Diesel Bombers - P0253 Question

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I was playing around with the truck last nite on my way home when I decided to listen to more of the surges i've been having, I Turned up the TST to 7 held my foot down for a little bit wating for it to spool up when finally it did I got a code. The book says something about Injection pump fuel valve open circuit problem.

Well, I was just Curious as to what this code meant. Can it be related to what i've been experiencing in the Thread "heres the plan".

SYMPTOM
P0253-FUEL INJECTION PUMP FUEL VALVE OPEN CIRCUIT

SET CONDITION
Engine speed > 100 RPM low current or no current detected at the Fuel Metering Valve.

POSSIBLE CAUSES

* Wiring/connector problem
* Other DTC'S
* Battery voltage below 12.0 volts
* Ground circuit open
* Fuel injection pump relay output circuit open
* Battery voltage below 8.0 volts
* Fuel injection pump

try adjusting your apps if that dont fix it then it may be the VP44

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.

My brother threw a PO253 code for about 6 months, then the injection pump went out. I called Brady at II & he said that the PO253 code usually means that the IAT inside of the injection pump is failing & it is a early sign of VP44 failure.

I replaced the VP in January, And wasnt sastisfied with the replacement so i warrantied the one from JAnuary a few weeks ago. Its has around 1k on it. If this is a sign of early failure, MBY i should defect this one too.

Quote:

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.

Do you just take a wild guess on how far to turn the apps and retighten it?

Turn it a little and see where it went to

Quote:

Originally Posted by crazytexan (Post 168526)

Put your meter on the wire and set it someplace you can see it while your turnin the set screw. Turn it until the meter reading matches your white tag, or as close as you can get it. Then write that nuber down someplace for future use. Thatw way you can check your APPS in a few seconds if you have problems later just by stickin the wire.

By the way. Be sure to use a straight pin to peirce the wire with and not the probe itself. Makes a much smaller hole that way. Just stick the wire with the needle and then use the gator grips to attatch to the needle.

Could this be related to the surging i've kinda been having?

OkayI just went for another joy ride to get some more info and under a throttle i diddn't get the code this time but the TST was on 4 not 7. I'll Definatly mess with that APPS sens tomorrow afternoon and see if the truck dosnt smooth out. Also that high pitch squealing sound also can be heard out of the drivers window. I'm wondering if it isn't also my boost gauge line leaking. It used to be just permatex holding the line into the fitting on the side of the head, Then i finally cleaned it up and used a ferrel and compression fittings. I'm still sure its related to the lp as well if not just that. Its a bad sound what ever it is. Thanks for the tips on the apps everyone. I'll check back and let all know how it goes.