Dead car - P0300 random misfire, no start
07-18-2005, 08:24 AM
#1
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Dead car - P0300 random misfire, no start For a few weeks now, my car has run a bad 02 sensor code (Bank 2 senosr 2). I installed LT headers a few years ago with no rear 02's so I installed O2 simmulators (SIMMS).
I re-tuned the car a few months ago with LS1Edit and forgot to turn off the OS tests for the rear sensors. I think the rear 02 SIMMS were OK until recently but must have gone bad recently. So earlier last week I re-tuned the car again and turned off the 02 sensor tests with LS1Edit.
P0137 HO2S Circuit Low Voltage Bank 1 Sensor 2
P0138 HO2S Circuit High Voltage Bank 1 Sensor 2
P0140 HO2S Circuit Insufficiency Activity Bank 1 Sensor 2
P0141 HO2S Heater Circuit Bank 1 Sensor 2
P0157 HO2S Circuit Low Voltage Bank 2 Sensor 2
P0158 HO2S Circuit High Voltage Bank 2 Sensor 2
P0160 HO2S Circuit Insufficiency Activity Bank 2 Sensor 2
P0161 HO2S Heater Circuit Bank 2 Sensor 2
P0420 Catalyst System Low Efficiency Bank 1
P0430 Catalyst System Low Efficiency Bank 2
I did not turn off the affected DTC codes in LS1Edit as instructed here as I was informed that would trigger a failure result if you have ODBII testing in my area.
The car ran fine for several days.
On Saturday I threw a SES light again so I check it with a code reader expecting to find another 02 sensor code.
Instead, the code came up PO300 which is random misfire. Until this point, I had not seen a PO300 code. I then pulled a few plugs to see it they were fouled - no problem. I then pulled all the plug wires and pushed them on to make sure they were tight. I then double checked the cable that connects the coil packs to the PCM. I also checked the injector cables and everything seemed good.
On a test drive the car ran fine for several miles. I stopped and picked up some stuff from the store and started to drive home.
The car died - no additional codes were thrown, however. Car will not start now.
So what could be the problem?
1. Bad rear 02 simmulator still causing problems with the PCM even though the test were terned off using LS1Edit?
2. Bad coil pack?
3. Bad injector?
4. Knock sensors swimming in a puddle of water?
5. Bad PCM?
6. Other?
Thanks
I re-tuned the car a few months ago with LS1Edit and forgot to turn off the OS tests for the rear sensors. I think the rear 02 SIMMS were OK until recently but must have gone bad recently. So earlier last week I re-tuned the car again and turned off the 02 sensor tests with LS1Edit.
P0137 HO2S Circuit Low Voltage Bank 1 Sensor 2
P0138 HO2S Circuit High Voltage Bank 1 Sensor 2
P0140 HO2S Circuit Insufficiency Activity Bank 1 Sensor 2
P0141 HO2S Heater Circuit Bank 1 Sensor 2
P0157 HO2S Circuit Low Voltage Bank 2 Sensor 2
P0158 HO2S Circuit High Voltage Bank 2 Sensor 2
P0160 HO2S Circuit Insufficiency Activity Bank 2 Sensor 2
P0161 HO2S Heater Circuit Bank 2 Sensor 2
P0420 Catalyst System Low Efficiency Bank 1
P0430 Catalyst System Low Efficiency Bank 2
I did not turn off the affected DTC codes in LS1Edit as instructed here as I was informed that would trigger a failure result if you have ODBII testing in my area.
The car ran fine for several days.
On Saturday I threw a SES light again so I check it with a code reader expecting to find another 02 sensor code.
Instead, the code came up PO300 which is random misfire. Until this point, I had not seen a PO300 code. I then pulled a few plugs to see it they were fouled - no problem. I then pulled all the plug wires and pushed them on to make sure they were tight. I then double checked the cable that connects the coil packs to the PCM. I also checked the injector cables and everything seemed good.
On a test drive the car ran fine for several miles. I stopped and picked up some stuff from the store and started to drive home.
The car died - no additional codes were thrown, however. Car will not start now.
So what could be the problem?
1. Bad rear 02 simmulator still causing problems with the PCM even though the test were terned off using LS1Edit?
2. Bad coil pack?
3. Bad injector?
4. Knock sensors swimming in a puddle of water?
5. Bad PCM?
6. Other?
Thanks
07-19-2005, 03:43 PM
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No thoughts here?
Would a bad ground wire on the cylnder head casue this?
How about a wet PCM?
How about a busted valve spring?
How about a wet knock sensor?
How about stuff that does not cost an arm and a leg?
Would a bad ground wire on the cylnder head casue this?
How about a wet PCM?
How about a busted valve spring?
How about a wet knock sensor?
How about stuff that does not cost an arm and a leg?
07-20-2005, 09:10 AM
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Since the car died in front of the chevy dealer I asked them to check it out. Apparently, a bad crank sensor. When plug wire #6 is dissconnected the car runs OK. So the coil pack may also be bad.
I replaced the cam sensor last year.... I'm also pissed that my diagnostic software (OBD-2.com) did not show any other codes for the ignition, crank sensor, etc. since I work on my car myself and would rather avoid chevy dealer labor costs......
This kinda sucks but it is better than a busted piston, bent valve or other bad hard parts.....
I replaced the cam sensor last year.... I'm also pissed that my diagnostic software (OBD-2.com) did not show any other codes for the ignition, crank sensor, etc. since I work on my car myself and would rather avoid chevy dealer labor costs......
This kinda sucks but it is better than a busted piston, bent valve or other bad hard parts.....
