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Old 01-15-2009, 03:06 PM   #1
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Question What are the signs of a fuel pump on its way out?

Car is sputtering/coughing when under load in the high rpm range... gonna check my plugs, but they only have around 3k miles on them. NGK TR55 Xi's...

also... would this cause any damage to the engine? is this a lean type thing that I would need to worry about if indeed my fuel pump is going out?

just had some 36# FAST injectors installed with a 13.1 A/F ratio across the board till about 6800...

tailpipes don't seem to have any white residue on them... still need to check the plugs to see what shape they are in though...

ideas?
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Old 01-16-2009, 03:19 AM   #2
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anyone?
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Old 01-16-2009, 08:22 AM   #3
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The pump will work and not work intermittenly. Car won't start, nose over. Could do exactly how you describe. Check fuel pressure at the RPM and loads you describe above and make sure the pump you have can handle the new injectors at the pressures you need.
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Old 01-16-2009, 02:21 PM   #4
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thanks!

what's the pressure supposed to be at across the RPM range? is it supposed to hold steady, fluctuate, or gradually rise...?
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Old 01-16-2009, 02:29 PM   #5
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hold steady, I have a thread below that I'm trying to find a solution to my fluctuations in pressure since swapping pumps. Don't know what the pressure is supposed to be for your LQ4, my LS7 is 58psi.
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Old 01-16-2009, 04:42 PM   #6
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Quote:
Originally Posted by ss dave View Post
hold steady, I have a thread below that I'm trying to find a solution to my fluctuations in pressure since swapping pumps. Don't know what the pressure is supposed to be for your LQ4, my LS7 is 58psi.
I wanna say it's 58psi also... but not sure either...

I'm pretty sure it's the same as whatever the LS1 is... seeing as I still have my LS1 fuel system on this setup... everything swaps over so...
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Old 01-16-2009, 05:26 PM   #7
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Wes,

It should stay around 58psi. My truck had a fuel pump failure over the holidays, it started hiccuping on my way out to visit a friend in Claremont. It hiccupped twice, then stalled, I tried to restart it and it was idling terribly like a misfire. I checked the rail pressure and it was going down. I could no longer hear the pump when I keyed on the ignition switch. Try that, have a friend key on the ignition switch and listen for the pump. If you do not hear anything buzz from the tank area for a few seconds, the pump is dead. They don't wear out and start to fail, they just go out and you are stuck. At least that has been my experience with EFI. Good luck!
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Old 01-17-2009, 01:54 AM   #8
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Wes,

It should stay around 58psi. My truck had a fuel pump failure over the holidays, it started hiccuping on my way out to visit a friend in Claremont. It hiccupped twice, then stalled, I tried to restart it and it was idling terribly like a misfire. I checked the rail pressure and it was going down. I could no longer hear the pump when I keyed on the ignition switch. Try that, have a friend key on the ignition switch and listen for the pump. If you do not hear anything buzz from the tank area for a few seconds, the pump is dead. They don't wear out and start to fail, they just go out and you are stuck. At least that has been my experience with EFI. Good luck!
hmm... good info George... I still gotta get my *** out there to pull the plugs lol... I will take some pictures though for sure of them

I took the car for a spin today, and no issues really. Course it only seems to happen when I get on it full throttle so...

I'm wondering if my pump isn't going out, but instead just can't keep up with the amount of fuel I need at WOT...
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Old 01-20-2009, 01:21 PM   #9
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Do you have an aftermakret unit or stock? How is the fuel filter? I experienced this as well, but it was my fuel filter being old.
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Old 01-20-2009, 05:18 PM   #10
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My buddy is having a similar problem on his Formula with a C5R 427. Was working fine a few months back. Right before it went into storage I did a few passes and the power would cut out at high RPM's and only under load. If the car is in park/neutral it will be fine with revs. When I checked out the Fuel pressure gauge under the hood the PSI does fluctuate +/- 5. So I'm thinking its fuel related... just not sure what yet...
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Old 01-20-2009, 07:13 PM   #11
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Be sure to check your grounds on the back of the DS cylinder head. If they are loose or broken, it could cause a problem just like you describe. Watching fuel pressure under load at WOT is really the only way to verify pump issues. If you do need a pump kit, we now have tons of Racetronix in stock ready to ship.

Thanks,
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Old 01-21-2009, 09:16 PM   #12
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First thing to do is replace the filter
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Old 01-21-2009, 10:06 PM   #13
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Quote:
Originally Posted by Soul TKR View Post
Car is sputtering/coughing when under load in the high rpm range... gonna check my plugs, but they only have around 3k miles on them. NGK TR55 Xi's...

also... would this cause any damage to the engine? is this a lean type thing that I would need to worry about if indeed my fuel pump is going out?

just had some 36# FAST injectors installed with a 13.1 A/F ratio across the board till about 6800...

tailpipes don't seem to have any white residue on them... still need to check the plugs to see what shape they are in though...

ideas?

When mine was going out i had the A/C on at stop light and i punched it and it bogged down (feels like lag). came home and was leaving made it halfway out of the driveway and it died. Was in Summer time.

(Car is sputtering/coughing when under load) your talking about could be fouled plug it makes it lag sputter under load. I put in New Plugs and month later it fouled one out. So i put ACDelco ones back in perfect sense.
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Old 01-22-2009, 12:29 AM   #14
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Quote:
Originally Posted by 12secSS View Post
Do you have an aftermakret unit or stock? How is the fuel filter? I experienced this as well, but it was my fuel filter being old.
my entire fuel system except for my new injectors are stock... It's just odd that these problems didn't start coming up till I got the new injectors installed...

Quote:
Originally Posted by XtraCajunSS View Post
Be sure to check your grounds on the back of the DS cylinder head. If they are loose or broken, it could cause a problem just like you describe. Watching fuel pressure under load at WOT is really the only way to verify pump issues. If you do need a pump kit, we now have tons of Racetronix in stock ready to ship.

Thanks,
Shane
I'll check that Shane thanks!

I gotta say, after reading all the bad customer reviews on Racetronics stuff I'm really hesitant to buy anything from them. They seem to have no customer service if you have any issues... It's one of those "email us... we don't have a phone number" places...

Quote:
Originally Posted by chpmnsws6 View Post
First thing to do is replace the filter
Yea... I gotta try replacing that I guess... last time I changed it was back in '05... probably about 15-20k miles ago... how often do most people change them? what's the rule of thumb...?

Quote:
Originally Posted by 1996firebirdformula View Post
When mine was going out i had the A/C on at stop light and i punched it and it bogged down (feels like lag). came home and was leaving made it halfway out of the driveway and it died. Was in Summer time.

(Car is sputtering/coughing when under load) your talking about could be fouled plug it makes it lag sputter under load. I put in New Plugs and month later it fouled one out. So i put ACDelco ones back in perfect sense.
yea these are NGK TR55's... only got about 2-3k miles on them... I gotta pull them. I'm a little worried of breaking them off in the heads like i read all the horror stories on here
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Old 01-22-2009, 11:03 AM   #15
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when i switched to 42lb. svo injectors i had to switch to a walbro 255 pump and haven't had a problem with it since then. you have to wire the walbro pump in but it goes in the stock location.
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Old 01-23-2009, 01:43 AM   #16
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when i switched to 42lb. svo injectors i had to switch to a walbro 255 pump and haven't had a problem with it since then. you have to wire the walbro pump in but it goes in the stock location.
yea I've researched that... only problem is, that looks a little more intensive than I feel I've got the skills for... but on the other hand the racetronix stuff already wire up is getting bad raps so...
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Old 01-23-2009, 09:14 AM   #17
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No need to do the racetronix stuff, or atleast my pressure never dipped down without it on a built 347 at 7200rpm.
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Old 10-11-2011, 10:06 PM   #18
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My high mileage car was hard to start, started on the third 5 second turn/hold of the ignition key.
Brand new 383 with a good tune from Madtuner,...he told me to check the fuel pump.
I swapped in a Walbro and it fires INSTANTLY now, hot or cold with pressure pegging 44psi on a test guage as soon as I turn the key to the on position.
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Old 10-11-2011, 10:06 PM
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