Huge Loss Of Power at WOT....

TEALBST · 08-11-2006, 08:52 PM

Hey guys Im new here so I hope this is the right place for this. I have a 1993 GT with the modes listed in my sig. Lately I have noticed a huge loss in power at WOT! It does it most of the time, but if I start out slow and roll into it real hard it does alright until about third gear at 4,000 rpm. Thats when it feels like I just hit a brick wall. I just put new plugs and wires on two days ago. The gap is set at .054 and all the wires are good and connected. Ive seen the thread about fuel pressure and I adjusted mine from 40 psi to about 38 psi. I drive the car everyday about 30 miles round trip. I have also noticed a slight drop in fuel mileage. Today on the way home I got on the gas real hard and in 1st and 2nd it felt real strong, but in third I ran into that same brick wall, so I let off the gas and jumped right back on it and the car bogged heavily and then gained some power, but not all of it! The timing is set at 12 deg. I would greatly appreciate any help you guys could give me. Im looking to take the car and have a dyno tune, but I dont want to waste my money if I know the car is not at full potential. Please help fix this gremlin!!

Coupe50h · 08-11-2006, 09:12 PM

My car did this when my fuel psi was too low, also did that when i had an unmatched maf and injectors, but i trust that someone here can help you.
Have you done any recent mods?
Run codes, might have to replace your computer, might be a bad distibutor too, efi can be tricky, could be alot of things.
Alot of guys here can help you better than i can....hope you figure it out, keep posted.
oh yea, try cleaning the maf with some brake cleaner, be careful with the electronics part of it.

TEALBST · 08-11-2006, 09:21 PM

I havent done any mods lately, but I will try giving the m/a a good cleaning. Thanks I will let you know what I found to be the problem.

Dark_5.0 · 08-11-2006, 10:16 PM

Check you TPS voltage

TEALBST · 08-12-2006, 02:56 PM

What should the voltage be at the TPS?

PonyXpress · 08-12-2006, 05:29 PM

.998 is about optimum.

TEALBST · 08-13-2006, 09:37 AM

TPS voltage is good. Im hearing that a possible cause could be the TFI module. Have any of yall had any problems with the TFI module?

Coupe50h · 08-13-2006, 11:41 AM

Yea, A code scanner should be able to diagnose a tfi, but i would think that would make it stall.
As i think about this more, we put my buddies car on a dyno trying to find why it would fall on it's face above 4k it had "spark scatter" as mike murrillo called it, sure enough it was his brand new msd coil! he had a bad one. so might try that too if you can borrow one or something.
good luck

LX5liter · 08-13-2006, 05:29 PM

Try to run the fuel pressure guage to a spot where you can see it when you're driving. It might be the pump is just not putting out enough under the larger load. The coil might be suspect like Coupe50h said as well.

rwhite65 · 08-13-2006, 08:09 PM

I also vote fuel pump.
Ryan

jimberg · 08-14-2006, 03:09 PM

Do you have any other problems with your car that you think are unrelated? Does your idle go high on you for unexplained reason? Does it run worse at night or during the day?

I don't see a 24# calibrated MAF sensor listed in your mods. Do you have one?

jimberg · 08-17-2006, 04:37 PM

Did you fix your problem?

Coupe50h · 08-17-2006, 06:05 PM

Quote:

Originally Posted by jimberg

Did you fix your problem?

fuel pump is a possibilty for sure.
but yea, did you fix it?

jimberg · 08-17-2006, 06:50 PM

For the longest time I had this weird problem where my car would just start idling at 2000+ rpms and I changed the TPS and IAB valve to fix it. No luck.

One day I got the bright idea to check the resistance between my negative battery terminal (disconnected from battery) and the chassis. It was something like 6k ohms. I discovered that the battery wire had corroded from within. I pulled it from the terminal, cleaned the wire with the brush and reassembled it and everything runs perfectly now.

The weirdest thing is that I have a 96 Olds 88 that I bought recently that started stalling for no reason. It could go months between stalls or couldn't last 3 blocks. It turns out that the mechanic who installed a used engine into it neglected to clean the rust off the block before reconnecting a ground. 9k ohms from ground wire to chassis.

Checking resistance from ground wire to chassis is now my first check when weird, unexplainable stuff starts happening.

Is your fuel pump really bad or is it just not grounded correctly? Our sensors depend a lot on voltages and extra resistance in the system can throw those sensors way off.

08-11-2006, 08:52 PM	#1
TEALBST Registered Member Join Date: Aug 2006 Location: Monroe,Ga Posts: 4	Huge Loss Of Power at WOT.... Hey guys Im new here so I hope this is the right place for this. I have a 1993 GT with the modes listed in my sig. Lately I have noticed a huge loss in power at WOT! It does it most of the time, but if I start out slow and roll into it real hard it does alright until about third gear at 4,000 rpm. Thats when it feels like I just hit a brick wall. I just put new plugs and wires on two days ago. The gap is set at .054 and all the wires are good and connected. Ive seen the thread about fuel pressure and I adjusted mine from 40 psi to about 38 psi. I drive the car everyday about 30 miles round trip. I have also noticed a slight drop in fuel mileage. Today on the way home I got on the gas real hard and in 1st and 2nd it felt real strong, but in third I ran into that same brick wall, so I let off the gas and jumped right back on it and the car bogged heavily and then gained some power, but not all of it! The timing is set at 12 deg. I would greatly appreciate any help you guys could give me. Im looking to take the car and have a dyno tune, but I dont want to waste my money if I know the car is not at full potential. Please help fix this gremlin!! __________________ stock bottom end, lunati 51014 cam, edelbrock performer rpm heads & intake port to match, 80mm mass air, 75mm t/b, 24 lbs injectors, adj. fuel press regulator, smog pump & a/c delete, mac long tubes & h-pipe no cats w/ 2 chamber flows turned down, electric fan, 3-core griffin, cai, king cobra 10.5, z-trans, 4.10 w/ 31 spline auburn.

08-11-2006, 09:12 PM	#2
Coupe50h Registered Member Join Date: Aug 2002 Location: SanAntonio, Tx Posts: 957	Re: Huge Loss Of Power at WOT.... My car did this when my fuel psi was too low, also did that when i had an unmatched maf and injectors, but i trust that someone here can help you. Have you done any recent mods? Run codes, might have to replace your computer, might be a bad distibutor too, efi can be tricky, could be alot of things. Alot of guys here can help you better than i can....hope you figure it out, keep posted. oh yea, try cleaning the maf with some brake cleaner, be careful with the electronics part of it. __________________ X-Texas highway patrol ssp 1990 coupe - exploder Gt-40 iron heads, Explorer intake, 19 lber's. E-cam. crane 1.7 rollers. 190fp. 75mm maf. 65mm tb, tubular subframe connectors, mac cai, Asp crank pulley, T-5, king cobra clutch, flowtech 1-5/8 unequals, mac X-pipe Frpp driveshaft, lakewood Lca's. race weight 3,160 12.69 @ 107.35, 1.71 60' 26x8.5 drag's 3.90 gear 13.20 @ 106.91 - 235/60/15 firestones 2.3 60' 3.27 gear

08-11-2006, 09:21 PM	#3
TEALBST Registered Member Join Date: Aug 2006 Location: Monroe,Ga Posts: 4	Re: Huge Loss Of Power at WOT.... I havent done any mods lately, but I will try giving the m/a a good cleaning. Thanks I will let you know what I found to be the problem. __________________ stock bottom end, lunati 51014 cam, edelbrock performer rpm heads & intake port to match, 80mm mass air, 75mm t/b, 24 lbs injectors, adj. fuel press regulator, smog pump & a/c delete, mac long tubes & h-pipe no cats w/ 2 chamber flows turned down, electric fan, 3-core griffin, cai, king cobra 10.5, z-trans, 4.10 w/ 31 spline auburn.

08-11-2006, 10:16 PM	#4
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	Re: Huge Loss Of Power at WOT.... Check you TPS voltage __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

08-12-2006, 02:56 PM	#5
TEALBST Registered Member Join Date: Aug 2006 Location: Monroe,Ga Posts: 4	Re: Huge Loss Of Power at WOT.... What should the voltage be at the TPS? __________________ stock bottom end, lunati 51014 cam, edelbrock performer rpm heads & intake port to match, 80mm mass air, 75mm t/b, 24 lbs injectors, adj. fuel press regulator, smog pump & a/c delete, mac long tubes & h-pipe no cats w/ 2 chamber flows turned down, electric fan, 3-core griffin, cai, king cobra 10.5, z-trans, 4.10 w/ 31 spline auburn.

08-12-2006, 05:29 PM	#6
PonyXpress Registered Member Join Date: Jan 1999 Location: Denver, CO Posts: 26	Re: Huge Loss Of Power at WOT.... .998 is about optimum.

08-13-2006, 09:37 AM	#7
TEALBST Registered Member Join Date: Aug 2006 Location: Monroe,Ga Posts: 4	Re: Huge Loss Of Power at WOT.... TPS voltage is good. Im hearing that a possible cause could be the TFI module. Have any of yall had any problems with the TFI module? __________________ stock bottom end, lunati 51014 cam, edelbrock performer rpm heads & intake port to match, 80mm mass air, 75mm t/b, 24 lbs injectors, adj. fuel press regulator, smog pump & a/c delete, mac long tubes & h-pipe no cats w/ 2 chamber flows turned down, electric fan, 3-core griffin, cai, king cobra 10.5, z-trans, 4.10 w/ 31 spline auburn.

08-13-2006, 11:41 AM	#8
Coupe50h Registered Member Join Date: Aug 2002 Location: SanAntonio, Tx Posts: 957	Re: Huge Loss Of Power at WOT.... Yea, A code scanner should be able to diagnose a tfi, but i would think that would make it stall. As i think about this more, we put my buddies car on a dyno trying to find why it would fall on it's face above 4k it had "spark scatter" as mike murrillo called it, sure enough it was his brand new msd coil! he had a bad one. so might try that too if you can borrow one or something. good luck __________________ X-Texas highway patrol ssp 1990 coupe - exploder Gt-40 iron heads, Explorer intake, 19 lber's. E-cam. crane 1.7 rollers. 190fp. 75mm maf. 65mm tb, tubular subframe connectors, mac cai, Asp crank pulley, T-5, king cobra clutch, flowtech 1-5/8 unequals, mac X-pipe Frpp driveshaft, lakewood Lca's. race weight 3,160 12.69 @ 107.35, 1.71 60' 26x8.5 drag's 3.90 gear 13.20 @ 106.91 - 235/60/15 firestones 2.3 60' 3.27 gear

08-13-2006, 05:29 PM	#9
LX5liter dude5l Join Date: May 2001 Location: Grande Prairie, Alberta, Canada Posts: 603	Re: Huge Loss Of Power at WOT.... Try to run the fuel pressure guage to a spot where you can see it when you're driving. It might be the pump is just not putting out enough under the larger load. The coil might be suspect like Coupe50h said as well. __________________ Good luck! Brad R. 1992 L.X. 5.0 coupe MODS: A few little bolt ons New Best time ...11.60 @ 128 mph @ 2000+ ft altitude. Rice Haters Club member #39 Users rides #2542

08-13-2006, 08:09 PM	#10
rwhite65 Ride Hard Join Date: Oct 2000 Location: Wyoming IL Posts: 1,094	Re: Huge Loss Of Power at WOT.... I also vote fuel pump. Ryan __________________ 65 Fastback 91 roller 306, H/C/I AOD-Bauman, PI Stallion, 4.10's and traction loc 04 Grand Cherokee Freedom Edition 79 Ford F-250 4x4 - Restored

08-14-2006, 03:09 PM	#11
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	Re: Huge Loss Of Power at WOT.... Do you have any other problems with your car that you think are unrelated? Does your idle go high on you for unexplained reason? Does it run worse at night or during the day? I don't see a 24# calibrated MAF sensor listed in your mods. Do you have one? __________________ 351W 89 Mustang GT Convertible

08-17-2006, 04:37 PM	#12
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	Re: Huge Loss Of Power at WOT.... Did you fix your problem? __________________ 351W 89 Mustang GT Convertible

08-17-2006, 06:50 PM	#14
jimberg Registered Member Join Date: Oct 1998 Location: Rogers, MN Posts: 2,089	Re: Huge Loss Of Power at WOT.... For the longest time I had this weird problem where my car would just start idling at 2000+ rpms and I changed the TPS and IAB valve to fix it. No luck. One day I got the bright idea to check the resistance between my negative battery terminal (disconnected from battery) and the chassis. It was something like 6k ohms. I discovered that the battery wire had corroded from within. I pulled it from the terminal, cleaned the wire with the brush and reassembled it and everything runs perfectly now. The weirdest thing is that I have a 96 Olds 88 that I bought recently that started stalling for no reason. It could go months between stalls or couldn't last 3 blocks. It turns out that the mechanic who installed a used engine into it neglected to clean the rust off the block before reconnecting a ground. 9k ohms from ground wire to chassis. Checking resistance from ground wire to chassis is now my first check when weird, unexplainable stuff starts happening. Is your fuel pump really bad or is it just not grounded correctly? Our sensors depend a lot on voltages and extra resistance in the system can throw those sensors way off. __________________ 351W 89 Mustang GT Convertible

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