WOT not as good as 3 quarters why??

DemonGT · 06-11-2002, 12:18 AM

it seems if i give my car the nuts it go's but it seems if i push the pedal down but not quite all the way it goes better? why would this be?

LX XLR8R · 06-11-2002, 08:35 AM

hmm..TPS could be wayy off, you could have a fuel pressure problem, dirty air filter, timing not right..

PKRWUD · 06-11-2002, 08:57 AM

I'm curious to know what your TPS reads at idle, 3/4 throttle, and WOT.

Take care,
-Chris

jimberg · 06-11-2002, 10:29 AM

I notice that you have a 76mm C&L MAF meter. What MAF meter did you transfer your electronics from? Was it a working stock meter?

My guess is that your MAF meter isn't working properly so the engine runs fine in closed-loop mode since the O2 sensors are used for making fuel adjustments. When you go to WOT, which your computer is clearly picking up, it uses readings from the MAF sensor to determine how much air is coming in to calculate fuel delivery. Since it's not correct, it runs crappy.

PKRWUD · 06-11-2002, 11:19 AM

Good answer! I don't know if that's it or not, but it certainly could be. Good idea, Jim!!!

Take care,
-Chris

DemonGT · 06-11-2002, 01:11 PM

yes the electronics were from a working stock one...and also..some times when im coiming to a stop i push the clutch in and push on the brake some times my engine will rev go way down...rev then some times die!?? some times it dosnt die but almost dose...it seems as though it dose it more when the wheel is turned..like i was backing out of a parking spot and had the wheel cranked and it just died?? wtf..also..when i start it, it starts then almost dies..then goes up..then almost dies..then starts to even the idle out

how do i check my TPS?

jimberg · 06-11-2002, 01:23 PM

The symptoms you are describing lead me to believe that it probably is the MAF. When you do a cold start you are in open loop mode using just MAF readings to determine fuel quantities.

Do you have working cruise control?

DemonGT · 06-11-2002, 11:46 PM

yes..the cruise control works fine

iv been thinken of going with a pro M 77 MAF...is that a good size to get? i building a 331

jimberg · 06-12-2002, 07:28 AM

I have a Pro-M 75mm and it works great. It comes with brand new electronics, too. A 77mm wouldn't make much a difference over your 76mm, though. You should find someone with a similar MAF sensor and swap to see if it really is part of the problem. You may also want to try swapping out your electronics.

I just bought a used stock MAF sensor for $25. If it works for me, great, if not, I'm gonna use it as a core to get a brand new one since I gave my old one away a long time ago. I wish someone just sold the sensing unit separately.

DemonGT · 06-12-2002, 10:47 PM

yea the 75 is what im thinken of going with..i had a brain fart when i put 77...will the 75 work ok with a A trim?

06-11-2002, 12:18 AM	#1
DemonGT Registered Member Join Date: Aug 2000 Location: Wisconsin Posts: 879	WOT not as good as 3 quarters why?? it seems if i give my car the nuts it go's but it seems if i push the pedal down but not quite all the way it goes better? why would this be? __________________ '91 GT,410W,10.5 to 1 comp,Victor Jr. heads,Victor 5.8 intake,FTI cam,Crane retro fit lifters,Scorpian 1.6 RR's,Melling HV oil pump,MSD distro.,Canton oil pan,FMS flywheel,Romac balancer,FMS timing chain,Accufab 90mm TB,C&L 76mm maf, 42lbers,HD clutch,K&N air filter,Mac long tubes,Pro dumps,powerchamber,FMS 9mm wires,180 thermostat,Ford Racing gauges,5inch Tach,centerline convo pro's,nitto DR's,Pro3i lower control arms,50/50 shocks,3.55 gears,TFS HD diff. cover Next year: Tremec TKO,Spec stage 3 clutch,alum driveshaft,complete fuel system www.angelfire.com/linux/demondan

06-11-2002, 08:35 AM	#2
LX XLR8R Dirk Diggler Join Date: Feb 1999 Location: SLOATSBURG, NY Posts: 1,931	hmm..TPS could be wayy off, you could have a fuel pressure problem, dirty air filter, timing not right.. __________________ 95 undecided cubes, AFR 185s,undecided cam, undecided intake, and a 150 hit 89 "turbonotch" 2.3T You might want to hold on..i saw this on a cartoon once

06-11-2002, 08:57 AM	#3
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	I'm curious to know what your TPS reads at idle, 3/4 throttle, and WOT. Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

06-11-2002, 10:29 AM	#4
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	I notice that you have a 76mm C&L MAF meter. What MAF meter did you transfer your electronics from? Was it a working stock meter? My guess is that your MAF meter isn't working properly so the engine runs fine in closed-loop mode since the O2 sensors are used for making fuel adjustments. When you go to WOT, which your computer is clearly picking up, it uses readings from the MAF sensor to determine how much air is coming in to calculate fuel delivery. Since it's not correct, it runs crappy. __________________ 351W 89 Mustang GT Convertible

06-11-2002, 11:19 AM	#5
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	Good answer! I don't know if that's it or not, but it certainly could be. Good idea, Jim!!! Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

06-11-2002, 01:11 PM	#6
DemonGT Registered Member Join Date: Aug 2000 Location: Wisconsin Posts: 879	yes the electronics were from a working stock one...and also..some times when im coiming to a stop i push the clutch in and push on the brake some times my engine will rev go way down...rev then some times die!?? some times it dosnt die but almost dose...it seems as though it dose it more when the wheel is turned..like i was backing out of a parking spot and had the wheel cranked and it just died?? wtf..also..when i start it, it starts then almost dies..then goes up..then almost dies..then starts to even the idle out how do i check my TPS? __________________ '91 GT,410W,10.5 to 1 comp,Victor Jr. heads,Victor 5.8 intake,FTI cam,Crane retro fit lifters,Scorpian 1.6 RR's,Melling HV oil pump,MSD distro.,Canton oil pan,FMS flywheel,Romac balancer,FMS timing chain,Accufab 90mm TB,C&L 76mm maf, 42lbers,HD clutch,K&N air filter,Mac long tubes,Pro dumps,powerchamber,FMS 9mm wires,180 thermostat,Ford Racing gauges,5inch Tach,centerline convo pro's,nitto DR's,Pro3i lower control arms,50/50 shocks,3.55 gears,TFS HD diff. cover Next year: Tremec TKO,Spec stage 3 clutch,alum driveshaft,complete fuel system www.angelfire.com/linux/demondan

06-11-2002, 01:23 PM	#7
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	The symptoms you are describing lead me to believe that it probably is the MAF. When you do a cold start you are in open loop mode using just MAF readings to determine fuel quantities. Do you have working cruise control? __________________ 351W 89 Mustang GT Convertible

06-11-2002, 11:46 PM	#8
DemonGT Registered Member Join Date: Aug 2000 Location: Wisconsin Posts: 879	yes..the cruise control works fine iv been thinken of going with a pro M 77 MAF...is that a good size to get? i building a 331 __________________ '91 GT,410W,10.5 to 1 comp,Victor Jr. heads,Victor 5.8 intake,FTI cam,Crane retro fit lifters,Scorpian 1.6 RR's,Melling HV oil pump,MSD distro.,Canton oil pan,FMS flywheel,Romac balancer,FMS timing chain,Accufab 90mm TB,C&L 76mm maf, 42lbers,HD clutch,K&N air filter,Mac long tubes,Pro dumps,powerchamber,FMS 9mm wires,180 thermostat,Ford Racing gauges,5inch Tach,centerline convo pro's,nitto DR's,Pro3i lower control arms,50/50 shocks,3.55 gears,TFS HD diff. cover Next year: Tremec TKO,Spec stage 3 clutch,alum driveshaft,complete fuel system www.angelfire.com/linux/demondan

06-12-2002, 07:28 AM	#9
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	I have a Pro-M 75mm and it works great. It comes with brand new electronics, too. A 77mm wouldn't make much a difference over your 76mm, though. You should find someone with a similar MAF sensor and swap to see if it really is part of the problem. You may also want to try swapping out your electronics. I just bought a used stock MAF sensor for $25. If it works for me, great, if not, I'm gonna use it as a core to get a brand new one since I gave my old one away a long time ago. I wish someone just sold the sensing unit separately. __________________ 351W 89 Mustang GT Convertible

06-12-2002, 10:47 PM	#10
DemonGT Registered Member Join Date: Aug 2000 Location: Wisconsin Posts: 879	yea the 75 is what im thinken of going with..i had a brain fart when i put 77...will the 75 work ok with a A trim? __________________ '91 GT,410W,10.5 to 1 comp,Victor Jr. heads,Victor 5.8 intake,FTI cam,Crane retro fit lifters,Scorpian 1.6 RR's,Melling HV oil pump,MSD distro.,Canton oil pan,FMS flywheel,Romac balancer,FMS timing chain,Accufab 90mm TB,C&L 76mm maf, 42lbers,HD clutch,K&N air filter,Mac long tubes,Pro dumps,powerchamber,FMS 9mm wires,180 thermostat,Ford Racing gauges,5inch Tach,centerline convo pro's,nitto DR's,Pro3i lower control arms,50/50 shocks,3.55 gears,TFS HD diff. cover Next year: Tremec TKO,Spec stage 3 clutch,alum driveshaft,complete fuel system www.angelfire.com/linux/demondan

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