Mass Air? Oxygen Sensors? What Could It Be?

BowTie Eater 5 Liter · 02-02-2006, 09:45 AM

heres the problem, my 91 lx isnt running properly, smells wayy too rich, not as much power as i feel it should have, and when im WOT for like 5 seconds(hard on in 2nd through end of 3rd) the check engine light will FLASH on then when i let off, it goes away.
ive pulled codes and i did have a KOEO code 56 (maf above max voltage) but found nothing o2 related. could the maf being above max voltage cause these issues? i was told its "probably" my o2's but i dont know for sure and dont want to spend a bunch of coin and find out that wasnt the problem.

any way to do tests(that i can perform at home) to figure out what the problem actually is? any info greatly appreciated!

redsn95vert · 02-02-2006, 06:03 PM

It's probably your mass air....Try to clean the element inside with some carb/fuel inj. cleaner, but just be careful not to damage it. If caleaning it dosen't fix the problem, you can pick up a used one on e-bay.
Good luck.

Hozer 88GTConv · 02-02-2006, 07:01 PM

any auto parts store will scan your car with a KOER test. Bad 02's could indicate a full lean, and the PCM compensates by referencing the get-home table and forces the injectors to run full rich.
good luck

Joel5.0 · 02-02-2006, 09:50 PM

Second Hozer 88GTConv, but you can run the KOER self-test yourself, follow the procedure right here @MustangWorks and LUK what KOER codes you get. GL

vristang · 02-03-2006, 02:57 AM

I have had problems with the mixture that were solved by replacing the O2s, but never saw an engine code.
Not saying it will work for you, but sometimes bad O2s don't throw codes.

Cleaning the maf as described above is a very good place to start. I would use Brake Cleaner though, as it will not leave ANY residue behind, unlike most solvents.

jason

redsn95vert · 02-03-2006, 07:51 PM

Another thing to worry about is, if both O2s are bad and are throwing codes, they may not be the problem, usually if they both throw codes, it means it's a bad MAF.

02-02-2006, 09:45 AM	#1
BowTie Eater 5 Liter Registered Member Join Date: Nov 2000 Location: Maple Ridge B.C. Canada, The Best Place In The World Posts: 871	Mass Air? Oxygen Sensors? What Could It Be? heres the problem, my 91 lx isnt running properly, smells wayy too rich, not as much power as i feel it should have, and when im WOT for like 5 seconds(hard on in 2nd through end of 3rd) the check engine light will FLASH on then when i let off, it goes away. ive pulled codes and i did have a KOEO code 56 (maf above max voltage) but found nothing o2 related. could the maf being above max voltage cause these issues? i was told its "probably" my o2's but i dont know for sure and dont want to spend a bunch of coin and find out that wasnt the problem. any way to do tests(that i can perform at home) to figure out what the problem actually is? any info greatly appreciated! __________________ 1984 Bronco II, 36" Michelin Military Tires, 95 EFI 5.0, NP435 Tranny, NP208 Doubler, NP205 Transfer Case, Fill Size Solid Dana 44 Front End, WH Progressive Rate Rock Crawling Coils, Bronco 8.8 Rear, Skyjacker Softride Leafs, 5.13 Gears, Detroit Locker. Final Crawl Ratio Of 175:1 88 GT Best 60ft. 2.181 Best ET 14.350 Best MPH 98.01 ~WRECKED!!!!~

02-02-2006, 06:03 PM	#2
redsn95vert Registered Member Join Date: Jul 2000 Location: Rochester Posts: 323	Re: Mass Air? Oxygen Sensors? What Could It Be? It's probably your mass air....Try to clean the element inside with some carb/fuel inj. cleaner, but just be careful not to damage it. If caleaning it dosen't fix the problem, you can pick up a used one on e-bay. Good luck. __________________ 95 GT convertable, ported+polished GT40 heads, port matched upper and lower Cobra intake manifold, Flowthech headers, Catco hi-flow h-pipe with 2 hi-flow cats, Mac true fit catback exhaust, 3.73 gears, underdrive pullies, Edelbrock 70mm throttle body, Mac cold air intake, FMS 24lb injectors, Granatelli 75mm mass air

02-02-2006, 07:01 PM	#3
Hozer 88GTConv Registered Member Join Date: Feb 2002 Location: Jacksonville, FL Posts: 706	Re: Mass Air? Oxygen Sensors? What Could It Be? any auto parts store will scan your car with a KOER test. Bad 02's could indicate a full lean, and the PCM compensates by referencing the get-home table and forces the injectors to run full rich. good luck __________________ 1988 GT Convertible 331 10:1 TW heads, GT-40 intake, MSD, TRW flattops, B Cam w/ 1.7's, MAC exhaust, 24's, 70 TB, 76 MAF, 3.73's, Pro 5.0, Koni's, Anderson PMS, Wideband 02, yatta, yatta... One week with new motor, two speeding tickets...joy

02-02-2006, 09:50 PM	#4
Joel5.0 Registered Member Join Date: Oct 2005 Location: Sabana Grande, Puerto Rico Posts: 33	Re: Mass Air? Oxygen Sensors? What Could It Be? Second Hozer 88GTConv, but you can run the KOER self-test yourself, follow the procedure right here @MustangWorks and LUK what KOER codes you get. GL __________________ ACRONYMS: LUK=Let Us Know, GL=Good Luck, LMK=Let Me Know, JIC=Just In Case, BTSTDTRT=Been There Seen That Done That Repaired That and the classic... DILLIGAS=Do I Look Like I Give A S*** 1986 Mustang GT w/T-Tops NOW: 5.0L Stock SB, X303 Cam, 700 cfm DP Holley, 289 '66 Heads, 1.7 RR, Richmond Gear 4+1 Tranny, Centerforce DF, 2.73 Gears WIP: 3.90 Gears, LS Overhaul, Adj. LCA's & UCA's (Granatelli), T-Top weather striping and rear braces bodywork

02-03-2006, 02:57 AM	#5
vristang Registered Member Join Date: Feb 2006 Posts: 50	Re: Mass Air? Oxygen Sensors? What Could It Be? I have had problems with the mixture that were solved by replacing the O2s, but never saw an engine code. Not saying it will work for you, but sometimes bad O2s don't throw codes. Cleaning the maf as described above is a very good place to start. I would use Brake Cleaner though, as it will not leave ANY residue behind, unlike most solvents. jason __________________ Check out my new Mustang website! - Including: TwEECer, EEC-IV, C&L, 351w Fox Swaps, PCV Oil Control, and more. 1990 GT - 408w - 17mpg TwEECer RT 1.30A10 - X3Z - A9L strat. / EA Forged Bottom End / Gapless Rings / CR 8.85:1 / Custom Cam / Ported Trick Flow Heads / Box Upr / Lightning Lwr 17x9 Cobras / Front 255s / Rear 275s / 5 Lug Cobra Disc Conversion / Auburn Ltd. Slip / 3.27 / 31 spline axles / Panhard Rod / Upr&Lwr Control Arms 1987 Red LX - 2.3L - Planning 2.3t Converison

02-03-2006, 07:51 PM	#6
redsn95vert Registered Member Join Date: Jul 2000 Location: Rochester Posts: 323	Re: Mass Air? Oxygen Sensors? What Could It Be? Another thing to worry about is, if both O2s are bad and are throwing codes, they may not be the problem, usually if they both throw codes, it means it's a bad MAF. __________________ 95 GT convertable, ported+polished GT40 heads, port matched upper and lower Cobra intake manifold, Flowthech headers, Catco hi-flow h-pipe with 2 hi-flow cats, Mac true fit catback exhaust, 3.73 gears, underdrive pullies, Edelbrock 70mm throttle body, Mac cold air intake, FMS 24lb injectors, Granatelli 75mm mass air

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