WOT at 5600RPM car shuts off/backfire HELP!!
10-23-2004, 06:45 PM
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WOT at 5600RPM car shuts off/backfire HELP!! I just did a th400 swap, deleted all codes related to transmisson and copied timing tables from in gear over into in park. As I roll into it at 5500-5600 car completely dies out, twice it back fired. Checked all plugs they are good, no vacuum leaks. O2's drop from 950mv to 50mv while car is still at 100% throttle. Fuel pressure does not drop below 58psi. Any idea's????
Last edited by TooSlowFiveOh; 10-23-2004 at 06:51 PM.
10-24-2004, 01:35 AM
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Originally Posted by TooSlowFiveOh
I just did a th400 swap, deleted all codes related to transmisson and copied timing tables from in gear over into in park. As I roll into it at 5500-5600 car completely dies out, twice it back fired. Checked all plugs they are good, no vacuum leaks. O2's drop from 950mv to 50mv while car is still at 100% throttle. Fuel pressure does not drop below 58psi. Any idea's????
I am doing a TH400 swap in my '95 right now. Everyone I have talked to have told me to just change the tranny tables in LT1 edit from auto tranny to manual. Dunno why you would switch your timing tables from gear to park as you are doing the shifting now not the 'puter.
The stock rev limiter is set at 5800 rpm I believe. Mine is now set at 6850!You hitting the rev limiter? Rev limiter cuts fuel that could be the reason for your low mv on your O2's.
Ken
10-24-2004, 07:56 PM
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what motor...what mod and HP level?
Mine did this and it ended up being the crank/reluctor wheel walking away from the CPS...cutting spark....injectors still firing...spark comes back...and BANG! Big backfires.
Its just a remote possibility...just an FYI.
Mine did this and it ended up being the crank/reluctor wheel walking away from the CPS...cutting spark....injectors still firing...spark comes back...and BANG! Big backfires.
Its just a remote possibility...just an FYI.
10-25-2004, 11:39 PM
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Originally Posted by 383LQ4SS
what motor...what mod and HP level?
Mine did this and it ended up being the crank/reluctor wheel walking away from the CPS...cutting spark....injectors still firing...spark comes back...and BANG! Big backfires.
Its just a remote possibility...just an FYI.
Mine did this and it ended up being the crank/reluctor wheel walking away from the CPS...cutting spark....injectors still firing...spark comes back...and BANG! Big backfires.
Its just a remote possibility...just an FYI.
That is exactly what mine is doing. I have an Iron Ls1 motor as well. How did you fix it??? Pull the motor and weld the reluctor wheel back on??
10-27-2004, 12:11 PM
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No...it was a worn out thrust bearing. There may be something to this with 6.0 motors. PSJ had a similar experiance....but I belive his reluctor wheel was loos. There was alos another guy not to long ago...6.0 motor...same thing...his thrust bearing was worn out.
Be sure to check you CPS plug, sensor, and ring out the wires for good continuity from plug to plug first.
I pulled my motor and put in a new crank, new bearings, new rings. Its back together now and waiting on new heads.
Be sure to check you CPS plug, sensor, and ring out the wires for good continuity from plug to plug first.
I pulled my motor and put in a new crank, new bearings, new rings. Its back together now and waiting on new heads.
