Air to Fuel Ratio Question

Watain · 10-04-2009

I started my car up yesterday and I think it might be running rich.(has a slight gassy smell which went away once the high idle came down) Question is, is there a way besides slapping it on the dyno, or putting a wideband on it to find out? I tried seeing if I could use the data logger in the SCT X3 to find it out. All I could monitor was fuel trim.

Other than the gassy smell, with the new tune the rear tires want to break loose when the car shifts into third gear a WOT I found out yesterday.

Thanks guys.

05horse · 10-04-2009

Quote:

Originally Posted by Watain

I started my car up yesterday and I think it might be running rich.(has a slight gassy smell which went away once the high idle came down) Question is, is there a way besides slapping it on the dyno, or putting a wideband on it to find out? I tried seeing if I could use the data logger in the SCT X3 to find it out. All I could monitor was fuel trim.

Other than the gassy smell, with the new tune the rear tires want to break loose when the car shifts into third gear a WOT I found out yesterday.

Thanks guys.

our cars come over rich from the factory.

a dyno tune will cure that

sqidd · 10-04-2009

Quote:

a dyno tune will cure that

He has one

It may be your tune. It may be you were just in an environment where you would notice it more. It could be a tank of smelly gas. It could be a million things. But aside from sniffing the exhaust with a A/F ratio monitor of some sort there is no way of telling what it "IS".

It may be set up rich as part of the tune for warm up. Back in the stone age that's what a choke did.

RedFire07GT · 10-04-2009

Like sqidd said it could jsut be the gas your running. My air/Fuel Ratio is rite between 12.5-12.7.

I run 93-Octane Fuel from Sunoco or sometimes Shell.

My car has you can deff. notice the smell of fuel. But i also have no cats. That might bring the smell out more too.

I wouldnt worry about the smell. You should be fine with a cusutomn dyno tune.

**stlwagon** · 10-04-2009

Do you have a mail order or dyno tune now?

Watain · 10-05-2009

Thanks guys for the info, I always fill up with 93 from BP. One thing too, I still have that exhaust leak in my X-Pipe. Just haven't found the time to get it welded up, I usually don't start my car with the door open but I did that night. So it might have been doing it a bunch of times before and I didn't notice it.

Watain · 10-05-2009

Quote:

Originally Posted by stlwagon

Do you have a mail order or dyno tune now?

Its a mail order tune, I'd love to get it dyno tuned but I don't have the money to ship them my car.

Watain · 10-05-2009

Quote:

Originally Posted by sqidd

It may be set up rich as part of the tune for warm up. Back in the stone age that's what a choke did.

That's also what I was thinking...

mustangdave2008 · 10-05-2009

The exhaust leak is most likely what you smelled; those fumes are deadly so you need to fix it. Also, most tunes cut off the rear O2 sensors which will cause more pollution (gas smell) to get through the exhaust.