07 Suburban rough idle P0304 code afm delete

[smokymtn65]

I wonder if your tuner jacked up the fuel pressure in the tune?

I would think having the higher fuel pressure with the bigger flex fuel injectors could be dumping too much fuel, but I would also think the O2 sensors would realize that it was rich and compensate for it as well.

Someone with more tuning experience will hopefully chime in.

@randeez @swathdiver

I have had an on and off noise that sounds like an injection knock in a diesel (idi) i have spent a lot more time under the hood of those
Lol, i will try to link a recording.

Sent from my SM-G960U using Tapatalk

 

[randeez]

a fpcm truck will have a base pressure of 43psi...under high load, warm up, cranking conditions it goes up to 58psi

 

[smokymtn65]

Good to know so back to square one! lol

 

[smokymtn65]

Still no progress on this CANDI module won't work on my TECH2 so still dealing with a idle miss. Have new module on the way maybe can figure out something.

Sent from my SM-G960U using Tapatalk

 

[smokymtn65]

 

[smokymtn65]

Anyone see anthing odd here , still chasin4 cyl 4 missfire at idle

 

[wsteele]

Still no progress on this CANDI module won't work on my TECH2 so still dealing with a idle miss. Have new module on the way maybe can figure out something.

Sent from my SM-G960U using Tapatalk

My CANdi module wouldn't work when I got my Tech 2. I found out a pin on the RS232 connector was bent. I straightened the bent pin and it fired up and works fine now. I leave it connected all the time now as the pins on that connector are very soft metal and will bend easily.

 

[smokymtn65]

Update , Had a continuing issue on #4 so pick up a set of heads and had them reworked. Only to cut down on downtime. swapped heads on Saturday 2 weeks ago. Truck ran better but misfire continued, as well as hard start after heat soak. Set up time to take back to tuner as I felt I have exhausted most "mechanical" fixes. He had it for 3 days didn't get to it. I picked it up and pulled are 6K travel trailer 100miles pulls good till you idle. took it back to tuner after another three days says come get it. All the details I got were " I changed a bunch of stuff, pulled valve covers, looked at a lot of stuff. and checked a lot of grounds. when I got it back together the miss was gone. " So no miss now, idle is not real smooth but the motor mounts do transfer some of the vibration i am sure. And sitting at idle it will rhythmically cut out every 10 seconds or so.

 

[smokymtn65]

My CANdi module wouldn't work when I got my Tech 2. I found out a pin on the RS232 connector was bent. I straightened the bent pin and it fired up and works fine now. I leave it connected all the time now as the pins on that connector are very soft metal and will bend easily.

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?

 

[Geotrash]

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?

@swathdiver