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2003 Super Duty with 24valve cummins

16728 Views 19 Replies 6 Participants Last post by  Saul

2003 Ford F-250 Super Duty Crew cab short bed 4x4. Was a 7.3 truck from the factory.

2001 5.9 24 valve cummins engine

4r100 transmission with electronic t-case

Destroked Billet Flex plate
Destroked 5.9 to 4r100 adapter
PCS trans controller

Its more or less a project not complete.

-It runs and drives but trans does not shift correctly. feels as if motor is hitting a rev limiter when tryin to shift gears.

-the wiring is ummmm wow (see pics). cant believe it runs.

-when in park runs fine at idle and when you rev it up to higher rpm's

However the engine came from auto truck. I've been told to swap to manual ecm or get it flashed at local dodge dealer......well i called dodge today and they said the can only update it to software of auto status.

Although i have located a ecm at a local wrecking yard but seems a bit pricey.

I have a ford FSM for 2003 Ford and working on getting wiring diagrams for 2001 dodge cummins truck.

YIKES! 7.3 harness

Plugs from 5.9 engine harness next red elbow.


another shot of 5.9 engine harness plugs

wires to injection pump (ahhh dude used black wires everywhere!!)

A pic of the truck if it all matters


Do i swap to manual ecm?
Do i swap to manual engine harness as well?
Or What is wrong aside from the wiring mess?

ALL in ALL Steel @ GOS Performance is great help and has earned my business
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Your ECM has nothing to do with it if the other pieces aren't there to cause this problem.

You need to take a good look at that mess near the VP. Don't use those splices on there. That signal doesn't like any additional resistance as that will change the signal value. Does your PCS just need the actual TPS signal? That's only one wire. The ground and +5V reference shouldn't be needed unless PCS is doing something different in their box. The RPM signal is an odd one. What are you using for that? A Destroked kit? Is it the right tone ring? I'm sure PCS is expecting one like the factory uses, which is a pretty low tooth-count ring. If you are using either the Cam position sensor in front of the VP or the Crank position sensor near the rear of the block it will cause all kinds of odd things since the tone ring is different. You may be able to adjust that with programming, though.

I use an Adrenaline and it can monitor fuel pressure but you have to buy more pieces. I run a cheap Autometer Z fuel pressure gauge on the motor block from my AirDog. I would make getting a pump a priority. You can run a hollow banjo from the test port on the VP. You will need to make sure you get the parts to keep the initial pressure on start-up from destroying your sending unit. If you mount there you should put a turn valve on there so you can disconnect the gauge hardware. Just make sure you get a gauge that uses a sending unit and avoid the ones that want you to run fuel line into the cab.

If you go through my thread when I took my truck apart again you will see which parts of the Cummins harness you need. Mine is a *** since I still use a few of the GM sensors (except tachometer) so my dash works AND the sensors the Cummins ECM wants to see.

Did you buy it this way or did you build it?
Hi can you help I have the same issue with my fummins
everything works ok except I can only go 65 mph and 1800 RPM
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