11 to 16 AFR at idle, not right?

[turborebel]

Could a vacuum leak on the throttle body shaft seal cause the wideband to show beween 11:1 and 16:1 AFR while at idle? What else would cause this?

 

[stickman]

Does your idle jump up and down at all??? Is your IAC valve going out?? Is your TPS sensor freaking out?? Check the voltage coming off the alternator to see if it's spiking and causing your fuel pump to send more fuel???

Just a couple suggestions.

 

[turborebel]

Yes it does. -Thanks for the ideas. The IAC is new, the TPS is old but stable, and the voltage reading from the pocket logger is always at 12 or 13 volts. I may change the GM MAF and see what happens. The idle really bugs me, the AFR can vary from 11:1 to as high as 17:1 sometimes.

 

[stickman]

I would pull the alternator and take it down to have it tested. it could be your fuel pump as well.

 

[turborebel]

I adjusted my exaust cam gear and the idle is better now. The AFR is still somewhat unstable but it seems better.

 

[Maglin]

what size injectors are you using? I've found with large injectors (ie.. 1000cc injectors) that the idle will fluctuate just like that. It's the correcting the computer is tring to do, It's to course for those large injectors. I had that same issue. I went and changed the code to native WB using 0-5v input. Also think I might have changed the amount of correction in the chip as well. (it's been almost 2 years since I did it) I got my idle AFR to go from exactly what you have to 14.3:1 - 15.1:1. Not to mention It was a lot easier to log AFR with a 5v input instead of a 1v input. If you have a keydriver chip ask Jeff about it. I dont think he advertises it but I know he can do it. If not I might be able to help you. My burner hasn't been used in over a year and I'm not totally sure that it is working correctly atm.

 

[turborebel]

My injector size is 550. I think I have a different problem. I would however, be interested in the keydriver chip. Thanks.