MSefi.com read only forum (Jan.15,2018)

Greetings,
I am running a DIY Autotune MSII, 3.57smd unit to control both fuel and spark (dual spark Ford EDIS 6 x 2 ) on a 3.6 Porsche 911 engine. I have had this engine running in this configuration, but no more........and this is wierd. I am getting a tach signal showing in Tuner Studio. I am getting the prime pulse, etc. for the injectors....and the dashboard shows injector puslewidth indication...so it appears that they are working. ......................but it just cranks and cranks.
No response to starting fluid, either. I've tested spark, by removing the spark plug from cylinder #1 and by grounding it to the case, I get good spark. I connected my timing light to the cable and was able to confirm that my crankwheel gap/TDC pulley mark was aligned to TDC when the plug fired/light flashed. Timing appears to be ok. Hey..i do have spark!!!. I re-installed plug #1, with the timing light still attached to plug cable #1 and .......d'oh!? no timing light flash now. I've removed all 12 plugs...and verified that they are all sparking, when grounded to the case, while i'm cranking. They all spark......until re-installed ...and then nothing.

What is happening????????????????? spark with the plugs out....no spark with the plugs in. I've check all wiring, voltage to the EDIS, coils, coil resistance (primary/secondary)....I'm now curled in a fetal position.

regards,
Al

What sort of plugs leads are you using? Plug type? Gap?

Dave,
I will have to double check..i'm away from the garage today, but if I remember correctly, the plugs are (Bosch?) copper tip, center electrode with three ground "probes"...gappage unknown.
I do not know if these are resistor plugs or what the total plug/cable resistance is, but I will check.
This is a 1991 Porsche 3.6 motor with about 50K miles...and i did have it running with these plugs, earlier.

Would the incorrect type of plugs and gap result in the failure I've described?

regards,
Al

I'm told EDIS needs a minimum resistance made up of the leads and plugs - if resistive type. So I just followed the guidelines.

Everything Dave asked is valid.

But, what I'm curious about is how you determined that you have no spark with the plugs installed.

Ken

The plug/wire resistance is approx 18K ohms. With the sparks plugs out I grounded them and got good spark. I also had my timing light attached to the spark plug wire and had a good, strong timing light signal and was able to verify timing. I left the timing light hooked up to the spark plug wire, installed the plug, attached the wire....and no timing light signal.

Regards,
Al

PS: I've searched and found one other person with this problem....but no resolution.

Have the plugs ever been flooded? I had this same problem once and changing to fresh plugs solved it.