...... checked all the vac lines, and did a leak test found nothing. AFR's are crazy high. Wont drop below 13. AFR's are being logged by the ZT2.

Any ideas of things to check?


**MENTAL NOTE** if my AFR's were that crazy would my stock 02 sensors not be throwing a CEL of a lean condition????

 

little more info... is it consistantly @ 21 or does it bounce around? is this only at startup or is it after the car is all warmed up? have you changed anything recently? how about while driving in closed loop, what kind of AFR's do you have?

 

OK let me see.

Car starts at like 16 right at start up, but climbs to 21 within 10 - 15 seconds.

Recent changes, he put inan EVO IX turbo and an ACT Clutch.

Not sure I know exactly what you mean when you say driving in closed loop.

 

bump for replies....

 

the first question would be is everything hooked up correctly, espically on the MAF pipe. sounds like your getting unmetered air in from somewhere.

closed loop just means the ECU is trying to maintain a 14.7:1 AFR while your driving. It attemps to do this by using the front o2 sensor to read how much air is present in the exhaust and adjusts the injector pulse width (IPW) accordingly.

open loop is when the ECU ignores what the front o2 is saying and dumps fuel based on the preprogramed maps in the ECU.

 

I'll go back through it again tonight and check for leaks and unplugged lines or ripped ones. I pulled the maf pipe off last night and checked all the clamps and fittings and they all looked A OK. I'll do another leak down test to be double sure.

It still baffles me that the stock 02 sensors arent picking up this super lean condition.

 

How many miles on the wideband sensor? Maybe that is bad... If your front o2 was bad it would usually throw a lean condition code and bounce around a lot (AFR's) in closed loop.

 

You need a new sensor cord, the one from the O2 sensor to the box. Same thing happen to me. You messed up the connector that goes to the box.

If you wiggle the cord and the AFR changes, you need another cord.

 

Not that many miles on it. Prob less then 5 - 7 K max.

 

Did it stay at 21 or did yours start at 21 at idle and work down to 16 or 15ish?

 

Check your narrow band O2 voltages with a pocketlogger, scan tool, or evoscan. If the wideband is right, you should be showing 0.00 volts on the narrowband (stock) O2 sensor. This is what the computer looks at to throw a too lean code.

 

It should read 21:1 for a while (about 60 sec after you start the car) before the WB sensor gets up to operating temperature. Only then it will read correctly.

 

I datalogged all the way to work today, I'll look at the data here shortly.

 

It reads 21.0 at idle no matter what. I ran it for about 10 minutes and it still shows 21 at idle.

 

Good that you confirmed it. It could be that the WideBand probe itself is going bad.
So what does it read when you stomp on it? Does it change from 21? If it doesn't, then you need a new WB sensor(should be around $60 is you looked hard)
If it DOES change then you have a tunning issue.
What injectors are you running? Anything special done to the motor/turbo?