This is tearing me down....I need some useful hints!

I get diffent AFR between LH/RH cyl.banks under acceleration

- Swapped injector drivers
- Swapped side of the injectors
- Checked for vacuum leaks
- Checked for exhaust leaks
- Relocated both WBO2 bung at the same distance from cyl.head.
- Swapped side of the WBO2 units/sensorn
- Disconnected all the other inputs from TPS/MAP... to eliminate elec.fault.
- Grounded all the WBO2 eq at the same place
-> Still no change

Se picture from scan http://medlem.spray.se/gta324/mods/log.jpg

Could a vacuum leak between intake/head to the lifter valley cause this?
Why is it diffrent when I accelerate and not else?

Purple- RH AFR
Yellow- LH AFR
Red- MAP
Green- TPS
Black - RPM

 

If I'm reading the chart correctly, you were running at about 2000rpm, and the the RH A/F was running about 15.5:1 and the LH was about 15.2:1. You opened the throttle (can't tell how much, the scale is cut off) and accelerated to about 2450rpm, then slowly continued to increase to about 2700rpm. During the gradual acceleration the RH A/F dipped briefly to about 13.5:1 and the LH to about 12.6:1, the the RH increase to 16.0:1 and the LH to 14.7:1.

The RH side is almost always a bit leaner than the LH side. When you are actually accelerating, the RH and LH A/F actually are the same (46.4-46.8 - appears the X-axis scale is seconds?)

What engine management sytem are you using? Is it a mass-flow or speed-density tune? Does it include a closed loop control system? Does the tune account for the boost, using a 1-bar MAP sensor, or are you running a 2-bar sensor? Is any other means used to add extra fuel under boost, like an FMU or a boost referenced fuel pressure regulator?

 

The dip is the AE, the scale is in seconds so its only a half second.

GM ECM, MAP, Open loop tune, 2bar code, this was done with no boost and around 80kPA and 50% TPS.

But I think I found something yesterday, burnt valves.............

 

Funny, I thought about this lat night and was going to recommend that you do a temp check on the primarys to see if you had a cylinder going south. That'll do it!

Steve

 

Did a temp check but didnt se anything at idle......

Anyway, searching for a EGT gauge on the net now to put in

Will remove the heads on thursday and see how bad it is.......

/N.

 

Could just pull the intake and headers off then do a leakdown an listen for the rushing air out the ports. However, when you get that far, yanking the heads is almost nothing. Don't ask me how I know


Steve

 

Pulled the headers yesterday (PITA) and put a hose down the intake runner and put AIR into the plug with pistan at TDC and felt air from the exhaust then went in and took a beer instead....so tired of this...........