Engine/Transmission (1994 - 1998) 97 3500 auto multiple problems

[S.Morris]

Hope someone can help out here. My sons 97 12V service truck has pulled a fast one (he is limping home to switch to my truck for his service trailer as we speak).

History

Alternator quit charging today earlier in AM. Replaced with brand new Mopar unit.



Worked for about 60 miles (to destination of another 18 wheeler truck down call) Just as he arrived truck quit. He could hear fuel solenoid power with key.



Engine would only start and run in park... as soon as put in drive fuel solenoid seems to cut fuel.

He has no speedometer, no tach, not charging, and transmission only works in drive(starts in drive and stays there).

He has disconnected fuel solenoid to get truck to run and is driving with a generator jerry rigged to charge batteries in truck to get the thing home.



I am working night shift and unavailable to help.



We dont have a manual for wiring diagrams etc.

Can anyone nail this one down or point in right direction?? Sure would appreciate it.

Steve

 

[snappy]

The crankshaft sensor serves two functions. First, it serves to send a signal to the PCM. This signal turns on/activates PCM. Second, it provides tach signal. When the PM is off, there will not be any speedo, tach, charging, A/C, any function that the PCM controls is off. Check the crank sensor just above the crankshaft. Inspect the plug as it might not be making contact or there may be corrosion. The sensor itself could be bad.

 

[S.Morris]

Snappy... . thanks for reply.



If CS has failed will this also affect transmission?

Dont have a manual and except for TPS problems this truckthis truck has run like a champ for belive it or not 850000km.



How does the fuel cut solenoid fit into the circuit?



I was under impression there were no computers on this?



Steve

 

[snappy]

You are welcome. I have manual trans trucks. So no experience w/auto. I think the first alternator failed. The batteries did not get fully charged by the second alt. They also might be weak. If there is not enough battery, the current is too weak to keep the solenoid in the up or run position. The computer does not affect starting or running. The solenoid is a separate circuit. The most common failures here are a failed fusible link. This wire comes off the battery and is blue in colour. The other problem can be the solenoid relay.
You have be beat in Kms by 200,000, But if there are combined 'nother story. I have forgotten which pin on the pcm to check for 5 volts and at the same pin is a specification for hertz.

 

[S.Morris]

Will post up tomorrow when we get it figure out.

Thanks

 

[KYOUNG]

Make sure the big fuse on the hot wire coming from the alternator is not blown! Been there done that! If you short a wrench when tightening up battery wire on back of alt, it will pop that fuse!

 

[Missouri Mule]

S. Morris, Engine Speed Sensor (crank speed sensor) will take out about everything you mentioned. The engine speed sensors sends data to the PCM for tach, voltage (thru the Automatic Shut down relay) Overdrive, and for some unknow reason the speedometer. Don't know about trans shifting thru gears.

The engine speed sensor connector if dirty or has broken/bent pins will cause the engine to die (but will usually restart).



Another possibilty is the PCM is on its way out.

 

[S.Morris]

Spent some time on it yesterday before heading back into another 12hr night shift. It would appear that it is the computer... .

Going to try and order a new one today as well as speed sensor.



My 04 (sons backup truck) is going to Florida in a couple of weeks and wont be available to him



Also going to look at a local truck that just came out on kijiji. It is another 97 12V 3500 and at least from pictures looks like it just drove out of showroom!! It was posted at 1 am this morning and may be sold this afternoon if things are all as they appear.



Will post up when we get this old girl going ... . He's got 1000km in service calls on my truck since friday night midnight when it got rudely awakened from hibernation.



Steve

 

[S.Morris]

Well the showroom 97 was a creampuff

Coverup... ... too bad... ... . body was mint

I believe mileage showing did not come cloae

To mileage on truck...



On to my sons 97... Finally got it up and running.

Found a used computer of correct vintage. as new one

On indefinite b/o with no delivery date.

Problem fix was frustrating... to say the least.

ESS was changed, as well as computer. Also found bad

Connection AFTER fuse supply power to ECM(in cab panel))

Thought it was fixed twice... ((Ran about 100miles ea time)

Brad left on service call last night and haven't heard from him since,

So I think we finally got it. Wiring schematics would have been nice.

Steve

 

[snappy]

Glad you have her fixed. It is not often that a computer goes bad. I'd say that you have experienced one of the more challenging problems.