SL/R129: 1991 500SL no spark
#1
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Join Date: Oct 2017
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1991 500SL, 2001 E320, 1988 420SEL
1991 500SL no spark
Hi everyone!! I have an odd problem I think.
About a month ago I got off of work and the car wouldn't start. It turned over fine, but didn't even attempt to start. I got it home and narrowed it down to what I thought was the crankshaft positioning sensor. I went ahead and ordered it and installed it. It started right up!!! It ran rough, but eventually evened out and was running fine. The next day I decided to drive it to work. Well, half way there I came to a stop light and while waiting for it to change, the car shut off, and I haven't been able to get it stated again. It is having the exact same issue as it did before. Both coils are getting power, but neither of them are putting out any spark.
I bought a code reader and it came back with like 27 codes, (one of which was i believe the ignition switch) so I cleared them and it says to drive it to see if any of them come back. Now, obviously I cant't drive it, but I do still have a few codes that will not clear.
They are:
Socket 6
code 2 - SRS control unit self test failure
code 3 - Driver airbag squib
code 9 - SRS warning lamp
Socket 10
code 20 - Hardtop installed, recognition circuit solenoid valve, roller extended
I have been told the the ignition switch, the ignition control module, and the camshaft positioning sensor can all stop the coils from producing spark.
Any ideas?
Its just hard for me to imagine that I replaced the crankshaft sensor, and it started right up, and now it's back to doing the exact same thing!
Thank you so much in advance for any help!!!
About a month ago I got off of work and the car wouldn't start. It turned over fine, but didn't even attempt to start. I got it home and narrowed it down to what I thought was the crankshaft positioning sensor. I went ahead and ordered it and installed it. It started right up!!! It ran rough, but eventually evened out and was running fine. The next day I decided to drive it to work. Well, half way there I came to a stop light and while waiting for it to change, the car shut off, and I haven't been able to get it stated again. It is having the exact same issue as it did before. Both coils are getting power, but neither of them are putting out any spark.
I bought a code reader and it came back with like 27 codes, (one of which was i believe the ignition switch) so I cleared them and it says to drive it to see if any of them come back. Now, obviously I cant't drive it, but I do still have a few codes that will not clear.
They are:
Socket 6
code 2 - SRS control unit self test failure
code 3 - Driver airbag squib
code 9 - SRS warning lamp
Socket 10
code 20 - Hardtop installed, recognition circuit solenoid valve, roller extended
I have been told the the ignition switch, the ignition control module, and the camshaft positioning sensor can all stop the coils from producing spark.
Any ideas?
Its just hard for me to imagine that I replaced the crankshaft sensor, and it started right up, and now it's back to doing the exact same thing!
Thank you so much in advance for any help!!!
#2
Banned
I would measure the DC voltage across each coil while the engine cranks to detect whether the ignition controller is switching the coil primaries to ground.