This may take awhile so sit down.

When I rebuilt the motor in my truck, I found several pintle caps cracked or broken. So I thought, what the heck, I'll just replace the injectors, and then if I later decide to get these repaired, I'll have extras.

Anyway, I bought new injectors at Autozone and they are different than the ones that came out of the truck. However, they look like one I had replaced a few years back that was found to be faulty. Now the truck is not running right.

A few things have happened over the past couple of weeks that make it hard to determine what is wrong, though. After the motor rebuild, the truck ran like doodoo. Didn't really have time to troubleshoot it, the weather was bad, and it did run, so it got put off. It was loading up real bad, like it was running rich. Finally found my fuel pressure gauge and found that after about 45 seconds, the fuel pressure went from about 40 up to >100psi. I pulled the return line from the tank selector switch and when the pressure went up, the fuel stopped running. Replaced the FPR, now pressure stays about 35. Goes up to about 43 w/ no vacuum.

But now it acts like it's starving for fuel if it isn't idling. And it isn't really a constant thing. It almost acts like a carb'd engine would if it wasn't getting enough fuel, but was getting almost enough. So, after a few hundred feet down the road, it starts to sputter and even backfires occasionally. When it sputters, it acts like the timing is getting retarded, which if it is leaning out, it could be. If it doesn't do that, it acts just like it would if I let one tank run dry before switching to the other.

Is is possible that the high pressure fuel pump is capable of maintaining pressure at low demand, but not at high demand? Could this have been caused by the excessive pressure it saw for a couple of weeks? Or could it be that the injectors were damaged by this pressure?

I haven't pulled the plugs yet, because when I can the motor is still hot, and I'd rather wait until it is cool enough to not need gloves. And when it's cool enough, I don't have the opportunity. I'll look at them this next week.

The reason I brought up the injectors that were replaced is that Autozone says these are the right ones, though the website says these are for a different Ford part.

Here's what the new ones look like:


Here's what the old ones look like:


The old injectors have the following on them: E5TE-A3B
Autozone's website says the new ones are for: E67E-B1A, E67E-B1B

The truck ran okay before the motor work, except for a broken head bolt (outside edge of head) presumably caused by a failed radiator cap.

Now it doesn't.

I think I have a broken vacuum line (going to the solenoid that controls vacuum to the EGR valve) as well, but it's enough that I can still feel suction on the end when I put the mitivac hand operated vacuum pump on it. (It does go immediately back to zero, but I can feel substantial suction initially.) I'm going to try to repair that on Monday, also. That broke when I was replacing the FPR, so it's hard to tell if it brought on any new problems. And I can't imagine that causing it to lean out like it is.

Thanks for sticking around this long.

Any ideas?

Dave

(edit: Forgot to mention this: 1989 F150, 302, AOD, Xcab, 2WD)
(And I can't find a place in the UserCP to put in a sig)

 

My thoughts:
Plugs would be my first thing to check with that much extra gas being injected. They could be fouled.

I just tested my fuel line pressure a couple days ago and it was 45 with key off and 45 running, solid as a rock. Different truck and year but it seems like a regulator should keep a constant pressure. Hmm

I wonder if the rebuilder set up the valve lash correctly. It wouldn't be the first time.

While sitting, rev it up, does it do alright without a load.

It might be nice to see what a vacuum gauge has to say. You mentioned vacuum line issues. Maybe you have a leak.

 

wrong injectors! i re-installed the originals and it runs much better. I'll be taking the new ones back to Autozone!

Dave