On the way back from the ALMS race at Laguna Seca the car died a few times at speed. Just an instantaneous stop, no bucking or anything. Popped the hood..... tapped on the DME relay and off I went again. Finally quit for good about the 4th time on the Pacheco Pass.

I started to figure the DME relay was not the culprit. Brokedown and had a tow(long story) 150 miles away from home.

So far the car just turns over without even coming close to firing.

1. Checked for voltage at the coil on both poles ....12 volts
2. Checked resistance on primary and secondary circuits. out of spec, not by much, so replaced coil. Still no start
3. Paper trick on relay. Fuel pump energizes and have 12 volts at the injector loom with key on. Replaced Relay anyway
4. Checked for spark at the plugs. Hard to tell but seems like there was no spark. I pulled a plug wire and threw in another plug to see for an arc while cranking..... no spark ALSO the tach bounces while cranking. I think the reference sensors are working.
5. Checked for power at the DME and KLR loom and had 12 volts
6. For ****s I twist the key at this point and the car starts! Runs for 3 minutes at idle then dies instantly. Try to restart no start. Tap on and or beat the DME and the car starts. Could be coincidental but seems like the DME has some bad joints.

What else should I check before I crack open the DME and what should I look for?

The car has a factory alarm, could this be the problem,? How do I test that

I just redid the motor this winter and the car runs like a champ, this kind of intermittent stuff make me want to bust out a Molotov cocktail and burn it.



any thoughts?

 

Reference and speed sensors. Been having a bunch of wire falures in the plastic connections at both ends. As these have a special lead wire you can't fix them.

 

yup, that was my recent problem, broke ref/speed sensor wire, it was also intermittent, but ramming my car into a cement barrier fixed that element of the problem

Cheers
Lance

 

I have been having these same probs on and off!! Finally just went and re-soldered all the connections in the DME and KLR. Seemed to do the trick for a day and a half, then no start again!!!! Was sure thinking about that Molotov by then! Tried wiggling the wires going into the DME/KLR and it starts right up. Must be a bad ground??

 

Just opened up the DME and found 1 broken solder and 2 other slightly cracked solder joints on the same transistor. It was the largest transistor of them all. I suspect this transistor gets extremely hot.

I'm not proficient at soldering, so I'll try and find someone to do it for me or take it to a TV/ VCR repair shop.

Also, what is the best way to test the speed and reference sensors?

For some reason I still think that the DME is probably not the problem.

 

My 951 acts the same way. I am sending my DME to a guy who says he can test it and fix it.

You can test the speed and reference sensors by measuring resistance at the sensor connector. Unplug the harness and check resistance between the center pin and the rearmost one (with respect to the car). Should measure 1000 ohms for both sensors.

You can also measure this at the DME harness pins 8 and 27 are for the speed sensor and 25 and 26 for the reference sensor.

You might also look at the place the wire goes into the sensor element. There is plastic molded in at this point to act as a strain relief. It ages and breaks which weakens the connecton.