7.3 IDI won't stay running

[Big Bart]

Sam,

Ok sounds like you are ship shape then. Thank you for clarifying!

1) I just wanted to confirm what was powering up the IP. Got it factory wiring which is great.
2) If others used Diesel Kleen then I guess it works, I have never heard that or seen that. But there are many ways to skin a cat.
3) I find it interesting that your fuel pressure rises before it dies. (Not after.)
a) I would try the following. Hook up the power to the fuel pump so it does not turn off. Start the truck (Based on your prior testing it should go to 5psi when running.) and then turn off the truck (Before it can stall.) and see if the fuel pressure jumps to 10psi. That would let you know something is restricting the fuel. (Like the IP solenoid is closing and causing the pressure to jump.)
b) Also a thought is your pump is creating more pressure at times(Varies), the PSI rises, then causes the IP to malfunction. But I think A is more plausible.

So if when you shut off the engine, with the fuel pump on, the PSI rises to 10psi. Then it could be your IP solenoid is failing, stays on briefly then cuts out. At that point you can put a new one in to confirm a fix. If not I would suggest you can also call a couple of IP rebuilders and say what do you think of my issue? Symptoms are X,Y,Z and my fuel pressure jumps from 5 to 10 and the truck stalls. See what they say, perhaps they can explain why the fuel pressure increases and the truck dies.

Also maybe someone else will have another thought on a different direction for you.

Let us know what you find out.

 

[lotzagoodstuff]

Nothing wrong with filling your filter with straight Diesel Kleen. Most folks changing a filter will fill up the new filter with Diesel Kleen or ATF, either one works just fine to run any IDI.

 

[Big Bart]

Good to know.

 

[saburai]

If you're going to contact an IP rebuilder, be sure to check with one that is expert with the Ford idi pump. Wes, Mel, Russ or Justin.

 

[Eric Ditwiler]

Hello I'm having trouble figuring out why my truck won't stay running. It's a 93 f250 with the 7.3 IDI. One day I was driving and the fuel filter light came on and the truck stalled shortly after. It would start back up easily but only for a second then stalled again and again and had to have it towed. Only way to keep it running was to hold the pedal to the floor and the RPM still so low it wanted to stall.

So far I've replaced the fuel filter and and replaced the manual lift pump with an electric facet pump. I have a clear line running from the fuel pump to the filter housing and another clear line from the IP return to the injectors. Both lines appear to be full of fuel and not seeing any air but still having issues. Now the truck will idle longer but very rough and will stall after giving it throttle. Sometimes it still dies shortly after startup at idle, it's pretty random.

If I give it throttle the RPMs go up briefly then fall back down/surge and stall. I'm not very familiar with this engine and haven't been able to find this exact issue online, so was wondering if anyone has any ideas. Was thinking replacing the injectors or injector pump next but I'm really not sure

 

[Eric Ditwiler]

I had a similar issue with my 6.9. It turned out that the cheap shutoff solenoid that I had installed, swelled up and was preventing the mechanism in the top of the IP from moving back and forth correctly.

 

[sam shelly]

I think I finally found the issue. Pretty sure it's the check valve that connects the return hose from the injector to the fuel filter. Took it off and there was a spring but no ball and I could blow right through it.

Plugged the end on the fuel filter with a fitting and blocked the hose off with my finger while my buddy started the engine. Sure enough it started right up and ran like a top until my finger fell off the hose. The pressure is so damn high I couldn't get a fitting to plug hose without leaking, so currently looking for a new check valve.

 

[Big Bart]

Hopefully that does the trick! Let us know.

 

[sam shelly]

I was wrong about the check valve...the old ball was actually still in there I just didn't see it. Replaced it with the new check valve and still having the same issue - runs for a few seconds then dies. I can still get it to run if I block off the check valve and return hose like in the attached picture. What could be causing this? Maybe the check valve ball isn't sealing correctly inside the filter housing?

Also what is the correct way to install the check valve? Do you put the ball in the filter housing, then the spring, then the brass fitting?

You must be registered for see images attach

 

[sam shelly]

Sorry for the late update. Truck has been sitting the past month to save up funds for a new injection pump. The only options seemed to be ~$400 for a pensacola IP or ~$1000 for a higher quality pump, so I went with the pensacola despite their reputation. The first one they sent me would instantly blow the 20a fuse that controls the FSS and glow plug controller so I wasn't able to start it. Requested a replacement and the new pump seems to be much higher quality than the first one they sent me. Bled the injector lines and the truck runs like a top now! Thanks everyone for the suggestions

Definitely recommend an angled wrench to get the IP off the studs. There is one bolt that is a PITA to reach and this saved so much time

Only issue now is my dual tank switch doesn't seem to be working anymore while it did before all this. But that is a problem for another day

 

[Big Bart]

Amazon has this, some have suggested it works. I have been meaning to try it as mine stopped working too.

Amazon.com

I also see this one.

Amazon.com

 

[sam shelly]

Having issues again once the truck warms up now. The truck runs like a top when cold but once it's warmed up it loses power. Drove fine on the way to the gas station but on the way back it would shake violently and stall constantly. Was barely able to go 10mph with the pedal to the floor. Does this sound like another bad injection pump?

 

[IDIBRONCO]

Did you have the timing set? Other than that, due to where you bought it from, I'd say yes.

 

[sam shelly]

I didn't remove the gears when replacing the IP. If I understand correctly then that means the timing should still be the same? I lined up the line on the IP and the line on the housing when putting it back in. Guess I'll be requesting another replacement pump and doing it for a third freaking time

 

[IDIBRONCO]

No I was talking about the pump timing, not the gear timing. The pump timing is checked with a meter and set by moving the IP to one side or the other. They all have slots in them where the studs stick through and the nuts hold it tight. Since you say that it runs better when cold (on fast/high idle?) than it does when warm, that makes me think pump timing. When it's on fast idle, there's also a solenoid that advances the pump timing at the same time. I'm not sure if it can be off far enough to run like you say that yours does, but it's worth a check. Those lines are just to get the engine running after the IP has been changed out for another one. You can check this for yourself by moving the IP toward the passenger's side (according to the lines) by about the width of a dime. Do this and then check to see how it runs. ALWAYS make this adjustment with the engine not running.