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1990 740 Turbo m46 No Crank

Airik

New member
Joined
Sep 27, 2014
Location
Illinois
As said in title i have a 1990 740 turbo m46 all factory, been running perfectly, up untill this morning

Car started up perfectly fine, and then about 5 blocks from my house stalled at a stop sign. when i went to restart the car it wouldnt even turn over! Altho i still had full power to accesories and lights!
I Hear Fuel pump kick on and relays/fuses all seem fine (tho im not on expert)

after pushing my car home (by myself i might add lol) i started checking out the usual, starter/battery/altenator combo. As far as i can tell the all the wires, grounds and connects between all 3 seem solid. Battery was charged, and i even tryed a known good battery just incase from my buddies car!

ive done some research trrying to figure out other possible culprits, but cant really find anything exaclty like this situation. Read soemthing about ignition switch possibly but besides that and just weird 30 year old wiring somehwhere i cant really figure it out!

if anyone has any suggestions or ideas it would be greatly appreciated!
 
Check your ground cables from the engine which connect back to the frame & thence to the battery.

Put your voltmeter on OHMS, touch the aluminum head, and the negative battery post. The engine will not CRANK without a path for those little electrons!
 
when i went to restart the car it wouldnt even turn over! Altho i still had full power to accesories and lights!

i started checking out the usual, starter/battery/altenator combo.

Did you try (carefully) shorting the 2 big terminals together on the starter solenoid with a screwdriver or similar? This bypasses the solenoid. If the starter spins, it's okay internally.

Next up is shorting the small blue/green wire's terminal to the big red incoming battery wire's terminal. If the starter cranks, it and the solenoid are okay.

Next is checking that blue-green wire's end connector. Mine kept coming loose, and the starter occasionally refused to spin, particularly after a nice drive when everything was hot. Squeezed it for a tighter fit, and no problems since.

Next up the line is the clutch interlock switch, then the ignition switch.

Voltmeter and another body is helpful for tracing where the power does or doesn't stop.

PS: Next time, make sure you stall on a hill, so you can roll down and pop the clutch to get it running again.
 
thank you MasterBlaster, that is exactly the thing i was looking for, figured id have to go in and do some wire chasing, but wasnt sure which ones and where, will probally tackle this tomorrow and will update with results
 
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