07 Suburban rough idle P0304 code afm delete

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BG1988

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a fpcm truck will have a base pressure of 43psi...under high load, warm up, cranking conditions it goes up to 58psi
43.65PSI if you want to be exact the pressure is higher with a cold key on though 58.01 PSI

I have see it as high as 80PSI in Auto Stop,, which instantly drops to 43.65 psi when the engine starts at 1500rpm
 

swathdiver

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I did look at my Tech 2 and it does not have the latest update in it , I guess that probably is a issue for no recognizing the CANDI mine is 27. something not 34 Anyone else know on this?

I do not know, wouldn't think that to be an issue for the Candi not working.

When I first got my Tech-2, my Candi was not recognized either. Turned out to be a defective OBDII adapter. Replaced that and all was well.
 
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smokymtn65

smokymtn65

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So, I could write a book about what all has happened since the DOD / AFR delete. Went to a new tuner because of the persistent hot hard start issue. He thought he fixed it but has not. however he found thing in tune that were wrong and fixed them and the truck now idles smooth and runs better. since the hard start issue started right after delete and first tune they thought is was connected. Since then the purge solenoid has been changed,(i know new doesn't mean good) and vent valve has been change neither helped.

Is there a way to test solenoid?

any ideas?

THanks
 

Geotrash

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So, I could write a book about what all has happened since the DOD / AFR delete. Went to a new tuner because of the persistent hot hard start issue. He thought he fixed it but has not. however he found thing in tune that were wrong and fixed them and the truck now idles smooth and runs better. since the hard start issue started right after delete and first tune they thought is was connected. Since then the purge solenoid has been changed,(i know new doesn't mean good) and vent valve has been change neither helped.

Is there a way to test solenoid?

any ideas?

THanks
Interesting. I have the BTR Stage 2 (v2) truck cam in my 6.2 since the winter, and it has stalled once and been a little hard to start when hot a couple of times (cranks an extra second or two), but it's very rare. Idle is definitely a little choppy but I like it. Is your stage 2 cam a v2 or a v1 version? I'm wondering if maybe they had some drivability issues with the v1 version that led to the v2. Just thinking out loud. Also, I had Black Bear do my cam tune and they did a great job so I wonder if it's worth having Black Bear do a tune for you. I know it's pricey, but might help solve your issue. You could always revert back if you need to.

The only other thing rolling around in my head is the possibility that the fuel pump is on its way out. When they start to fail, stalling and hard starting, as well as throwing the stabilitrak code are some of the ways that they start talking. How many miles on your rig?

What else have you experienced since your cam swap that might be significant that's not already mentioned in this thread. Anything else I should be on the lookout for? We're fixin' to pull our camper 4500 miles in the next 3 weeks, so it's gonna get a good shakedown.
 

wsteele

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So, I could write a book about what all has happened since the DOD / AFR delete. Went to a new tuner because of the persistent hot hard start issue. He thought he fixed it but has not. however he found thing in tune that were wrong and fixed them and the truck now idles smooth and runs better. since the hard start issue started right after delete and first tune they thought is was connected. Since then the purge solenoid has been changed,(i know new doesn't mean good) and vent valve has been change neither helped.

Is there a way to test solenoid?

any ideas?

THanks

Have things moved on from the #4 miss to an evap code (P044x)?
 
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smokymtn65

smokymtn65

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Your going to force me to write the book huh? LOL
I've had an oil pump failure, trans failure, and head replacement all in between. The oil pump relief decided to stick open.
Trans was unrelated to missfire at idle we fought for a long time (fixed) that kept triggering stabilitrack.

Cam; BTC- 1461218132

reworked heads due to valve issue on 4 which was the miss fire code. but it didn't fix the missfire.

Truck runs good now except for the hard start when hot. I got 17.5 mpg highway without DOD so happy enough.

I can smell gas when it gets parked sometimes
 
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smokymtn65

smokymtn65

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I did a test last fall or earlier this year to check for injector leak down and there was none. Wont cost me anything to check it again though but time. After all these headaches hard to look at it fresh you know. partly why I went to another tuner, Its my wife's daily driver so data logging is not something i want to put her through but I will do some this weekend So i know more about engine temp range it happens with.
 

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