Running too rich, what to do??

[forcedfedgsx]

im running a 1.08 o2 voltage at wot, anyone want to donate a safc???

 

[Kevin Jewer]

Originally posted by Romogst
The guy from the dyno place gave me a print out of my run and on it, was Max AIR/FUEL = 17.5 that's all, i'm assuming that number is too high, like he said that is way too rich and i need it to bring it down some. No flames or smoke coming out of my exhaust, car runs good.

I just noticed this. There seems to be a potential massive case of miscommunication here. I'm going to assume max airfuel is the highest numerical ratio, like something as ridiculously high as 17.5 to 1. To hell with that number, and tell us what AF ratio was under full boost, at say 6k rpm. AF ratio will start high at the begining of the run, and as rpms increase, and the operator increases load, AF ratio will drop and settle down in the midrange. I'm assuming the chart shows a graph of the AF ratio across the run.

 

[Romogst]

Originally posted by andol469


Yes, a 17.5 A/F ratio is too high. It's too high because it's LEAN. Think about the numbers man, the ratio of air/fuel. Higher numerator means leaner, lower numerator means richer. Just think about it. If it's at 17.5, that's way too lean.

How can that number be lean when it shows on my gauges and on the instruments from the guy where i dynoed my car that i'm running rich???? Give me a good number for the air/fuel mixture.

 

[turbotalon92]

A good number has been given, just read the posts?

 

[jpolizo]

Air-to-fuel of 17.5 is lean, just like everyone is saying. The optimum mix, called the stoichiometric mixture, is 14.7:1. It may be that under one set of conditions it's lean but on others it's rich.

Let's try to psyche this out because all of this makes very little sense.

The O2 sensor is only used during idle and cruise, so the ECU is going to actively try and maintain an optimum ratio in that range. If you're pumping too much fuel and the pressure goes up, the ECU has to cut the injector duty cycle. Injectors don't work well at very high duty cycles or very low duty cycles. Maybe the duty cycle of the injectors at idle is such that you get a lousy A/F ratio.

When you go to WOT, the ECU will try to go full rich and to hell with optimum ratios. Now you are way rich because you've got all this gas in there under probably too high a pressure so you end up running very rich.

That's my best WAG on this. If that's not it, maybe it's spooks.