Quote:
Originally Posted by KTL
We had a no-start issue with an '86 BMW 325e that uses a similar Motronic engine management system. The set screw in the flywheel was installed loosely and the gap was not proper. Thus the sensor couldn't detect the screw and it wouldn't start. Ironically the guy we bought it from traced the same no start problem when he bought it to a missing set screw. He "fixed" the issue with a new screw that eventually came loose again!!!  |
Jae Lee built a 3.4 for my 1987 nine months ago and ever since the rebuild, I've been having a hot start issue. For around ten minutes post a full operating temp shutdown, the engine will crank, but will not fire. If I try to start the car immediately after shutdown, it just cranks. One minute later, it just cranks. Five minutes later, it just cranks. Ten minutes later... It starts.
Car runs GREAT otherwise.
We tried a new two wire CHT sensor, but that didn't solve the problem (switched back to the previous two wire CHT) and I've been casually troubleshooting the issue, including unplugging the CHT sensor and jumping the CHT sensor (no change in either case).
The motor has an @salcarceller MAF / injector / ECU setup, but that was on pre-rebuild and the hot start problem started with the rebuild.
@KTL your BMW flywheel set screw issue is interesting. We did replace both flywheel sensors, but we also installed an Aase lightweight flywheel as part of the build.
I wonder if my issue is heat related with the set screw or set screw sensor. Could the gap grow enough at full operating temp to cause the no-start, but 10 minutes later shrink enough to allow starts?
I believe I need an oscilloscope to test the flywheel sensor outputs? Alas, I don't have one and I wouldn't know how to use it if I did.
Apologies for the tangent here.