No Start After Clutch Job
02-14-2015, 09:53 PM
#212
Instructor
Thread Starter
Thanks to all the people that posted since I got the car running.
I drove the car about 60+ miles today without any real problems--the airbag light stays on--and got fresh gas. The clutch worked normally, which was the point of all this. I will probably buy two new Bosch sensors later this week.
Thanks to Remember2 for re-formating my resistance grid. I made it in Excell and it went weird when I copied and pasted it onto the forum box.
I'm not sure if the FAE sensors are defective. Since both exhibited the exact same behavior, and since I got them from two different venders, I believe that they are working as designed. It's just that this feature (having the center pin continuous with the exterior shield) prevented them from working in my car. I'm intensely curious if anyone else has had this problem. Has anyone bought and used FAE speed/reference sensors? I would like to know if they worked or not.
I will let everyone know how the car progresses over the next weeks as I drive it more (weather permitting).
Perry
I drove the car about 60+ miles today without any real problems--the airbag light stays on--and got fresh gas. The clutch worked normally, which was the point of all this. I will probably buy two new Bosch sensors later this week.
Thanks to Remember2 for re-formating my resistance grid. I made it in Excell and it went weird when I copied and pasted it onto the forum box.
I'm not sure if the FAE sensors are defective. Since both exhibited the exact same behavior, and since I got them from two different venders, I believe that they are working as designed. It's just that this feature (having the center pin continuous with the exterior shield) prevented them from working in my car. I'm intensely curious if anyone else has had this problem. Has anyone bought and used FAE speed/reference sensors? I would like to know if they worked or not.
I will let everyone know how the car progresses over the next weeks as I drive it more (weather permitting).
Perry
02-17-2015, 06:14 PM
#213
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WOW - Amazing Story. Hard to believe about the sensors, but it was good thinking to start at the beginning again. One thing was certain, your DME didn't run in my car which has Bosch sensors, so you had to get some of the DME work done.
Glad to hear it's up and running. Van was right - Signals weren't getting to your DME. This thread is a testament to your perseverance. Well Done!
Glad to hear it's up and running. Van was right - Signals weren't getting to your DME. This thread is a testament to your perseverance. Well Done!
02-19-2015, 09:47 AM
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I have been following this thread from the start, but declined to comment because I didnt feel my 944 skills (or rather lack thereof) would be of any use. I'm glad you got it running. I must admit that I always believed the solution would be, almost had to be, the sensors because of what happened to them during the clutch job.
I recently replaced the head gasket on mine and in the process one of the reference sensor connectors crumbled to fragments so I started searching for replacments as both of mine looked original. I saw that the FAE brand was about the cheapest option available but when I did a forum search to see if anyone had any good or bad reviews of that brand I found you had used them on yours and have gone through this year long no start. So I went with the more expensive Bosch sensors. I have yet to start mine as there are a few more things left to do.
Again, congrats on getting yours up and running.
I recently replaced the head gasket on mine and in the process one of the reference sensor connectors crumbled to fragments so I started searching for replacments as both of mine looked original. I saw that the FAE brand was about the cheapest option available but when I did a forum search to see if anyone had any good or bad reviews of that brand I found you had used them on yours and have gone through this year long no start. So I went with the more expensive Bosch sensors. I have yet to start mine as there are a few more things left to do.
Again, congrats on getting yours up and running.
02-20-2015, 02:47 PM
#217
Instructor
Thread Starter
Thanks to everyone that responded since I got the car back on the road.
I have not yet bought replacement sensors. Intruder196, if you could test your new Bosch sensors for continuity between the metal shield end and any of the male pins at the harness connection end and see what the resistance is, I would greatly appreciate it. My belief is that there should be infinite resistance in this test but I've only had one sensor to test, other Bosch sensors might be like the FAE in this regard.
Specs, thanks so much for all your help and encouragement during this process. It really helped me understand the electrical system on my car as well as kept me from giving up when things looked bleakest. You are right about the test that you performed, the DME didn't work in your car so maybe there was something besides these FAE sensors that was causing my no start. I will most likely never know.
I am very empathetic to all the other posters that are having or have had no start issues. If I've learned anything from this work, I am happy to share that information with anyone that might need some help. Please contact me with a private message or on this thread.
Perry
I have not yet bought replacement sensors. Intruder196, if you could test your new Bosch sensors for continuity between the metal shield end and any of the male pins at the harness connection end and see what the resistance is, I would greatly appreciate it. My belief is that there should be infinite resistance in this test but I've only had one sensor to test, other Bosch sensors might be like the FAE in this regard.
Specs, thanks so much for all your help and encouragement during this process. It really helped me understand the electrical system on my car as well as kept me from giving up when things looked bleakest. You are right about the test that you performed, the DME didn't work in your car so maybe there was something besides these FAE sensors that was causing my no start. I will most likely never know.
I am very empathetic to all the other posters that are having or have had no start issues. If I've learned anything from this work, I am happy to share that information with anyone that might need some help. Please contact me with a private message or on this thread.
Perry
03-05-2015, 12:35 PM
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Perry,
Sorry about the delay in getting back to this. I checked my sensors and get infinite ohms between the metal shield end and each connector pin. It was the same for both sensors. I hope this helps.
Sorry about the delay in getting back to this. I checked my sensors and get infinite ohms between the metal shield end and each connector pin. It was the same for both sensors. I hope this helps.
03-06-2015, 11:52 PM
#221
Instructor
Thread Starter
Intruder196,
Great, thanks, that's what I had hoped you would find. Now these were OEM Bosch sensors, correct? Sorry, but one more question: Can I ask where you bought them from?
Thanks!
Perry
Great, thanks, that's what I had hoped you would find. Now these were OEM Bosch sensors, correct? Sorry, but one more question: Can I ask where you bought them from?
Thanks!
Perry
03-10-2015, 05:28 PM
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Yes they were Bosch sensors. Got them from an Ebay seller. The only difference in these and my old ones (which may have been originals) is the length of the wires. The new ones were a few inches longer.
Here is the link
http://www.ebay.com/itm/PORSCHE-944-...ht_2604wt_1238
Here is the link
http://www.ebay.com/itm/PORSCHE-944-...ht_2604wt_1238
04-03-2018, 02:56 PM
#223
Drifting
I am currently going through an incredibly similar issue (see thread "DME Destroyed?" https://rennlist.com/forums/944-turb...destroyed.html).
I have just ordered a new harness. FYI I too have new FAE sensors. With the prices of Bosch sensors varying (up here in Canada they are over $200 each), I am prepared to try a set at the more reasonable prices I see Stateside. However, I'm not certain: other than the length of connectors, if they are "Bosch", are the all the same?
Thanks,
Dan
I have just ordered a new harness. FYI I too have new FAE sensors. With the prices of Bosch sensors varying (up here in Canada they are over $200 each), I am prepared to try a set at the more reasonable prices I see Stateside. However, I'm not certain: other than the length of connectors, if they are "Bosch", are the all the same?
Thanks,
Dan
04-03-2018, 06:06 PM
#225
Three Wheelin'
I have been a reader of this forum since before I bought my 1987 951 in December of 2011. I have never had to ask for help, but I have gained much useful information from many posts and replies. I recently registered and hope that readers can help me.
Unfortunately, I have not been able to start my car since last December. I took the car off the road to begin a clutch job that took about one and a half months. After finishing, I went to start the car up for a test drive only to find that the car would crank, but not start.
I have tried for the last one and a half months to diagnose this problem but have had no success. I have also posted on the Clark's Garage forum, but am still unable to fix this problem. Please bear with me as I describe all the work that I did during the clutch job, and the subsequent work I did trying to cure the no start.
Removed exhaust from turbo discharge pipe back.
Removed transaxel.
Removed torque tube and rebuilt it.
Removed bell housing, replace clutch--including pilot bearing, T/O bearing, rear main seal, fork bearings, pressure plate.
Resurfaced flywheel.
Removed speed and reference sensors.
Removed and replaced the oxygen sensor.
When I removed the speed sensor I broke it. It was stuck in the mounting block and it broke off in my hand as I was twisting it to remove it. I replaced it and the reference sensor, as I was also pretty rough with it during removal. I slotted the bell housing opening to ease re-installing it. I set the clearence between the speed sensor and the ring gear with a feeler gauge before installing the bell housing.
I re-installed everything without incident.
I also replaced the timing and balance belts and the crank gear that drives the timing belt.
I also changed the engine oil and filter!
I cleaned the ground connections at the top of the bell housing and the back of the block (as well as the one on the firewall and the B- connection).
The car cranks strongly but does not start. It has neither spark nor fuel injection nor tach bounce.
I have tested the coil for primary and secondary resistance. It checked out.
I jumped the DME relay with a three wire jumper. Fuel pump runs, mid 30's psi when just running, low 30's when cranking.
I have tested the new speed and reference sensors for resistance, cranking voltage, and, after borrowing an oscilloscope from the local science teacher, peak to peak voltage. All values are correct.
I also replace the wiring harness for the speed and reference sensors. Still no start.
I tested the continuity between the DME computer hook up and grounds, the AFM, coil, ignition switch. When I tested the speed and reference sensors I took their values at the DME connection.
I tested for cranking voltage at the DME: 11.1 volts when cranking.
I removed the KLR and jumped the ignition pins (#16 and #9, if I remember correctly). Still, no spart, no fuel injection.
I concluded that the DME seemed to be getting all the correct information, but was not putting out the correct outputs. I bit the bullet and replaced the DME with a rebuilt one. Still, no spark, no fuel injection.
Am I missing something? What could I have done during the clutch job that would cause this condition? I am severely depressed and am looking to the gurus on the forum to point me in the right direction to fix this car.
I will greatly appreciate any help.
Thanks,
Perry
Unfortunately, I have not been able to start my car since last December. I took the car off the road to begin a clutch job that took about one and a half months. After finishing, I went to start the car up for a test drive only to find that the car would crank, but not start.
I have tried for the last one and a half months to diagnose this problem but have had no success. I have also posted on the Clark's Garage forum, but am still unable to fix this problem. Please bear with me as I describe all the work that I did during the clutch job, and the subsequent work I did trying to cure the no start.
Removed exhaust from turbo discharge pipe back.
Removed transaxel.
Removed torque tube and rebuilt it.
Removed bell housing, replace clutch--including pilot bearing, T/O bearing, rear main seal, fork bearings, pressure plate.
Resurfaced flywheel.
Removed speed and reference sensors.
Removed and replaced the oxygen sensor.
When I removed the speed sensor I broke it. It was stuck in the mounting block and it broke off in my hand as I was twisting it to remove it. I replaced it and the reference sensor, as I was also pretty rough with it during removal. I slotted the bell housing opening to ease re-installing it. I set the clearence between the speed sensor and the ring gear with a feeler gauge before installing the bell housing.
I re-installed everything without incident.
I also replaced the timing and balance belts and the crank gear that drives the timing belt.
I also changed the engine oil and filter!
I cleaned the ground connections at the top of the bell housing and the back of the block (as well as the one on the firewall and the B- connection).
The car cranks strongly but does not start. It has neither spark nor fuel injection nor tach bounce.
I have tested the coil for primary and secondary resistance. It checked out.
I jumped the DME relay with a three wire jumper. Fuel pump runs, mid 30's psi when just running, low 30's when cranking.
I have tested the new speed and reference sensors for resistance, cranking voltage, and, after borrowing an oscilloscope from the local science teacher, peak to peak voltage. All values are correct.
I also replace the wiring harness for the speed and reference sensors. Still no start.
I tested the continuity between the DME computer hook up and grounds, the AFM, coil, ignition switch. When I tested the speed and reference sensors I took their values at the DME connection.
I tested for cranking voltage at the DME: 11.1 volts when cranking.
I removed the KLR and jumped the ignition pins (#16 and #9, if I remember correctly). Still, no spart, no fuel injection.
I concluded that the DME seemed to be getting all the correct information, but was not putting out the correct outputs. I bit the bullet and replaced the DME with a rebuilt one. Still, no spark, no fuel injection.
Am I missing something? What could I have done during the clutch job that would cause this condition? I am severely depressed and am looking to the gurus on the forum to point me in the right direction to fix this car.
I will greatly appreciate any help.
Thanks,
Perry