is this the fuel supply line?

[Craig 94 TA GT]

Man, like a noob here...hate to ask a dumb question but, is the picture correct? I'm trying to locate the area of where it's leaking pressure. I tried using vice grips to clamp off the supply line once it's pressurized. I also tried the return line once it's pressurized in order to see where it's leaking. (The supply line is slightly bigger than the return line in case you can't see the pic well). It didn't seem to matter where I clamped it off...still kept losing pressure.
In fact, I tried clamping off the supply line (or what I think to be the supply line) before I even pressurized the system, yet it still keeps initially pressurizing to 44 psi.
By the way, I tried 3 clamps and am 99% sure I cut off the whole line.
If I'm wrong, where would I clamp it off in order cut off the supply/return line?
Thanks in advance.

[fastTa]

A little hard to tell from that pic but it looks like you have the arrow on the supply line. It will the larger of the lines.

[Craig 94 TA GT]

Thanks Kevin....
Man, I'm stumped then. Is there another way to cut off the fuel supply line once it's pressurized? I don't want to go overkill on the clamping because I'm afraid I might destroy the line.

[TraceZ]

I would not use anything to try and clamp those lines. They are not meant to be smashed like that.

The only place it can leak is at the joints. Is there fuel visably leaking? If not, what makes you think it is leaking?

[fastTa]

Do you have the supply line disconnected? What about inserting a bolt into the end of the line.

[TraceZ]

Originally posted by fastTA
Do you have the supply line disconnected? What about inserting a bolt into the end of the line.

No way!

that end is a fitting that cannot be nicked or damaged. If you try to shove a bolt in it you would destroy it and it would leak for sure.

I dont understand what he is doing. If he has a fuel leak he should see leaking fuel. Unless it is an injector leaking.

[fastTa]

The ID of the actual line is smaller than the crimped ends and you could plug the actual line w/o damaging the crimped ends or the line itself.

I think Craig is trying to pressurize the lines to check for leaks.

[Craig 94 TA GT]

Sorry I didn't elaborate...most of it was in my earlier posts.
This is what's going on:
I just got my fuel pump replaced at a mechanic (covered by insurance) and they also changed the filter, and cleaned my injectors. When I got it back, I noticed that it still has a shaky idle. The idle speed is perfect, but somewhat shaky and every so often, hesitant off the line. So I checked my fuel pressure...
turned the key to "ON", and it read 44 psi...but as soon as the pump stops charging, the pressure instantly goes down to 30 psi, then 20, then 10. After a few more seconds, it's practically at 0.

The mechanic claims it's my regulator and I need new injectors. I think otherwise...I checked for leaks in my injectors by pulling up the rails and pressurizing the system. Nevertheless, I do not see any drips whatsoever. I also checked the vacuum line in the FPR...no trace of gas. As a matter of fact, I checked the pressure at idle, 37 psi. Then I took the vacuum line off the FPR to simulate WOT, and it responded as normal...went up 6-8 psi.

I have no sign of visible leaks, so my last resort was to do as Shoebox said in Camaroz28.com...which is: pressurize the system, then cut off the supply line. If the pressure does not go down, then you have a leak at the pump (possibly the check ball). This I doubt because I have a brand new pump. If the pressure still drops, then try to cut off the return line when the system is pressurized. If it does not drop, then you have a leak at the FPR.

Needless to say, I've tried them both, but I don't think I want to clamp too hard. I've found other ways of doing them, but they involve a fuel line disconnect tool and attaching a fuel line shut off valve to each line...so you can tell which end is the problem.
What do you guys think? Thanks a bunch...

*EDIT*
Yup, you got it right on, Kevin...checking the system for leaks...good analysis before I stated it!

[fastTa]

It might be easier to block the supply line before the inlet side of the fuel filter. Just a thought.

[Craig 94 TA GT]

That's true....a good point, I'll need someone else's help to do so...because I need to charge the system, then clamp off the line, then read the pressure. And by then, the system loses pressure so fast, it'll probably be nearly 0. And of course, the gauge's hose is only 2 feet long, so I'll need to get to the engine area again.

Unless...is it bad if I were to manually run the pump using the PCM wire...then clamp it off when it's still running...then get up, stop the charging, and then read the gauge? I'm kind of leary of clamping it when it's continuously charging...but I'm no expert

[fastTa]

I guess the worst that could happen is you would get gas everywhere.

When you had the fuel rail lifted and were checking the injectors for leaks, did you have the fuel pressure gauge connected?

[TraceZ]

I have an idea...

1) Go buy a fuel filter.
2) Take a 1 foot piece of rubber fuel line and attach it to the engine side of the filter.
3) attach a pressure guage to the end of the fuel line
4) plug it into the fuel line from the tank
5) pressurize the test system
6) see if it holds pressure after shut off

if it does, you have a leak forward of the filter.

[Craig 94 TA GT]

Kevin, when I checked the injectors for leaks, I did have the fuel presssure gauge on. I charged it, shot up to 45, but again, as soon as it stopped charging, it immediately shot to 30, then 20, then 10 and so on. I saw absolutely nothing dripping from the injectors. I put the injectors/rails back down to what I thought was centered, and tightened the bolts to ~10 ft-lbs. I hope I did that right!

Tracy, you have a good idea...I will try that tomorrow.

I also forgot to mention, it takes more turns to start it than ever before. I would guess this to be correct because it's not holding any pressure in the system. So I wanted to make one more test, in order to rule out leaky injectors that are dripping into the piston(s), and causing a rich condition. The test was, I tried to start the T/A up in flood mode by flooring the throttle when I tried to turn it over, but it wouldn't even start.

I guess tomorrow, I'm going to do what Tracy suggests...if it shows fine, I guess there's some leak in my injectors/FPR that I am not seeing. I really have a feeling it's something not tightened well in the fuel pump because I lose all pressure in a matter of seconds, yet I am not seeing any gas whatsoever.

Thanks for your guys' help

[KnightFire]

Try pulling the vacuum line off the FPR, do you see any fuel? Are you running an aftermarket AFPR?

The stock FPR uses a flap check valve, some of the aftermarkets use a ball/check valve, these are supposed to leak down by design. If you have an OEM FPR, I would suspect the diaphram has gone bad.



KnightFire

[TraceZ]

Originally posted by TraceZ
I have an idea...

1) Go buy a fuel filter.
2) Take a 1 foot piece of rubber fuel line and attach it to the engine side of the filter.
3) attach a pressure guage to the end of the fuel line
4) plug it into the fuel line from the tank
5) pressurize the test system
6) see if it holds pressure after shut off

if it does, you have a leak forward of the filter.

I just had a thought...
this test rig will not allow for fuel to pass through a regulator, down the return line. You will see a very high pressure. You will also need to bleed the air out of the test rig to get a good reading. I would recommend filling it with fuel before hooking it up.