Please Help With Code 66

cptkng79 · November 8th, 2006, 06:01 PM

haveing problems with my 91 mustang.. when you first start it up it runs great fro about 30 seconds and then it all turns to crap... major hessitation, backfireing, over 2k rpm.... starts find and idles fine. scanner keeps picking up code 66 which is maf sensor below minimum test voltage, and thats after i changed it. among other parts i swapped out are tps sensor, coil(needed one anyway) ignition modular, o and computer.
my guy at the performance shop is stumped. PLEASE HELP.....

Tony_90fox · November 8th, 2006, 06:25 PM

what MAF did you get?

cptkng79 · November 8th, 2006, 06:26 PM

i forget the brand right now
but i know it was new and calibrated to 42 lb injectors

Tony_90fox · November 8th, 2006, 08:32 PM

i was just making sure it was calibrated for the injectors that you have. Sounds like you do...Now its way over my head!

terribleonexx88 · November 8th, 2006, 11:11 PM

double check you timing

cptkng79 · November 9th, 2006, 12:14 AM

why do you think it would be the timeing???

tomorrow night my bud is comming over with a meter to test continuity in the 4 maf wires that go to the computer.

any other suggestions, cause im 99.9 %sure the timeing is dead on

cali 5.0 · November 9th, 2006, 01:37 PM

why did u go with that big of a maf sensor.. what kind of injectors do u have

cptkng79 · November 9th, 2006, 02:02 PM

i have a 347 stroked out /supercharged w/10lb of boost right now with 42 lb injectors.

cali 5.0 · November 9th, 2006, 06:00 PM

well the thing is the computer doesent see .5 or .05 volts i forget which one it is but the computer is seeing it... make sure that u have the connector in their real good.. take a volt meter and probe the wires and see how many volts the maf sensor is actually reading... also make sure that all of your cai tubing has no leaks,

cptkng79 · November 10th, 2006, 10:44 AM

does any one know if a faulty fuel pressure red could be to blame

gauge says at idle car is running 19psi with vaccume tube on

tried adjusting it but no luck

cali 5.0 · November 10th, 2006, 03:31 PM

19 psi of fuel pressure...?????????
hell yeh thats bad it should be at 40-44 psi for fuel pressure if thts wht ur talkin about

cptkng79 · November 10th, 2006, 09:27 PM

fixed the prob
it was a faulty fuel regulator

thanx guys

November 8th, 2006, 06:01 PM	#1
cptkng79 Regular Join Date: Nov 2006 Posts: 122	Please Help With Code 66 haveing problems with my 91 mustang.. when you first start it up it runs great fro about 30 seconds and then it all turns to crap... major hessitation, backfireing, over 2k rpm.... starts find and idles fine. scanner keeps picking up code 66 which is maf sensor below minimum test voltage, and thats after i changed it. among other parts i swapped out are tps sensor, coil(needed one anyway) ignition modular, o and computer. my guy at the performance shop is stumped. PLEASE HELP.....

November 8th, 2006, 06:26 PM	#3
cptkng79 Regular Join Date: Nov 2006 Posts: 122	i forget the brand right now but i know it was new and calibrated to 42 lb injectors __________________ 518.9 Wheel HP!!!!! 491 Torque!!!!!!!!

November 8th, 2006, 11:11 PM	#5
terribleonexx88 Enthusiast Join Date: Oct 2006 Location: new england Posts: 813	double check you timing __________________ 85 4 banger stanger, it likes to sneeze alot when i hit the gas

November 9th, 2006, 01:37 PM	#7
cali 5.0 Regular Join Date: May 2006 Location: grand prairie tx Posts: 385	why did u go with that big of a maf sensor.. what kind of injectors do u have __________________ 89 gt 3.73 gears, full exhaust, holley system max2 intake manifold, 70mm throttle body, jet chip

November 9th, 2006, 02:02 PM	#8
cptkng79 Regular Join Date: Nov 2006 Posts: 122	i have a 347 stroked out /supercharged w/10lb of boost right now with 42 lb injectors. __________________ 518.9 Wheel HP!!!!! 491 Torque!!!!!!!!

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November 9th, 2006, 12:14 AM	#6
cptkng79 Regular Join Date: Nov 2006 Posts: 122	why do you think it would be the timeing??? tomorrow night my bud is comming over with a meter to test continuity in the 4 maf wires that go to the computer. any other suggestions, cause im 99.9 %sure the timeing is dead on

November 9th, 2006, 06:00 PM	#9
cali 5.0 Regular Join Date: May 2006 Location: grand prairie tx Posts: 385	well the thing is the computer doesent see .5 or .05 volts i forget which one it is but the computer is seeing it... make sure that u have the connector in their real good.. take a volt meter and probe the wires and see how many volts the maf sensor is actually reading... also make sure that all of your cai tubing has no leaks, __________________ 89 gt 3.73 gears, full exhaust, holley system max2 intake manifold, 70mm throttle body, jet chip

November 10th, 2006, 10:44 AM	#10
cptkng79 Regular Join Date: Nov 2006 Posts: 122	does any one know if a faulty fuel pressure red could be to blame gauge says at idle car is running 19psi with vaccume tube on tried adjusting it but no luck

November 10th, 2006, 03:31 PM	#11
cali 5.0 Regular Join Date: May 2006 Location: grand prairie tx Posts: 385	19 psi of fuel pressure...????????? hell yeh thats bad it should be at 40-44 psi for fuel pressure if thts wht ur talkin about __________________ 89 gt 3.73 gears, full exhaust, holley system max2 intake manifold, 70mm throttle body, jet chip

November 10th, 2006, 09:27 PM	#12
cptkng79 Regular Join Date: Nov 2006 Posts: 122	fixed the prob it was a faulty fuel regulator thanx guys

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