Cps/pcm/alternator/tach

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Vice97

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Feb 22, 2014
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I just got my truck back together and it will not charge and the tach doesn't work. I don't know much about these electronics but I hear that the CRANK POSITION SENSOR feeds the PCM and it turns on some of the electrical functions, one of which is the ALTERNATOR. And I would also guess that the RPM measurement is taken at the CPS ? I figure the gap on my CPS is not set right. Does this sound right? If so what is CPS gap supposed to be set at? Also what other functions does the CPS govern?
 
Correct... Most likely either the CKP is bad or the gap is incorrect. I set them by eye but you could use a dime or a business card folded in half to double it's thickness would be close.
 
Crank position sensor. Sorry, I call it that out of habit because that's how you will usually see it labeled on wiring diagrams.
 
Vice97 said:
Thanks. Hey I was reading your sig and I'm kinda curious as to how those 5x.018s and that 28* timing are treating you with that 64mm charger?
Click to expand...


Runs good. I still push a 9' plow and tow lightly with it but you have to be mindful of throttle input. But I'm switching to a steed speed T4 manifold and a Billet S475 from Taylor Manning in the near future... ( I have everything but also acquired a broken leg) so we'll see how it likes it with the new setup. Right now it is very drive able and has great all around power. If you plan to tow a lot I would lean towards a 62mm single or twins and if you have bigger power goals go with a 66 single or larger or big twins. The 64 was in the middle because I wasn't sure where I was going with the truck when I bought it. I dynoed 518/907 with the 64 and 5x18s on an unbenched 160 pump and now I have over double the fuel with the new 180 pump but haven't had it on a Dyno since... I would guess high 600s now?
 
stubz616 said:
Runs good. I still push a 9' plow and tow lightly with it but you have to be mindful of throttle input. But I'm switching to a steed speed T4 manifold and a Billet S475 from Taylor Manning in the near future... ( I have everything but also acquired a broken leg) so we'll see how it likes it with the new setup. Right now it is very drive able and has great all around power. If you plan to tow a lot I would lean towards a 62mm single or twins and if you have bigger power goals go with a 66 single or larger or big twins. The 64 was in the middle because I wasn't sure where I was going with the truck when I bought it. I dynoed 518/907 with the 64 and 5x18s on an unbenched 160 pump and now I have over double the fuel with the new 180 pump but haven't had it on a Dyno since... I would guess high 600s now?
Click to expand...


S475 and 5x0.018s for the win!
 
Alright, I gapped the CPS and it didn't fix it. So I checked all 3 wires with a test light and none of them are hot, at least not hot enough to light up a test light. It would seem to me that at least one of the wires should be a hot wire. Mabey it's lower than 12 volts, mabey it's disconnected at the source. Anybody know where the feed is? And is there any way that I could
jumper the ALTERNATOR to make it charge or could I run a new hot to the CPS?
 
Orange is a 5 volt supply. You need to check it with a multimeter. Most likely the sensor is bad. Always check wiring first though.
 
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