Fuel pump issues..

[96speedZ28]

I was heading back from work just and just got on the Interstate when the car starts to spudder and died. I try to start it and just barley starts and dies again. So I call for some help and after waiting for about 10-15 minutes I try to start it and it starts, but pretty rough, so I start driving it and make it about a mile and it dies again. Try to start it back up and I got nothing. I wait another 10-15 minutes and it starts up again make it about 2 miles (keeping the RPM's up so it doesn't die) and then she dies again. I wait another 10-15 and it trys to start and sounds like its running on like 4 cylinders, but wont start up. So I end up towing it home.

Im thinking its the fuel pump because last time I was on the Dyno the guy showed me that my fuel pressure was going down as the RPM's got higher. I've also noticed the car to kind of have a random "hickup" lately on WOT. I also started to barley hear the pump prime when you turn the key to the "on" position, and now you can't hear anything at all. I hooked up a fuel pressure guage and it didn't read anything at all. Cycled the key a few times and tried cranking it over, but still got nothing. Is it for sure the fuel pump or do I need to check something else? I'd want to say fuel pump since it died and started back up a few times.

If it is indeed the fuel pump, I think im going to get this... http://www.racetronix.biz/customkititems.asp?kc=RFPK-003&eq=

Is this what everyone is running?^^

Does anyone actually drop the tank or does everybody cut up the car and do the "trap door" mod? I hate to cut up the car.

I also just realized I don't have the vacuum control hose coming from the regulator to the intake. Its been off of the car since I did the cam and it was tuned with it off. Is this a big deal if I have this off? Is it going to change my tune if I hook it back up?

http://shbox.com/1/fp_reg.jpg

Thanks ahead of time to anyone that can help! I've never done a fuel pump before, so this is a first time thing.

[jaysz2893]

You need the vac line. I cut my trap door. Was no big deal, metal was thin enough to use shears.

[CALL911]

I would be a little concerned that if you tried to run it that much and it kept dieing that possible damage may have occured. When it doesn't have fuel, you are running it lean, and if it gets to a point it dies, you should leave it until you have it fixed. Starting and driving it until it dies over and over again... I would be at least slightly concerned.

That being said, I would say that you have a fuel pump issue. The Racetronix would be my pump of choice. I have cut access panels in each of my F-bodies (and several friends as well). It won't hurt anything as long as when you are cutting the panel you don't go too deep and cut part of the fuel lines. There are many "how to" threads on LS1 tech (and maybe even a few here) on how to do this. You can't tell the hole is even there because it is covered with the carpet and insulation. The frame isn't any weaker either.

I would also reccomend getting a fuel pressure gauge to have in the car. It is probably the most important aftermarket gauge that you can get when it comes to making sure your car is getting the proper fuel pressure at all times.

[jaysz2893]

I agree with call911 100%. I added a in car gauge when i had my fueling issues. I ran a -4 an line off the schrader valve to an electronic sensor. I had a lean issue. After screwing around too long trying to fix the lean I ended up with a bad bearing. I dunno if it was related, but I did pull the motor and rebuild it. My issues was 2 bad injectors and a weak pump. I will be pulling my interior this weekend, I can take some pics of my trap door. I have already used it twice. Well worth the cutting

[96speedZ28]

I would be a little concerned that if you tried to run it that much and it kept dieing that possible damage may have occured. When it doesn't have fuel, you are running it lean, and if it gets to a point it dies, you should leave it until you have it fixed. Starting and driving it until it dies over and over again... I would be at least slightly concerned.

That being said, I would say that you have a fuel pump issue. The Racetronix would be my pump of choice. I have cut access panels in each of my F-bodies (and several friends as well). It won't hurt anything as long as when you are cutting the panel you don't go too deep and cut part of the fuel lines. There are many "how to" threads on LS1 tech (and maybe even a few here) on how to do this. You can't tell the hole is even there because it is covered with the carpet and insulation. The frame isn't any weaker either.

I would also reccomend getting a fuel pressure gauge to have in the car. It is probably the most important aftermarket gauge that you can get when it comes to making sure your car is getting the proper fuel pressure at all times.

You know I actually thought about that after I finally got it home, and now that you say that, I realize that it was a bad idea. I just didn't have any way to get it on a trailer and didn't know how I was going to get it home. I really hope I didn't mess anything up... Thank you for your input though, this site seems a lot more helpful than LS1tech lately.


I agree with call911 100%. I added a in car gauge when i had my fueling issues. I ran a -4 an line off the schrader valve to an electronic sensor. I had a lean issue. After screwing around too long trying to fix the lean I ended up with a bad bearing. I dunno if it was related, but I did pull the motor and rebuild it. My issues was 2 bad injectors and a weak pump. I will be pulling my interior this weekend, I can take some pics of my trap door. I have already used it twice. Well worth the cutting

Yeah, I'd appreciate that. I'll probably end up doing that.

[96speedZ28]

Racetronix fuel pump kit ordered.

[jaysz2893]

here is the picture of my hatch.
http://i4.photobucket.com/albums/y136/TheKeenans/IMAG0419.jpg
I cut a L shape to make getting to the disconnects easier. I got a piece of sheetmetal and self stick gasketing from lowes to make the cover. I used good metal shears (the ones with yellow, red, and green handles.) I used a drill with a stop collar to punch holes in the corners. Just take your time. HEre is the writeup I used to get started, it has good measurments to use.
http://www.ls1tech.com/forums/lt1-lt4-modifications/1256372-fuel-pump-trap-door-mod-pics.html

[96speedZ28]

Thanks man. The tracking number says the pump arrived at my house this morning, so ill probably start the install this weekend. I might have a few questions also. haha

[96speedZ28]

Got the pump and racetronix harness installed and it runs again, but now my fuel gauge is stuck on 1/4 tank. I put $20 off gas in last night and it didn't move :confused:. I followed the directions word for word. Im guessing it might be a mechanical problem with the float and how I put it in the tank because if it were an electrical problem, wouldn't it be at E or F?

Also haven't put the regulator vent line back on, should I?

[CALL911]

Got the pump and racetronix harness installed and it runs again, but now my fuel gauge is stuck on 1/4 tank. I put $20 off gas in last night and it didn't move :confused:. I followed the directions word for word. Im guessing it might be a mechanical problem with the float and how I put it in the tank because if it were an electrical problem, wouldn't it be at E or F?

Also haven't put the regulator vent line back on, should I?

What your problem most likely is that the metal rod that connects your float did not get re-attached properly (or popped out when you put it in). Try taking the fuel pump assembly back out and checking it out, I would bet that your problem is there and will be an easy fix.

[96speedZ28]

Thats what im thinking, thank god I did the trap door mod.

[CALL911]

Thats what im thinking, thank god I did the trap door mod.

The trap door mod has saved me already numerous times with issues I miscellaniosly had. If by some chance the metal rod is attached correctly, sometimes just resetting the float and putting everything back in the tank can make it more accurate.

For example; for the las few years, my fuel gauge has always shown WAY past the full mark when full, then when on fumes, it would show about half a tank. Its been a few years since I have been in my fuel tank until this summer. On my way to the LTXshootout, I had fuel issues, and I was in the tank a handfull of times until I got the issue fixed. After I did (and the fuel pump assembly was out of the tank like 4 times total) I noticed the fuel gauge finally was back to being accurate again. These things can be finicky. So sometimes just taking them out, and putting them back in can set them back. But if yours really isn't showing any movement, again, I bet you just need to set that metal rod back correctly.

[96speedZ28]

Thanks for the response, 911. These cars go through gas far too quick to not have a gas gauge lol. I am going to try that tonight after work and hopefully I didn't damage anything and it works. Can you possibly explain what you mean by "setting" the rod? Or do you just mean take it out and put it back in (making sure it goes in smoothly without any force).

[CALL911]

I am notoriously bad for trying to explain, but I will try my best; The rod attaches to a round wheel with a clip, then on the other part of the rod is the float. If the rod isn't attached to the clip on the wheel properly, the wheel should be the part that the fuel gauge reads, so in other words, if the rod moves with the float, but it isn't clipped, the wheel won't be moving, and thus you won't have a fuel gauge. Just make sure it is attached. If it is, sometimes just taking the whole assembly out of the tank and putting it back in can sometimes "reset" things and make it more accurate again.

[96speedZ28]

Fixed it! The thick anti-kink line off the pump was in the way of the float so it couldn't move up any farther.

[CALL911]

Good deal!

[ksmyss]

I have done it by dropping the tank on the trap door. To get the tank out the rear end and exhaust have to be out of the car since the filler neck is all one piece or the tank will not come out. I now have a trap door and will be adding a second pump later this year and it will save me a ton of time and headache.