92 T/D........no charge, cruise, A/C, or O/D and wait to start light

[JWell]

Hi, Guys...



Never posted here before, but I've been reading this site to part of two days to get my brothers '92 T/D to charge the battery.



History... . it started intermittenly charging 3-4 weeks ago and I knew about brushes and bearing kit that Geno's sells so I installed those. Old brushes were badly worn, but no charge still existed after the rebuild. Autozone bench tested the alt and it is working OK.



I've been checking and cleaning connections for past couple days and can find nothing wrong with the wiring.



What I know. .

"wait to start lite" stays on after engine starts, brother Larry says O/D, A/C nor cruise control works..... maybe some other things, I haven't driven it.

Alt is definitely charging when I put 12 volts to the lower "field" stud on the alt. Continuity thru all wires so far, even to the #20 port on the PCM. Swapped out the ASD relay for the A/C relay and still no charge. Connection to the ESS/CPS appears good, but have not tried a new CPS yet. I'm down to either a bad PCM not signaling the alt to charge or bad crank position sensor. Truck has 215K on it and basically a pretty solid truck. I cannot find a big fuse on this truck and assume that is something the newer trucks have out under the hood. ??



If all wiring is good, what's left but crank position sensor or computer? I haven't found anything wrong in 2 days of fighting this thing!



Any help or suggestions would be greatly appreciated... ... . thanks, Jerry

 

[cerberusiam]

Couple more things to check. There is plug in the CPS harness behind the fan mount below the upper radiator hose. Follow the harness from the IP around to the front and you should be able to see it. The pins can get bent and not make contact in the plug, or, it falls apart. Verify continuity thru that before buying new sensor.



There is no big fuse, just a bunch of fusible links on the driver side fenderwell. I *think* one of those powers the SBEC computer. Checking to make sure all of them are good is another step.



All the functions you are talking about are controlle dout of the SBEC and will quit when the CPS signal is bad or gone. If everything else checks good it may be new computer time.



Good luck and let us know what you find.

 

[Paychk]

check that the key returns to the run position, when released from the start position. Sometimes it hangs between start and run position and when it won't power the above mentioned items.

 

[JWell]

Thanks so much for your suggestions... .

Paychk... tried to wiggle the ign. switch back and forth while running ,made no difference, but the switch seems to be working OK .

cerberusium... . I believe the contacts in the CPS harness are OK. I tightened them up a bit but it made no difference. I did check voltage in the female end of the CPS harness and could only get 3. 7 and 3. 9 on two contacts and zero on the third. Does this sound right??

Checked all the fusible links on the left fenderwell an they all had continuity. I believe my best shot right now is a new CPS. Ordered one from our forum sponsor so should have that in a few days and see what that does.

I know the fan nut is a left hand thread. Had my biggest wrench on it this morning and holding the pulley as best I could, but could not get the nut busted loose. Any tricks to getting this bugger loose??
Changing this would be a whole lot easier if I can get that fan off... .

Thanks in advance, Jerry

 

[cerberusiam]

I though it was supposed to 5 volts at the sensor nut not positive. If I get a chance will check the FSM, if nothing else for personal knowledge.

As long as you fond the plug at the top of the block and it checks good then its likely computer or CPS.

A long extension and a chain clamp is what we used to get the fan nut loose the first time. If you have an air chisel and a flat bit hit the edges of the nut will frequently knock then loose.

 

[DVolk]

have you unplugged your cruise to see what would happen ?

 

[JWell]

Thanks cerberusium & Dvolk..... Yes I do have a chain clamp so I'll remove the drive belt and see if I can get that pulley locked up... ... ... . I'll get it off somehow. Also have an air hammer and I may be able to squeeze a chisel bit down there and give the shoulder of the nut a few whacks! It will come off!!!!

No, DVolk... ..... have not unplugged the cruise, but I'm game for anything at this point... . I'll give that a try

thanks again... ... ... . Jerry

 

[DVolk]

A couple of other thoughts just poped into my mind , out near the ECM have you made shure no wires have worn though ? this happened on a mini van we had . the other thing that poped into my mind was is your cab leaking in the a pillar area ? im thinking maybe theres a short in side the truck from water in near the fuse box or ignition switch

 

[JWell]

Morning, Donovan... ... ... ... ... . I've checked all the wires around the left fenderwell and they all appear to be in pretty good shape. The fusible links are ok and I don't see that anything has rubbed thru.
I had the fuse block down out of the truck and all looked good there too. I checked the grounds that are located there beside the fuse block but they, too, looked to be in excellent shape. Subsituted the A/C relay for the ASD relay, but that did not help the "no charge" situation. I'm hoping the CPS from Geno's will turn the tide... .

I appreciate the suggestions... ... ... ... ... ... Jerry

 

[DVolk]

This might sound real dumb but if there is a bone yard or a pull your own yard that you can snag a 90s mini van ecm

unplug yours and plug that one in as ive checked the plugs there identicle as it only really controlls the voltage see what happens . have you had the Alternator checked to varify it charges ? I have also used mini van alternators on cummins trucks other than the pully they mount up just fine , try it see what happens . i have seen some place before but i think any rebuild shop can do it but they can make your alternator into a interal regulated unit then you can run a hot wire to the positive side of the battery , also are all the connections clean ?

 

[JWell]

H, Donovan... ... ... . good tip on the minivan ECM. Just happens to be a junkyard that I'm good friends with just a mile from me. If they have one I know they would let me give it a try.
I've got a new Crank Position Sensor, but haven't had a chance to put it on yet.

Yes the alt is good. I put new brushes and bearings in it. When I finished that and it didn't charge my brother had it bench tested and they (local Autozone) said it was working OK. After that and as part of the troubleshooting I ran a constant 12v wire to the field side of the alt momentarily and it showed it was charging on my DVM, so I'm pretty confident it will charge.

If the new CPS is a bust I'll try the minivan CPM and thanks for the hint..... have a good week end, I'll keep all posted.

Jerry

 

[cerberusiam]

You can try the mini-van PC to see if it will work but doubt it. Its not only charging but AC, OD, grid heaters, etc, that it runs. Pretty sure the mini-van didn't have grid heaters.

 

[HHhuntitall]

Where can you get the old one reman'd at?

 

[DVolk]

Ive checked sevral years on the ecms that they will plug into , my guess is that Ma mopar didnt use new boxes with the same plug my guess the boxes fit multiple vehicles

 

[cerberusiam]

Where can you get the old one reman'd at?

Schucks used to have them reman exchange. Trying to find a reman place that is any good is a total pain.

Ive checked sevral years on the ecms that they will plug into , my guess is that Ma mopar didnt use new boxes with the same plug my guess the boxes fit multiple vehicles

They may fit but that doesn't mean they will operate the same. All one can do is try to see if the functions will work correctly.

 

[JWell]

Good afternoon, cerberusiam, dvolk and others. Hope your weekend is going well.

Man what a puzzler this 92 TD has been! Bought a new CPS and spent quite a bit of time today installing this and guess what... ... ... ... . nothing any different!! Decided to drive it around a little thinking the computer may have to re-learn or something if it is now seeing a signal out of the CPS where it may not have gotten a signal before. I dunno, just trying things.

Well, anyhoo, after driving 15 min or so everything suddently started working exactly as it should. I felt it shift into O/D, turned the A/C on and it got cold, 'wait to start' lite went out, cruise..... everything!?!

Problem is, that was exactly what it was doing a month or so ago when I first thought it had a bad alt and rebuilt it for my bro. Shut the truck off, started it and everything works.

So bottom line is the alt is good, wiring and all connections must be ok, new CPS, so why does it take 10 miles or 15-20 minutes of driving for all these things to wake up and join the party??
I can only guess it's a computer, I dunno.

I'll let it sit tonight and see what it does in the morning. Has been fun and informative, but frustrating at times too!!!

Can't tell you how much I appreciate you guys helping me troubleshoot "ole rattler" as my bro calls it...

Thanks, Jerry

 

[cerberusiam]

Nope, should work instantly and never quit. If this is an intermittent issue and you can positively trace to warm condition smake things work thats probably the naswer.

The computers have a habit of developing cracks in the solder joints on the board. They will work when warm and quite when it is cool. Usually you see this happening when temps drop below 30 degrees or so then when the engine or air temp warms enough things work again. Once the solder and computer warms the joints make contact and things are good for a while.

Juast anothe rone of the annoying intermittent issues that cause hair loss.

 

[JWell]

Good afternoon Cerberusiam, DVolk and others.



What a puzzler this 92 TD has been. Spent the better part of this afternoon putting on a new CPS and result was ... ... ... ..... zero. Nothing different what so ever. Anyway, I thought I would drive this thing around a while thinking maybe the computer may have to re-learn or something if the old CPS was defective. Well drove 15-20 minutes or so and all of a sudden it shifted into O/D, A/C started working, cruise, "wait to start" lite went out, charging just l ike it should, everything!



Shut the motor off and restarted and still all is good. Only problem is; this is exactly what the truck was doing a month or so ago when I thought brother had a bad alt and I rebuilt it for him.



So bottom line is the alt is good, wiring and all is apparently OK, now a new CPS, so why does it take a few miles for all these accessories to wake up and join the party ??? Only thing I can think of now is the computer is somehow coming to life after a few minutes/miles. Make any sense??



I'll let it sit till tomorrow morn and see what it does then. My guess is it won't charge.



Can't tell you how much I apperciate the ideas and suggestions you have given me in troubleshooting "old rattler" as brother call it!





Have a good rest of the week-end and thanks again, Jerry

 

[HHhuntitall]

Personally, that'd make me look for the crank trigger. But that's JMO. Intermittent reading, sudden start up of the new PCM, works when warms up... ... . hmmmm.

 

[JWell]

Hi, HH:... ... ... . just put the crank position sensor on this afetrnoon. That made no difference. The PCM is the original so I'm leaning toward a bad computer now. I've checked everything I know to check and can find nothing wrong. But, yes, everything started working today after driving it maybe 8-10 miles. Pretty warm ambient temp out today maybe 92-94*. I drove it long enough to get the temp gauge up to what I would call normal, but that's hard to say with only the factory gauges to go by. .



At least I know it will charge ... ... ... ... ... sometimes!!!



Thanks for your input