and sounds like its farting and realllly slow to rev. Cycling the ignition eventually brings it back to life. But if i'm experiencing issues with a timing reference sensor, why would it adjust throttle measurements and idle high? What would it be trying to compensate for? Yesterday a couple of times it surged like I said earlier, but it didnt seem vacuum related. It did in fact seem controlled, by the DME. Since doing the coolant temp switch, it has not started up in "limp home mode (or so im thinking)", but in the morning it is taking longer to start. Having to stay on the starter for 4-5 seconds or so and it sputters up to a 1700 RPM rev and slowly comes down.. Blah anyways, just some more thoughts. I hope this thread helps other eta owners. Since creating this thread I've had several others (locals included) say they have the same problem in some form or fashion.

Back to the Bentley....

[scabzzzz]

O2 sensor in the Bentley does mention irregular idle issues and starting issues. Also mentions O2 is not an issue when the engine is cold, only when its warmed up to normal operating temperatures or close to it. My problems are in fact warm related...

[jlevie]

Correct. data from the O2 sensor is not used on a cold engine. The DME only uses O2 sensor data when the engine is at normal temperature.

Given what replacements you've tired, I'd go for the timing reference sensors.

[scabzzzz]

All right Mr. Levie, ordering this piece as we speak.

If this fixes it, I'm driving to your garage and buying you a steak.

[scabzzzz]

Come to think of it as I'm ordering the sensors (2, 1 reference and 1 for speed sensor) I can recall several times the last few days where my speedometer would drop to 0 mph while im traveling down the highway and then come back to life. I thought it was my cluster itself considering the mileage stopped counting about a month ago. Hmmmmmm.....

[scabzzzz]

Reset battery last night for an hour. Car is running better, a lot smoother. Still has the intermittent startup problems and idles a little higher than I like but lower than before. 2 reference sensors came in today. Installing tonight....

[scabzzzz]

all right people.. finally. looks like j levie saves the day again. thank you jim. replaced the camshaft position sensor on the trans and the other reference sensor (speed) while i was down there. the old sensors magnets wouldnt even stick to this metal beam i was working next to while the new ones definetely would. replaced them, initially had them backwards thanks to the bentley messing me up. got that sorted, car fired right up. cycled ignition at least 10-15 times. started up everytime. im gonna go drive it here in a bit see what happens. but i think i can chalk this one up and move on to other things.

PM'd the people with what fixed the car that said their cars do the same thing.
Thanks again Jim.
I may be down your way soon.. Lunch on me? :)

[alpineE30]

I would post a new thread but I want to keep general info in the right sections. Now the reference/speed sensors I was wondering if the haynes is correct on this. I probe 1 and 2 pins on both sensors and it came out to be 900 or so. Now it says to probe 3 and 1, 3 and 2, it says its supposed to be 100,000 ohms I got nothing. I made a nifty connector I used old multi-meter wires with negative speaker female connectors and soldered them up and shrink tubing. You can use it on the majority of the sensors it works perfect. Anyways is the haynes correct on the ohms on the 3 and 1, 3 and 2? Thanks

[Mr.sexymorningvoice]

so to bring this thread back to life...86 ETA here

ever figure out the cause of the wierd problems?

because i have a wierd one now of my own, i can hear my fuel pump run...and i know im getting fuel. The car ran when i parked it 2 nights ago, but had a slight occasional miss to it. Now i try to start it and it runs for a few seconds and misses and dies no matter how much you try to keep it running.

any ideas?

tomorrow im gonna try pulling the cap, and checking it and the rotor, because it started this after this little bit of rain...and maybe it just has moisture in it.

any ideas are welcome...unfortunatly i am stuck at my buddies frat house with my tools from school

[Sean T Sat]

yea prob seems to be common cause i got it to on my 325 eta 87

[Mr.sexymorningvoice]

after doin what i can in a parking lot with no shops having parts for a 22y/o bmw, i am pretty sure my problem is either the coil, or an ignition module somewhere

is our ignition module right on the end of the cam with the rotor?

[scabzzzz]

Didnt even know people were bumping this.

For the record, I'm not sure what fixed it but I believe ultimately what killed the issue was replacing the reference/speed sensors on the bellhousing. "I" cars dont have those I dont believe, only specific to ETA's. I cars use a pulse sensor and its located on the front of the engine and counts teeth on the crankshaft piece. I will have to say though, coolant temp sensor did smooth things out .

[SamE30e]

I have the same issue, my car has a brand new Timing reference sensor in it, but not the Engine speed sensor. Doesn't bother me too much, all I do is turn the car off then start it up and it works fine.

[scabzzzz]

Yeah thats what I did too. Its really annoying though. In fact, its done it to me maybe twice in the past several months. I'll eventually run out of shit to replace lol

So far i've done all new ignition pieces, almost all of the sensors on the thermostat housing and front of the head, all new cooling etc.. Only thing left to replace is the engine speed sensor and fuel pumps.