Question : grand am gt 3400, no start intake/exhaust backfire

[tubov6cav]

iv got a 3400 v6 that i put in my cavalier, the problem im running into is a no start, and it will backfire out the intake and exhaust. i have all coils and wires in the right place. what would be causing this to happen? what could i have wired wrong that would cause the ignition timing to be off?

[caffeine]

Sounds like a spark issue for sure. If the ICM is wired correctly it will fire the spark at base timing without input from the ECM. So I would start at the crank sensor and work your way back.

[tubov6cav]

I tested the 7x, resistance and AC voltage. Both tested perfect.


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[caffeine]

Double checked the wiring for the ICM?

[tubov6cav]

Yes, all the coils spark, I have 12v and ground and still does it. I checked "timing" by removing the valve cover and getting cyl #1 at TDC compression stroke and making sure both valves were closed and they were. Not sure what else to check at this point.


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[caffeine]

Wires are all in the right order?

[tubov6cav]

Yes, for sure.


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[Superdave]

Sounds like wires to me...

[tubov6cav]

No, not the wires, I have that 100% correct.


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[88corsica5spd28]

Stupid question but does it have gas in it? My Alero did the exact same thing when it was out of gas.

Have a friend spray carb cleaner or something flammable into the PCV tube while you crank it. If it runs you're either out of gas or you have super low fuel pressure.

[tubov6cav]

Nope, tried running it in starting fluid and it did the same thing...


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[caffeine]

Bad ICM or coil(s)?

[tubov6cav]

No, I put the ICM & coils on another 3x00 vehicle we have at the house and it ran just fine..


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[caffeine]

Well it can only be so many things... compression, cam timing, crank sensor, ICM, coils, wire, plugs, fuel injectors, FPR, fuel pump.

Are you sure all 6 injectors are firing? You could try removing the rail with the fuel lines still attached and cranking the engine to see if they are all firing.

[tubov6cav]

That would cause a intake and exhaust backfire?


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