![SEARCH](http://www.mustangworks.com/images/search.png)
![The Mustang Works](http://www.mustangworks.com/images/mw_footer_logo.gif)
© Copyright 1995 thru 2008 - The Mustang Works™. All Rights Reserved.
MustangWorks.com is designed and hosted by Aero3 Media.
MustangWorks.com is designed and hosted by Aero3 Media.
![]() |
#1 |
Registered Member
Join Date: Jan 2006
Posts: 1
|
![]() Hi, I'm new to this site and I just bought a 5 speed 89 Mustang GT. The car seems to run fine and strong doing normal driving but everytime when I try to step on it under hard acceleration (above 4000 rpm), the exhaust starts to make some sputter noise, the engine hesitated and lost power instantly. It seems like a backfire from the exhaust. If not, What can it be? The car have the following modifications: 65mm throttle body, 70 mm mass air, mac cold air, pulleys, 1 5/8 shorty headers, mac pro chamber, 2 1/2 mac catback and 3.73 gears. Any help or advices will be greatly appreciated.
Last edited by excitement302; 01-29-2006 at 04:45 PM.. |
![]() |
![]() |
![]() |
#2 |
Mizzou Tigers
Join Date: Apr 1999
Location: weston, MO United States
Posts: 1,455
|
![]() It could be that a fuel injector is bad. I had the same thing happen with my 90, but it usually happened under load. The dealers have some way of flow testing the injectors without major work (they only charged me an hour of labor to do it). It was never a loud backfire, but it was a popping noise coming from the exhaust.
__________________
2006 Mustang GT 1990 LX GT-40 motor 262 horsepower, 307ft-lbs (sold but forever loved) 1998 Contour SVT Rice Haters Club Member #244 |
![]() |
![]() |
![]() |
#3 |
Registered Member
Join Date: Feb 2002
Location: Jacksonville, FL
Posts: 706
|
![]() An Actron CP9015 code scanner can help you out.
In addition to the Key On Engine On test, you can further diagnose a problem by running the cylinder balance test(this tests each injector individually while the car is running and will tell you if it is malfunctioning). I have become a big believer in this diagnostic tool. It doesn't always tell you everything, but it sure beats guessing, good luck...it's $30 at Sears or any parts store...
__________________
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 |
![]() |
![]() |
![]() |
#4 |
Moderator
Join Date: Sep 1998
Location: Grand Rapids, Michigan, USA
Posts: 1,001
|
![]() Check your fuel pressure. This sounds like a classic case of a failing fuel pump and/or regulator. Yes, leaning out causes backfiring.
Do a little Googling, and you can find out how to perform a cylinder balance test. All you need is a paper clip and about five minutes of your time. Good luck.
__________________
Capri306, Moderator The Mustang Works Online 1979 Mercury Capri 1987 5.0L Mustang LX Notchback 1993 5.8L Eddie Bauer Bronco ![]() |
![]() |
![]() |
![]() |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
Yessir! Another backfiring issue! But please read. | FSirignano | Small Ponies | 1 | 09-10-2005 08:29 AM |
Help! Backfiring and loss of power | spuckie | Blue Oval Lounge | 1 | 11-24-2003 01:08 AM |
Help! Backfiring and loss of power | spuckie | Windsor Power | 1 | 11-21-2003 07:40 PM |
Backfiring Problems! | MITCHL | Windsor Power | 5 | 11-21-2002 01:52 PM |
Backfiring on Deceleration... | Idhomustang | Classic Mustangs | 12 | 08-31-2000 01:59 AM |