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What does a bad CPS do?


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I thought i was having a security issue, but maybe it a CPS. I wanted to take the sensor off to check it and clean it, only to find out it was pretty loose. So i cleaned it and tighten it back up. The truck still starts for a few sec. then dies. Is there a way to test these sensors? Is this even a common symptom of a bad CPS?

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It doesn't sound like a CPS issue. If the CPS was dead, it wouldn't start.

 

You can check it, get a multimeter that can check ohms(resistance). Check the resistance between the two terminals on the plug. It should (IIRC) read between 125-275 ohms. That was the check I did on my Renix, I'm not sure if the numbers are the same for a HO or not.

 

You mentioned it's got a 91 motor in an 88 or 89... was all the wiring switched over? Or is the Renix system running the HO motor?

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Since my CPS has 3 terminals on it, it must be the HO system. Do you guys know alot about these? I am pretty sure i have the alarm bypassed. Still getting good fuel pressure and spark but the truck will only run for a sec or so. And will keep running on starting fluid. I jumped the 2 wires going to the ballast resister. ANY IDEAS PLEASE

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I thought i was having a security issue, but maybe it a CPS. I wanted to take the sensor off to check it and clean it, only to find out it was pretty loose. So i cleaned it and tighten it back up. The truck still starts for a few sec. then dies. Is there a way to test these sensors? Is this even a common symptom of a bad CPS?

You also said it will keep running on starter fluid. That rules out the CPS, because with a bad CPS you have no spark.

 

Your problem is the security system killed your fuel pump. Hotwire the fuel pump and I'll bet it'll run.

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Its getting too late to try it now, but that was going to be my next move. I did jump out the relay for the fuel pump under the hood, to run some gas out to change the fuel pump. And i tryed to start it like this but it acted the same. But i will try and run a wire directly to the fuel pump too see. Thanks for the help.

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An infernal (no, that's not a typo. Y'all know exactly what I mean) requires three things to run: Fuel, air, and spark.

 

You have spark, since it'll run on starting fluid.

 

You have air, since it'll run on starting fluid.

 

One way or another, the problem has to be gas.

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An infernal

Ya, i understand that. The truck starts you can hear the fuel pump run before start up, then it dies, like i shut the key off. Then once it dies you hear the fuel pump running still. I am unsure if it shuts off when the truck dies the starts pumping after the truck dies, but i do know i never loose fuel pressure. That is why i was questioning what a CPS does, thought it may control the injectors.

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Ok so i unplugged the ignition in order to get to the bolts to move it like you said. And i decided to try and start it with it unplugged, And guess what it starts and runs!!!! So it the switch bad or do i need to move it, or do i leave it unplugged.

This is great either way its been 3 days since i've heard this thing run!!

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