Running rich and backfiring
10-08-2008, 10:52 AM
#31
Jane Bond 007
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The DME gets an engine coolant temp. signal from the blue connector at the front of the block under the intake manifold. Coolant temp is one of the main inputs to the ecu as far as mixture determination is concerned. Cold engine-rich mixture and vice-versa. The sensor has a high resistance with the engine cold and the resistance goes down as the engine warms up, so if there is a connection problem at the sensor the computer gets a cold engine signal and richens the mixture. An easy way to see if it is working is to unplug the sensor while the engine is running, it should stall or almost stall.
Good luck, Mark T.
Good luck, Mark T.
10-08-2008, 11:13 AM
#33
Race Director
its the sensor on the front driver side of the cylinder head. It has a blue fuel injector type connector. Right behind it is the gauge temp sensor (2 wires with female connectors)
10-08-2008, 11:16 AM
#34
Nordschleife Master
No the DME temp sensor is in the block, it uses a 2 pin AMP connector just like the injectors. It's very close to the other temp sensor (for instrument cluster) that has 2 open pins.
If you're running rich AND backfiring it's not a fuelling issue. You can run sub 10:1 A/F at idle and it will idle smoothly.
As other has stated, sounds very much like an ignition / timing issue.
Have you tried another DME-box and switched out DME-relay just to make sure?
If you have access to an adjustable timing light you could check your timing at idle.
You can check it against the cam wheel to get a ballpark figure.
Other than that, an oscilloscope sounds like the next step to check if the signals are OK or not.
Good luck! I really hope you find the problem.
If you're running rich AND backfiring it's not a fuelling issue. You can run sub 10:1 A/F at idle and it will idle smoothly.
As other has stated, sounds very much like an ignition / timing issue.
Have you tried another DME-box and switched out DME-relay just to make sure?
If you have access to an adjustable timing light you could check your timing at idle.
You can check it against the cam wheel to get a ballpark figure.
Other than that, an oscilloscope sounds like the next step to check if the signals are OK or not.
Good luck! I really hope you find the problem.
10-08-2008, 12:17 PM
#36
Three Wheelin'
But to check it, all you have to do is remove the sensors and turn the engine until you see the pin.
Backfiring is a timing issue, especially if it is out of the exhaust. I can disconnect the ECT sensor and it will just run rich...
10-08-2008, 01:12 PM
#37
Jane Bond 007
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No the DME temp sensor is in the block, it uses a 2 pin AMP connector just like the injectors. It's very close to the other temp sensor (for instrument cluster) that has 2 open pins.
If you're running rich AND backfiring it's not a fuelling issue. You can run sub 10:1 A/F at idle and it will idle smoothly.
As other has stated, sounds very much like an ignition / timing issue.
Have you tried another DME-box and switched out DME-relay just to make sure?
If you have access to an adjustable timing light you could check your timing at idle.
You can check it against the cam wheel to get a ballpark figure.
Other than that, an oscilloscope sounds like the next step to check if the signals are OK or not.
Good luck! I really hope you find the problem.
If you're running rich AND backfiring it's not a fuelling issue. You can run sub 10:1 A/F at idle and it will idle smoothly.
As other has stated, sounds very much like an ignition / timing issue.
Have you tried another DME-box and switched out DME-relay just to make sure?
If you have access to an adjustable timing light you could check your timing at idle.
You can check it against the cam wheel to get a ballpark figure.
Other than that, an oscilloscope sounds like the next step to check if the signals are OK or not.
Good luck! I really hope you find the problem.
Yes, I had to remove the flywheel in order to repair it... it wasnt pleasant. I started at 8am and finished by 5pm...
But to check it, all you have to do is remove the sensors and turn the engine until you see the pin.
Backfiring is a timing issue, especially if it is out of the exhaust. I can disconnect the ECT sensor and it will just run rich...
But to check it, all you have to do is remove the sensors and turn the engine until you see the pin.
Backfiring is a timing issue, especially if it is out of the exhaust. I can disconnect the ECT sensor and it will just run rich...
10-11-2008, 05:29 PM
#39
Jane Bond 007
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(I can't remember if the flywheel can only be mounted one way or not.)
"
10-11-2008, 05:51 PM
#42
Race Director
I don't know how long your arms are but i was just able to reach a rachet on the crank pulley while looking down there. I was also able to see the pins from the bottom center of the bell housing. I just can't figure out why there are 2 pins and 1 is broken and 1 is not..