Ford 7.3 IDI Question/Problem

   / Ford 7.3 IDI Question/Problem #1  

miramadar

Gold Member
Joined
Apr 18, 2009
Messages
269
Location
Eastern Kentucky
Tractor
Kioti CK27
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:
 
   / Ford 7.3 IDI Question/Problem #2  
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?
 
   / Ford 7.3 IDI Question/Problem #3  
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.
 
   / Ford 7.3 IDI Question/Problem #4  
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
 
   / Ford 7.3 IDI Question/Problem
  • Thread Starter
#5  
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
 
   / Ford 7.3 IDI Question/Problem #6  
try the Dieselstop. Nothing but Fords and like here, tons of information and help.
 
   / Ford 7.3 IDI Question/Problem #7  
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.
 
   / Ford 7.3 IDI Question/Problem #8  
Maybe i am wrong, but here is a thought. Does this truck have throttle position sensor? May be the culprit.
 
   / Ford 7.3 IDI Question/Problem #9  
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.
 
   / Ford 7.3 IDI Question/Problem #10  
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.
 
 
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