Man I have hit a road block with this one. 87 with no DME signal. UPDATE- no go
12-21-2010, 10:18 PM
#1
Drifting
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Man I have hit a road block with this one. 87 with no DME signal. UPDATE- no go
Got a 87 N/A in with no start problem. Engine cranks fine. Tested DME in good running car, good. Checked cranks senosrs in good running car, good. Checked DME relay in good running car, good. Reset sensor heighth, still no DME singnal. Got voltage at DME. Got sensors resistance for sensors at DME plug. Still no signal. HELP!!!!!!
OH, one more thing, car does NOT have factory alarm. Does not have after market alarm. Cleaned the grounds also
OH, one more thing, car does NOT have factory alarm. Does not have after market alarm. Cleaned the grounds also
Last edited by tod84944; 12-24-2010 at 01:23 PM. Reason: update
12-22-2010, 12:37 AM
#3
Three Wheelin'
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Hi Tod, Does the Tack Needle bounce about 1/16 inch? If no bounce, the Speed Sensor is not reading or sending a signal to the DME. Could be a bad connection where the Sensor plugs into the harness to the DME. Wiggle them around and see what happens.
Cheers,
Larry
Cheers,
Larry
12-22-2010, 08:15 AM
#4
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What I mean by no signal, as Grandpa stated, the tach is not bouncing, the injectors are not firing, and the pump is not kicking in. Grandpa, tried that. I tested the resistance of each sensor at the sensor plug. Then checked the resistance of each sensor on the dme plug. Got the same results. I don't have a way to read the voltage of the sensors as the car is cranking. I know I need 2.5. I know I have a good connection at the plugs.
12-22-2010, 08:29 AM
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Was this car running in it's current electrical configuration (no alarm, etc.) and suddenly stopped working, or is this a newly acquired project car you are trying to get running?
12-22-2010, 08:38 AM
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Read post #178 on this thread:
https://rennlist.com/forums/924-931-...-no-start.html
This is how I tested my sensors at the DME while the engine was cranking. Your pin numbers might be different but the prinicipal is the same. It works! I feel your pain man, I really do.
https://rennlist.com/forums/924-931-...-no-start.html
This is how I tested my sensors at the DME while the engine was cranking. Your pin numbers might be different but the prinicipal is the same. It works! I feel your pain man, I really do.
12-22-2010, 09:27 AM
#7
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I think that's the link to the LEDs on the DME plug - a very good idea.
But, if you're not getting the fuel pump to turn on, I think you have a wiring problem at the fuse/relay block.
But, if you're not getting the fuel pump to turn on, I think you have a wiring problem at the fuse/relay block.
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12-22-2010, 09:33 AM
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You can jumper the DME relay to test this out.
No switching power from the DME would be consistent with everything else it isn't doing.
If the DME itself is tested good, and the sensors test good, then wiring/connection problems seem to be likeliest answer.
12-22-2010, 10:05 AM
#9
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What about the ignition switch - have you swapped it out? It is a strange case. No fire and no fuel and no injector pulse. Known good DME and speed/ref sensors and DME relay.....
12-22-2010, 10:06 AM
#10
Race Car
Scan through this thread: https://rennlist.com/forums/944-turb...f-options.html
There are some things in there that might help. LED on the coil, inexpensive oscilloscope, which pins should have power, etc. It was for a turbo, but I think it will still be helpful. After verifying power to all of the pins you need, try the LED thing first (easiest and cheapest). If that checks out okay, get that oscilloscope and check your speed and reference signals as close to the DME as you can (could be the wiring).
There are some things in there that might help. LED on the coil, inexpensive oscilloscope, which pins should have power, etc. It was for a turbo, but I think it will still be helpful. After verifying power to all of the pins you need, try the LED thing first (easiest and cheapest). If that checks out okay, get that oscilloscope and check your speed and reference signals as close to the DME as you can (could be the wiring).
12-22-2010, 06:27 PM
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Post 178 in this thread is great. The will save everyone a ton of time trying to figure out cranks sensors
https://rennlist.com/forums/924-931-...-no-start.html
https://rennlist.com/forums/924-931-...-no-start.html
12-22-2010, 09:13 PM
#14
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When I bought my project 944 the PO and his P mechanic could not get it started and it had set for 18 months. I changed out the ignition switch module and then the complete fuse box because of corrosion. After that I've had no more NO START problems.
Cheers,
Larry
Cheers,
Larry
