TieRod

There was a orange rock crawlin Jeep with a 8.1l that use to run around here. Not sure if he sold it. Brett called once asking about runnin nitrous on it. He won 2nd place in the 2009 Top Truck Challenge

406jeep

116 degree, idles smooth as a sewing machine (with 3" header turn downs)

406jeep

Still have not figured out why bank 2 is running lean.

Summary up until last night
- fuel pressure is logged on scanner. Acceptable
- Replaced plug wires
- Stock injectors at 100% duty, swapped in new 42# marine from FiveO, running stock injector files with voltage offset provided by Five0, and 42# rate
- Started swapping coils from bank 1 to bank 2, looked like maybe I had a couple that were questionable, but never narrowed it down to exactly which ones. Found set of D585 coils on 2005 suburban and swapped those in yesterday and started logging data to adjust VE tables.

Attached graph is bank 1 wide band, bank 2 wide band vs rpm. I deleted all the data hits with 0 ETC pedal position. The point where the data is widest apart is also the region with the obvious problem on the road test. Why would bank 1 and bank 2 swap over at higher rpm's? Both exhaust dump out on the drivers side of the jeep to avoid the transfer case on the passenger side. It's wide open 3" exhaust so there is not much restriction. Could the location of the O2's on the shorter Bank 1 cause an error at higher RPM. I would think this would be a low RPM issue.

Photos are of the plugs 2 > 8 left to right. #4 and #6 are lighter in color, with #2 having some stain on the insulator

oldred95

I had always read the 8.1 liter likes a 180 degree thermostat and a little timing and they wake right up. Whats up with the E3s? I wouldn't even put those in my trash can let alone my engine. Go back to AC Delco's and I bet all your problems go away especially the breaking up at 2800.

LS1FREEK

iTrader: (1)

I'm with oldred95, AC Delco or even NGK TR5/TR55 work good in our stock engines. No one has ever had much luck with those weird aftermarket plugs like yours or the Bosch +4s

02_2500avalanche

Ditch those plugs!....and just out of curiosity how does the fuel filter look? I have seen fuel filters with low miles on them get pretty plugged up from the pumps picking **** out of the tank....never mind a decently flowing aftermarket pump. Any vacuum leaks? id watch the wide bands well spraying the intake around the gasket with carb clean to see if the fuel trims fluctuate. Also how is the MAF? or is it speed density tuned....if the MAF is there give it a good cleaning. Never over look the basic stuff though....I am always amazed at how somewhat simple things can cause much aggravation when trouble shooting

406jeep

It had a burnt collector gasket on Bank 2. Changed it out and relogged data, the banks are still running different but Bank 1 is lean by 3% with spikes upto 8% At least the difference is consistent from low RPM to high.
Still has a stutter in the mid rpm range and is not making the RPMs that it should. I think the highest I have seen in any WOT run has been around 4400 rpm.

I will change the plugs out and check the fuel filter. Vacuum leaks around the intake was my next target. MAF is new and clean. These sets of data have been run with MAF disabled and fuel trims off and reset.

406jeep

It was the plugs! Put in the NGK TR55's and it made a huge difference.

Thanks