This article will hopefully give you some insight on how to adjust your fuel injection pump on 88-93 7.3L Non-Powerstroke, IDI. This will probably work the same way on a 6.9L Navistar(Ford) engine as well.
To start off, I would recommend putting in a pyrometer gauge before doing any kind of performance upgrades. I would also make sure that you clean the area that you will be working. We are going to be opening a side door on the Injector Pump and we DONT want dirt going inside.
I’m not going to say how much you should turn the adjuster, as I’m not a mechanic and I dont know for sure. I wouldnt go more than a 1/4 turn at a time without seeing how my truck deals with it, and what my pyrometer does going up hills. Lets get started!
The tools you will need:
- Mirror
- 5/32 Allen Wrench with at least 3″ of span in each direction.
- 15/16 Deep Socket, or a regular with an extension.
- Long handled socket wrench
- Flashlight (can come in handy)
First off, here is what we are looking for. The first pic is from the top of the injector pump, the second is from the left of that big hose that looks like it will be in the way.
Speaking of the big radiator hose that you see in the second picture, the first time I did this, I removed it to make it easier to get in there. I wont do that again. You can if you want, but I warn you, it was quite messy. Lots of radiator fluid everywhere.
First thing to do is take off the top bolt on the cover with the 1/4″ socket, then loosen the bottom bolt. Now slide the cover over, if you only loosen the bottom bolt, it will slide but not fall off. Dont be surprised if a little bit of fue guzzles out at the beginning.
Ok, if you look from the side, or use a mirror, you should be able to see something like this illustration. If you look carefully, you will see deeper hole in the left notch of the area you just opened up. If you look in that deeper hole, you might see the Allen nut that you need to adjust, if you cannot see this, it is possible that you will have to turn your bellhousing until it shows up.
To adjust turn your bellhousing, put your truck in neutral(make sure your emergency brake is on and your wheels are blocked). Grab your 15/16″ deep socket and long ratchet and head under the front of your truck. Just behind your fan area, you should see something like this picture. Turn the center nut inside the bellhousing there, until the Allen Nut on the injector pump shows up.
After the Allen Nut in the injector pump shows up, use your 5/32″ Allen Wrench and turn the nut clockwise, I only recommend a quarter turn. Go ahead and put the cover back on the injector pump. Make sure you did not leave your ratchet and socket still connected to your bellhousing. Clean up all your tools and fire your truck up!
You may have to play with this a couple of times to get the desired results that you want. I have mine set to where it has just enough power, but lets out huge plumes of black smoke if I start out in a high gear.
I hope this little tutorial was helpful.
[thanks to powerstroke.org used with permission]