GFB

Not sure if I have the surging problem from too much fuel. During a steady cruise the truck lightly jerks 2-3 times a second. It's like I'm quickly and lightly tapping on the accelerator. It did this slightly after I installed the jammers, but only below 1200rpm. Now that I have the quad box it does it all the time except under hard acceleration. I have tried quad's injector tunes and they haven't helped. I have disabled the banks box to make sure that isn't causing it. Is this the same thing that others are experiencing with heavy fueling boxes that they call surging? Could it be an APPS problem?

Redliner

Mine have done it sense ive put it in. I called the place that I got mine from and they said that this is normal on edge injectors. Ive been running mine for about 10k now and no other problems. Ive also had mine re-tested and they were not out at all. Just something with edges design.

GFB

I think I'm gonna try an apps reset anyway. It gets pretty bad sometimes. I can't even run the quad box on fuel unless I've got the pedal to the floor. The jammers did it ever so slightly and it wasn't a big deal-- I just kept the rpm above 1200 and it wasn't a problem.

GFB

I did some driving and playing this afternoon and I cannot get the truck to do this while the cruise control is on. Other than my foot (I don't have cerebral palsy so I don't think that is the problem), what variable does the cruise control eliminate?

OlBlue

On the 2001.5 and 2002, the cruise control is electronic. It doesn't have a vacuum solenoid. The parts of the devices and circuits that are inactive when using the cruise control are the APPS and related wire to the ECM. Added circuits are from the PCM.

You could try replacing the APPS, but it didn't help my friends 02. We're still trying to find the stumble/surge answer....We've tried tightening the female plugs on the bottom of the APPS, replacing the APPS, replacing the MAP, replacing the IAT, cleaned all the grounds we could find.....

The odd thing seems to be that the black with light blue tracer (sensor ground) wire has a high impedance to the battery negative terminal. Is the "sensor ground" supposed to be at the same potential as the battery????

Sorry I'm not really helping, but these are what we've tried and noticed.

HOHN

My problem started as a surge, then became all dead pedal.

Bad ECM.

JH

OlBlue

Bad ECM eh? OK, I've got a loaner coming and we'll try it maybe this weekend. I'll try to remember to post the results for GFB as either another - this didn't help, or (keeping fingers crossed), woooo hoooo!

OlBlue

Holy cow! I went to find this thread and it was already buried to page 10!

Well, the loaner ECM did NOT help the stumble/surge problem.

The loaner was an original ECM and never flashed from the dealer or anyone. When the key was first turned on, the lift pump would run for the longer period of time (2 to 3 seconds). That was changed on one of the first few dealer reflashes to just a blip of the lift pump.

The reason I typed that, is because with the longer lift pump time, fuel pressure was higher when attempting to start the engine. Much of any fuel pressure to the VP, and the engine wouldn't start.

From what I've read, that indicates a injector pump that has "worn" internals due to low fuel from the lift pump. It doesn't necessarily mean the pump is dying - yet.

Would anyone have a used but good SO VP we could try in an attempt to further isolate the surge without spending $1200??

Oh, the rig has had a FASS on it for the last 45k miles or so, and fuel pressure has been great ever since.

TIA
Rob