No Tach, No charging from Alt either

[FSecosky]

Hey there, maybe you guys can direct me. I just put a new Everstart 1000 CA battery in the truck 2 weeks ago. The truck was fine, until now. Last weekend my tach stopped working... then it flickered on a little, then it maxed out at 4k, then it just stopped altogether again. Then, I noticed my voltage getting lower and lower on the gauge. I cleaned up my battery connections when I replaced the battery, even replaced the ground to engine cable. (sidenote: now I don't think the autozone cable that replaced the OEM cable is quite as big, but it is probably a 2 gauge, instead of the 1/0, I hope that should not matter this much). So, did all that, then since I tested the voltage before and after the truck was started, I did not see an increase in voltage at all--so I and the parts store figured it to be the alternator. I replace the alternator, and still, no increase in voltage when I start up the truck, no change at all.



I have been reading on the forums about the voltage regulator being a problem--or in my case the PCM. Okay, if that is the problem, how do I test it, and how can i just install a new voltage regulator instead of buying a new PCM.



Also, I have been reading that the Crank Sensor could be bad, since the tach and alternator are not operating... is there a way to test that without going to buy a new one--or would my truck even run without the CPS working?



My voltage on the panel reads the first tick after 8V, and sometimes below. Also, the lights dim when I turn on my turn signals, wipers, or anything else electrical.



Please, any help is greatly appreciated, I am trying to avoid having to take it into the dealer... I try to do all my own work on my vehicles, being in college still and all.

 

[DavidC]

General consensus is the tach pickup sensor could be bad. There is also a wiring issue where the sensor pigtail plugs in that you should check before condemning the sensor. The alternator will not charge if it does not know the engine is running (tach signal).



Dave

 

[Philip]

Like stated the plug by the front valve cover has problems. Look real close into the plug on the female side. There are small tabs used to make the connection. Take a small screw driver and bend the tabs out.

 

[FSecosky]

Thank you guys SOOO much! I went out there to try those things, and guess What!? I eventually dropped the male end (that leads down to the sensor)... and I was like "okay, where'd ya go?!"... then I found it (granted it IS dark here right now, and i was using my new LED lights to find my way around), it was severed inline to the sensor! I guess the belt got to it somehow and wore throught it or something, so it was making NO connection whatsoever!

Thanks a million you guys!

Peace,

Forrest Secosky

 

[Paychk]

Another satisfied customer!



BTW Welcome to the forum

 

[Greenleaf]

COOL,



Oh, by the way. You just paid for your TDR member ship six times over and cheated the dealership out of several hundered dollars





Nice going



-S

 

[DavidC]

Sometimes we get it right. It sure is nice to save someone the grief and money of a repair. Wish all the problems had an outcome like this one, not to mention the fairly easy diagnosis.



Dave

 

[JKrider]

hey guys I am new to the forum and I am having the same problem. I how ever do not have a tach so where should I look? I have a 92 gen 1. Also my check engine light came on. Thanks Jack

 

[Paychk]

It doesn't matter if you have a tach in your cab, the PCM (engine computer) still reads the tach sensor to know when the engine is running so it can engage the alt. to charge the battery.