MPI S/C Apex Lean at idle. Solved!

[LANEO]

I have a MPI s/c apex that is running very lean at idle & when I let off from Wide Open Throttle. When I start the sled the a/f ratio is 14/1 then after about 45 seconds of running the a/f ratio climbs from 14/1 and pins my gauge at 19.9 to 1. I turn off the machine & restart it happens again.

I think the proper A/F for 45 seconds may be helped by the apex computer adding more fuel at start for a short time or the A/f sensor or gauge may need to warm up?

Otherwise the A/F ratio is good from part throttle till WOT. I have checked & rechecked all zip tied hoses as well as engine to throttle body to intercooler charge tubes connections. I have also fattened up all modes 1-6 on the computer none affected the High idle A/F ratio at all.

Any ideas what may cause such a high idle A/F ratio. It may be higher than 19.9/1 since my gauge maxes at 19.9. Sled is running 9 lbs at sea level with a excell exhaust.

Thanks

 

[JDMCRX]

What wideband u using?

 

[TWIN TURBO]

I don't think the engine will run at 19:1 Sounds like you have an air leak after the engine before the O2 sensor or something is wrong with your wideband.

 

[LANEO]

Wideband

I am using a PLX dvices 500 model. I have not ruled out that the problem is with the gauge or the O2 sensor. The sled seems to run well. I will check for leak in the exhaust.

 

[Ted Jannetty]

Re: Has anyone else had this problem? MPI S/C Apex Lean at

I have a MPI s/c apex that is running very lean at idle & when I let off from Wide Open Throttle. When I start the sled the a/f ratio is 14/1 then after about 45 seconds of running the a/f ratio climbs from 14/1 and pins my gauge at 19.9 to 1. I turn off the machine & restart it happens again.

I think the proper A/F for 45 seconds may be helped by the apex computer adding more fuel at start for a short time or the A/f sensor or gauge may need to warm up?

Otherwise the A/F ratio is good from part throttle till WOT. I have checked & rechecked all zip tied hoses as well as engine to throttle body to intercooler charge tubes connections. I have also fattened up all modes 1-6 on the computer none affected the High idle A/F ratio at all.

Any ideas what may cause such a high idle A/F ratio. It may be higher than 19.9/1 since my gauge maxes at 19.9. Sled is running 9 lbs at sea level with a excell exhaust.

Thanks

Yes I did an install for a customer and it was also lean at ldle, just bump the mode one up and it will be fine.

Every sled has a personality and you must tune to it.

Ted.

 

[LANEO]

Twin Turbo you got it! Blew loose the Y pipe
Thanks