SOLVED 944S Start up trouble after rebuild
 

I have an 87 944S that I just rebuilt the head on and after a year of rebuild and fixing I finally started the car this saturday.
It ran great, with a little lifter noise (all brand new VW 16V lifters).

I took the car for a drive and it ran smooth.

I took the car for a wash, in a machine because i just wanted it clean it off before i did a hand wash and wax the next day. But it was after this that the trouble started.

When i parked the car in my garage right after, and turn off the ignition, the engine stopped, but the starter kept turning and turning. And a turning the key all the way to the right resulted in the car roaring back to life. I could not manage to turn it off! I popped the hood and found there to be a lof of soap foam around the battery and the fuse box, which I cleand up. The car still didnt want to turn off. So i decided to try and disconnect the battery, but I didn't have a wrench that fit so it proved difficult.
Then, suddenly I heard what sounded like someone dropping or hitting metal, and the engine sound changed slightly. So I tired to turn it off, and it did.

I decided to leave the car off and deal with it the following day, which I didn't. I returned on Monday to look at it, changed the starter with another one that was working, tried to start the car but nonthing. Turned out the battery was almost completely drained, then it died (this was a brand new battery, only 2-3 days old).
I took the battery from my other NA 944 and installed it.
Now the car has power and the starter works, it cranks and cranks but there is no igintion. Nothing happens.

Anyone had any similar issues? Or any idea of what it could be or what to look for? Would really appreciate this. Have been looking forward to driving this car for the past year.

Thanks!

marius

Starter sat for too long, then also got wet. Obviously an electrical short telling the starter to spin and or extend the Starter gear into the starter ring on the pressure plate. Starters don't like to turn for a long time. If your starter was still extended and spinning and then you turned the engine off you might have broken teeth. Your starter might have seized finally and then possibly could have broken teeth off the starter ring?
When you say it cranks and cranks, is the engine turning or just the starter?

Sounds like the eningne turns but it doesnt fire up. I turned the engine by hand and didnt see any broken or missing teeth on the starter ring.

Holy ****! Man what a story! I think that the starter motor was stuck in an engaged state. The metal sound might have been the starter motor finnally disengaging.

So now you got her cranking again...fuel, spark, compression...?

Rick

yeah, it was quite the day and the day after hehe. There appears to be no spark, but I have yet to check that, i am also checking to see if i can hear the fuel pump start up.

I belive the metal sound was the starter disengaging too.

starter solinoid might be toast from being engauged that long.

yeah the starter that was in the car at the time is completely dead. I put in a new starter and it cranks the engine but doesnt fire up.

If the starter damaged any teeth on the ring gear or the starter itself, the metal particles may be sticking to the crank sensor and causing not to "see" the rotation of the flywheel. If it doesn't sense rotation, you won't get spark....

Thanks Rod, I'll look into that. No teeth on the flyweel appeared to have been damaged. I assume I can just pull the two crank sensors to check for metal particles?

Yes, they *should* pull out of the bracket. Be careful not to loosen the bracket or you'll have to reset the clearance between the sensors and the flywheel. See Clark's garage for more info if needed.

Wait! Does the tachometer bounce?

Thanks, will pull them up, and not move the bracket.
Rick, I'll check that later today but if I recall correctly the gauges seemed to function correctly.

I'd leave the One Crank sensor you have and see if the solinoid blew your DME relay. Remove the relays cover and with someone turning the car over, manually make the 2 contacts touch.

The DME relay is good, I swapped it with the relay from my other running 944.

I did some more testing today, tested the coil, it gives the same readings as the running car, but there is no spark.

I can also not hear the fuel pump running, and disconnected the fuel line into the rail and it was not pumping gas when the ignition is turned.



*By the way, this car has the alarm system but i dont have the key

If you open the DME relay, the top contact touching with the key in the 2nd ignition position, you should hear your fuel pump running. If you just touch the lower contact it sends the signal to the ignition.
Power starts at the battery,
then goes to the ignition switch,
then to the Alarm system,
next to the relay,
DME, (sends signal for spark)
then back to the relay to run the pump.
If you have power to the coil, then maybe the coil bad? Checked all your fuses? Blown ignition module?

but would a bad coil stop the fuel pump from engaging?
The DME relays is good, no problems with it because I took it off my running 944 and im using the one from the stalled car in the running car now.
I'm measuring the voltage on te coil today again to make sure it gets the power it needs.
If the alarm system was failing, would the car crank? Would it crank but not send signal to fuel pump and spark?
How can i check the ignition module? This is the one that's in the driver side by the fender? Or by the headlight? I've read both.

Thanks

There's 12v on the coil measurring the + side of the coil to the engine or the - on the battery.
Checked the inition module in the headlight bay. There's 12v coming across on the plut going into it. How do I check to see if the module is blown?
All the fuses are good.

I sometimes use the DME relay to direct me to general area of trouble. You manually make the contacts touch. See other response. I had a "professional" Porsche mechanic change 8 years ago, relay and modules with "Known" to work parts, charged me $700, without fixing the car. It was the ignition module the whole time. I'm not sure how to check it, but I would imagine if you have volts to the coil its working. Maybe no fuel.

Dan, I'll try connecting the DME with the top contact only, to start the pump. The coil has power and there's power in the plug that goes to the ignition control unit (module). But guess there's no way of testing that? If the ICU is gone, would that make the pump not start up?
I filled it up with fuel the day before.

Update.

I tested the fuel pump/dme relay as per the manual by connecting a test lead between two pins on the DME plug, and the fuel pump didn't engange with the ignition on.

I also tried to jump the dme relay with a 3-way wire on 87, 87b and 30 and this did not engange the fuel pump either with the ignition on, and when I tired to start it, it just kept cranking as usual.

What to look for after this? Any ideas anyone?

Thanks!