1987 NA. I am not getting any spark, but am getting fuel. Here is what I have replaced/tested:
1. Replaced DME Relay. Tested original and was not working (no fuel/spark).
2. Replaced DME Computer with another used computer that tested good. After DME relay, still had no fuel/spark. Purchased used computer off eBay.
3. Removed Fuel Rail end cap, crank motor, fuel comes out, so I have fuel now.
4. Tested coil per Clark's Garage:
a. Voltage at coil: 11.67V (battery is a touch low...86% shown on charger)
b. Tested for spark per Clark's Garage by removing coil wire, plugging in spark plug, remove ground wire, wrap spark plug threads with a ground wire connected to battery. Installled test ground wire on coil. Turned car to start position. Touched coil ground test wire to battery. Get spark at battery but nothing at spark plug. Tested ohm resistance, tested fine, so I know the plug is grounded.
Thoughts? Is the coil the next piece of the puzzle? I have a spare MSD 6 box (spare from one of my other cars). Is it worth converting to the MSD and get an MSD coil? Thanks in advance.

 

Could be the coil but the crank sensors is the problem 99% of the time when there are spark issues.

 

Assuming the car turns over. Does the tach move or bounce? If it does not, it's the sensors. They pick-up the movement of the inserts in the flywheel as they move past the sensor. After you check the sensor, if no joy, have someone rotate the crank and see if you can see the threaded inserts through the sensor mounting holes. On my friends car, the inserts were sheared off and had to be replaced.

 

I replaced both sensors (Speed & Reference) first, as the connection plugs were in bad shape. Tach doesn't bounce a lot, just bumps up once when trying to start. I have looked at the threaded inserts and can count 3 when I turn the motor over. Should there be more? If that is the issue, do I need to replace the flywheel?

 

I would doubt that the flywheel is the problem. It could be the gap is off, also are you sure the plugs on the sensors are not switched around? There is a gap check procedure at www.clarksgarage.com Basically what it tells you to do is glue a washer to the bottom of a sensor, find the sensor burr on the flywheel by rotating the engine by hand and insert the washered sensor down untill it stops. At that point you tighten the bolts and take the washer off. Reinsert and you should have the correct gap. I do not know the size washer used though.

 

3 inserts is correct. There are two located towards the front of the car for diagnostics and one maybe 1/2-1inch behind for the position sensor. If you can see them, they should be slightly elevated off the flywheel. Sounds like they're ok. The next step would be to check the gap.

 

If your getting voltage at the coil, and it doesn't spark when grounded, then it sounds like your coils is bad to me.

 

Bypass the factory alarm.
http://www.clarks-garage.com/shop-manual/elect-23.htm

 

I set the gap on the sensors when I replaced them, as I didn't want to take any chances. My 944 doesn't have a factory alarm...pretty much a stripped down 44 with very few options on it.
I have an MSD coil and MSD 6AL to install. I figure I will attach the coil first and see if I get any spark using the Clark's Garage test procedure, before installing the 6AL. Fingers crossed that it works. I need to get my 944 running before the end of this month. My office is moving another 15 miles away, making my drive 53 miles each way. I don't want to keep piling miles on my 08 Corvette. That and the Corvette doesn't like city streets (large cam stroker 418 LS3 under the hood).

 

OK. New coil is doing the same as the old coil. Back to the sensors this morning to double check again. Is it possible to get two bad new sensors? I am getting quite frustrated with this problem. I will report back once I check the sensors again.

 

I think if you have new sensors and they are gapped correctly, I would double check the wiring for a defect. There is a good chance the wiring from the ECU to the harness plug has a problem somewhere. We had a broken wire on the wiring harness on the ECU side of the connector plug that caused a no spark.

 

Well, took another look at the flywheel. Rear threaded insert is sheered off. Called the stealership to get a price...$2,500 in labor, $1,500 in parts....about $1,000 more than I paid for the car. So...should I cut my losses and scrap/sell for cheap (just finished engine maintenance)? Wiring harnesses are good...checked that out. Any shop recommendations in the Palm Beach, FL area? Would have to get the car towed there. Thanks in advance.

 

I wonder if there is any possibility of getting enough access to drill and tap a new one in.

 

That was something I was thinking about too. I wonder if the housing that holds the reference sensors, removed, would let me see where the threaded insert goes and allow me to do that. Anyone know if that is possible? The front two inserts are there, just need to replace the rear insert.

 

I had no spark, no start and would cut out driving down the road . The issue I had was in the fuse box I put in a used fuse box never had an issue since . I think the problem was dirty contacts where the wiring harness plugs into the fuse box . More then likley if I had just cleaned up the connections buy unplugging the wires from the fuse box and reistalling them ever thing would have worked . Just my 2 cents. Good luck let us know.