Misfire on start up
11-27-2013, 11:14 AM
#1
6th Gear
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Misfire on start up
Hello,
I'm running a 95 LT1 in my 64 coupe. The wiring harness and reprogramed ECM came from Howell. ECM reprogramed to speed density, no MAF, AIR or EGR. When I start the engine, cold or hot, it ocassionally will start, come down to idle with no misfire but most of the time one or more of the injectors will not fire until it runs for 20 or 30 seconds when all of a sudden it settles down and all injectors are firing. I've been chasing this problem for a year replacing the opti, spark plugs, wires, coil, ICM, MAP, TPS, IAC and sensors. The plugs are firing but not the injectors and out of frustration I replaced the ECM with no improvement. I have gounded the wiring harness direct to the battery and used dielectric grease on all the connectors and have exhausted my technical abilities to solve this problem. Can anyone help?
Dennis
I'm running a 95 LT1 in my 64 coupe. The wiring harness and reprogramed ECM came from Howell. ECM reprogramed to speed density, no MAF, AIR or EGR. When I start the engine, cold or hot, it ocassionally will start, come down to idle with no misfire but most of the time one or more of the injectors will not fire until it runs for 20 or 30 seconds when all of a sudden it settles down and all injectors are firing. I've been chasing this problem for a year replacing the opti, spark plugs, wires, coil, ICM, MAP, TPS, IAC and sensors. The plugs are firing but not the injectors and out of frustration I replaced the ECM with no improvement. I have gounded the wiring harness direct to the battery and used dielectric grease on all the connectors and have exhausted my technical abilities to solve this problem. Can anyone help?
Dennis
11-28-2013, 12:46 AM
#3
Race Director
…or at least measure the injector resistance.
Have you verified with a noid light that the signal is not getting to the injectors when they are misfiring?
This is pretty "out there": Do you have the correct ECM and programming for sequential firing of the injectors?
Have you verified with a noid light that the signal is not getting to the injectors when they are misfiring?
This is pretty "out there": Do you have the correct ECM and programming for sequential firing of the injectors?
11-28-2013, 10:46 AM
#4
6th Gear
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Thanks C409 and Cliff,
Forgot to mention that injectors were replaced with rebuilt Bosch but will check all for resistance and with a noid light, good suggestions. As far as the proper ECM and sequencial firing I have put my trust in Howell which has a good reputation.
Thanks again,
Dennis
Forgot to mention that injectors were replaced with rebuilt Bosch but will check all for resistance and with a noid light, good suggestions. As far as the proper ECM and sequencial firing I have put my trust in Howell which has a good reputation.
Thanks again,
Dennis
