1987Porsche944WithRealLongName

Haven't had much help on the 944 general board so I figured I'd try asking here

I have a 951 with mtune, bigger turbo, etc.
I started having cut out issues where I could restart the car easily and eventually these cut outs turned into no-starts. I was getting the occasional bad idle start (not as bad as below though).
Turns out the alternator cable had made contact with the exhaust and it gave the entire car a charge, so much so that I saw sparks under the hood and some interior pieces were actually smoking.

After getting everything buttoned up I can get the car to turn over and if I'm lucky run, albeit very poorly. Usually doesn't start without holding the throttle pretty far down. When it does start the car bucks badly and the wideband shows 16.5 to off the charts lean. There will often be smoke in the engine bay. I smell gas (not unusual for my catless exhaust) and cylinders 1-3 will have wet sparkplugs. I am getting 15hg of vacuum however.

I pulled the DME and there did look like there was damage on the strip of the board where the plug connector makes contact. I repaired it as I have had to on another DME in the past and tested it.
I've also made sure the DME is seeing ground, as well as tested the injectors and injector harness, maf signal, tps, disabled the klr, checked the resistances on the speed and reference sensors, unplugged the o2 sensor, vacuum lines, checked the ignition coil resistances, and some more stuff I'm probably forgetting.

I'm at a loss of where to go from here and the 944 is my only personal transportation for the time being.

Dave W.

Sorry to say, but you just need to troubleshoot each electrical circuit to see if anything shorted. Trust the plugs, it's too rich. If it's so rich that it's misfiring and stumbling the wideband will show lean from having unburned oxygen flowing over the sensor. Since you have the Mtune, plug in the logger and verify all sensors are reading correctly. If the coolant temp sensor wires were damaged the engine would run extremely rich.

1987Porsche944WithRealLongName

First of all thanks for responding

I have the mtune but not a logger
I've tested everything from the DME plug itself and nothing seems out of spec. My tach works fine as well although I'm considering replacing the R&S sensors with some spares I have from an old car just to see. I even did some very unlikely things like checked the coil, ignition wires, distributor cap, etc.

I can't even get it to run anymore, it'll turn over several times and give me a slight cough when it tries to start.

raleighBahn

Maybe find someone who can let you try a known good dme.

1987Porsche944WithRealLongName

nvm

Dave W.

Are you saying the map sensor is not putting out a signal?

1987Porsche944WithRealLongName

Nevermind, measured incorrectly
That's what happens when you get excited and forget to think
MAP works fine