[Andrew]

Hey yall, I've got a pretty heavily moded 2003 mustang gt, and i'm getting some wierd throttle response in the lower gears, especially from neutral to first. Basically, when i'm starting off it feels like the power's restrained some how. Like the power break's on or something. The car's geared (not sure what the ratio is cause the previous owner did it) so i'm wondering if it could be the throwout bearing. On the other hand, I have an accufab throttle body on it, but my fuel injectors are stock, so maybe i have to change out the fuel injectors. I'm sort of lost though, so if yall could help me out i'd really appriciate it. thanks,
andrew

[00vabchgt]

welcome to the site. you say heavily modded, well, what else besides gears and a throttle body do you have done that make the car heavily modded? more information would really help in diagnosing your problem...

[DickH]

Traction control? I should hope if your car is heavily modified you would know better, but it could be traction control. Try turning it off and see if its better.

[brianm]

Originally Posted by 00vabchgt welcome to the site. you say heavily modded, well, what else besides gears and a throttle body do you have done that make the car heavily modded? more information would really help in diagnosing your problem...

i agree we need more info, but i can be confident by saying its not your t.o.b. or your injectors from what your saying.

[03gtfirered]

from his garage:
Vortech Supercharger, BBK Intake, Accufab Throttle Body, SLP heavy Clutch, Manual Trans: 5 speed- geared w/ short throw shifter, SLP Loudmouth II Exhaust w/ highflow catalytic converters, SCT Tunning Chip, AutoMeter Mach Adapter Model 9117, AutoMeter Fuel Pressure Gauge, Boost Pressure Gauge, Autometer Memory Capable Tachometer w/ shift light, Suspension lowered to 4 finger wheel to well

[03gtfirered]

you shouldnt still be running stock injectors with a supercharger! do you have stock plugs etc. you probably are having a problem with fuel. do you have upgraded fuel pump or a BAP? how much boost you running? did you upgrade your fuel system at all? the only way we can help is if you give us as much information as possible.

[brianm]

Originally Posted by 03gtfirered from his garage: Vortech Supercharger, BBK Intake, Accufab Throttle Body, SLP heavy Clutch, Manual Trans: 5 speed- geared w/ short throw shifter, SLP Loudmouth II Exhaust w/ highflow catalytic converters, SCT Tunning Chip, AutoMeter Mach Adapter Model 9117, AutoMeter Fuel Pressure Gauge, Boost Pressure Gauge, Autometer Memory Capable Tachometer w/ shift light, Suspension lowered to 4 finger wheel to well

well thats a different story? lol

[slow02gt]

i dont think the guy knows whats up with the car he just bought it like that and the guy told him what was on it lol.... i doubt you have the stock injectors if you did im sure the car isnt running worth a shit.. if they are red at the top they rae 30s. if they are blue they are 39s..check and see dude

[Andrew]

sorry it's been a few days. thanks for the welcome "00vabchgt." the diagnostics that "02gtfirered" got from my garage are correct. To get the basic stuff out of the way, i've fixed the traction control so that it's permanently off and i'm using 93 octane gasoline for the street tune and 105 octane for my racing tune. I agree though, that i could be something with the fuel. I'm currently using NGK cold spark plugs, and i think they're working fine, but it has been about 6 months since i've changed them out so that could be it. good call "02gtfirered"!

That said, this is the 3rd mustang i've owned and it's the first time i've encountered this problem. On the other hand, the first 2 were automatic and very nearly stock. and to answer "slow02gt's" post, the fuel injectors in the car are definitely stock. At least, that's what the nice people at HPP racing (dallas's premier late model high performance shop) who tuned my car told me. i'm no engine wizard, but that's why i'm here. to learn from the best

[03GTguy]

Has it been like this since you bought it? You definately want to do something about the stock fuel system though...

[BakerFX4]

Stock inj. on a SC mustang would suck. I get my car tuned at hpp also and im sure they told you that needed to be changed huh. They are pretty good at this stuff. Have you been to hpp's new shop yet?

[Andrew]

Yea, it's been like this since i got it. Actually HPP was just moving into their new shop when i got it tuned and you're right, they were the ones that told me to redo my fuel injection first chance i get. But they said that it would only be a problem when i'm using alot of boost. btw, i forgot to mention i'm running 14 pounds of boost for whoever asked that. Anyways, i'm taking my mustang up there sometime next week to change out my map sensor and to get a tune up. So i'll ask them while i'm there

[BakerFX4]

good deal... they will hook you up. I'll be headed that way sometime within the next month.

[Eagle2000GT]

Stock 23 lb. injectors with 14 psi boost? You need at least 42 lb. injectors. Did the previous owner mention if it has stock rods and pistons or if they were forged?

[slow02gt]

you porbably need a maff to dude.. you should have detuned the car to nothing to be on the safe side b4 you blow that bitch up.. and get 42 and a 90mm.. so instead of wasteing money to keep haveint to get retuned... wait till you get 42s or at least some cobra 39s and a maf.. i can get you a 90 mm for 50 bucks..

[zinc02GT]

Originally Posted by Eagle2000GT Stock 23 lb. injectors with 14 psi boost? You need at least 42 lb. injectors. Did the previous owner mention if it has stock rods and pistons or if they were forged?

Uhmmmm I was unaware that the stock injectors are 23 lbs... I thought they were 19 lbs..

Get 42lb injectors and call it day. check the fuel pump as well.

[Eagle2000GT]

I could be wrong but I remember someone telling me that they changed from 19 to 23 in '02 or '03.

[B0B]

ok, andrew welcome to the site!

looks like you haven't been around mustangs too much by the way you're describing your mods.



"Vortech Supercharger, BBK Intake, Accufab Throttle Body, SLP heavy Clutch, Manual Trans: 5 speed- geared w/ short throw shifter, SLP Loudmouth II Exhaust w/ highflow catalytic converters, SCT Tunning Chip, AutoMeter Mach Adapter Model 9117, AutoMeter Fuel Pressure Gauge, Boost Pressure Gauge, Autometer Memory Capable Tachometer w/ shift light, Suspension lowered to 4 finger wheel to well"

could you go into detail a little more? what trim of vortech are you running? is your car intercooled? have you taken the car to a dyno? you're not running a bbk intake with the vortech, there is no such thing. gears are located in the rearend, not the transmission. my guess is they are probably 3.73 gears because the 4.10's are a little low for a supercharged car. take some pics of under the hood and we'll look at your setup and try to help you out more man. unless you have a built engine, 14psi will throw a rod very soon. also, you must have some sort of upgraded fuel system because a supercharger requires bigger injectors. you'll find a ton of good info on this site, we'll try to help you out but we might need to know a little more about your mods.

Sounds to me like if it seems to lose power in 1st gear it could be something as simple as your tires spinning without you noticing it or something more complicated like low fuel pressure or spark blow out.

[Andrew]

Great info. ok, i'll take some pics right now

[Andrew]

Ok, I've uploaded several photos of my engine bay to my garage, so tell me what you think. I really appreciate yall's help