Fuel pump?

Isambard · September 25th, 2011, 12:13 AM

I've got a bit of a problem with my 5.0 LX. Car has a smog delete and no cats but everything else is stock. Was running okay when we first bought it and got it running but for the last month or so it's been stuttering very badly on acceleration and it flat out died on me while cruising home in 5th gear.

Wouldn't restart and we're guessing fuel pump, except I can hear it prime when I turn the key.

Relay is fine, inertial switch isn't popped, and the fuel pressure regulator isn't squirting out fuel or anything so I assume it's mechanically sound. And to top it off sometimes it'll start, run for a bit, then the pump will just kick out and give up.

Anyone had a similar problem with a fuel pump on it's last leg or am I missing something obvious? Thanks in advance!

1LOUDGT · September 25th, 2011, 07:49 AM

When was the last time you replaced your fuel filter?

fogged306 · September 25th, 2011, 09:50 AM

Check the fuel pump relay. They have a reputation for going bad and doing just what you're describing. Also check the inertia switch behind the drivers tail light.

Isambard · September 25th, 2011, 01:28 PM

Originally Posted by 1LOUDGT

When was the last time you replaced your fuel filter?

The filter was replaced right after we got the car running and did a full tune-up on it.

Originally Posted by fogged306

Check the fuel pump relay. They have a reputation for going bad and doing just what you're describing. Also check the inertia switch behind the drivers tail light.

The relay was replaced a couple of days ago and the problem persisted. And the inertia switch in the trunk isn't popped so I don't believe that's the issue. If it was I think I'd get zero pressure no matter what, as it stands the pump decides when it wants to work, abet poorly.

fogged306 · September 25th, 2011, 02:34 PM

So what's your fuel pressure when the car quits?

Isambard · September 26th, 2011, 05:33 PM

Originally Posted by fogged306

So what's your fuel pressure when the car quits?

Not even 5 PSI.

DShort · January 27th, 2012, 12:56 AM

Originally Posted by Isambard

I've got a bit of a problem with my 5.0 LX. Car has a smog delete and no cats but everything else is stock. Was running okay when we first bought it and got it running but for the last month or so it's been stuttering very badly on acceleration and it flat out died on me while cruising home in 5th gear.

Wouldn't restart and we're guessing fuel pump, except I can hear it prime when I turn the key.

Relay is fine, inertial switch isn't popped, and the fuel pressure regulator isn't squirting out fuel or anything so I assume it's mechanically sound. And to top it off sometimes it'll start, run for a bit, then the pump will just kick out and give up.

Anyone had a similar problem with a fuel pump on it's last leg or am I missing something obvious? Thanks in advance!

Did you figure this problem out? I have the same issue right now

ryanw · January 27th, 2012, 01:34 AM

I bet it was the fuel pump. Mine wouldnt cut out, but when i tried to start it, it wouldnt go, id turn the key off then back on let the pump prime a second time and then it would start, it would buck and back fire a little and my fuel pressure when it was running was only 16 psi..... the pump was replaced, now all is good

SSteady98 · January 27th, 2012, 02:28 AM

I'm guessing I have a similar problem, too. Car takes 5-6 switchovers to get gas going and for about the first 10 minutes of driving it smells absolutely horrible and bucks when I shift. Also after the car is warmed up a bit, giving full pedal in 2nd gear results in the car being really draggy after 2500 rpm. It's like it had no top end whatsoever.

ryanw · January 27th, 2012, 02:45 AM

Its got to be the pump. Since im sure your replacing it, upgrade to a walbro 255lph there about 100 to 125 bucks, its well worth it, if you plan on future power upgrades

Dont replace it with a stock pump.

September 25th, 2011, 12:13 AM	#1
Isambard Regular 2001 V6 1990 5.0 Join Date: Aug 2010 Posts: 51 iTrader: 0 reviews	Fuel pump? I've got a bit of a problem with my 5.0 LX. Car has a smog delete and no cats but everything else is stock. Was running okay when we first bought it and got it running but for the last month or so it's been stuttering very badly on acceleration and it flat out died on me while cruising home in 5th gear. Wouldn't restart and we're guessing fuel pump, except I can hear it prime when I turn the key. Relay is fine, inertial switch isn't popped, and the fuel pressure regulator isn't squirting out fuel or anything so I assume it's mechanically sound. And to top it off sometimes it'll start, run for a bit, then the pump will just kick out and give up. Anyone had a similar problem with a fuel pump on it's last leg or am I missing something obvious? Thanks in advance!

September 25th, 2011, 07:49 AM	#2
1LOUDGT Enthusiast 2006 GT 11.99@114 Join Date: Sep 2006 Location: Orlando, FL. Posts: 802 iTrader: 0 reviews	When was the last time you replaced your fuel filter? __________________ 2006 GT (Fastest) 2004 COBRA (Faster) 1990 LX 5.0 (Fast)

January 27th, 2012, 01:34 AM	#8
ryanw I Post Entirely Way Too Much 1991 Ford Mustang GT Join Date: May 2007 Location: San Diego, California Posts: 6,063 iTrader: 0 reviews	I bet it was the fuel pump. Mine wouldnt cut out, but when i tried to start it, it wouldnt go, id turn the key off then back on let the pump prime a second time and then it would start, it would buck and back fire a little and my fuel pressure when it was running was only 16 psi..... the pump was replaced, now all is good __________________ DART 331ci stroker, AFR 185 heads, Trick Flow R intake, Accufab 70mm tb, 75mm pro m Maf, 30lb injectors, jba headers, 2 1/2" x pipe flowmaster super 10 mufflers, 255 fuel pump, 3:27 gears Last edited by ryanw; January 27th, 2012 at 02:40 AM.

January 27th, 2012, 02:28 AM	#9
SSteady98 95ish5.0 1995 GT Slow Join Date: Aug 2010 Location: San Angelo Posts: 490 iTrader: 0 reviews	I'm guessing I have a similar problem, too. Car takes 5-6 switchovers to get gas going and for about the first 10 minutes of driving it smells absolutely horrible and bucks when I shift. Also after the car is warmed up a bit, giving full pedal in 2nd gear results in the car being really draggy after 2500 rpm. It's like it had no top end whatsoever. __________________ 1995 Mustang GT BBK Shorty Headers, H Pipe, CAI, UDP, 255lph Fuel Pump Spec Stage 3 Clutch FR500's all the way around Cobra R Hood Want Gears, Cam, TW Heads, Turbo(Last)

January 27th, 2012, 02:45 AM	#10
ryanw I Post Entirely Way Too Much 1991 Ford Mustang GT Join Date: May 2007 Location: San Diego, California Posts: 6,063 iTrader: 0 reviews	Its got to be the pump. Since im sure your replacing it, upgrade to a walbro 255lph there about 100 to 125 bucks, its well worth it, if you plan on future power upgrades Dont replace it with a stock pump. __________________ DART 331ci stroker, AFR 185 heads, Trick Flow R intake, Accufab 70mm tb, 75mm pro m Maf, 30lb injectors, jba headers, 2 1/2" x pipe flowmaster super 10 mufflers, 255 fuel pump, 3:27 gears

September 25th, 2011, 09:50 AM	#3
fogged306 MM Fanatic 89 GT Join Date: Apr 2007 Location: NY Posts: 4,875 iTrader: 2 reviews	Check the fuel pump relay. They have a reputation for going bad and doing just what you're describing. Also check the inertia switch behind the drivers tail light.

September 25th, 2011, 02:34 PM	#5
fogged306 MM Fanatic 89 GT Join Date: Apr 2007 Location: NY Posts: 4,875 iTrader: 2 reviews	So what's your fuel pressure when the car quits?

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