Engine/Transmission (1994 - 1998) Help lost my speedoand......

[Desperado]

I lost my Speedo, tachometer, AC, and the alternator is only charging at 12 volts, the rig starts fine and all of the lights work fine. I checked all fuses and relays. What have I missed?

 

[Missouri Mule]

Desperado,

Check engine speed sensor and components(wiring,especially connector-can be dirty inside, bent pin... ) the connector is located at top front of engine behind wiring harness, sensor is right above balancer ( engine speed sensor also known as crank speed sensor).

 

[Desperado]

Ok, I think it looks like the PCM so heres what I've done, checked the volts with engine off (12. 59), started eigine checked volts again (12. 46), with engine running unhooked batteries, engine dies faster then if I turn the key off. I also checked the volts on my dads 1991 CTD (14. 85) and on Ol Blues (14. 01) still not sure what may be the problem. Help!!!!!!!!!!!!!!!!!!!!!!!!!!

 

[WMonroe]

Maybe your altenator is starting to go bad and not sending out the correct voltage? Just a thought.

Good luck.

Will

 

[Howard Durand]

I agree with Will, take the alternator off and have it checked on a test bench. If it checks OK, then suspect the PCM.

 

[Lift Tech]

Do you have working engine grid heaters, are the dash warning lights working properly? If these are working properly the PCM may not be your problem. Check that crank sensor the throttle position sensor and all negative or ground connections made to engine. If heaters and dash indicators are working then check the 12V input ,battery negative and 5V senor output values at the PCM connectors. Lost my PCM last spring it wasnt cheap so verify its bad before replacing . Its a plug and go so dont let them tell you it needs to be flashed to your vin#.

 

[illflem]

Missouri Mule has the right idea, the engine speed sensor. If it's not working correctly many things will go haywire including the alternator not putting out. Sensor is telling the PCM the engine isn't running, in turn telling the alternator and A/C to shut down.

 

[gcorron]

Guys,

I agree all these things need checking, but the way to check an alternator is to remove the battery connection while running. Now that IS for a gas engine, and I don't know WHY it would affect the diesel, but I also vote have alternator checked first. Then there is the famous grounding PCM problem for 2nd place.



Just my opinion.

 

[Desperado]

Ok, as per some great suggestions, I checked all grounds (clean and tight), pulled alternator and had it checked OK. Now I’m still lost, I still think it’s the PCM will talk to the dealer tomorrow and see what they come up with.

 

[Desperado]

I took my pick-up to the dealer today thinking worst case scenario (CPM), I get a call right after noon and they say that it is fix,Oo. I ask what they found bad , and they say that it was my crank position sensor total cost less than $200. 00. I’m really glad it wasn’t the CPM at $500. 00 plus labor. Anyway I have my wheels back. Oo. Thanks for all the suggestions and help. You guys are the best.

 

[WMonroe]

Glad to hear you got the truck back and everything is back to normal. Now you can get back to enjoying driving it.

Will

 

[Desperado]

Thanks, but You forgot the important stuff like BOMBS