07 Suburban rough idle P0304 code afm delete

[wsteele]

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.

I think a leaky injector (especially given you tested them) is probably a long shot, just trying to figure the gas smell.

You might try a flood clear procedure when you are about to restart when hot. If it fires right up after a short flood clear, you know something is causing a lot of gas to leak into the intake after shutdown.

 

[Fless]

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

The canister vent valve opens when the ignition is shut off but closes when the ECU commands it to, so you may smell some venting back by the tank when you shut off the truck. It vents to prevent pressure buildup as the fuel temp changes and the fuel expands.

 

[Geotrash]

@Geotrash She is sitting 223,000 right now

If it's still on the original fuel pump, you're on borrowed time.

I'm a little worried about the comment that oil pump relief valve stuck open. Do you mean the one on the pump or the one in the pan? And was the one that failed original or replaced when you did the cam swap?

 

[smokymtn65]

If it's still on the original fuel pump, you're on borrowed time.

I'm a little worried about the comment that oil pump relief valve stuck open. Do you mean the one on the pump or the one in the pan? And was the one that failed original or replaced when you did the cam swap?

It was the one in the pump, I was told it was replaced @ 180k just before I bought it. It would run 80 psi cold 60+ hot

 

[smokymtn65]

The canister vent valve opens when the ignition is shut off but closes when the ECU commands it to, so you may smell some venting back by the tank when you shut off the truck. It vents to prevent pressure buildup as the fuel temp changes and the fuel expands.

So smelling gas at shut off indicates the casnister vent is working correct? is the there a way to test the purge solenoid?

 

[Geotrash]

So smelling gas at shut off indicates the casnister vent is working correct? is the there a way to test the purge solenoid?

I believe you can test it with a Tech2.

 

[smokymtn65]

I believe you can test it with a Tech2.

I was afraid that would come up.. LOL Never have got it to communicate with the CANDI again..

 

[Geotrash]

It was the one in the pump, I was told it was replaced @ 180k just before I bought it. It would run 80 psi cold 60+ hot View attachment 347442

Thanks for that. I installed a new Melling when I put mine back together, along with a new relief valve in the oil pan. It runs 55 psi when cold and 45 when hot, and 30-35 at hot idle. Fingers crossed that my workmanship and parts choices are good enough to cover the next 4500 miles of towing out to Yellowstone and back reliably. My goal was to end up with better reliability than when I started, but when I hear horror stories it always makes me bite my nails.

Also, I see that your cam is a 1-bolt cam, so you retained VVT. Makes me wonder if your stalling issue has a similar root cause to the one that guys running the L92 have been reporting for a while, which has 2-3 different potential root causes - one of them being low hot oil pressure not being enough to shift the cam back to idle profile, and another being the printed circuit board on the bottom of the fuse block starting to separate.

 

[smokymtn65]

Thanks for that. I installed a new Melling when I put mine back together, along with a new relief valve in the oil pan. It runs 55 psi when cold and 45 when hot, and 30-35 at hot idle. Fingers crossed that my workmanship and parts choices are good enough to cover the next 4500 miles of towing out to Yellowstone and back reliably. My goal was to end up with better reliability than when I started, but when I hear horror stories it always makes me bite my nails.

Also, I see that your cam is a 1-bolt cam, so you retained VVT. Makes me wonder if your stalling issue has a similar root cause to the one that guys running the L92 have been reporting for a while, which has 2-3 different potential root causes - one of them being low hot oil pressure not being enough to shift the cam back to idle profile, and another being the printed circuit board on the bottom of the fuse block starting to separate.

No i dont have VVT mine is a LC9 Went back with the Melling I will have to look part number up, but I know low op effected CAM bearings when pump failed. I have low OP now but, it does have some lol . 40cold 15 hot running 15w-50 Till I find a block and do a total build it is what it is. But I don't think that should have anything to do with the hot long crank issue. I like you, was hoping to just have a reliable DD and occaisional TT puller.

 

[swathdiver]

I was afraid that would come up.. LOL Never have got it to communicate with the CANDI again..

Did you replace the OBDII adapter?

No i dont have VVT mine is a LC9 Went back with the Melling I will have to look part number up, but I know low op effected CAM bearings when pump failed. I have low OP now

M365 oil pump?