2007 Chevy Tahoe Post DOD Delete Misfires at Idle

[joseph.rogers]

2007 Chevy Tahoe. Recently installed new non-dod lifters, non-DOD stock cam, non-dod valley plate (kit from TSP). Changed DOD and DOD DTC settings and turned off flex fuel in HP Tuners and started her up. Random Misfire at idle... seems to be concentrated at Cylinder 4 to start and then Cylinder 2 jumps in the mix with a few in Cylinder 3.

Have checked for spark and fuel on cylinders 2 and 4. Plugs looked good but replaced them anyway and checked spark again. Confirmed all fuel injector wires are connected properly. Compression in cylinder 4 is similar to the others. Cant quite figure out the source of my issue. Log and settings below. Doesn't look like a vacuum leak per fuel trims but they appear to give up shortly after startup.

Any help would be appreciated.

2007 Chevy Tahoe 8 January 2021.hpl
2007 Chevy Tahoe 8 January 2021 DOD DELETED and Flex Fuel off.hpt

[blindsquirrel]

Fuel System #1 Status: OL - Fault

O2 sensors not switching.

Weird that the log shows no current DTCs for misfires, or anything else for that matter.

How much run time do you have on it since the swap? Have you driven it?

[joseph.rogers]

How much run time do you have on it since the swap? Have you driven it?

Not much, no driving. Misfires are so immediate and check engine flashes so I haven't pushed the issue. OL fault happens so quickly after startup.

I saw the Bank 1 sensor switches at first then gives up shortly after the fault. The bank 2 sensor just never switches. Going to switch 02 sensors later today to see if Bank 2 sensor is faulty.

Have you tried swapping #4 injector and coil packs to different cylinders?

Can you warm it up enough to get it into closed loop and see what happens with o2 readings and fuel trims?

Will swap later to see if misfire follows. See above... flashing CEL has kept me from trying to get it warm.

[frankmarroquin]

Try Engine - Fuel - Lean Fuel Saving - Enable ECT - Set @ 493

Engine Diag - Misfire - Cylinder Mode & SCD Mode... Max those tables to turn them off.

But I'd just replace the 02 to be honest.

[blindsquirrel]

Try Engine - Fuel - Lean Fuel Saving - Enable ECT - Set @ 493

Engine Diag - Misfire - Cylinder Mode & SCD Mode... Max those tables to turn them off.

But I'd just replace the 02 to be honest.

Why, if it didn't do this before when in V8 mode, does it need these changes just because it's now prevented from entering V4 mode?

[redmonjack]

I had this problem. I plugged in the vlom I had removed and it stopped all problems. my truck would not go into closed loop until i did this,

[Alvin]

That's odd.. usually setting the DTC's for the solenoids to No error reported works.