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I used an OBD1 scanner to pull codes from the truck in the hopes of fixing any problems with it. It has a couple small running issues.
Well, it spit out a heap of codes telling me basically every sensor was bad. They are: 237,519, 341, 118, 123, 113, 337. This is in a simple Key On Engine Off (KOEO) test. The problem is very similar to this thread (http://www.therangerstation.com/forums/showthread.php?p=31788) except my truck runs basically fine - just a few hiccups.
So, I don't believe every sensor is bad and start by backprobing the TPS. I find that with the positive probe on grey/white (wiper) and negative probe on grey/red (return) that I'm getting -0.1V at idle and -0.5V at WOT, but again the truck runs basically fine.
I pull the plug and check that I'm getting 5V on brown/white when grounded to the battery - yup checks out good. Then, I check that I'm getting 0V on grey/red, and I'm getting 5.5V at the reference ground, which is not what I expected at all. Further, it seems to explain the -0.1V and -0.5V at WOT - that's just the difference between the two reference values.
What could be causing this? Would another sensor being shorted cause this? Do you check if a sensor is shorted by doing a continuity test? Should the reference ground read 0V when grounded at the battery?
I asked for help here:http://www.ranger-forums.com/sohc-2-3l-2-5l-lima-engines-135/vref-issues-150118/#post2116006
But I just can't buy what he's saying. That the reference ground to PCM being 5.5V is no big deal. I think it matters because the TPS is SUPPOSED to read between 0 and 5Vs and if the top wire is 5Vs when grounded to the battery then the bottom wire had better be 0Vs when grounded to the battery.
I used an OBD1 scanner to pull codes from the truck in the hopes of fixing any problems with it. It has a couple small running issues.
Well, it spit out a heap of codes telling me basically every sensor was bad. They are: 237,519, 341, 118, 123, 113, 337. This is in a simple Key On Engine Off (KOEO) test. The problem is very similar to this thread (http://www.therangerstation.com/forums/showthread.php?p=31788) except my truck runs basically fine - just a few hiccups.
So, I don't believe every sensor is bad and start by backprobing the TPS. I find that with the positive probe on grey/white (wiper) and negative probe on grey/red (return) that I'm getting -0.1V at idle and -0.5V at WOT, but again the truck runs basically fine.
I pull the plug and check that I'm getting 5V on brown/white when grounded to the battery - yup checks out good. Then, I check that I'm getting 0V on grey/red, and I'm getting 5.5V at the reference ground, which is not what I expected at all. Further, it seems to explain the -0.1V and -0.5V at WOT - that's just the difference between the two reference values.
What could be causing this? Would another sensor being shorted cause this? Do you check if a sensor is shorted by doing a continuity test? Should the reference ground read 0V when grounded at the battery?
I asked for help here:http://www.ranger-forums.com/sohc-2-3l-2-5l-lima-engines-135/vref-issues-150118/#post2116006
But I just can't buy what he's saying. That the reference ground to PCM being 5.5V is no big deal. I think it matters because the TPS is SUPPOSED to read between 0 and 5Vs and if the top wire is 5Vs when grounded to the battery then the bottom wire had better be 0Vs when grounded to the battery.
