Ford 7.3 IDI Question/Problem

[Dmace]

Certainly check the plug on the Throttle Position Sensor as it tends to get corroded or loose. Is the O/D light on the shifter flashing? That is one of the tell-tales of the TPS not working properly. You can adjust it and if I remember right from my old 94 IDI F350, it was a screw to adjust the max open position and fully closed position.

This page has some great info on the old Ford diesel's.
Ford diesel 6.9 7.3 IDI

 

[miramadar]

This truck is a manual transmission.

Thanks for the replies.

 

[PoorMansCat]

check/verify as ModTech suggested... I am also thinking that the injectors you purchased are of poor quality or are not the right VOP for your M.Y. pump...
If you have the originals, stick them back in right quick and see if your issues subside.
My B.I.L. has a 93 model with the 5-speed. Started having issues with it airing up if it sat for more than 24 hrs.... ended up replacing all the seal orings in the fuel filter housing and the drain valve to fix it... although it never seemed to leak to the outside.
Pull the nozzles and have them checked at a local COMPETENT diesel shop.
Just did a quick search on Napa Auto Parts... they have them for about 65.00 each... there was a note indicating E or G coded pump.... You might investigate and see waht the real difference between the E and G pumps are... apparently they take different nozzles... There may also be other differences..

 

[miramadar]

I figured I'd update this thread...

Well, the "lack of power" ended up being a couple of totally unrelated things. First, there was a red plastic part that resided inside the spring in the throttle linkage. This had broken and was restricting the movement of the throttle somewhat. Also, we cut out part of the mat beneath the accelerator pedal. Over time it had wadded up and wouldn't let the pedal be fully depressed.

I ended up taking out the reman injectors and putting the old ones back in. The old injectors were stamped "D". The reman injectors are stamped "BB". Is there a real difference here? I know the "G" stamped injectors are for turbo engines. But are "D" and "BB" interchangeable?

I came to realize that a lot of the fuel leaking was coming from the return lines. At one point, I had a stream as big as a large-guage needle shooting out of the return cap on the rear, driver side injector. I ordered a complete return line kit and replaced the caps, o-rings, hoses and hose clamps. I'm still getting a little bit of leakage from that same injector. It's not streaming now, it's just "bubbling" sort of...no air though. I've also noticed diesel leaking from the back of the motor somewhere. I haven't located it though. I figure that is a hose clamp that needs reset or something where the long hose connects the rear passenger-side injector to the main return line.

 

[2458n]

Thanks for posting your update. I have a old 7.3 in a 89 dual 4x4. Have not fooled with it in a year or so. The diesel man was a good site for getting the "o" rings and stuff for the leaky fuel return lines. Our local Ford dealer has no injection lines available and says none of this exists anymore. This truck was a good first Diesel and was kind of like driving a old volkswagon. Very user friendly if you understood how it worked.

 

[miramadar]

I came home this evening to inspect the "new" leak a little further. I took off the breather and found that I do not have 2 leaks...just 1 BIG leak. The same injector...now it's shooting a stream of fuel towards the passenger side of the engine. I removed the hard line and the fuel return cap from the injector and found that the bottom o-ring was chewed up pretty badly. Funny thing is that I just replaced it. And when I removed the old one a few days ago, it was chewed up as well. Any idea why this is happening??

 

[Diamondpilot]

I came home this evening to inspect the "new" leak a little further. I took off the breather and found that I do not have 2 leaks...just 1 BIG leak. The same injector...now it's shooting a stream of fuel towards the passenger side of the engine. I removed the hard line and the fuel return cap from the injector and found that the bottom o-ring was chewed up pretty badly. Funny thing is that I just replaced it. And when I removed the old one a few days ago, it was chewed up as well. Any idea why this is happening??

Did you put the old one back in and throw away the new one? Its happened before.

Chris

 

[crashz]

Not sure on the injector markings, but if you got those injectors online, I'm willing to bet on one of two things:

- the pop pressure was not tested at all on any of them; or
- pop pressure was set a bit high to allow of a good spray pattern.

High pop pressures will force the fuel to spray at a higher pressure and cause a finer mist of fuel. This results in better performance, less smoke and better emissions. However the injection pump must be able to develop those pressures. If its shot, the engine will not run. If its merely worn, you won't get full fuel delivery. You could be feeling the effect of that, but I'm more inclined to beleive that those injectors are just poor quality or wrong for your engine.

The rotary pumps on the Ford and GM V8 diesels were fairly dependable, but do wear out. I have replaced them around 100-150K miles in the past (GM 6.2L and Ford 6.9L diesels), but have heard of folks going longer. Maybe we get lousy fuel up here?

 

[rec]

put grease on the o rings before you put return cap back on the inj. or you can damage the new o rings

 

[newbury]

Certainly check the plug on the Throttle Position Sensor as it tends to get corroded or loose. Is the O/D light on the shifter flashing? That is one of the tell-tales of the TPS not working properly. You can adjust it and if I remember right from my old 94 IDI F350, it was a screw to adjust the max open position and fully closed position.

This page has some great info on the old Ford diesel's.
Ford diesel 6.9 7.3 IDI

Just stumbled on this thread.

The O/D light on my new to me 2002 F350 7.3 is flashing, no other problems, should I replace the TPS?