Can’t get my E30 M3 started at all

Posted this already on S14.net but wondered if anyone here could help?

Car was running fine, but fuel was in the red, no warning light though. I pulled out of a junction and it stalled, then it wouldn’t restart. I went and stuck 5l of fuel in still wouldn’t start. I pushed it the 1/2 mile home and got it towed up my road, put the battery on charge overnight. I reconnected the battery and tried to start it while spraying an ether based starter spray into the plenum, still nothing at all. Car cranks over but does not fire. Since the car should at least try and fire on the ether even if it's getting no fuel I figured it's ignition related. Checked for a spark on the plugs, nothing (They were really sooty too) Checked for 12V at the coil, that's there. Then shorted the coil LT side to get it to fire independent of the ignition, using the coil lead to ground you get a very weak spark.

I proved the coil was okay in the end by using a switch to get it to fire on the bench. The resistance on the secondary coil was actually 5.7k the autorange had me fooled for a bit!

Following the troubleshooting guide I found on S14.net I've found that there is no ground signal from the ECU the resistance measured between ground and pin #1 is about 42 Meg ohms and stays the same as you try and crank the car over.

I also put a timing light on the coil to see if the EMF in the coil was being generated. It worked fine on the bench but not on the car.

Now I have the ECU apart it looks visually okay no burnt transistors or anything.

I could really do with a known to be working ECU just to prove that is the problem. If any UK guys have a spare on I could borrow to try I would be very grateful.

Many Thanks
Andy

Dunno if this could be helpful but I was having some intermittant problems a while ago, the car would just cut out and sometimes fail to re-start. Seems E30's have two relays behind the cover at the bottom of the windscreen, Fuel pump and DME, they can easily fail with age, they don't cost much to replace. I don't know what the affect of the DME relay would be if it failed though? 
I swapped both of mine and its been perfect since.

Mags

No.. that's the fuse box.. we are talking behind the long plastic cover below the windscreen. Perhaps, if like me you were unaware that it ever came off.. I thought it was the wiring loom in there. Anyway, open the bonnet and look at the plastic shroud just below where the vin number is etched onto the scuttle.
.. trouble is, I still don't know what the gizmo's do.. I do know however that sometimes you can get a dead car to start just by wiggling them!

Kev, you are indeed becoming the font of all E30 M3 knowledge.

yes, but not all of them are always on-line. 2.5k posts in two years is no mean feat.

didn't bother reading the replies, but is your fuel pump priming(/buzzing)? As this is sure sign of no firing.

 

Rags

Finally got it running again, learnt lots into the bargain too!

Turned out to be one of the main 12V supply cables (the smaller of the two) from the battery to the engine bay had broken somewhere internally.

This meant that although my main relay was clicking on and off there was no supply for it to switch, I've not pulled the old cable out to find where it broke but have run a temporary replacement in (with inline fuse!!) which started the car fine first time.

This was after I thought I had a bad coil / ECU so I'm pretty happy that it's a cheap fix !

Thanks for you 're help guys
Andy

Moral of the story, if you can't start you're car because you have no spark check the battery connector block both sides for 12V!!!!

Dave Thanks so much for the loan I'll get it back to you ASAP

Edited by andyb

BINGO!
this time it's me with the non starting car!
No spark like Andy's.
Dave have you actually tried the ECU you gave to Andy? Just to be sure not to shoot into the dark before I pull everything to pieces. I will start with the 12V supply Andy described. Hopefully I will be as lucky as he was.

Edited by UweM3

Dave,
I have tried ECU but still no spark. I will have a more in depth search tonight.
Have fun tomorrow.
Uwe

Thanks but sensors are both new (June 04) and I have a working spare ECU from DawieM3 to make sure it will start if the rest is ok.