I know this is a bike forum but I figure you can expand your horizons a little.

I have a 1990 Chevy Suburban V1500 4x4 5.7L 350 TBI, drove it to work one day 4 hours later it wouldn't start. I assumed it was the cold (it was 20 below but it had started at those temps before)so I tried to jump it to no avail. I left it in the parking lot over night and tried to jump it again. I finally towed it home and plugged in the block warmer. The injectors do fire, and I tried starting fluid as well so I began looking into the ignition. I checked spark, and got a weak orange spark using a spark tester at the plug, retested the spark coming off the coil with the same results, so I began running through the system.
New Coil
New Cap/Rotor
New Spark Control Module
New ECM
New Battery
TestedIgnition Control Module and replaced anyway
Tested Pickups (750ohms within specs)
Plug Wires are a month old

The only thing that changed during the 4 hoursI was at work was the temperature. I'm tired of driving the little woman's monkey mobile. I feel I might be going in the wrong direction, I'll take any suggestions helpful or otherwise, just as long as it gives me something to do.

 

Did you check your voltage drop while turning over the engine? I would guess even with a good battery, at those temps, it may be dropping a little too low to provide a good spark.

 

Didnt check voltage, got a new battery and had it hooked up to a running car after it warmed up to about +15, still nothing

 

Check the hall effect switch ( crank sensor). It should be up front by the harmomic balancer. If ice, dirt, etc gets in that switch, it's just a magnetic pickup coil, it can cause that.

 

Well,
You would think the jumper cables would correct any voltage drop problems, unless you have dirty or loose battery connectins, did you check that. I would also look at the ignition switch and the distributor / ignition ground.

Good luck Dude............The Worlok

 

LOL, I thought you were making that up, crank sensor does make more sense.It can cause a weak spark? I thought it would just make it run rough.

 

HMMM

"On your 1990 Chevrolet Truck V1500 1/2ton Sub 4WD (5.7L TBI), the Crankshaft Position Sensor is located:
This vehicle is not equipped with selected component "

 

Don't think so. theignition modulewill only read that signal as receivinga pulse, or no pulse. If the clearance is out of check, the magnetic field won't be strong enough to createthe pulse spike, which themodule justwouldn't pick up then.

 

I guess thepick-up module in the distributerwould be the closest thing to it.

 

Did it try to start with the Starting fluid? Are you getting fuel and or good fuel pressure? Those vehicles are critical on correct fuel pressure. At temps that cold, the fuel line could have frozen if there was any water in it or in the tank. Check all your EFI, ECM andIGN fuses.An iced up fuel pump can blow a fuse due to too much current draw.