HELP: Fuel pressure issues

[TIMINATOR]

Leaking pressure hose between the pump and hanger drops the volume, and the leak is inside the tank so you wouldn't know it.
I check before installing a pump by immersing it installed on the hanger in a coffee can of WD-40, deadheading the pump into a 150 lb. gauge and powering it up. I do this on customers cars before replacing or reinstalling any in tank pump.
Ya gotta consider that since the hose is inside the tank, it is being degraded on the inside and outside from the fuel and additives.
TIMINATOR

 

[tt455]

Leaking pressure hose between the pump and hanger drops the volume, and the leak is inside the tank so you wouldn't know it.
I check before installing a pump by immersing it installed on the hanger in a coffee can of WD-40, deadheading the pump into a 150 lb. gauge and powering it up. I do this on customers cars before replacing or reinstalling any in tank pump.
Ya gotta consider that since the hose is inside the tank, it is being degraded on the inside and outside from the fuel and additives.
TIMINATOR

After replacing the fuel filter and seeing what came out it, this makes even more sense. Thank you.

 

[tt455]

I saw a scroll thru a SM.....
Hardly a saved/reviewable log.
But thanks anyway for reminding me.

I do understand what you’re saying but like I said this wasn’t my build. I’m relatively new to the turbo world so even at 68 I’m still learning.
I just don’t have the, experience, knowledge or equipment for quick results.
The problem just arose so I’m trying to figure it out and posting videos may trigger a response from a member that may have had similar issues.
Sometimes you search and read comments without pictures or videos and without the experience it gets a little confusing.
Put me in a pre 72 A-body and I can find my way around. Anyway thank you for taking the time to reply.

 

[TIMINATOR]

When I upgraded my pump a few yrs ago, I decided to see what the pressure was at the old pump by doing the WD-40 thing. It sprayed all over the bench! In my app at that time, the stock pump probably would have worked with a good hose, but I had the new pump and was in there anyway.
I checked the new pump and found the pump outlet was larger than the hangers swaged smaller end and I couldn't find a hose to seal both ends correctly, a lot of WD-40 later, I cut off the swaged end and soldered a larger tube on the end. Problem solved!
For info purposes, the new pump was a Walbro 255 and its outlet was about .090 larger than the hanger inlet.
Do the test with whatever pump you buy before you install it. I have seen several leaking in tank hoses since I found mine.
TIMINATOR

 

[TIMINATOR]

Several of us are older than you!
I am tired of back ordered Buick parts and a general lack of quality, so I bought a 72 E body in January, and spent about 11k on engine and other parts so far, and only the rear deck duck tail spoiler was back ordered. But 3 other parts sellers have them in stock anyway!
P.S. I'm building a 512" stroker and it should make around 700 H.P. on the motor! Also have a 300 H.P. plate, 4200 stall and a trans brake. Should be a fun street car! P/S, P/B, A/C and since one of the window crank deals needs to be replaced, I'll probably do power windows too!
TIMINATOR

 

[tt455]

When I upgraded my pump a few yrs ago, I decided to see what the pressure was at the old pump by doing the WD-40 thing. It sprayed all over the bench! In my app at that time, the stock pump probably would have worked with a good hose, but I had the new pump and was in there anyway.
I checked the new pump and found the pump outlet was larger than the hangers swaged smaller end and I couldn't find a hose to seal both ends correctly, a lot of WD-40 later, I cut off the swaged end and soldered a larger tube on the end. Problem solved!
For info purposes, the new pump was a Walbro 255 and its outlet was about .090 larger than the hanger inlet.
Do the test with whatever pump you buy before you install it. I have seen several leaking in tank hoses since I found mine.
TIMINATOR

So the mechanic that worked on this car installed an aem 340 fuel pump with hot wire and new sending unit which was installed before I purchased the car two years ago. I'm not sure when it was installed before I bought it but from what I remember it couldn't have been that long ago. Is it possible that it's leaking in the tank with only a few years on it? Honestly the car hasn't been driven very often this past year.

 

[SCOOBY DOO]

Change the hose between the pump and the hanger. It's likely leaking. Be sure to use the correct hose. It's a 2 beer job.

 

[TIMINATOR]

Mine was leaking on the initial assembly with the brand new factory supplied hose and clamps. You also don't know the manufacture date of those items.
TIMINATOR

 

[John Larkin]

Buy the good multi-fuel hose at NAPA, I sound like a broken record. Dropping the tank isn't difficult but it is cumbersome. Pump out as much fuel as possible to keep it light.

 

[TIMINATOR]

A transmission jack without the arms, just the flat plate is a great help in tank R & R. Ùse the full circle F.I. hose clamps, not the worm screw type too, and leak check before installation. Around half of the pump replacements I do, are leaking at the hanger to pump hose when removed. Also make sure the pump outlet shank and hanger inlet diameters are the same. If not, it may seal now, but leak later. Not all H.P. hangers have the larger inlet nipples that are the same size as the H.P. pump outlets.
Unlike other fuel hoses, this one is exposed to fuel not just on the inside, but on the outside also.
TIMINATOR

 

[tt455]

Buy the good multi-fuel hose at NAPA, I sound like a broken record. Dropping the tank isn't difficult but it is cumbersome. Pump out as much fuel as possible to keep it light.

Thank you hope to get to it this week. It seems like a lot work for a hose, why wouldn’t they just make it with a stainless line? By the way, what size is that piece of hose 3/8 or 5/16?

 

[Dan SS2471]

Have you checked the IAC? Innercooler hoses all tight? I chased similar issues a few years ago. I can't remember if it was a bad IAC but I do remember for one of the issues, it was a simple dumb ass problem. Bottom hose on the innercooler popped off and was causing all kinds of (expected) issues. I don't think that one caused any idle issues but just mentioning it. I changed out the MAF for one of the issues too but it wasn't the culprit.