Truck just quit on me

[Jppr26]

Ok we have a running truck, sort of, so it took a lot of luck, charm, or a lot of cussing, you pick but the truck started up. It blew a good amount of black smoke when I reved it up and would backfire, cough, and sputter then catch its self and be ok. Then all over again when I pumped the gas.

I put a timing light on it and my crank mark was about 1/4”-1/2” counter clockwise past the marker tab. It is not a vacuum advance distributor, I’ll check again. Is there something to unplug on the distributor for timing, and where should it be at on the block marker tab.
Thank you guys

 

[Jppr26]

Ya no vac advance, and if I had to guse it is around 16° befor tdc. Where should the timing be set at typically, and is there anything I need to disconnect befor setting the timing on the distributor

 

[1987 GMC Jimmy]

Yeah, there’s a round, single wire weatherpack connector on the driver’s side of the firewall. Tan and black is the wire color, I believe. You won’t have an idea of your timing until that EST bypass is disconnected. The advance/retard on these is controlled electronically so no weights, springs, or canister.

 

[Jppr26]

Ok so I found the wire and unplugged it and tried again, now it is at 6° before TDC and running the same. I did get code 42 which is from unplugging that wire. I did take it for a test drive just a little way down the road and it was backfireing and poping like crazy at low RPM but ok at the higher RPM

 

[Jppr26]

Also with the timing light on it and Erving the motor, whenever it would start cutting out my timing light would would quit flashing

 

[Jerry phillion]

It sounds to me you have a few plug wires crossed. Either at
Distributor or spark plugs. Probably happened when you
Replaced module. As a note, mine quit running 3 weeks ago
and it was the module. If you have gas, spark and compression
It has to run , unless timing is off. ( caused by above )

 

[Jppr26]

I put a new module in it about 2 weeks ago because out of no where it started running like ****, then a few days later, truck died on me and I’m dealing with all this

 

[Jerry phillion]

Sounds like maybe the 12 v power wire from the fuse block
to the dist may be the culprit. Make new one from 10 ga.
Wire and try. That elec stuff will drive you crazy. It does me.
Oh, also make sure the ign fuse is pushed in tight . Stranger
Things have happened before. Good luck.

 

[Jppr26]

So when I ease into the throttle the truck revs up fine, when I hit it hard and fast it cuts out and backfires a few times then revs up, if the rpms are up above an idle it will rev up just fine, but let the truck idle a bit then hit the throttle hard and it cuts out and catches up again