Starting problems

[Tux]

Car gets used daily. Never had a problem until today. Went to work and back, stopped at the post office, and when I got back in the car, the starter motor didn't work (it may have clicked —a not sure). Switched off, tried again, and it started. Went home.

An hour later I went back out again. Drove the car for 30 mins, and stopped the car for 15 minutes, returned, and the car wouldn't start. All the lights on the dashboard were on. Radio on. No dimming when the key was turned. Nothing from the starter motor.

Had to get a bump start from two passers by.

Went to Tescos (leaving the car parked on a hill!), started fine.

Any ideas?

[Brianmoooore]

Either ignition switch or starter motor.
Take the cover off the diagnostic socket and identify pins 11 and 14. Mark them with something so that you know where they are.
The next time it happens, open the bonnet, remove the cover and short together these two pins with a short piece of wire. This should engage the starter motor, regardless of whether the ignition is on, so make sure the car is not in gear.

[Tux]

Excellent, thanks. The car has a Cobra alarm (fitted by the previous owner). Not sure if it's got an immobiliser on it, but I was thinking maybe there is a problem there. I will have to see if I can find any non-standard connections to the starter.

Are E30 starter motors normally reliable?

[wildeian]

Check the earth on the starter motor (solenoid). Sometimes the terminal snaps inside the casing and it works intermitantly.

[Brianmoooore]

Are E30 starter motors normally reliable?

E30 starter motors are extremely reliable, but do have a finite life.
Linking across the diagnostic socket would normally bypass any immobiliser.

[Brianmoooore]

Check the earth on the starter motor (solenoid). Sometimes the terminal snaps inside the casing and it works intermitantly.

???? There is no earth strap on an E30 starter motor.
All the E30 starters I've seen earth to the engine block by their bolts.
There's an earth strap between the engine and the chassis rails, but if this connection was intermittant I would expect it to be accompanied by much sparking and burning.

[FlappySocks]

Great thanks, that gives me much more confidence. I will get some tipex or something to mark out the pins I need to short.

[wildeian]

I'm talking about the small black cable that goes to the solenoid (might be a pos, in fact I think it is now!!)

Anyway, my terminal (solenoid pos) broke inside the casing and gave the same problems.