7.3 idi misfire?

[Macrobb]

to the OP...
while you have your sticks out, I would do a leak down test.
why go through the trouble of replacing the sticks if you have a bad valve or lifter?

I just want to throw a couple of things out there:
1. I'm less concerned about a bad valve than you are.
Why? In my experience, if a valve or lifter isn't working right, you *know* it - you'll get popping noises and other weird sounds.
Plus, a valve really going bad is pretty rare, except on newly rebuilt motors(mainly due to tolerances not being followed...). You may have a valve not seal perfectly, but it takes a *lot* to cause a misfire that way.
Also, even with /really/ bad rings, once the engine is running, it takes a massive amount of leakdown to actually not fire, considering the volume of air being compressed vs the size of the piston ring area.

2. Every single IDI I have come across has needed injectors. Just plain and simple. So, unless you *know* the injectors were replaced recently(and with *good* ones), that's a very, /very/ likely problem.
Pumps going bad is also really common, though in my experience what usually ends up happening is that something sticks in the retarded position internally. The pump still injects fuel, but about 6 degrees retarded compared to where it should be. Advancing the pump by that much ends up letting said worn out pumps work, at least temporally.

3. To add to that, I've bought multiple "non-running" or "barely running", "parked under a tree for a couple of years" rigs. They have *all* been retarded when I got them started, by probably around 6 degrees. Advance the timing enough, and you end up with a decent running rig(I end up replacing the injectors as soon as I get around to it, too, which makes a better running truck).
I also had one truck that I bought running decently, drove it home, parked it for about 8 months... started it up, and the pump stuck retarded just like the others.

4. If you are going to be doing a leakdown or pressure test(honestly, a pressure test is probably easier and will be good enough), you use the glow plug holes, not the injector holes.

 

[OLDBULL8]

In Idaho you get some pretty cold winters, I would make the Cold Hi Idle solenoid work.
Here is how. Turn the key on but don't start, cycle the go peddle to the floor once. now see if the solenoid plunger has touched the IP throttle shaft tab, of course it has to be energized, see if it has advanced the IP throttle off the idle screw, if it hasn't, adjust the plunger out with a 1/4" open end wrench, if it's not energized, check the connection on the sensor on the passenger side under the alternator, if it's energized, start the engine, adjust the plunger until your running at 900 to 1000 RPM. On that sensor you should have 12+ VDC on both sides, if you don't, then the sensor is bad. When the head on that side reaches 120*F, the sensor will de-energize and the idle will return to 650 to 700 RPM, adjust idle screw to that RPM.

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[Macrobb]

To add to that, the entire bracket that the high idle solenoid mounts on has play in it, once you loosen the two bolts holding it in place. So do your "macro" adjustment by just loosening those, moving the entire bracket forward or back, then re-tightening. Adjust the actual solenoid shaft for a 'fine adjustment'.

 

[OLDBULL8]

If your going to buy rebuilt injectors be very careful from who you get them from. Type4, Conastogadiesel and R&D are your best sources. Read the http://www.oilburners.net/threads/the-oilburners-hall-of-shame.19805/ first.

 

[Fordfan90]

In Idaho you get some pretty cold winters, I would make the Cold Hi Idle solenoid work.
Here is how. Turn the key on but don't start, cycle the go peddle to the floor once. now see if the solenoid plunger has touched the IP throttle shaft tab, of course it has to be energized, see if it has advanced the IP throttle off the idle screw, if it hasn't, adjust the plunger out with a 1/4" open end wrench, if it's not energized, check the connection on the sensor on the passenger side under the alternator, if it's energized, start the engine, adjust the plunger until your running at 900 to 1000 RPM. On that sensor you should have 12+ VDC on both sides, if you don't, then the sensor is bad. When the head on that side reaches 120*F, the sensor will de-energize and the idle will return to 650 to 700 RPM, adjust idle screw to that RPM.

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I tested the plunger when the truck is cold and I press the pedal to the floor and go and check it the plug won't stay out I can move it back and forth. So I'm guessing it's bad then?

 

[franklin2]

I tested the plunger when the truck is cold and I press the pedal to the floor and go and check it the plug won't stay out I can move it back and forth. So I'm guessing it's bad then?

Double check it when cold with the key on with a testlight for voltage like was mentioned in a previous post. You can also find the sensor and unplug it, take the plug and put a jumper across the plug. The solenoid should then push out and stay once you open the throttle. That will verify your circuit is working, and the sensor is bad.

The sensor is a little hard to get to. On my truck it's on the pass side top of the engine down in a cavity behind the alternator.

 

[Fordfan90]

Double check it when cold with the key on with a testlight for voltage like was mentioned in a previous post. You can also find the sensor and unplug it, take the plug and put a jumper across the plug. The solenoid should then push out and stay once you open the throttle. That will verify your circuit is working, and the sensor is bad.

The sensor is a little hard to get to. On my truck it's on the pass side top of the engine down in a cavity behind the alternator.

Will check it tomorrow probably broke my hand changing oil on it a couple hours ago. Jiffy lube made sure the oil filter was tight enough that it broke a oil filter wrench