86951

I just recently rebuilt my 951 engine. Now that i have the enigne back in the car there is no spark. The engine cranks, there is oil pressure and fuel. New rotor, cap, plugs, cables, coil, reference sensor, rpm sensor.
Any ideas on where the problem may be....

Dmitry S.

Could also be the DME relay. I say just take out the test light and start poking.

86951

I replace the DME relay about 1500 miles before I removed the engine..
so it is fairly new.

gratian

Check connection to DME and all grounds!
Maybe you crash a little your DME in rebuilt process?I ask this because I have a "no spark problem" and after two weeks I find a "cold" solder in DME (and that because vibrations)...

86951

where exactly is the DME unit?

SoCal Driver

The electronic brains to run the injection. It's under a wood cover in the passenger foot well.

I would adjust the clearence on the sensors and check that they are plugged into the correct connectors.

0.8mm on the rear sensor. About the thickness of a dime.

Check the set screw pin on the flywheel. Hopefully you didn't bent this or have this come loose.

86951

How would i go about accurately adjusting the clearance on the sensors?
The screw pins on the flywheel are undamaged.

SoCal Driver

Glue a dime to the end of the rear sensor and adjust the bracket so the dime just touches the teeth on the starter ring. Remove the sensor, remove the dime, reinstall sensor, check that the sensors are plugged in to their respective connectors.

86951

ok, I set the clearance and still no spark.
checked and made sure that sensors were connected to their respective connectors, and stil no spark.
Does anyone know how to test the relay?
How could i tell if i had a cold solder in the DME unit?

SoCal Driver

Turn on the key and check for 12 VDC at the coil and at any of the injector connectors. If you have 12 volts then the first part of the DME relay, the contact that powers the DME and the injectors, is closing.

You should have this 12 volts during cranking too.

I take it you have checked the spark at the end of one of the spark plug wires. Pull the wire out of the coil and move a spark plug wire to it. Should have spark. If you don't then it's either the reference sensor or the DME. If you do have spark at the coil then check the coil to dist wire and the rotor. Could have the screw on the rotor fall out.

Some where the knock sensor comes in but I don't think that will keep it from sparking.

86951

Ok, I have 12 volts at the coil but only when cranking. Nothing at the injectors....
I don't think that it's the reference sensor because they are brand new, never been used. Ummm....so do you mean its the DME relay or CU is the a way to jump that relay connections to verify? Thanks for your help i really appreciate it..

SoCal Driver

Misplaced. Sorry what's left of my brain was in another thread when I posted this.

Dmitry S.

I also see that you're in Redwood City, close by, if you need help, i'm sure some of the Bay Area guys would gladly come over with me to help out.

86951

It turns out that the injectors are not pulsing but gettting battery voltage at the connectors. Used DVOM to check this and i noticed that when i checked one side I was getting battery voltage and the other side i was getting 7-8 volts, I don't know if that is normal. I assumed that one side would be ground and the other power. Oh and by the way the injectors are new OE.
I don't know anyone in the area that specializes on these cars except for the dealer. Unless you (Dmitry S.) is up for the challenge.
DME control unit is getting battery voltage at pins 35, and 18 which tells me that DME relay works. I got testing info from Mitchell Repair info 2004.]
My car had an alarm that was in the car when i got it a year or so ago. The alarm never worked to my knowledge. I thought it might be causing this NO SPARK problem, so i removed and still nothing.
Does anyone know where I can get a DME CU?
Or have any ideas on how to test the computer if that is possible?

Dmitry S.

Give Rennwerks a call tomorrow if you're still having problems, and talk to Steve. You can find their number on their website at www.rennwerks.com. They're in Mountain View, and Steve has built many 951 race cars and knows A LOT about these cars. If you want, I can bring over the factory manuals.