hey all, just wondering if anybody has any info on what may be going on with my truck.

I have intermittenly experiencing a loss of power in 5th gear. It has been getting worse now and has happened a couple times today. You will be cruising along and go to give it throttle and it will be very "flat" for power. If I downshift into 4th and give it throttle everything returns to normal.

The other problem, which is probably related is twice I have had tons of blue smoke pour from the exhaust and the truck actually "stumbled". It cleared right up and on my way I went.

I was thinking maybe APPS, but not totally sure

any insight folks? Let me know

Thanks

Scott

 

I bet someone will be around soon to answer this fer ya! :pc:

 

Blue smoke is generally a lack of fuel. I see you have a pressure gauge installed, so what kind of pressure are you getting at idle and WOT.

If it is an APPS problem it is usually, but not always periods of dead pedal and momentary loss of Tach.

You also need to run it by an Auto Zone or someplace to have the codes checked. If you maintaining Lift Pump pressure the next likely culprit is gonna be the Injector pump. Makes sure you don't do any power upgrades until after you have increased fuel flow to much more then a stock pump is going to provide. The stock fuel supply in these trucks is far from adequate even in the stock powered truck.

 

What does the fuel pressure guage say?

Are you sure that isnt white smoke? How about hard starting when warm - does it do that? White smoke, dead pedal, hard starts when warm are all classic signs of VP-44 failure.

My initial guess is APPS or VP-44.

Have you scanned it for codes?

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You could reset the APPS and see if that helps. Heres the easy APPS reset:

"Resetting the APPS causes the ECM to 're-learn' where the throttle is at all times when something happens to cause the ECM to not understand what the APPS is telling it like a dirty spot or something like that. What you do is disconnect BOTH batteries (yes you will need to reprogram your radio), turn the key on and wait for atleast 10 minutes, then turn the key off and hook up the batteries. Once that is done turn the key on but don't start it yet. SLOWLY and steadily push the throttle to the floor and SLOWLY and steadily release it. Turn the key off and then you can start it. You have now re-set the APPS. Normally when you need to do this your APPS is in the process of failing but you bought some more time for it."

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Heres the more accurate method:

"This is different than resetting it. I did it to mine today and it made a nice difference. Boost comes up faster and smoke is down. You have to measure the voltage that the APPS is putting out then compare that to the voltage that it's supposed to be set at. For example. My apps was putting out .450 volts and it was supposed to be putting out .584 volts. I went and adjusted it and now I'm putting out .580 volts. It's not a major difference but it is nice. I've only put maybe 5 miles on it so far but come wednesday I'll be doing 500 miles a week so I'll give yall a better idea on how it drives.

Instructions:

Tools: Digital Volt Meter, T-20 Torx bit, #1 phillips, 10mm socket

With the key on, engine off you need to probe the APPS wire to see where the voltage is currently set at.
The best location to probe the wire is on the PCM (Power Control Module) which is located on the passenger firewall behind the air intake.

* You want the C1 connector, this is the connector closest to the engine
* You want the orange wire with a dark blue tracer which is pin #23
* Voltage should be somewhere around 0.5 volts,
* At this point the voltage reading does not matter, it just has to be accurately written down for later reference

TURN THE IGNITION OFF ON THE TRUCK

Remove the black plastic cover off of your APPS. There are two plastic screws. One on the top and one on the front facing the radiator. It takes a little prying to pull it off.

Undo the 6-10mm bolts that hold the bracketru in place but DO NOT REMOVE THE CABLES!!

You will notice the APPS is on the back of the bracketry that you just removed, it is held in place by 2-T20 torx bit screws. These screws have a little bit of locktite on them so make sure you have a good socket and gently give a little tap with a hammer before attempting to loosen. Be very careful because these screws strip VERY easily and you only get one shot at them (VERY VERY VERY IMPORTANT; They are VERY tight).

On the APPS you will find a white tag that gives you the information on what the APPS voltage should be.

* After loosening the screws (do not remove) you can rotate the APPS clockwise or counter clockwise to get the adjustment (towards the front of the truck increases voltage and towards the rear of the truck decreases voltage)
* The reading you took at the beginning of the process on pin #23 should match the white tag on your APPS. If it doesn't the adjust accordingly."

 

At idle the truck has 16psi, WOT - is between 13-14psi

I have never lost my tach, but I am experience periods of dead pedal

I pulled the codes from it a little while back after it happened the first time and nothing was stored - I guess I should do this again - I was going to be looking into a Smarty in the next month, but I guess that's on hold as of now.

any other info let me know

Thanks
Scott

 

Youe fuel pressure definitely is good - but the IP can fail with good fuel pressure. Not the norm, but it can happen.

I would get it scanned for codes, try the first APPS reset and see what happens from there.

Good luck with it.

Maybe someone that knows more than me will chime in with some suggestions.

 

If the VP had a period of low or no pressure before this (maybe different owner) than it is likely that it is just had enough and is starting to go down.

P0216 is what you will see. Along with the code for low voltage at the injection pump - I can't remember that number. You'll have a 1693 companion code as well.

 

I would guess you are looseing the VP, old friend of mines did the same thing two years ago going to Terra Haute. It was dead when he got home. Shut her down and it would not start again.

Andy

 

as a few said bfore its most likly going to be the vp-44. but i would not put apps
aside as the culprit. my apps did the weirdest things before it thru a code and went totally dead. from going wide open at a stoplight, to complete dead pedal. i tried cleaning it etc. nothing

 

I've never seen an apps cause blue smoke though, I have seen a VP do it.

Andy