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View Full Version : Diagnosing A/F , possible exhaust leak?


Nemesis
07-13-2005, 10:35 AM
Under full load im running 12.8:1, and under Nitrous Im running 11.5:1. However, at idle its around 15.6:1, which is not close to stoich. However, I think I might have a very minute exhaust leak. Could this be causing the problem under very light load situations and cruise?
green91
07-13-2005, 08:06 PM
alot of cars dont idle at 14.7:1. ive seen a crx HF that idled closer to 18:1. i wouldnt be terribly concerned.
Spyder
07-13-2005, 08:10 PM
cars run rich at idle, especially when they are cold it helps them warm up.. is that according to a nice highly accurate wide band.. or is that according to a light show aka air to fuel ratio gauge?
green91
07-13-2005, 08:21 PM
15.6:1 is not rich! actually, most cars run slightly lean under cold conditions.. lean = warmer egts.
Spyder
07-13-2005, 08:42 PM
15.6:1 is not rich! actually, most cars run slightly lean under cold conditions.. lean = warmer egts.

correct, sorry i had them backwards.. i realized it while i was eating dinner and came back to check this post and edit it :o
Nemesis
07-13-2005, 09:16 PM
cars run rich at idle, especially when they are cold it helps them warm up.. is that according to a nice highly accurate wide band.. or is that according to a light show aka air to fuel ratio gauge?


All data was taken from an LM-1. Its impossible to obtain a steady reading from a narrow b. All of my readings are taken from the sensor position where BATLGround welded a bung on. I have no main cat and I have MSDS Headers which remove the precats, so Im getting a good clean EG reading

Thanks for the replies everyone.