My '87 325is had a hard time starting on Tuesday. After starting I drove it 10 miles to work and it was its usual free spirited self. After work it was again hard to start but ran great on the way home except for a slight hiccup while sitting at a light. Now it won't start at all - no spark. I 've traced it back to the coil but no spark there. Coil resistances seem ok and I have coil voltage with the ignition on. Is there anything else it could be beside the DME? By the way, I never got a check engine light.
I don't think that particular car has a CEL. Do you have a service manual? Can you track down a spare known good DME to swap in? A spare coil?
Cel? Thanks for your reply. Not sure what a CEL is. Car is Motronic. Negatory on the coil and DME. Seems like EBay is now on my list. Yes, I have a Bently manual and have been able to resolve all my past problems and get car in good shape until now.
Yeah, be sure to check the crank position sensor. It's located on the front of the motor and reads off of a gear behind the harmonic balancer. It's common for their wiring to short against the balancer, especially if someone's been in there recently. Of course, sometimes they just go bad.
Yes, it does have a CEL and you can read fault codes with it if you have the list. It has been very helpful and did point me to the crankshaft position sensor a couple of years ago. When I originally replaced it I routed the wires incorrectly and...... obviously you know the rest of that story! I did pull the main relay and it looks as if it overheated at some point. I will try to pick one up at the dealer in the morning.
CR, this is Motronic 1.3, no bell housing sensors. Does it have injection pulse? If it has injection pulse but no ignition pulse (you can use a test light on the coil + and - terminals) then I suggest looking for another DME. If it has no injection or ignition pulse, I would suggest a relay issue or an on board computer problem. You can jump out the main relay with a couple of pieces of wire. You need to jump terminal 30 to both 87 terminals. If it fires up, replace the relay. If that doesn't help, it is likely the on board computer relay module or possibly the ignition switch.
Well, it wasn't the main relay. The crankshaft position sensor is way out of spec according to my ohm meter (digital). I' m pulling it this weekend for a closer look.
Finally got back to it. Yes, it was the position sensor. Apparently when the engine was running the crank wheel was spinning fast enough to produce enough signal to fire the DME and keep things purring happily along. When starting, the slow crank speed couldn't generate enough of a signal to fire. This one apparently had a really short life span as I replaced it less than 2 years ago. Thanks for the help.
