Engine Randomly doesnt start.

[Alluvium]

Hey Guys here is my issue\s

I got a '89 e30 coupe, and some times the engine does not start, heres how it goes.

The engine does not start on seemingly random times, the car is great 95% of the time. and starts fine, although sometimes when i turn off the motor and come back to start it up it wont start.

the two ways i know (and use) to get it started are... a push, or jumper leads.

BEFORE you say .."battery dumbass" i had it checked out, battery is good to go.

and when i say push i mean if i roll it 5 meters and get enough momentum going (with the clutch in) i pop the clutch out and the car jerks, and when it jerks i switch on and it sputters to life...

WHEN i jump it, all thats needed is to hook the cables up and i turn the car on.

when the car if 'dead' the wipers, elec windows, lights and sound system work great


IS the battery really fine ?

COyuld it be the starter motor?

I have a sound system of reasonable power, could that cause a battery drain, and thus not get the high current to start the car?

IN jerking it is it forcing the starter motor to turn?

Does the starter motor get bybassed when you jump your car?




-i am a bit of a car newb sorry :(



Annnyway any advice would be great.

[EWAustin]

OK, my immediate thought is that your battery CABLES are corroded or not making good contact. Take them off and clean them using a mixture of baking soda and water, and an old toothbrush. Also be sure to inspect the other end of the cables to make sure it's getting good contact there aswell.

The starter motor is another possibility, but it's not as likely.

When you pop-start your car (with the clutch), you're using the back tires and the transmission to get the engine started turning instead of the starter motor. So in effect, you are bypassing the starter.

When you jumpstart your car, the start is NOT bypassed, just getting more power from the other car. Which also leads me to believe that the problem is that the battery terminals are corroded.

Good luck,
-Eric

[Alluvium]

But would corroded battery terminals be faulty like once a week or once a month, and some times in patches?

[EWAustin]

Yep

[Alluvium]

Right polished them solidly, sanded them on the inside of the contact rings, polished the terminals with a bit, they were grubby, but i wouldnt think they were that grubby.

If it happens again,(wont start) first thing ill do is check the connections, with a meter

in the mean time (beacuse this freaking problem is intermitant) if this is not the answer any other ideas ?

[netcsk]

I would have to agree that this is/was likely the problem.

[DoriftuEvo]

Second guess is starter. I had the same symptoms and although my starter checked out good, a new starter got rid of the problem forever.

[lordofthewaters]

I'm going to say a dying starter/starter solenoid. Although I suppose it could be an issue with the starter ground as well, making and breaking contact.

[Axxe]

If it still does it, check all the connections on the starter.