HOWDY from Marietta, GA. Having hard time with 1990 Dodge Ram D250 Diesel - Will NOT START!! Idled all crazy last week, shaky shaky shaky. Then no heat getting to the manifold? Problem seems to lie in a mysterious black box located at the firewall and investigating this box has been a nightmare! Is it a PCM? ECM? Now read about a SBEC? No salvage yards ANYWHERE have this model truck either! Mercy Mercy!! Nice to meet all you Dodge Truck Owners that are passionate about it!! Hope to get this one running place an antique tag on her!!

 

If I turn my key and the engine turns over but won't fire, I immediately check my fuel shutoff solenoid. If it was running rough leading up to it dying completely, sounds to me like fuel delivery related to the IP or LP.

Your starting (or not starting issue, as it were) is not a computer-related problem. All 12 valves have mechanical fuel delivery systems and do not require a computer to run, so I'd start looking elsewhere.

What do you mean by "no heat getting to the manifold"?

 

If this is the truck in your signature, it does not have an ecm, pcm tps or cps. I think that the only brain it has is behind the glove box and controls the RWAL brake system, so you never need to worry about those things and can skip all the threads about those thing, unless you want to learn about them for future reference. Has it ever run in your presence? It may have an air leak before the injector pump, which can be hard to find, because they usually don't leak. If that truck has 12 volts to the fuel shutoff solenoid, fuel and air, it will run, so those are the things to look for. Try opening up each injector with a 17mm wrench, starting in front and see if you have fuel coming out. When it is right, you should have high pressure fuel shooting out of them...Mark

 

X3 on the fuel shutoff solenoid.

 

A pic or two of the offending box on the firewall would be helpful.

 

Box on firewall is control box for grid heaters.

 

If the box has 2 little wires running to it that plug into a triangular thing on the lower end wouldn't that be the external regulator for the alternator? About the size of a sandwich and located near the center top of the firewall?

 

the black box on the fire wall is the air heater controller(electronic control module) ecm used to control the grid heaters thru the heater selonids.the temperature in the intake manifold must be below 15 degrees(for early ecm below ser.#80000) and below 59 degrees for the later ones to start the preheat cycle..you most likely have a later one in a 1990 truck (serial # is on the back on a white paper sticker).i have a couple spares on the shelf if you need one "pm" me.there can be other problems from the thermistor to the selonids to fuseable links causing your problem. it's not that bad to figure out. just ask questions.

 

Considering the fact that it's the middle of June and he's in Marietta "hot as the surface of the Sun since May", Georgia, I'm going to go out on a limb and say his grid heater not firing has f-all to do with his truck not starting.

 

"she" and "her", rather.

 

I'll make a scientific wild guess. A week of rough running followed by no start, either a tank of dirty fuel plugged up the fuel filter, or the lift pump is dying, or an air leak between the lift pump and the tank. All are common problems.

 

Yeah, this.

 

Now I want a sandwich

 

We need a picture, cause everybody is going in way different directions.

But I think the "mysterious" black box is a red herring (herring sandwich Twitchy?) and nothing to do with how it runs. Based on the limited info, I'm with the rest - bad/old fuel.