2G Disconnect fuel pump pressure line at pump

[waltah]

With symptoms of possible very low fuel pressure in my 'parts' car project I'm about to pull the pump out to have a look at the strainer, gas, etc. With the cover plate off it looks just like my 1G Expos but on those cars what appears to be a flare nut fitting accessible through the trunk floor is actually silver soldered. There's a flex hose that goes from there to the steel line under the body and you disconnect the pump down underneath and sort of corkscrew it up out of the tank and hole in the floor.

Rather than try applying lots of force to see what happens I decided to ask. Can you disconnect the pressure line through the access hole or is the real (undo-able) joint down below?

(Symptoms ... Runs fine at idle for a couple seconds, will not run above idle, eventually dies but can be restarted immediately. Also -- car has largely unknown history, came in non-running condition, and has had a very hard life -- nothing can be trusted. Fixed so far -- valve timing off by 1 tooth, coil for 1-4 weak/replaced, ECU died 'no CEL.' )

 

[steve]

I haven't done a 2G but on 1G and 3k's the fitting on the fuel pump assembly doesn't spin so you have to disconnect the hose under the car and then remove it from the fitting.

I assume the 2G is the same.

Have you tried measuring at the return line at the regulator and powering the pump to see how it flows. With the engine off everything has to go out the return so you get a good idea of flow at the regulated pressure.

 

[Adam]

What Steve said is true. Line at the pump doesn't spin so gotta disconnect it under the car first. Sucks

Oh also, make sure you use good line wrench's, the line out of the sending unit is easily stripped and most are fairly fragile with the age of them now

 

[pauleyman]

I haven't done a 2G but on 1G and 3k's the fitting on the fuel pump assembly doesn't spin so you have to disconnect the hose under the car and then remove it from the fitting.

I assume the 2G is the same.

Have you tried measuring at the return line at the regulator and powering the pump to see how it flows. With the engine off everything has to go out the return so you get a good idea of flow at the regulated pressure.

Hold up. I've done dozens and they do spin. Now I will say I've run up against many that were seized also and they did require going to the other fitting. There are many horror stories about twisting that line and its probably even worse now.

 

[luv2rallye]

I did mine recently and couldn't spin it. If it's spinable it was siezed on so tight that I'd have to break it to get it apart. Go with the fitting under the car where the rubber hose attaches and use flare nut wrenches:

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[steve]

Hold up. I've done dozens and they do spin. Now I will say I've run up against many that were seized also and they did require going to the other fitting. There are many horror stories about twisting that line and its probably even worse now.

Are you speaking about 1G's or 2G's?

 

[pauleyman]

Are you speaking about 1G's or 2G's?

1g

I did mine recently and couldn't spin it. If it's spinable it was siezed on so tight that I'd have to break it to get it apart. Go with the fitting under the car where the rubber hose attaches and use flare nut wrenches:

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I agree it appears welded. I'm fortunate enough I was dealing with these cars and in the south and my fitting spun. It's a flare fitting just like brake lines. At this point I agree treat all cars as if they were welded and go after the other fitting. Dunno why but it doesn't seem to seize as bad. I remember even back in the digest days when the cars were at most 10 years old people posted about twisting the line. I'm guessing in salt states you get any up there it's difficult if not impossible to get salt off and everything rusts horribly on top of the tank. I didn't experience that. My fuel assembly was still gold colored and many others I did in oklahoma too.

 

[steve]

Interesting, not been my experience but perhaps my memory is faulty.

I'll make a point of looking more closely in the future.

 

[waltah]

Have you tried measuring at the return line at the regulator and powering the pump to see how it flows. With the engine off everything has to go out the return so you get a good idea of flow at the regulated pressure.

Done this AM. 2 min. 20 sec. to fill a 1/2 gallon milk jug = 1.89L. Or 48.6 L/H I don't know the spec for an OEM pump but that's certainly enough to get above idle. Since the engine's not running there's no vacuum meaning that's at the maximum regulated pressure. Or does the regulator respond to boost?

An easy and useful test to do when fuel delivery problems are suspected. Thanks.

I wonder about the fuel being so old that it does not vaporize adequately in a cold engine. At some point the car sat for a year, maybe quite a bit more. it was full of paper wasp nests -- dozens of them. Only one still active -- so far.

Fond memories of pulling something from the dash of a '50 Cadillac with a large and active nest in the vent system, some time around 1975.

I've got 4 gal. of new fuel for it so this issue will be checked out pretty soon.

 

[steve]

Since the engine's not running there's no vacuum meaning that's at the maximum regulated pressure. Or does the regulator respond to boost?

To make it easy on the computing needed in the ECU the fuel pressure tracks manifold pressure. That means the injectors deliver the same fuel amount/unit time at idle as at boost by always having the same difference in pressure (delta) across the inlet and outlet of the injector.

It does mean that since the base pressure on a 2g is 43.5 psi, at 20 psi boost the pump has to push 63.5 psi, and the only way to do so is flow (volume) against the restriction of the regulator to make pressure.

I'm dreading going out and trying to start my GSX. It's been sitting about 3 years now and the wasps have been busy. The last time I started it it spit out a 4" round nest from the exhaust.

 

[waltah]

I agree it appears welded. I'm fortunate enough I was dealing with these cars and in the south and my fitting spun. It's a flare fitting just like brake lines.

Awright, I was just going to button it up and move on but I gotta see if I can tell for sure. I don't think I've got a flare nut wrench for the larger end of that joint but I'll go carefully and see what can be discovered -- it's not rusty. And order the right wrench.

It doesn't look like it's silver soldered as all my Expos are. I have to wonder if that was some sort of FSB or midyear change 'cause a leak there could be a lot worse than one down along the frame rail at the other joint. Of course the mechanics who worked on my cars in the past either never saw a need for 6 nuts on the cover plate (parts car has 3) or they used an air tool and pulled off one or more studs, so there's that ...

The problem with turning the upper flare nut on the Eclipses might be that the line is slightly out of round due to the nearby bend.

 

[1990TSIAWDTALON]

1g


I agree it appears welded. I'm fortunate enough I was dealing with these cars and in the south and my fitting spun. It's a flare fitting just like brake lines. At this point I agree treat all cars as if they were welded and go after the other fitting. Dunno why but it doesn't seem to seize as bad. I remember even back in the digest days when the cars were at most 10 years old people posted about twisting the line. I'm guessing in salt states you get any up there it's difficult if not impossible to get salt off and everything rusts horribly on top of the tank. I didn't experience that. My fuel assembly was still gold colored and many others I did in oklahoma too.

1g's are flare fittings. They are almost always seized and need removed from below then I take mine to the VISE and clamp the hard fitting in then loosen the rubber line from it to keep it from rounding off. The connection under the car usually requires VISE GRIPS the first time, from then on it is removable with wrenches, says the guy that did 3 of them last year only to find the tank being contaminated. Just trying to help.
Marty

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[pauleyman]

To make it easy on the computing needed in the ECU the fuel pressure tracks manifold pressure. That means the injectors deliver the same fuel amount/unit time at idle as at boost by always having the same difference in pressure (delta) across the inlet and outlet of the injector.

It does mean that since the base pressure on a 2g is 43.5 psi, at 20 psi boost the pump has to push 63.5 psi, and the only way to do so is flow (volume) against the restriction of the regulator to make pressure.

Yes. Fuel pressure rises 1 to 1 with boost as you have described.

I'm dreading going out and trying to start my GSX. It's been sitting about 3 years now and the wasps have been busy. The last time I started it it spit out a 4" round nest from the exhaust.

Gasoline kills wasps. You could spray a little in there and shove a towel in the end. I'm sure in a few min the vapors would kill them.

1g's are flare fittings. They are almost always seized and need removed from below then I take mine to the VISE and clamp the hard fitting in then loosen the rubber line from it to keep it from rounding off. The connection under the car usually requires VISE GRIPS the first time, from then on it is removable with wrenches, says the guy that did 3 of them last year only to find the tank being contaminated. Just trying to help.
Marty

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I knew I wasn't crazy. Thing is none of the cars I've ever worked on ever looked like that. The fuel pump sending units were all nice and gold. That's gotta be why I didn't have trouble. What did it take to free up the one in the pic?

 

[steve]

Gasoline kills wasps. You could spray a little in there and shove a towel in the end. I'm sure in a few min the vapors would kill them.

I think the car is pointed away from anything that might burn down when the flaming wasp fireball comes flying out...

BTW, Thanks for questioning the issue on the fitting. I'm happy to learn something new.

 

[1990TSIAWDTALON]

I knew I wasn't crazy. Thing is none of the cars I've ever worked on ever looked like that. The fuel pump sending units were all nice and gold. That's gotta be why I didn't have trouble. What did it take to free up the one in the pic?

Paul, I think I put the rubber line fitting in the vice jaws and then grabbed the flare nut with vice grips IIRC. Then I cleaned the threads and nut with a wire wheel on a drill. I did it so many times, I can't really remember which part I put into the vice, but one side was in it.
I've had to break every one of my 1g's loose below. I can't ever get that top flare loose from above until I break it loose the 1st time. Thats one nice thing about AN fittings.

 

[waltah]

To make it easy on the computing needed in the ECU the fuel pressure tracks manifold pressure. That means the injectors deliver the same fuel amount/unit time at idle as at boost by always having the same difference in pressure (delta) across the inlet and outlet of the injector.

(Picture of light bulb going on over my head.)

Also of course the spray pattern would go to pot as the pressure differential fell with increasing boost.

I'm dreading going out and trying to start my GSX. It's been sitting about 3 years now and the wasps have been busy. The last time I started it it spit out a 4" round nest from the exhaust.

Could be pretty exciting if the wasps were still in residence.

1g's are flare fittings. They are almost always seized and need removed from below then I take mine to the VISE and clamp the hard fitting in then loosen the rubber line from it to keep it from rounding off. The connection under the car usually requires VISE GRIPS the first time, from then on it is removable with wrenches, says the guy that did 3 of them last year only to find the tank being contaminated. Just trying to help.
Marty

2g are also flare fittings but my '95 GS-T is silver soldered.

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This is the parts car after a minute's discussion with Mr. Wirebrush. Notice the smooth radius where there ought to be a crack. With natural light (rather than the flash) you can see the color difference at the radius indicating silver solder. The earliest car for which I know I've checked this is a '93 Expo LRV and it was as pictured above though there might be model differences in details.

What I guess we know is 'some are, some aren't, and even those that aren't, are often frozen by rust.'

The vise grip trick is a good one. Not only does it give you a good grip but the tiniest distortion of the parts -- not enough to interfere with function -- will be enough to unseize the joint meaning much less torque will be needed. Might squeeze the larger (hose) side 'just enough' from at least two angles (pairs of flats) and then switch to the flare nut wrenches to take it apart.

I learned not long ago that if a flare joint has been overtightened so that it will no longer seal (the nut bottoms first) you can get a 'flare nut gasket.' These are dished washers of copper that fit right in there and give a perfect seal again. They're sized by the line size -- 1/4", etc.

And -- Fresh fuel makes a considerable difference in how the parts car runs. It still has to be started a few times but the least warmup is enough to let it keep running and once it is, it'll go up to 2000 RPM without any oddity.

Until I have a good radiator cap (yeah that was crapped out too) and the radiator and fans are properly mounted I'm not letting it run for over 20 seconds or so.

It is still acting lean so I'll investigate air leaks -- starting fluid and other methods. I have EvoScan on a laptop and a cable that works on these cars so I can also compare injector pulse widths to my working car.

There are probably sensor issues that could cause lean starting: Heaven knows if such issues exist, this car has 'em! But it would have to be something that OBD II doesn't notice as there are no codes.

 

[pauleyman]

(Picture of light bulb going on over my head.)

Also of course the spray pattern would go to pot as the pressure differential fell with increasing boost.


Could be pretty exciting if the wasps were still in residence.



2g are also flare fittings but my '95 GS-T is silver soldered.

You must be logged in to view this image or video.

This is the parts car after a minute's discussion with Mr. Wirebrush. Notice the smooth radius where there ought to be a crack. With natural light (rather than the flash) you can see the color difference at the radius indicating silver solder. The earliest car for which I know I've checked this is a '93 Expo LRV and it was as pictured above though there might be model differences in details.

What I guess we know is 'some are, some aren't, and even those that aren't, are often frozen by rust.'

The vise grip trick is a good one. Not only does it give you a good grip but the tiniest distortion of the parts -- not enough to interfere with function -- will be enough to unseize the joint meaning much less torque will be needed. Might squeeze the larger side 'just enough' from at least two angles (pairs of flats) and then switch to the flare nut wrenches to take it apart.

I learned not long ago that if a flare joint has been overtightened so that it will no longer seal (the nut bottoms first) you can get a 'flare nut gasket.' These are dished washers of copper that fit right in there and give a perfect seal again. They're sized by the line size -- 1/4", etc.

And -- Fresh fuel makes a considerable difference in how the parts car runs. It still has to be started a few times but the least warmup is enough to let it keep running and once it is, it'll go up to 2000 RPM without any oddity.

Until I have a good radiator cap (yeah that was crapped out too) and the radiator and fans are properly mounted I'm not letting it run for over 20 seconds or so.

It is still acting lean so I'll investigate air leaks -- starting fluid and other methods. I have EvoScan on a laptop and a cable that works on these cars so I can also compare injector pulse widths to my working car.

There are probably sensor issues that could cause lean starting: Heaven knows if such issues exist, this car has 'em! But it would have to be something that OBD II doesn't notice as there are no codes.

I can't remember if 2g awd is like that but I do remember the fwd is solid and you have to undo the other end of the hose. There is a writeup somewhere, maybe vfaq.com, that had you cut a small slit in the sheet metal to get the hose out the top side but I was able to do it with no cut at all. I would have to look at my 2g awd again to see how it is.

 

[waltah]

I can't remember if 2g awd is like that but I do remember the fwd is solid and you have to undo the other end of the hose. There is a writeup somewhere, maybe vfaq.com, that had you cut a small slit in the sheet metal to get the hose out the top side but I was able to do it with no cut at all. I would have to look at my 2g awd again to see how it is.

On the Expos you undo the end under the frame rail, disconnect the return line and power, remove the nuts holding the pump assembly, then rotate it clockwise as you lift it from the tank bending the pressure hose as necessary to pull it up through the hole in the floor pan as you turn/lift the assembly. It's good to note the position in which it comes out so you can start putting it back in that same way but turning left to screw it in rather than out.

It's actually easy once you do it the first time though it took me an hour for the first one. I'd bet they all work that way.

 

[Tyeler18]

1gs/GVR4 swivel, 2g's AWD and FWD are solid. I have a couple of each at home right now to confirm

 

[pauleyman]

1gs/GVR4 swivel, 2g's AWD and FWD are solid. I have a couple of each at home right now to confirm

I was thinking awd was solid also. I think the difference is you can undo the hose and it all comes out easily vs the fwd if I recall. I really don't know why they made they different with the ring on the awd.