WhiteFoxGT

Alright, I've been gettin bad gas milage lately. After I installed my BBK o/r H-pipe (has stock on before) you can REALLY smell how rich my car is. Even the guys at work were tellin me its way too rich. How do I go about leaning my mixture a tad? Do i need to turn the fuel pressure down? If so how do you go about doing that with stock fuel rail? Any suggestions as to why it would be running like that. Only started doing it when I switch computers to an A9L when I did the AOD-T5 swap.

50mikey

i doubt its running too rich. now that you have no cats on your car your really going to smell it. ive had ALOT of people comment on how smelly my car is, and it doesnt run rich or lean...right at 14:1 at idle

but no there isnt too much you can do to make it run leaner except getting an adjustable FP regulator....but i assure you that you dont want to do that.

WhiteFoxGT

So getting 100 or less miles on like 8 gallons of fuel isnt bad? 12.5 MPG, just seems like its running really rich because it stinks. Before I could get about 150 miles to like 8 gallons.

vristang

The first thing you should do is pull the codes.
Most likely the computer will be able to tell you exactly what is wrong.

I suspect the O2's, ECT/ACT, or fuel press. reg.; in that order.

Do just start throwing parts at it though, check the codes first.

If you don't get any codes, then there may be someting wrong with the setup.

Are you still using the stock injectors and MAF?

Adjusting the fuel pressure can only be done with an aftermarket fuel pressure regulator. The stocker isn't adjustable.

50mikey

is this 12.5 mpg in the city? and it really depends on how your driving it. i normally get about 16mpg in the city, but the other day i went through half a tank of gas in 50 miles...it was a fun day

WhiteFoxGT

So the comp will tell you if its rich even though the CEL isnt on? I'll have to do that at work one day. Also, what kind of scan tool will hook up? its not OBD-2, is it that connector under the hood?

WhiteFoxGT

I'm all over the place here. Could old/worn O2 sensors cause rich running?

50mikey

yeah, it wouldnt be a bad idea to replace the O2 sensors. but scanning the car is a good idea.

5.0 MPG

make sure your fpr isnt bad. you need to make sure it holds a vacuum. this could be the source of runing rich.

mpswirl

You need to hook up some sort of afr sensor to help you out, or a 5 gas analyzer. Cheapest is a regular afr gauge or get a wideband like i have. Then if your car shows its runnig rich try to lean in out temperarily. NEVER check codes and throw parts on because you get a code. Maybe it has a rich code becuse of leaky injectors for example and it thows a rich code and people think its injectors right away. So if it runs rich try to lean it out ( vacuum leak etc) if it show its running lean then richen it up(spray carb cleaner in the throttle body) then if they dont change after you do that then change the O2s. The point is NEVER change parts just because you get a code for it because 1 thing bad can cause a number of other codes.