lt1 cranks but no fire.

[Esoteric18]

backround.

its a 96 firebird that came with a 3.8 auto. well i decided that eventually had to change so after a few years i finally got around to a lt1 t56 swap. the swap is done and all buttoned up except it wont fire. getting 40 psi fuel pressure and vats is deleted. it started for about 5 seconds the first time then never again. just cranks and backfires. the reason i believe is because the spark at the plugs is extremely weak. the opti is a brand new summit opti with msd cap and rotor. its a 94 so we were very careful lining it up and it slid right on with no issue. the coil is also brand new. i swapped between 3 icms i have and no difference.


small other problem, the ground going from the bock to the driver side frame rail becomes burning hot to the point it smokes while cranking. normal?

[95ImpySS]

small other problem, the ground going from the bock to the driver side frame rail becomes burning hot to the point it smokes while cranking. normal?

HECK no that's not normal lol. You need to repair that ground. Maybe add a few more. I'd use 4 awg from the battery, to the block, from the block to the frame rail and from the battery to the body.

Can you confirm the injectors are pulsing? Use a screwdriver on an injector and against your ear and listen for a rhythmic clicking wile someone cranks the car over. EDIT: Best thing to use would be a stethoscope or a noid light.

You can also test for a fuel problem by spraying some carb cleaner (Carb cleaner is less violent than ether based starting fluid) into the throttle body ad see if it runs. Be careful when doing this. The car may spit fire at you.

[popo8]

I was just gonna say... a ground that is over heating... is NOT enough ground....

[Esoteric18]

I was just gonna say... a ground that is over heating... is NOT enough ground....

i figured that lol. what do you guys use for ground wire? i will check the injectors tonight. its an hour drive away. any idea what woul;d be causing the weak spark? its almost non existent

[94Blackbird]

Are the plug wires themselves brand new?

[Esoteric18]

yes.

[Fastbird]

Fix the ground, check back.

[MeanTA]

^^^^^ i was going to say the same. a bad ground can cause havoc on the ignition/fuel system.

[Esoteric18]

so more grounds from block to frame/k member? it only has the racetronix battery ground, engine harness grounds and the ground from block to the frame rail. wheres it missing them?

[Fastbird]

It's probably not missing any from what you're saying there, so I'd look for an electrical issue if you've got one heating up. Potentially a torn or frayed ground wire or something.