MudderChuck
New member
I'm not really familiar with the GC, bit it's likely there are two O2 sensors, one in the exhaust manifold down pipe and one after the catalytic converter. The O2 sensor after the cat is a known trouble spot, the wires get ripped loose and cook on the exhaust.
Code 32 throws me a little, are you sure you have the I-6 4.0 Ltr motor? Code 32 is a malfunctioning EGR, to the best of my knowledge, the later models (after around 1990 Jeeps, other than the V-8's) don't have an EGR. If yours does have an EGR it would sure explain the stalling if it is always open.
MIL (enginee lamp) type trouble codes can fool you, most just show a particular sensor out of the envelope. The reasons can be many, other than the specified sensor being bad, open or shorted circuit, a bad sensor using the same driver (power source) as another shorted sensor.
They say Napa will hook up to your serial port and have a reader for the P codes. The P codes will give you a more complete fault list.
I've misread my MIL codes before, I repeat the test a few times. I even find a friend and write down the number of flashes as somebody else is reading them. It is easy to get the count screwed up.
Like I said, I'm not real familiar with the GC, this is a learning curve for me also.
A few basics that may be helpful and are fairly universal.
If the PCM doesn't get a signal from the CPS, telling it the motor is running, it will open the the ASD relay. I don't know exactly how many pulses from the CPS has to be missing to open the ASD relay, but it can be a sometimes thing. ASD relay opens and effctively shuts off the ignition coil and opens the fuel pump relay (stops the pump from pumping).
If a sensor falls out of the system, or gives wacky readings, in most cases the PCM will default to a preprogramed set of values. The engine will run, but sometimes poorly.
In my experience, it is about a fifty fifty probability that the problem is the sensor, as often as not it is the wiring. Most sensors give a reading in changing resistance (or voltage), bad connections, shorted wires or whatever, are bound to mess with the resistance/voltage and cause bad values. The computer codes will often tell you you are getting bad values, but not the cause. I've found many problems, just by systematically inspecting the harnesses and wiring, find out were the harness is cooking or rubbed through. Look for likely troublespots, disconnect electrical connectors and inspect them for corrosion (nasty white and green stuff), clean them out with a quality contact spray and a little scrubbing. You have to be carefull with connectors, they get old and brittle, use your brain and a flashlight before your brawn.
Electrical troubleshooting is time consuming. The dealer mechanics likely have experience to help find the problem (have seen it before). Sometimes a WAG (wild arsed guess) is all they have. At $90 an hour, troubleshooting can get real expensive really quickly.
Like mentioned, heat can cause intermittent failures, the coil gets hot and fails, even a fuse with a hairline crack, can heat up and act like a switch. Connectors that are corroded can also heat up and become real iffy. Sometimes dark or discolored connector pins will lead you in the right direction. I've even seen the pins in connectors back out of the housing as the two parts of the connector were stuck together and cause iffy contact.
Code 32 throws me a little, are you sure you have the I-6 4.0 Ltr motor? Code 32 is a malfunctioning EGR, to the best of my knowledge, the later models (after around 1990 Jeeps, other than the V-8's) don't have an EGR. If yours does have an EGR it would sure explain the stalling if it is always open.
MIL (enginee lamp) type trouble codes can fool you, most just show a particular sensor out of the envelope. The reasons can be many, other than the specified sensor being bad, open or shorted circuit, a bad sensor using the same driver (power source) as another shorted sensor.
They say Napa will hook up to your serial port and have a reader for the P codes. The P codes will give you a more complete fault list.
I've misread my MIL codes before, I repeat the test a few times. I even find a friend and write down the number of flashes as somebody else is reading them. It is easy to get the count screwed up.
Like I said, I'm not real familiar with the GC, this is a learning curve for me also.
A few basics that may be helpful and are fairly universal.
If the PCM doesn't get a signal from the CPS, telling it the motor is running, it will open the the ASD relay. I don't know exactly how many pulses from the CPS has to be missing to open the ASD relay, but it can be a sometimes thing. ASD relay opens and effctively shuts off the ignition coil and opens the fuel pump relay (stops the pump from pumping).
If a sensor falls out of the system, or gives wacky readings, in most cases the PCM will default to a preprogramed set of values. The engine will run, but sometimes poorly.
In my experience, it is about a fifty fifty probability that the problem is the sensor, as often as not it is the wiring. Most sensors give a reading in changing resistance (or voltage), bad connections, shorted wires or whatever, are bound to mess with the resistance/voltage and cause bad values. The computer codes will often tell you you are getting bad values, but not the cause. I've found many problems, just by systematically inspecting the harnesses and wiring, find out were the harness is cooking or rubbed through. Look for likely troublespots, disconnect electrical connectors and inspect them for corrosion (nasty white and green stuff), clean them out with a quality contact spray and a little scrubbing. You have to be carefull with connectors, they get old and brittle, use your brain and a flashlight before your brawn.
Electrical troubleshooting is time consuming. The dealer mechanics likely have experience to help find the problem (have seen it before). Sometimes a WAG (wild arsed guess) is all they have. At $90 an hour, troubleshooting can get real expensive really quickly.
Like mentioned, heat can cause intermittent failures, the coil gets hot and fails, even a fuse with a hairline crack, can heat up and act like a switch. Connectors that are corroded can also heat up and become real iffy. Sometimes dark or discolored connector pins will lead you in the right direction. I've even seen the pins in connectors back out of the housing as the two parts of the connector were stuck together and cause iffy contact.
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