I would check the coolant temp sensor itself and the wiring harness for it. One way of doing that would be to swap your old one back in or if you know what the new one should ohm out to,
And then check for power/ground at the plug. I see that you are in the northeast so I would be looking for corrosion any/everywhere, especially in any of the wiring that you may have handled when you did the intake gaskets, which, (as I was looking at today on my spare motor) could be several.
You could try testing continuity on the harness between the sensor plugs and the DME plug
I agree with doing some continuity tests but if you did not disconnect the plug from the DME during the last round of repairs I would not do that until I first checked the specific harness connections that you did disconnect to do the last round of work. In the process of checking plugs I was going to suggest connecting your old injectors to the harness and see if you can verify that they are all (or any of them) clicking while someone else cranks the engine. At that point I would also ohm out the injectors that are in the engine just to make sure that you don’t have one shorting out because in some cars/injection systems, that will cause all of them to quit working
Last edited by msservices; 12-06-2018 at 03:04 PM.
E30zone wiki ecu pinout
Did you do a comp test yet?
I sent you a pm about wiring diagrams
Most auto parts stores will loan those out for free.
No. Cylinders, rings, head gasket, head cracks, valves, valve seats, or some mechanical failure are generally what cause comp issues. A bad exhaust gasket wouldn't cause a no start either.
Also, a motor with slightly low compression would still start and run, if it’s way low on compression, it will tend to crank way easier, and faster, as if there is little load on the starter. It’s not as accurate as a test but it helps with the gut feeling aspect of it
I had a '91 iX that had a similar issue (start then die). Issue seemed to be related to the AFM connector. Cleaning the connector with electronics de-oxidizer cleared up the start/die issue for me. Perhaps removing/reattaching the connector solved the issue by completing a dodgy circuit in the harness? I dunno. Car was fine after that and was sold several years later.
Joe M in WV
Just throwing this out there- Have you swapped out the Main relay with a good one?
Also - did you swap out the dme with another to check?
So basically everything in the motronic system has been checked (and is within spec) or replaced?
Fuel (injectors, regulator, pump, O2, Temp sensor) and Spark (coil, plugs, wires, cap, rotor, CPS) and Air (Vacuum leaks, ICV, TPS, AFM) as well as electrical function (DME main relay, FP relay and DME itself).
So maybe bad fuel - bad compression? I guess for me - Compression check would be next.
If that turns out to be perfect - Sell it for parts - because it is possessed.
Last edited by 95BMWIC; 03-14-2019 at 04:38 PM. Reason: spelling
you know what just hit me? a buddy had a no start issue on his 528e. we looked and looked and it ended up being corrosion on the underside of the fuse box. a shop found it for us
No e30s again.
So apparently you can put the harmonic balancer on wrong. It is keyed but you can still line up the 6 holes and thread the bolts in. When I did that it pushed the indexing pins in so the harmonic balancer was just spinning and the infinite was sending to the DME and not in time even though the motor was actually in time. Working on the car from the top I couldn't see it when I was installing it so I went by feel....think it was keyed and would only go one way but you can actually fuck this up....ask me how I know haha
Dude, that sucks but at least you found it
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