Fuel pump saga...

[Paul Workman]

My pressure issue was the pumps, after all - got plenty of push now - WOT pressure stays just above 50 all the way to redline. Apparently, someone had been in there before...I found traces of red lint on the old strainers, followed by finding a red shop towel drifting around on the bottom of the tank!:jawdrop: Somehow, I don't think that was suppose to be there...:rolleyes:

Had to go back in and replace the stock plastic hose clamps with some worm-gear clamps as it wouldn't hold pressure. That helped a lot, but where the old pumps held pressure, since the change to new pumps, it won't hold. One of the packages holding one of the fuel pumps had been opened before I bought it, but since it was the last pair they had, I took it. That might have been a mistake. I'm wondering if I can use air pressure to back pressure the pumps and go hunting for the leak that way. Gonna find out later today, I recon! (I didn't intend on getting good at pulling the pumps. Got it down to under 20 minutes from removing the door to installing it again...sheesh!)

P.

[tomtom72]

Jeeze louise.....that's like the sponge left in the abdominal cavity trick, isn't it? I don't see why shop air can't help find any remaining leaks....mho.
Sorry to see you have so many small issues to contend with to sort out the delivery system. I guess that's to be expected with our cars getting on 19 yrs old. They ain't new any more, no matter how good they look.

Good luck with it Paul!:thumbsup:

:cheers:
Tom

[XfireZ51]

Paul,

I'm a bit confused. You say you have >50psi through WOT but you also say you're not holding pressure?

[Paul Workman]

Paul,

I'm a bit confused. You say you have >50psi through WOT but you also say you're not holding pressure?

Switch on = >50#. But! Turn switch off, and pressure leaks down to zero w/in 5 seconds (give or take). This is a phenomenon I'm assuming is related to the new pumps. The old pumps couldn't hold 50# at WOT, but wouldn't leak down more than a couple pounds in 5 minutes with the switch off. Course, it could be an injector stuck open, but I didn't have any indication of that when it ran last. A stuck injector in coincidence w/ everything else would be an incredible long shot...(Not to say that would be impossible, gauging on my luck of late. :rolleyes:)

P.

[ittlfly]

The 3rd possibility is a FPR going south. ...just a thought.

[WB9MCW]

"I didn't intend on getting good at pulling the pumps. Got it down to under 20 minutes from removing the door to installing it again...sheesh!"

Guess I know who to call when the day comes I need a pump replaced. :cheers:

[Paul Workman]

The 3rd possibility is a FPR going south. ...just a thought.

Oh, BITE THY TONGUE! (Sheesh! You had to go n say that, didnya!?:rolleyes: Ol' Murphy (Murphy's Law) doan need no mo ideas! Seems he's had a pretty rich imagination already this month re my Z.;))

P.

[WB9MCW]

Paul we expect this ordeal to make you the resident expert in fuel delivery on ZR-1's.

It is important you cover all the bases.

That is why olde Murphy is givin ya da workout indeed.

[ittlfly]

Oh, BITE THY TONGUE! (Sheesh! You had to go n say that, didnya!?:rolleyes: Ol' Murphy (Murphy's Law) doan need no mo ideas! Seems he's had a pretty rich imagination already this month re my Z.;))

P.

I hear ya brother...... but it is easy to check and rule out before having to tear into the beast again. Hey, what the hell, you weren't doen nutten anyway. :mrgreen:

[Paul Workman]

Now for you "old hats to ZR-1s", feel free to skip this... But, for those interested in breaking down a delivery issue, I got some pix fer ya.;)

Leak down issue...

Is it injectors or FPR leaking down? Or is it the check valve in one of the pumps?

Pulling the pressure line off of the top of the pump assembly flange and connecting a 50# air line proved the injectors and the FPR were OK.

The pump delivery tube...(accessed by removing four screws holding down the gas fill cap door assembly).

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/7-25-09003.jpg

I set my air pressure regulator for 50# and kluged a fitting to the delivery line going to the fuel rail, where my fuel pressure gauge was waiting.

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/7-25-09004.jpg
http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/7-25-09005.jpg

A squirt of air until equalized and then monitored the pressure gauge attached to the Shrader valve on the fuel rail. No leaks!

Next to pressurize the fuel pump outlet pipe the same way and see where it leaks. In this case, remember that pump I said I bought with the packaging having been opened before I got it? Guess what...The check valve on that pump was for all intents and purposes...non-existant!

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/7-25-09008.jpg

Trick: ya can test the bitches by putting you mouth on the exit pipe of the new pumps. If you can blow air thru it...it isn't going to hold pressure, I find. (However, even with a good pump, I was just able to force air out - very slowly. But 50# of liquid was quite a different story!

Anywayz...That problem solved. Now onto that leak, apparently on #8. Valve? A compression tester awaits...We'll see if it is a valve, or just a leak on a new set of headers!

Mo later,

P.

[WB9MCW]

Good info Paul -- Keep up the good investigative work!

[ittlfly]

Dang!, I forgot about testing the FP check valve...good catch. :-D