95 at it again.....Help
Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
95 at it again.....Help
History: 95 6sp, turned out to have a bad PCM. Got a rebuilt one and all was good for 3 weeks until tonight.
Tonight: engine begain to cut-out...no power....Check Engine lite came on....but so did the Security lite....huh????.....engine finally just died.
Pulled codes: 43: Electronic Spark Control failure
42: ESC Timing Circuit grounded
41: ESC Timing is open
36: Baro sensor low
48: Mass Flow Flow system failure.
Also when pulling the codes, the AIR pump cycled on and off.....never had that happen before.
So I am thinking the rebuilt PCM has died...well actually the car started in the morning just fine...no problems at all. Again I say the PCM has a hot failure...just like the previous one did...quite different symptons though...end result is the same....engine will not run.
Pulled PCM and shipping back for another replacement.
Tonight: engine begain to cut-out...no power....Check Engine lite came on....but so did the Security lite....huh????.....engine finally just died.
Pulled codes: 43: Electronic Spark Control failure
42: ESC Timing Circuit grounded
41: ESC Timing is open
36: Baro sensor low
48: Mass Flow Flow system failure.
Also when pulling the codes, the AIR pump cycled on and off.....never had that happen before.
So I am thinking the rebuilt PCM has died...well actually the car started in the morning just fine...no problems at all. Again I say the PCM has a hot failure...just like the previous one did...quite different symptons though...end result is the same....engine will not run.
Pulled PCM and shipping back for another replacement.
Last edited by LannyL81; Oct 17, 2008 at 01:30 PM.
Drifting
Joined: Sep 2003
Posts: 1,363
Likes: 7
From: 1994 LT1 Coupe 6-speed with FX3 & 2000 LS1 Vert 6-Speed with F45 Hunterdon County, NJ
From our 94 FSM (Should be same as for your 95):
DTC 42 -- Ignition Control (IC) circuit (shorted or grounded circuit) 5.7L (VIN P) "Y" Carline (SFI).
Circuit Description:
THe distributor ignition system provides two timing inputs to the PCM, high resolution signal (180 pulses per crankshaft revoultion) and low resolution signal (4 pulses per crankshaft revolution). THe PCM uses these two references pulses to determine individual ignition spark timing for each cylinder.
Once the PCM calculates ignition timing, the timing signal will be sent to the gnitioin coil module on the IC circuit. Each timing pulse received by the ignition coil module on the IC circuit will trigger the ignition coil module to operate the ignition coil. Secondary ignition voltage is induced and is then sent to the ditributor for distribution to each spark plug.
THe IC Signal ranges from about .5 volts to 4.5 volts.
DTC will be set when PCM detects 84 crankshaft revolutions (versus 180/crankshaft revoultion) without any IC activity.
DTC Chart Test Description:
3. if the ignition coil module loses its voltage source, secondary voltage wil not be produced and a DTC42 will be set.
4. since the ignition coil module gets its power from the coil, check the ignition feed circuit to the ignition coil for opens.
Diagnostic aids: dtc 42 will set only during cranking.
So, with all the above info, I would speculate it is more likely a coil or Opti-spark distributor problem versus the PCM.
DTC 42 -- Ignition Control (IC) circuit (shorted or grounded circuit) 5.7L (VIN P) "Y" Carline (SFI).
Circuit Description:
THe distributor ignition system provides two timing inputs to the PCM, high resolution signal (180 pulses per crankshaft revoultion) and low resolution signal (4 pulses per crankshaft revolution). THe PCM uses these two references pulses to determine individual ignition spark timing for each cylinder.
Once the PCM calculates ignition timing, the timing signal will be sent to the gnitioin coil module on the IC circuit. Each timing pulse received by the ignition coil module on the IC circuit will trigger the ignition coil module to operate the ignition coil. Secondary ignition voltage is induced and is then sent to the ditributor for distribution to each spark plug.
THe IC Signal ranges from about .5 volts to 4.5 volts.
DTC will be set when PCM detects 84 crankshaft revolutions (versus 180/crankshaft revoultion) without any IC activity.
DTC Chart Test Description:
3. if the ignition coil module loses its voltage source, secondary voltage wil not be produced and a DTC42 will be set.
4. since the ignition coil module gets its power from the coil, check the ignition feed circuit to the ignition coil for opens.
Diagnostic aids: dtc 42 will set only during cranking.
So, with all the above info, I would speculate it is more likely a coil or Opti-spark distributor problem versus the PCM.
Drifting
Joined: Sep 2003
Posts: 1,363
Likes: 7
From: 1994 LT1 Coupe 6-speed with FX3 & 2000 LS1 Vert 6-Speed with F45 Hunterdon County, NJ
Checked for additional codes: 41 and also a 36. This sure seems to me that the rebuilt ECM I got has died. Have not tried to start it again after sitting all night....but I think I will pull the ECM and ship back and get another one...AGAIN.
What else could cause all of these codes all at once??
What else could cause all of these codes all at once??
41 is still coil, but 36 is high-res signal from opti --
how many miles and any anti-freeze leaks from pump or strong engine washing done recently?
even though your 95 should have the 'vented' opti and be less prone to these problems -- if one of the opti-spark vent hoses came off or cracked and allowed moisture/anti-freeze to enter -- it could be toast...
Thread Starter
Melting Slicks
Joined: Nov 2005
Posts: 3,323
Likes: 142
From: Green Valley Arizona
Doubt it is the OptiSpark...replaced it in troubleshooting the PCM last month.
Error code is not 16 which is the Hi Resolution one.
Also replaced coil in troubleshooting and the water pump when I replaced the OptiSpark.
Error code is not 16 which is the Hi Resolution one.
Also replaced coil in troubleshooting and the water pump when I replaced the OptiSpark.
Last edited by LannyL81; Oct 17, 2008 at 01:32 PM.
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Melting Slicks
Joined: May 2007
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From: Warwick RI
