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Must be something crazy in the air, I'm having the same symptoms aswell. My car runs and idles good with good a/f ratio at cruise speeds, but goes way rich under load like you guys are describing. My lightning maf is less than a year old tho.
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98Gt with pro 5.0shifter, 3.73's Pi swap and stage 2 CompCams, BBK Lt's, catless H pipe, Flows. Procharged 8psi
Must be something crazy in the air, I'm having the same symptoms aswell. My car runs and idles good with good a/f ratio at cruise speeds, but goes way rich under load like you guys are describing. My lightning maf is less than a year old tho.
Yep, my MAF is like a little over a year.
Wierd that ive never seen this before now, and all the sudden theres 3 of us
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03 alum. Pi motor, v2 s-trim @ 11 psi, full exhaust, built 4r70w with 3800 stall, 3100 lb curb weight. 385 rwhp
You said yours does it all the time, like when its cold and operating temp? I just went out this morning, fired the mustang up, went around the block a few times and it ran great, never stuttered or nothing pulled right up to 6k no problem, so I'm thinking wtf it was running like crap last weekend... I let it sit for 20 minutes or so and left out and its back to crap again.. Are there some sensor and stuff that doesnt input information till it gets to operating temp?
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98Gt with pro 5.0shifter, 3.73's Pi swap and stage 2 CompCams, BBK Lt's, catless H pipe, Flows. Procharged 8psi
join the club Chris! my lightning maf is a little over a year old, but in its defense it did suck in quite a bit of water, which is more than likely the cause of my problems. and yes, mine runs like sh*t all the time. i posted a video a few pages back showing how my car acts while cruising. a/f ratios jump around the low-to-mid 13's, then just drop down to 11:1 or lower. i've got a new lightning maf on its way, so hopefully the weekend after the holidays i'll be able to get it on the car and see if that fixes it.
on another note, i really need to get a new pipe leading from my air filter to the blower. the one that came with my kit (used kit) was custom-fabricated and puts the air filter way the hell down in the fender. i measured it yesterday and the bottom of my air filter sits about 9 inches above the ground. i'm looking at an AFM power pipe, but i'm not sure how high the air filter will be compared to my current setup.
i posted a video a few pages back showing how my car acts while cruising. a/f ratios jump around the low-to-mid 13's, then just drop down to 11:1 or lower. i've got a new lightning maf on its way, so hopefully the weekend after the holidays i'll be able to get it on the car and see if that fixes it.
I saw this and had to say something. For the folks that are new to the game...when cruising at a steady rpm your A/F ration should NEVER be stable. You should normally read 13.0-17.0 (constantly fluctuating) and down to 11.0-15.0 on the hotter days. This is completely normal. What's causing the "bouncing" is your O2 sensors working properly. They're always talking to the PCM adjusting A/F ratio for the optimum MPG. If your A/F doesn't bounce around, it usually signifies a bad sensor. This is also the importance of having a dual bank (one wide band per side) Wideband system. You could have a bad O2 sensor on your pass. side and not know it because your wideband is in the drivers side. You wouldn't even notice a problem until you fill up and notice that your MPG is really crappy. Also a PCM correction for a bad O2 sensor is max rich. Rich is always safer than lean. When I went to my PLX setup, that's when I finally noticed I had a bad O2. Drivers side was bouncing from 13-17 while pass side was holding at 10.0 (<--PCM MAX RICH). Swapped O2 sensors and all was well.
Only when you go into open loop (WOT, max load) should your A/F ratio be steady. Even then it will move around a bit, but only until it reaches desired (read: comanded) A/F ratio.
EDIT: After reading a few previous posts...
Guys, long gone are the old 5.0 days of just getting a bigger MAF and running it with correct injector calibrations. A lot of you guys are wasting your money of un-needed parts. A MAF is a very needed part (obviously), but changing them isn't always necessary. A stock meter is fine in almost EVERY application. I still have a stock MAF in my car (albeit with a MAFia). A MAF is just a sophisticated sensor...nothing more. It's job is to tell the PCM the criteria (density, volume, BARO, etc.) of the incoming airflow. Why people "upgrade" MAF's is often due to resolution issues. Meaning how "clean" the meter reads/interprets the data. By changing MAF's you're doing nothing for your performance without telling the PCM what you're doing...in other words, you need a tune. Keep in mind, the MAF doesn't "control" anything. It's just a communication device just like every other sensor. So by swapping meters and injectors, you just added more fuel capacity by upping injectors, but the PCM doesn't know unless you tell it what you did. It can "hypothesize" due to the adaptive learning tables, but the combination will never be dialed in without a tune. That's why all you guys are running rich. Spend the money on a tune, not a MAF. Stock MAF's (with an extension of some kind) are good for tons of power and can be run in any configuration, draw-through/blow-through. So hang onto them and just get a bigger housing if you're worried about airflow.
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Silver 04 SVT Cobra
Twin 57mm Garrett Turbos
Full Maximum Motorsports (and QA1) Suspension
Huge Brakes
Loud Audio
900 HP Daily Driven Boulevard Monster
See a full mod list, Dyno Vids and Build Slideshow here:www.fquick.com/smokin04 Just click on the Cobra.
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