Not Charging, No A/C, No Cruise Control - Bad Computer?

[Whitefirstgen]

so i found the battery not charging, alternator is less than a year old so starting reading posts. I was told to verify A/C and Cruise and YEP they don't work either. Sounds like could be a number of things, but most likely the ECM. Any thoughts on last checks before i send mine in to be rebuilt?

some one said crank sensor, but not sure how to test that - wires look ok.

thanks
mike

 

[DVolk]

I'd take a closer look at the fusible links by the battery ,I've had one go south on my 92 of which I bi passed also had one happen on a few gassers as well ,also there is a quick connect that goes bad too

 

[Whitefirstgen]

fusible links look ok and appear not to be blown. Which disconnect? i checked the one under turbo and looks good. the crank sensor connector at top of engine looks good as well.

 

[JDancoe]

I'd bet on the engine speed sensor. Geno's Garage has them, Cummins P/N 3924432. About $80.00

Jack Dancoe

 

[Whitefirstgen]

how can I test the speed sensor? I know I can disconnect the connector at top of motor, but what should I see on those connections.

Additional testing - I let the truck run for about 30 minutes and then the alternator started charging. shut it down and restarted NOT charging again. just thought I would mention that tidbit.

 

[nBs]

Maybe voltage regulator.

 

[MMeier]

Clean up that connection on front of head and also clean the sensor itself, I do this by running a busisness card between sensor and damper . report back !!

 

[Whitefirstgen]

connector on top of engine is nice and clean. ran a business card between sensor and shaft - seemed to get some grime out of there and was thinking maybe that was it. NOW IT WILL NOT EVEN START! OY boy.....now what does that mean??

 

[DVolk]

You said the starter is a year old , I'd pull it off and take it to the parts store and have it checked ,

 

[Whitefirstgen]

i took voltage readings on the 3 wires to the cps:

ground to batt was 0 OHMS

Voltage supply was 4 volts (expected 8 based on another post)

signal back was just under 4 volts (expected 5)

i am kindsa stumped but seems to me the computer is not sending the cps the correct voltage so it will not work. any thoughts?

 

[MMeier]

Just PM'ed you, thought I was replying to this post !

 

[Whitefirstgen]

Did you see voltages?

 

[MMeier]

Yes, saw what you have posted, can't recall what was what up there, if you look through here some it should tell. Engine does turn over, correct, just wont lite off ?

 

[Whitefirstgen]

yes turns over but will not lite off. seems like something is preventing start

 

[MMeier]

Like I said, check the connections on your fuel solenoid, maybe you knocked one off when you were checking the CPS.

 

[Whitefirstgen]

still think the voltages don't make sense so something is up there too.

 

[Whitefirstgen]

MMeier - you are correct i knocked the wire off - starts right up again. BUT still not charging. tested 3 female pins going to CPS and found only 3.7 volts coming from computer and the "signal" wire has 3.5 volts when not connected to CPS. all the posts i have seen say the computer should be sending approx 8 volts to the CPS so i believe my issue is with the computer and not the CPS. can anyone confirm that?

 

[DVolk]

Go grab a mini van computer ,there available all over cheap and plug it in and try it or you can call a alternator shop as they can make it self regulating

 

[MMeier]

Cool, glad to have helped ..... somewhat. Still haven't had time to dig into the CPS issue much... damn job !!

 

[Whitefirstgen]

I think I am going to have to give up and send the computer off. I found a company in IL (SIA electronics) that says they can refurb and give lifetime warranty for about $170. Seems like a good idea for a truck I am planning to keep for awhile.

Mike