7.3 Rough Idle - PowerStrokeNation : Ford Powerstroke Diesel Forum
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post #1 of 6 (permalink) Old 11-20-2018, 09:08 PM Thread Starter
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7.3 Rough Idle

I am brand new to this forum thing. Well I say that. I've read and reviewed this forum for years but this will be my first post. I'm trying my best not to break any rules but if I manage to do so please tell me and I will correct my mistakes.

Anyways I have a 1996 F250 7.3 Auto that has given me issues. It had a very poor idle that would hunt or search and occasionally bog down and abruptly shut off. The motor has recently been rebuilt due to loss of compression on a cylinder but the same symptoms at idle are showing up again. It is worse when the motor has warmed up but still present slightly when cold.
Now here's the tricky part. This truck has been given the works. Stage 2 Full Force injectors, comp cams valve springs that are shimmed, head studs, EFuel, Terminator T500 HPOP, KC Turbos TP38R turbo, CXRacing intercooler kit, aftermarket intake and 3" to 4" straight pipe exhaust. The truck has a brand new front cover, waterpump, fan clutch, motorcraft IPR and ICP sensor and pigtails, motorcraft dark blue/purple Cam position sensor and pigtail, Alliant Power Valve cover gaskets, UVCH'S, and Injection pigtails that were soldiered in not butt connected, and a new reman IDM. Finally it has a PH Hydra chip with Powerhungry custom tunes mounted on a T3 port that was rebuilt by Powerhungry themselves.
After all of that the truck still has issues idling when warm. When it is at operating temp the ICP pressure is usually around 425-440 PSI with IPR duty cycle around 9-10%.
This truck has me stumped any and all help is appreciated. Thanks again.
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post #2 of 6 (permalink) Old 11-21-2018, 02:47 AM
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Re: 7.3 Rough Idle

Welcome to psn. Hmm. That's a tough one. All the usual suspects are new.
What happens when you unplug the icp?
No codes?

01 f-250, Standard
Rev tech 4" lift, 37" military wrangler Mt tires
KC diy 66, Full force 160/100 and custom tunes from PHP
Banks intercooler and full 4" exhaust, Diy S&B intake
Diy quad feed, Hydra, Isspro boost, pyro, and fuel pressure
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post #3 of 6 (permalink) Old 11-21-2018, 04:13 AM Thread Starter
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Thank you and yeah no codes. When you unplug the ICP the symptoms stay the same but obviously the computer displayes the "default" amount of roughly 550 PSI on the scanner if I remember correctly. Both the new ICP and IPR have been swapped for used known good units with no change.
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post #4 of 6 (permalink) Old 11-22-2018, 11:10 AM
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Re: 7.3 Rough Idle

Your hpop psi seems a little low for a T500. Have you checked your hpop reservoir to see if it is full before you start the engine?

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post #5 of 6 (permalink) Old 11-22-2018, 12:42 PM Thread Starter
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The hpop reservoir is full when starting the truck. The ICP pressure actually starts out much better than that. When the motor is cold it idles around 550-575 PSI and gradually falls to 425-440 PSI once reaching operating temp.
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post #6 of 6 (permalink) Old 11-22-2018, 06:44 PM
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Re: 7.3 Rough Idle

Hey, how do I start my own discussion. i need help with my truck's interior.

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