Need help, air/fuel way lean
Thread Starter
Drifting
Joined: Dec 2002
Posts: 1,472
Likes: 1
From: Reynoldsburg oh
Need help, air/fuel way lean
I just got the car off the wide band dyno. On just the motor only pull my air/fuel was 15.6. Way lean. I talked it over with the dyno guy and they said since I got a k&n air filter that maybe some of the oil or dirt has gotten on the MAS and causing it to lean out. Or maybe the computer is trying to lean the car out from taking the cats off. I was wondering if anyone else had a prob of this sort. Or if anyone could get some help, it would be appreciated. I did not spray the car since it was so lean on the motor.
Pro
Joined: Mar 2001
Posts: 568
Likes: 1
From: South Florida
Re: Need help, air/fuel way lean (sprayedc5)
I just got the car off the wide band dyno. On just the motor only pull my air/fuel was 15.6. Way lean. I talked it over with the dyno guy and they said since I got a k&n air filter that maybe some of the oil or dirt has gotten on the MAS and causing it to lean out. Or maybe the computer is trying to lean the car out from taking the cats off. I was wondering if anyone else had a prob of this sort. Or if anyone could get some help, it would be appreciated. I did not spray the car since it was so lean on the motor.
The only time I have ever seen such a lean ratio is when at part throttle and even then it is closer to 14.8-15.0 and usually never leaner.
Tell us more about the car. What mods have been done to it. Did you ever have your PCM tuned before?
You mentioned you had a K&N filter. Did you recently oil it? As you said, it is possible that some oil has gotten on the MAF sensor wires. If this is all that you have done, I would take off the MAF and CAREFULLY clean them with some q-tips and some alcohol. VERY Gently wipe them down with the q-tip turning it towards the clean side often. Discard the q-tip and use another one on all of the wire sensors.
Let us know how everything turns out..
Thread Starter
Drifting
Joined: Dec 2002
Posts: 1,472
Likes: 1
From: Reynoldsburg oh
Re: Need help, air/fuel way lean (sprayedc5)
Oh the only thing done is ported mas ends, k&n filter, cutouts with no cats, and spray. Dont know what the fuel pressure was but I am thinking on buying a mas translator that way I can recalibrate the mas. Your thoughts on this?
Safety Car
Joined: Aug 2000
Posts: 4,537
Likes: 84
From: St. Joseph MO
Cruise-In III Veteran
Cruise-In IV Veteran
Re: Need help, air/fuel way lean (sprayedc5)
I'd look at your fuel pump and fuel filter. After you cleaned your maf. Your O2 readings look like your motors ready to go BOOM. :eek:
Thread Starter
Drifting
Joined: Dec 2002
Posts: 1,472
Likes: 1
From: Reynoldsburg oh
Re: Need help, air/fuel way lean (JoeyG)
I'd look at your fuel pump and fuel filter. After you cleaned your maf. Your O2 readings look like your motors ready to go BOOM. :eek:
Safety Car
Joined: Aug 2000
Posts: 4,537
Likes: 84
From: St. Joseph MO
Cruise-In III Veteran
Cruise-In IV Veteran
Re: Need help, air/fuel way lean (sprayedc5)
I'd look at your fuel pump and fuel filter. After you cleaned your maf. Your O2 readings look like your motors ready to go BOOM. :eek:
Thanks for the boost of confedence :rolleyes:
Thanks for the boost of confedence :rolleyes:
Thread Starter
Drifting
Joined: Dec 2002
Posts: 1,472
Likes: 1
From: Reynoldsburg oh
Re: Need help, air/fuel way lean (sprayedc5)
Kinda got good news, took the mas off and the elements are completely black. So goin to go clean it off, and let air dry for the night. Goin to clean the sir filter also. .
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Pro
Joined: Mar 2001
Posts: 568
Likes: 1
From: South Florida
Re: Need help, air/fuel way lean (sprayedc5)
Oh the only thing done is ported mas ends, k&n filter, cutouts with no cats, and spray. Dont know what the fuel pressure was but I am thinking on buying a mas translator that way I can recalibrate the mas. Your thoughts on this?
1: Clean your MAF sensor wires as indicated in the previous post.
2: Change out fuel filter
3: Confirm that there are no intake leaks present. Check especially around where your K&N filter connects to your MAF and from the air bridge to the throttle body.
4: MOST IMPORTANT!! Go somewhere that has either an autotap tool or similar device or a Tech2 scan tool. This way you can see what is going on in your engine. For example, where are your LTFT settings at given fuel cells? What kind of timing and or KR are you getting?? These are things that can only be answered by using a scan tool connected to your vehicle.
The A/F ratios that you are currently running is a recipe for disaster. Seriously, get this fixed ASAP!! The computer is smart enough to lower your timing advance through KR but it only goes so far. The other post about the engine going boom is not so far off... Especially at WOT under severe knock..
Let us know how you do and if you need any further help...