TBI to Carb swap, no spark

[80goldenburb]

i recently bought an 87 longbed (custom deluxe) as a worktruck. Just my luck, after i completed a week long oddjob; went out for leisure and she leaves me stranded 6 miles from home. When this happened a short may have taken place somewhere since the tbi injectors would not pulse and i lost all vehicle lighting (dash, gauges,headlights tailinghts, brakes lights, etc) Naturally I already planned a carb swap, since i had an extra Quadrajet sitting around and an HEI distributor from my (now motorless) Suburban.

Long story short, the conversion is complete. i have the low pressure external inline pump pushing fuel to carb no problem. The factory pink 12v ign wire is connected to the HEI's "BAT +" terminal but is supplying no power whatsoever.
The first attempt at cranking resulted in a LOUD backfire (similar decibels to a shotgun) and since then have had no luck in starting her up.

Any ideas???

 

[1987 GMC Jimmy]

i recently bought an 87 longbed (custom deluxe) as a worktruck. Just my luck, after i completed a week long oddjob; went out for leisure and she leaves me stranded 6 miles from home. When this happened a short may have taken place somewhere since the tbi injectors would not pulse and i lost all vehicle lighting (dash, gauges,headlights tailinghts, brakes lights, etc) Naturally I already planned a carb swap, since i had an extra Quadrajet sitting around and an HEI distributor from my (now motorless) Suburban.

Long story short, the conversion is complete. i have the low pressure external inline pump pushing fuel to carb no problem. The factory pink 12v ign wire is connected to the HEI's "BAT +" terminal but is supplying no power whatsoever.
The first attempt at cranking resulted in a LOUD backfire (similar decibels to a shotgun) and since then have had no luck in starting her up.

Any ideas???

You say no spark so I'm guessing you tested this at the plugs and not at the wire itself? Ignition Control Module could be bad. I'd start by testing that. Timing way wrong can make stuff like that happen, too. Did you use the rotor orientation at cylinder 1 or No. 1 cylinder compression to set your base timing? I'd go back and look at that, too. I mean, maybe there's a simple wiring problem, a damaged distributor gear, or a timing chain issue, but I'd check timing and the ICM first.

 

[80goldenburb]

yep, while cranking, no spark at plugs. i used a breaker bar to turn crankshaft pulley and get no. 1 cylinder up closest to head. the rotor was pointing in that direction of the no. 1 when the distributor finally sat flush. at first i wired directly to the battery but no spark at all. Then i found the 12v ignition wire (that went to TBI coil) and then the loud back fire occured. since then no spark at all. PRIOR to ripping off the TBI unit, intake and distributor i could spray starter fluid and it would fire right up. doubt its the timing chain or dizzy gear, timing is correct. where is this icm located? if you got a diagram of what to look for that would be helpful.

 

[1987 GMC Jimmy]

ICM is in/on the distributor as "4-pin module."

 

[80goldenburb]

ICM is in/on the distributor as "4-pin module."

ok then i pulled that sucker out and took it to autozone to get tested and it passed all tests on the machine. So that not an issue. Possibly no power to the factory 10 gauge pink ign wire at crank mode? What to do next ....


EDIT: ahh i didnt notice this black ignition switch, maybe this it.

 

[1987 GMC Jimmy]

I thought about that. I'd first test the voltage at the end of the BAT wire when you're cranking it over and see what you're getting. If you get zero, then that's clear cut no power to the wire, but if you get a low number like 10 or 12, the ignition coil may be worth looking into.