1994 7.3 IDI not running puzzler

[crazytwo]

I am looking at a 1994 Intl truck with an IDI. This is an auction vehicle and the listing states that the truck starts but does not run. I have not been able to get ahold of someone that can explain the problem with the engine.

Here is my question, what kind of issues could cause something like this to happen? The truck is too far to diagnose the problem before the end of the auction. Could this be a bad pump, clogged filter, something of that sort or maybe something else. I'm just trying to figure out what this might cost to fix. Any input is welcomed and appreciated.

 

[towcat]

i *love* vehicles that are for sale and the seller can't figure out why. As long as the motor turns over, it can be as simple as no power to the pump or the pump is no good. I'm surprised you can even bid on it. Everything at the auction that falls under the looming smog laws, are not allowed to be sold to be registered in kali. They have already started VIN blocking at the auction level.

 

[crazytwo]

This is in a different state and its the guberment. They make up their own rules.

When you say power to the pump, is that the shutoff solenoid? How hard is it to change out the IP on an IDI?

 

[icanfixall]

Changine the pump on an idi is stupid simple if... The engine is not in a van.. Then its doable but not much room to work. You just do not want to remove the pump, housing it bolts to and the gear as one piece. Doing it that wat you loose the gear timing and thats tuff to fix. It could be as simple as the truck is out of diesel too. To remove the pump just take off the two bolt cover on the front of the injection pump gear cover. Then you see three 5/16 12 point bolts. Remove those. Then the three 9/16 nuts that holds the pump to the gear cover. Then remove the hard lines at each injecter. Then remove the filter feed line. Now remove the throttle cable and bracket. Simpley push the pump with the lines attached towards the intake. Shift the drive end towards the passenger side fender and lift that end up bwtween the passenger side and top stud the pump bolts to and its out.. That simple. Doing it this way there is no chance of messing up the gear timing and installing the differant pump will be easy. As for actually looseing the timing of the pump.. Not the gears, yes.. You do loose the timing but have it timed after the job is done. No matter what pump you install the engine will need to be timied. All injection pumps are internally timed differantly and the marks stamped into the housing and the pump are not much more than a cloes enough mark.

 

[crazytwo]

Changine the pump on an idi is stupid simple if... The engine is not in a van.. Then its doable but not much room to work. You just do not want to remove the pump, housing it bolts to and the gear as one piece. Doing it that wat you loose the gear timing and thats tuff to fix. It could be as simple as the truck is out of diesel too. To remove the pump just take off the two bolt cover on the front of the injection pump gear cover. Then you see three 5/16 12 point bolts. Remove those. Then the three 9/16 nuts that holds the pump to the gear cover. Then remove the hard lines at each injecter. Then remove the filter feed line. Now remove the throttle cable and bracket. Simpley push the pump with the lines attached towards the intake. Shift the drive end towards the passenger side fender and lift that end up bwtween the passenger side and top stud the pump bolts to and its out.. That simple. Doing it this way there is no chance of messing up the gear timing and installing the differant pump will be easy. As for actually looseing the timing of the pump.. Not the gears, yes.. You do loose the timing but have it timed after the job is done. No matter what pump you install the engine will need to be timied. All injection pumps are internally timed differantly and the marks stamped into the housing and the pump are not much more than a cloes enough mark.

, it sounds like brain surgery since I've never had my hands on one. The good news is the hood flips up and gives easy access to the engine. Is it strange that it would start but not run?

 

[crazytwo]

Come on guys, brainstorm with me. I'm a little handicapped in that dept since I'm only working with about a half a brain.

 

[icanfixall]

It could be as simple as a dirty fuel filter too or a bad lift pump. Only being there and testing the pressure and flow in and thru the filter will tell you if thats an issue or not. Might also be someone changed out the injection pump and got it 180 degrees off gear timing.. These engines will run not do it poorly. Its amazing how these engines will run like that.

 

[ocnorb]

Most of the starts but don't runs I've seen around here are due to leaking return lines. One truck I bought actually did run good, but the dual mass flywheel had come apart and the racket made the owner think the motor was bad. ( I did explain to him that is might just be the flywheel before I bought it.)

 

[crazytwo]

It could be as simple as a dirty fuel filter too or a bad lift pump. Only being there and testing the pressure and flow in and thru the filter will tell you if thats an issue or not. Might also be someone changed out the injection pump and got it 180 degrees off gear timing.. These engines will run not do it poorly. Its amazing how these engines will run like that.

The fuel filter was the first thing to get changed. I guess I need to hit up youtube to see some IP action.

 

[crazytwo]

Most of the starts but don't runs I've seen around here are due to leaking return lines. One truck I bought actually did run good, but the dual mass flywheel had come apart and the racket made the owner think the motor was bad. ( I did explain to him that is might just be the flywheel before I bought it.)

OK, help a dummy out. How does the return line keep it from running.

 

[ocnorb]

OK, help a dummy out. How does the return line keep it from running.

Air intrusion. Starts and stalls.