Please Help: No spark after clutch job
09-09-2003, 02:31 PM
#1
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Please Help: No spark after clutch job
I've done some searching and all signs point to the reference sensors but I'd like someone to validate my diagnosis. I'm 1000 miles from the car and trying to help my mechanic solve this.
Clutch was just done on the car and it's all bolted back together.
There's no spark from the coil while the car is being cranked but once you release the ignition key, you'll see one or two sparks jump.
It did catch once and start but only ran on three cylinders.
Are those indicative of the reference sensors? In my searches I've seen plenty of reference to no spark after the sensors had been nudged or re-installed but I didn't see any detail as to whether people saw my exact symptoms.
Any help would be greatly appreciated.
Clutch was just done on the car and it's all bolted back together.
There's no spark from the coil while the car is being cranked but once you release the ignition key, you'll see one or two sparks jump.
It did catch once and start but only ran on three cylinders.
Are those indicative of the reference sensors? In my searches I've seen plenty of reference to no spark after the sensors had been nudged or re-installed but I didn't see any detail as to whether people saw my exact symptoms.
Any help would be greatly appreciated.
Last edited by ninefiveone; 09-09-2003 at 02:57 PM.
09-09-2003, 02:46 PM
#2
Burning Brakes
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Did the mechanic reconnect the main engine ground? It goes under one of the bellhousing bolts, all of which had to be removed to do the clutch. It's a big fat wire with a black shroud, goes straight to the negative battery terminal (on my '88 944).
Bryan
Bryan
09-09-2003, 02:54 PM
#3
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most likely that the sensors were installed in the wrong holes, also possible that the small ground wire was not hooked up, if the fat one was left off the car would not crank.
09-09-2003, 03:33 PM
#4
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Thanks for the replies. Both grounds are connected.
Any other thoughts? Both the mechanic and I are pretty convinced it's the ref sensors but the only thing that puzzles me is the spark we get when we stop cranking the motor over. It would think we'd get no spark at all if it was just the ref sensors.
Any other thoughts? Both the mechanic and I are pretty convinced it's the ref sensors but the only thing that puzzles me is the spark we get when we stop cranking the motor over. It would think we'd get no spark at all if it was just the ref sensors.
09-09-2003, 03:49 PM
#5
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Did he just remove the sensor or did he remove the mounting bracket as well.
If he removed the whole bracket he will need to set the correct gap for the sensor in the rear.
Clarks garage has a good write up on this.
If he removed the whole bracket he will need to set the correct gap for the sensor in the rear.
Clarks garage has a good write up on this.
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09-09-2003, 05:52 PM
#8
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Well, the sensors have been realigned but still no start. One of the sensors had brittle wiring which has been replaced but still nothing.
We're wondering if the position pin on the new flywheel might have the incorrect depth?
We're wondering if the position pin on the new flywheel might have the incorrect depth?
09-09-2003, 06:12 PM
#9
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Most likely the mech damaged the sensors and/or the bracket was moved. I've never had any luck replacing the wiring on a sensor as this is a shielded impedence matched cable.
Also could be plugged in wrong -- 50-50 chance.
As to the pins moving; not unless the mech dropped the flywheel.
I would check the resistence on the sensors; verify the 2.5 volt pulse when the engine is cranked and try swapping plugs.
If there is voltage to the injectors with the key on then the DME relay is most likely working. The coil gets it's voltage from the ignition key either directly or through a relay on the post 85.1 cars.
Grounds to the engine are important too.
Also could be plugged in wrong -- 50-50 chance.
As to the pins moving; not unless the mech dropped the flywheel.
I would check the resistence on the sensors; verify the 2.5 volt pulse when the engine is cranked and try swapping plugs.
If there is voltage to the injectors with the key on then the DME relay is most likely working. The coil gets it's voltage from the ignition key either directly or through a relay on the post 85.1 cars.
Grounds to the engine are important too.
09-09-2003, 06:23 PM
#10
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What relay sends the coil it's voltage? That might explain why we're only seeing spark when we release the ignition key. It's an '86 951. I'll ask him to check the fuse box cover.
The flywheel is new so there might be a chance those pins could be off? Trust me, the mech didn't drop it.
Grounds are all as they should be.
The flywheel is new so there might be a chance those pins could be off? Trust me, the mech didn't drop it.
Grounds are all as they should be.
09-09-2003, 08:22 PM
#12
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The coil receives 12 volts through the ignition key and the alarm system if you have one. With the ignition key switched on, you should see 12 volts at terminal 15 of the coil (black wire). If not, the gremlins may lie in the ignition switch or alarm system.
09-09-2003, 08:51 PM
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Looking at the 86 951 schematic the ingition switch circuit 15 branches; one branch directly to the coil. No relay. The other branch of 15 does go to the relay board.
New flywheel? Aftermarket? If so then were there pins in it or did these need to be installed?
Since you get a bit of a spark turning off the key I would check the DME relay and the DME.
New flywheel? Aftermarket? If so then were there pins in it or did these need to be installed?
Since you get a bit of a spark turning off the key I would check the DME relay and the DME.
09-09-2003, 09:25 PM
#15
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We've swapped the DME relay for a new one to no effect. Any tips on how to check the DME itself?
New aftermarket fidanza flywheel was installed. Waiting to hear back from the mechanic on whether the pins were in it and whether they were checked against the old fw. He's pretty thorough so I'm hoping that's not the case.
New aftermarket fidanza flywheel was installed. Waiting to hear back from the mechanic on whether the pins were in it and whether they were checked against the old fw. He's pretty thorough so I'm hoping that's not the case.