My 97 250 HD has been running great after a bunch of issues. Mileage is good all good.
Went to start is this morning it popped and banged and no start. After the initial back firing it did nothing but turn over.
I pulled the spout connector it fired right up and runs great. Put the connector back it test drive no issues and no codes.
I'm leaving for a trip should I be worried about it letting me down on the road.
All new ignition plugs wires cap rotor and black ICM

 

Did I ask a dumb question or is it one nobody can answer?

 

I would expect you have a problem with your computer or maybe the harness. Pulling the computer and inspecting the board for damage is a good place to start.

Removing the spout connector removes the computer from the ignition circuit and you are just running on the mechanical timing.

 

Thanks for the reply. I've gone through a dozen stop start cycles truck seems to be running fine.
I'm not getting any codes.
This is driving me nuts.I hate driving something that I don't trust to get me home.

 

Maybe the spout connector was loose?

 

May well be this truck seems to have gremlins.

 

Do you know if the PCM has ever been replaced? I agree it sounds like the truck has gremlins, what I suggest is remove the PCM for inspection and while you are in there closely inspect the PCM connector and pins to see if any are pushed back in and that the connector fully seats when bolted to the PCM. Take the cover off the PCM and inspect the circuit board for corrosion or other damage, water from the cowl area drains inside the outer fender skin and can somtimes get inside the cab where the PCM lives if there is a crack or rust hole.

Be sure to disconnect the battery before doing any of this work.

 

Thanks but not what I wanted to confirm.
Will the PCM fail completely and leave me sitting on the side of the road or just continue to be an aggravation?
Going on a short trip this week, then parked for the winter.

 

Most computer failures in these trucks are from the electrolytic capacitors leaking onto the board and causing random damage. Water damage will do the same kind of random damage. Either way a visual inspection will let you know if something is amiss.

The symptoms are random because the impacted circuits are random.

 

A leaking capacitor might not cause any symptoms for a long time. It might leave you on side of the road. It might burn up components or damage your powertrain. It might start a fire.

Harness trouble might do all those same things.

The computer is a known, and common problem that is free and easy to diagnose with a visual inspection. That is why i said it is a good place to start.

 

Its warming up outside so I may be able to give it a look without freezing my fingers. It's winter time up here in the frozen north.
I think I'll pick up a spare. are they model, year specific?

 

Yes & no, actually. It's simple, but you have to pay attention to details.

There's a list that goes with the info below:




There sometimes is a label like the small one shown here on the back of the computer, located on the door frame or behind the driver's kick panel.



What you want to match is the number that contains ****-12A650-*** to be 100% sure.

You can match ****-12A650 & if your truck is 100% the same as the donor truck in year, engine, transmission, but the last digits not, then chances are, it will run your truck.

The last letters/digits are the equivalent of "version" , like 1.0, 1.2. 1.3, etc.

Example: the open computer is F4TE, "1994 Truck" (12A650 is generic " EEC or computer"), yours could be F7 or maybe F6.

 

Well you don't know if the PCM is part of the problem or not.. that is the reason this work was suggested.. if you find the PCM looks fine and the connector was properly attached you can take it off the list.. for now at least. In general a PCM that isn't physically damaged in any way will continue to work perfectly indefinitely, but if the caps are leaking or it has water damage all bets are off.. it could go up in smoke at any minute.. or just be a random gremlin generator for years to come.
But it is far more likely that your problem is related to the wiring harness... a bad connector.. some chafed wires somewhere, or an issue with the TFI module or distributor, both of these are crital parts of the ignition system and random issues with them is not uncommon.

 

Thanks for all the help. I'm going to run it for a week (I Hope) then park it for the winter. working with old wiring in the cold doesn't always go well.

 

Here is an update and a new twist on the no start.
Cold overnight went to start it NO GO!
Pulled the spout and it fired right up. Plugged the spout back in running fine.

???