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Discussion Starter #1 (Edited)
My wife just brought my truck home in limp mode. CEL is on and is throwing 3 codes - P0089, P0090, P0404. Truck is bone stock, just replaced fuel filter 800 miles ago. there is also a knocking sound at idle, im guessing fuel knock. throttle hasnt been as responsive as it was when i puchased it a year ago either. Also, the exhaust smells funny, smells like an additive, but there is no additive in the tank. Any help would be awesome. Thanks. :help
 

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Discussion Starter #2
Please help

Anybody?
 

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Codes:

Code:p0089
Description:Fuel Pressure Regulator Performance

Code: P0090
Description: Fuel Pressure Regulator Control Circuit

Code: PO404
Description: Exhaust Gas Recirculation Control Circuit Range/Performance.



Soooo maybe you have low fuel pressure? That would make it feel like a turd, matches your symptoms. Could be a bad CP3 or a bad FPRV?
 

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LLY's are known to have injector and FICM harness issues, both are easy DIY fixes. I'll see if I can find you some links
 

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Discussion Starter #6
Thanks for the links La77:drink. Ill try those and post back with results. also is there an easy way to tell if i have a bad fpr or cp3 without ripping the top half of the motor apart? test procedures, etc.?
 

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No problem bud :drink The injector harness came loose on me about a year ago and threw all kinds of codes, fuel knock, and limp mode. Not gonna lie, I was skeered LOL. But it turned out to be an easy fix. I went ahead and wrapped up the FICM harness before it could rub through and cause problems
 

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Discussion Starter #8
So i just did the ice pick method and checked the ficm harness for chafing, didnt find any chafes on any of the wires in the harness. i taped the shit out of it and the alternator bracket it sits on just for safe measure. Still in limp and running like shit. It sounds like an old 6.5 when its starting then quites down slightly. FPR or CP3? ideas
 

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Few suggestions for the P0089 and P0090:
1) Check your FPRV with the bottle test
2) Check for bent/damaged fuel lines
3) Verify you have prime at the fuel filter head (open bleed screw and check for bubbles)
4) Check demand vs actual fuel rail pressure

Most common fixes for this seem to be change the fuel filter first (which you did) and otherwise replace the FPRV and fuel pressure sensor.

The P0404 may be a clogged EGR system, but I would just solve that one with an EGR blocker plate and a "fingerstick".
 

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Now I have 3 more codes, p0299, p0403, and p1093. Could a bad cp3 or fpr cause all these codes or is everything failing in my truck at the same time?
 

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Now I have 3 more codes, p0299, p0403, and p1093. Could a bad cp3 or fpr cause all these codes or is everything failing in my truck at the same time?

Ok, here's your latest set of codes:

Code: P0299
Description: Turbo Underboost

Code: P0403
Description: EGR Circuit Malfunction

Code: P1093
Description: Fuel Rail Pressure Low During Power Enrichment

It still seems like the codes are centering around your EGR and the fuel system. I doubt it's a bad CP3 or FPR, but I do think you may have an issue with fuel not getting to the CP3. Again double check all the engine bay wiring harneses for chaffing and rubbing and ensure all your grounds are good. I'd pull off the fuel filter again and just verify everything was done well and you don't have any air leaks at the WIF, filter head or bleeder screw. You can also pressurize your gas tank (5-10 psi max and leave it pressurized for at least 1 hour) and see if you have any leaks in the fuel lines leading going from the tank all the way to the CP3. I already mentioned how to tackle the EGR issue above. In order to monitor any of the other electronics and sensors beyond that, you're either going to need some sort of unit like an Edge Insight or bring it to the dealer.
 

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Any chance some bad/wrong fuel was added while she had the truck? Just a thought.....
 
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