No spark, need advanced help.

[jhanson1750]

I just completed yet another headgasket replacement on my 86' and now I am getting no spark. Here is the list of things I have checked so far.
1: Crank sensor, had a lifetime warrante so I changer it out. Back probed the wires at the 3 wire plug and have good continuity through the plug.
2: Ignition module, same as above.
3: Checked the cam sensor, getting 5.07v at pin B to either pin A or chassis with 12.20v on the batt.
4:Ohmed the coil pack tower to tower and got 7.8k to 8.0k on all three.
5:Checked the power at the PCM and have batt voltage, hooked up powerlogger and reading the PCM just fine with no codes.
6:Have fuel PSI and injectors are firing, fuel on the plugs. Pulled the INJ/FP fuse so I dont flood the engine.
7:Went through the No start flow chart (No Start Tree) and it pointed me to the ign module so see #2

I usually feel pretty good with electrical (its my full time job) but this has got me stumped. Car ran great pre-headgasket (broke a rocker shaft at 28lbs and boost spiked costing me the hg's. Its amazing what happens when your flowing that volume of air and in an instant you only have 4 intake valves opening instead of 6, boost was @ 38psi for an instant and now this.)
I am wondering is there something else that would cause no spark? I have not changed the coil pack out but it checks out good on the secondary side. I didn't check the primary side (convinced myself the module was the issue) of the coil pack but I will tomorrow. Thanks for any help you can give me. Jon

 

[fc227]

Double check your wiring. If it worked before it could be a harness unplugged and or pinched.

 

[eric_1984ttype]

Check for power and signal at the module plug. Then check to make sure you hooked all the grounds back up.

 

[turbo nasty]

Check the grounds (harness and batt), all connectors (engine compartment and ECM) and fuses again.

 

[jhanson1750]

Im heading back out to see what I can find.

turbo nasty Check the grounds (harness and batt), all connectors (engine compartment and ECM) and fuses again.
I have all engine grounds routed to the driver side rear intake bolt. On my setup there are three plus the one to the firewall so I know they are good. I will check the others.


fc227 Double check your wiring. If it worked before it could be a harness unplugged and or pinched.
I did some cleanup on the engine bay harness and you may be correct on the pinched wire. I will be going over every thing and will let you know what I find.


eric_1984ttype Check for power and signal at the module plug. Then check to make sure you hooked all the grounds back up.
I have power to the module and will verify the signal going to it.


Thanks for the input and I will let you know what I find. Jon Hanson

 

[fc227]

Is the ECU plugged in ?

 

[jhanson1750]

GOT IT!!!! Tried 3 different ignition modules (Borge Warner is CRAP!!!) and no fire from the coil pack. Found the BW ignition modules did not have the correct refrence voltage for either the cam or the crank sensor. When I checked I found the voltage comming out of the module should be 6-9vdc but the ones I had (all 3) were only putting out 4.93, 5.01 and 4.78 volts which I NOW know is not enough to let the pcm fire off the ignition system but it is enough to fire the injectors. So to anyone out there, if you have a BW ignition module and/or coil pack check it with a good volt/ohm meter and be careful. If the refrence voltage (incoming voltage/batt/altenator) ever drops then there is a chance of misfiring and/or going lean if there is an alky system on the car. I am now wondering if this has been the true culprit of many engine falures I have read about here on Turbobuick. I can only recommend using ONLY factory ignition parts. AC delco will be the only parts that EVER go back on my car and I will be changing out any items that were bought trying to save a few bucks. Jon