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Worthless PCM

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I am not sure why I never did this but I pulled all 3 plugs on the PCM and the only thing different was I lost all the check engine lights (THANK GODDD!). So I am wondering why there are a million wires going to it. I had lost some functions after rewiring my truck but I thought the PCM was still doing other things, apparently not. From what I can gather, this is all it runs on my truck:

[*]Coolant Temp Gauge (Got my own, accurate to the degree exactly (digital))

[*]RPM Gauge (Got my own, accurate to the 100ths of a revolution, 1000ths if I am below 1000RPM(digital))

[*]Grid Heater Relays/WTS Light (don't care)

[*]Water In Fuel (WIF) Light (especially don't care)

[*]Check Engine Light (an issue would be obvious on a 12v)

[*]ABS (never worked anyways)

[*]Cruise Control (never worked right)

[*]A/C Compressor (rewired to run off of pressure switches)

[*]Maybe Airbags (Don't want to check)

[*]Voltage Regulator (Got an external one for 1st gen)

I don't think it runs anything else. I think I will put the grid heaters on a timer relay, got everything else taken care of. Then I will get rid of all those wires. Maybe even, eh, hmmmmmm.

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You forgot the voltage regulator... :duh::lol:

There I fixed it. That is the only thing I wish still worked. The PCM did a good job of keeping the voltage around 13.5-13.8. And no, battery temp had nothing to do with it because I threw that sensor away long ago. This 1st gen regulator runs at 14.1+ all the time.

ISX, Just out of curiosity, why did you rewire your truck?

  • Author

I absolutely hate the stock wiring. I hate that ribbed black casing and the way all the wires come together around the p7100 and just make everything harder than it needs to be. I hate looking at wires so I got rid of them on the engine and routed them differently. Lately everything has been getting to me that people do crappily. The heater core line (the steel one), why can't it be stainless? Along with all the injector lines.. I'm going to slowly redo all of it to make it the best it can be. I can't stand all of this ignorance nowadays that allow for CEO's to buy islands and such. An example of how a business should be is ARP [studs], they produce nothing but quality and don't sacrifice it to make money. I need to rewire my engine, again, only a lot better, planning it out first and I found I can remove the PCM completely in place of something much simpler. I would love to tackle the dash wiring if it wasn't such a PITA to take apart. I could really do some damage to a 1st gen :evilgrin:

I absolutely hate the stock wiring. I hate that ribbed black casing and the way all the wires come together around the p7100 and just make everything harder than it needs to be. I hate looking at wires so I got rid of them on the engine and routed them differently. Lately everything has been getting to me that people do crappily. The heater core line (the steel one), why can't it be stainless? Along with all the injector lines.. I'm going to slowly redo all of it to make it the best it can be. I can't stand all of this ignorance nowadays that allow for CEO's to buy islands and such. An example of how a business should be is ARP [studs], they produce nothing but quality and don't sacrifice it to make money. I need to rewire my engine, again, only a lot better, planning it out first and I found I can remove the PCM completely in place of something much simpler. I would love to tackle the dash wiring if it wasn't such a PITA to take apart. I could really do some damage to a 1st gen :evilgrin:

Alrighty then! Thats impressive ISX. I hate electronics. Re wiring 1970s mopars sucks enough, but rewiring a modern truck would probably make my head explode.
  • Author

Eh it's not that hard, if you have a labelmaker. I didn't so it was a PITA.Just found out the PCM also controls the speedometer :banghead: Just when I was going to throw it out.

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