Archived '93 12 valve weirdness with electrical, help!

[dieselworld]

Ok here goes. I have a '93 D350 206k miles automatic. Went to start the truck this morning and noticed the "wait to start" light not on. Hmmm... Started anyway right up. Then the "wait to start" light stays on while running. Noticed the volt guage not charging, A/c not working and the Overdrive not working. All this was just fine last night. Took alternator off and verified it is putting out 14 volts on the test stand, just not while on the truck. No fuses are blown. Battery tested fine also. On some other threads I have read that the main culprit is the Crank sensor?



But what is keeping the "wait to start" light on while running. I check the voltage on the manifold to be sure the maniforld grid was not being "powered" while running and it is indeed not.



Any ideas?????

 

[Kirwin]

Check the fusible links

Overdrive solenoid is supplied by a fusible link. When the link burns out I had some similair wierd electrical issues that were ultimately traced back to a shorted OD solenoid wire. This solenoid is hot all the time and the PCM mearly grounds the return side to cause the up shift to OD.



Also the Wait to Start light does weird things if it senses and out of range resistance value on the intake manifold temperature sensor. I'd look at these items first. Good luck. Ken Irwin PS I have an 85 Ramcharger that I put a late model 91 CTD in and it uses the system for the late 91 through 93 trucks.

 

[Paychk]

Check the ignition switch is fully returning to the run position, sometimes it sticks in between the start & run positions.

 

[dieselworld]

I am wondering if I have 2 seperate issues. Maybe a crank sensor and something else. It is just weird that I have all the symptoms of a bad crank sensor and the wait to start light.



Would the manual from Dodge or Cummins help more?

 

[Paychk]

Pull any fault codes by cycling the ignition switch on-off, on-off, on (on = run position, not start position). The codes are displayed by the check engine light; the sequence is set of flashes, pause, and set of flashes. End of codes is 55. No crank reference signal = 11 the engine computer wont turn on the alternator if it doesn't see engine rotation.



I would urge you to check the ignition switch, if it hangs between positions it will cause many unrelated weird symptoms. It is easy to do when the truck is screwing up bend over and look at the key, make sure it is in line with the run position.

 

[paccool]

My boy's 92 had the same symptoms as you have. Check your cruise control because it probably isn't working either. It turned out to be the ECM. Replaced that and everything returned to normal. It took a while to get a replacement module so he rigged up a voltage regulator and was able to keep driving the truck. Got the replacement unit through the local Dodge dealer, don't remember the exact amount but was less than $250.



Good luck finding the problem!

 

[dieselworld]

ok I will check out the key switch. This truck does not have cruise. There seems to be one other problem. The check engine light does not work! I verified that the bulb is new. I never noticed it before this time. Cant remember if it lit before all this weirdness. Sounds like maybe a ECM. Hmmm.....

 

[dieselworld]

I checked to make sure the switch is in the proper position and it is working fine. I had a friend connect his snap on scanner to the truck and it never would communicate to the computer. So I believe the computer is bad. I pulled the computer and all connections were tight and nothing seems to be wrong as far as I can tell. Must be an internal problem. New computer from Dodge is $206. I think that is the answer.

 

[Paychk]

Check one last thing before you spend on a computer, check the computer ground, it is between the battery & the radiator. It should have two black wires one runs to the neg. cable and the other to the computer. Make sure it is clean, bright & tight! Good luck!

 

[dieselworld]

Ok I got it fixed... ... ... ..... it was the computer. Bought one from a Dodge dealer here for $206.



Thanks for all the input

 

[Paychk]

Cool, glad to hear ya got it fixed!

 

[paccool]

Well, too bad it cost that much to fix but at least it was something you could put your finger on. I suspected that was it as it had the same symptoms as my Sons had.



Could have been worse, could be some wierd thing that you could still be looking for.