Hey guys i recently got my car back from the dyno with some shocking results, i went in to install a test pipe, first run a/f ratio of 15.1 and with the test pipe it lowered it to 14.76

Weird thing is i heard earlier ap1's should run rich, the car runs strong, no CEL. and my cars smells rich, you could definately smell some fuel. and my exhaust tips are slowly turning black. car is on a stock ecu too.

It couldve been the dyno was reading wrong because according to that dyno i only have 178whp. is there any easy ways to tell if im running lean? at least till i get a wideband installed. Car has brand new oil and spark plugs. and recently did a valve adjustment.

 

14.76:1 is RICHER then 15.1:1

 

i know....

but since when do test pipes make your can run richer....?

 

thats not that much richer. The ECU can learn that fairly quickly and cahnge the STFT to accomodate.

 

i know its not alot but test pipes usually lean out the car right?

all i want to know is how could i tell if im running lean, i would imagine if i were running that kind of afr i would get a CEL.

 

over a period of time your car would throw a lean code, and possibly a p1399 random misfire if it can't be detected.

 

so back to my original question....

how would i be able to tell i am running that lean?

 

Hmmmm. There is no chance of you running too lean. By your own admission you are already on the rich side. The computer eventually adjusts to meet the mapping on all OBDII, which tries to keep you at stoich exc. at WOT.

Pulling plugs is the best way to read long-term richness, but does you no good for instant (which you will know with the wideband). Hope you have logging.

Does the test pipe have a second O2?

 

well im not sure the car is rich but it does smell rich. i just wanna know if theres any quick easy way to tell if im running lean or not besides installing a wideband. and test pipe only has one o2 sensor, comes with the CEL fix.

 

where are you getting the A/F's? if its out of the tailpipe it might be skewed... especially if you were taking them post cat, as the cat is designed to burn the unburnt gasses... however you stated that it was 14.7 afterwards... so im guessing a bad shop gauge...