Ford 7.3 IDI Question/Problem

[miramadar]

As I had announced in a thread on here a few months ago, I recently purchased a used 1993 Ford F350 SRW with the International 7.3 IDI diesel engine. I love the truck. It's not all that powerful, but it meets my needs nicely.

Anyway, after owning the truck for a few weeks, I noticed that some repairs were needed. The truck has 260k miles, so this is to be expected. First, the water pump had to be replaced because you could rock the fan back and forth with your hand. No biggie.

Next, I noticed that the injectors were leaking diesel fuel. After doing some reasearch, I found this to be somewhat of a common problem with the older 7.3's. I figure it has something to do with the introduction of the ULSD fuel. So, I ordered some remanufactured injectors from Diesel Care. I wanted to get new injectors, but they were on back order until the end of the year. So, I settled on the remans.

Replacing the injectors wasn't that hard of a job. But we did run into a problem when the reman injectors would not screw into its hole. We tried 3 different reman injectors, and ended up having to put one of the old injectors in it.

Anyway, the new injectors stopped the leaking problem. That's good. But now I've noticed a somewhat significant performance decline. When pulling a hill, unloaded, the truck just bogs down. For example, there are a couple of long and somewhat steep hills on my drive to work. Before, I could downshift into 4th gear and pull the hills with no problem...and even accelerate up the hill if I wanted. But now, when I hit the hills, the truck bogs down to about 1500 rpm in 4th gear and will not accelerate at all. I held the accerator to the floor...nothing. Just putted along at 1500 rpm (about 40 MPH). Today, I decided to pull the hill in 3rd gear. Pretty much the same result...it accelerated to about 1500 rpm and wouldn't go any faster. I noticed that there was no black smoke coming out of the exhaust either.

Does anyone have a clue what's going on with my truck?:confused2:

 

[mooseracing]

Was there any type of smoke - like white? I would suggest going over to oilburners.net forum. I would only buy injectors that are pop tested otherwise you are buying unknowns that may not work.

Also did you put on new return lines and o-rings at the same time?

You may be at the time where it needs a new Injection Pump. Do you know any of the past maintenance?

 

[powerstroke444e]

1st thing is check or replace the fuel filter fixes over 1/2 the problems with the old 7.3l trucks. If thats not it I would bet that the new injectors have not been pop tested and may have been set wrong.

I loved those old smokers had one that I ran bigger injectors and had pump redone to give it a little more smoke/hp. When I was lugged down it looked like there was something on fire but normal running it didnt smoke unless i got on it real hard.

 

[Diamondpilot]

Filters, injectors, pump. That is all there is to these old truck so check this stuff first.

The injectors not fitting give me a clue you got taken. Get quality injectors from a known source that have been tested. We have a good diesel shop here in town that is know world wide for his work with Cummins but also does others. Lives just across the street and 2 doors down if you need anything.

One last though is could it be just the weather? Its hot in our neck of the woods and I am sure it is in yours also. These old diesels were pretty doggy in the warmer weather.

Chris

 

[miramadar]

Was there any type of smoke - like white? I would suggest going over to oilburners.net forum. I would only buy injectors that are pop tested otherwise you are buying unknowns that may not work.

Also did you put on new return lines and o-rings at the same time?

You may be at the time where it needs a new Injection Pump. Do you know any of the past maintenance?

As always, when the truck is "cold", there is a lot of white smoke. Once it warms up, the white smoke goes away. The injectors came with new O-rings. I did not replace the return lines. As far as I know (and by the looks of it), it has the original fuel injection pump.

1st thing is check or replace the fuel filter fixes over 1/2 the problems with the old 7.3l trucks.

I put a new fuel filter on day before yesterday. Same performance...

One last though is could it be just the weather? Its hot in our neck of the woods and I am sure it is in yours also. These old diesels were pretty doggy in the warmer weather.

It's actually been relatively cool here the past few days. The morning temp, during my commute to work, was about 65 degrees. So I don't think that's dragging it down.

Thanks for the responses. I sure hope I didn't buy junk injectors! :mur:

This is the link where I got the injectors... Diesel Care Inc

 

[Rhon]

try the Dieselstop. Nothing but Fords and like here, tons of information and help.

 

[cowski]

if the injectors are good, i would say that you are sucking air through the fuel line some where. i have seen this before,the line will not leak but it will suck air.be sure and check the lines before the pump.

 

[deerefan]

Maybe i am wrong, but here is a thought. Does this truck have throttle position sensor? May be the culprit.

 

[ModMech]

I have a very similar truck, '93 F-250 7.3L IDI 5spd.

The injectors on these engines DO NOT LEAK, the "spill caps" leak, often and in some cases badly. Both Ford and IH have kits to replace the spill caps, hoses and clamps for under $100 which takes a couple of hours to do.

I have removed, installed, diagnosed and fooled with everything possible on these engines since 1988 and the 6.9L IDI (very similar product).

The injectors you have are most likely no good as that is really the only power affecting thing that you changed. However, do not discount the idea that a fuel filter restriction could be causing your power loss. Algea in the fue lis a HUGE problem now where it was not in the past. Algea will clogg the filters fast, but still let enough fuel thru to run ok at low power.

Did you get all the "coppers" out of the injector holes? Leaving even one in can cause trouble with power and performance because the injector spray is going into the completely wrong place. I once found THREE "coppers" stuck in the bottom of one injector hole. No wonder it had a bad misfire!

D@mn good engines though, not power houses but very easy to work on and reliable. Ours has 330k on the original engine.

 

[ModMech]

Maybe i am wrong, but here is a thought. Does this truck have throttle position sensor? May be the culprit.

If it's an AT, then yes, which would explain the lack of down-sifting.

 

[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?