Wide open throttle bog when accelerating issue.

True!
Process of elimination

 

I dont recall seeing rubber midway on the 65-67 cars

 

I would not spend a minute on this, until I verified fuel pressure. Lots of possible problem areas beside pump and carb, but those are the obvious first places to look.

JW

 

Those years may be different as far as the rubber sections.
They made Buick’s before 1970?

 

I agree Jim. I bought a gauge and wet line kit so I can plumb a fuel pressure gauge into the car so I can watch the fuel pressure while driving. I am just going to do a temporary setup. I would have tried it already if I was not away from home doing my shift at work. I will be back home mid next week and plan to check the fuel pressure first as soon as I have a moment to work on it.
Greg

 

This car was a 5/16" fuel line originally. I bent up a new 3/8" line when I had the body off for the restoration 20 years ago. I also made a new 3/8 pickup for the tank at the time. It had a nice new sock then but that was some time ago. It The rubber line from the tank to the steel fuel line would be 20 years or so old too so that is where I am going to look. First step is to monitor fuel pressure when it acts up. Then I will know where to start looking.
Greg

 

Keep us posted Greg

 

I will. I hate looking for info on forums for issues and find similar ones that no one ever closed with an answer to the issue. We have to learn from each others issues so we don't have to suffer through them all ourselves. As an aircraft mechanic I am always quick to share our troubles with others especially our apprentices so we help increase the knowledge base. In our case it can save lives or at least keep people much safer.
Greg

 

Well I got a chance to go out and do some trouble shooting today and it is indeed running out of fuel still. I have a fuel pressure gauge plumbed into the car right now and when it falls on it's face the fuel pressure is dropping to about 1 psi. It seems to normally run at 4.5 or 5 psi and drops to about 3.5 psi wide open throttle. Sometimes I can make a full throttle run through the gears and it will hold steady 3.5 or 4 PSI other times it runs out. I checked the tank and it is spotless inside. The pickup sock is perfectly clean and all lines look fine. It has a 3/8" pickup and 3/8" steel line from front to back. I am thinking my home made fuel pump made from the Chevy one is not pumping enough even though it should have tons of capacity. It is rated at 120 gph unrestricted. Maybe swapping the arm over does not allow it to make a full stroke the same as the chevy arm. I had found a Stage 1 pump that I was going to order as backup in case this one did not work out. I ended up buying it and it will be here next week. I guess I will swap it out again.
Greg

 

So it’s intermittently loosing fuel pressure?
SOMETHING is causing a restriction, seems the pump is able to keep up most times, but sounds like something is plugging up the works

 

Glad you were able to isolate the nature of the problem

 

It is possible but I had a look at the line, tank and pickup. I don't see anything that would cause a restriction. With the other pump it would fall on it's face every time somewhere early in the second gear pull wide open. Now it will sometimes make it through the pull but only about 3.5 psi. I think this pump is flowing more but still not keeping up. It is probably just close to keeping up. I found a Stage 1 pump so when it arrives I will try it out.
Greg

 

The pump you have on there now MAY be able to overcome the restriction (wherever it may be) better than the other pump you had on there, but eventually “throws in the towel” like the other pump, only it takes longer, so that would tell me it’s NOT the pump, it’s elsewhere.
Remember you have a Buick 455, it’s not a 1200 hp turbo or supercharged race engine, a stock pump should do fine.
Exactly what kind of fuel pumps have you had on there?
If you have compressed air available I’d try blowing the lines out, disconnect the feed line at the pump, then blow air (20/30 lbs is enough) from the pump end back to the tank. What your wanting to hear or feel is the air (after it blows the fuel back to the tank) flowing back to the tank FREELY, and the fuel bubbling in the tank, that way you’ll know the line is not restricted in some way.
Process of elimination, you say your an aircraft mechanic, so I’m assuming your pretty darn smart with mechanical, thorough and methodical
Is your 455 stock, mild build, big lumpy cam and big compression??

 

Grandpa had similar sounding problems on the old 78 chevy rv. He was finally able to find it after driving with the dog house off for a while. What he was able to see while driving is when it would start to starve a rubber hose was collapsing. Replaced the hose and never had the problem again.

Most likely not you problem. Good luck in your search.

 

The lines have been blown out. I checked the vent. I pulled the pickup out of the tank and checked the sock and tank. All lines are clear and everything is spotless clean. I see no restrictions in the lines at all. I could swap out the 12 inches or so of rubber line from the tank pickup to the steel line. I am not convinced that the new fuel pump is good. This engine is very mild. 70' SF 455 with a GM Stage 1 cam, headers, intake and ignition/carb tuning. It always survived with a non stage 1 pump but that pump was 30 plus years old so I thought it would be time to swap it out when this problem started. My first instinct was to swap in a Stage 1 pump but I could not find one. I will sort it out. I could add an electric pump but feel a mechanical can easily handle it and really don't want to add more wiring to the original wiring harness, it has enough add ons already. I found driving around last night that much of the time even at really light throttle cruise the fuel pressure was only 3.5PSI. The specs on that modified chevy pump say 6.5PSI. This pump I am running is a HP Carter pump for a Chevy with a Buick arm swapped in. I am not ruling anything out yet. At least I can focus on fuel delivery.
Greg

 

You say it ran fine with the pump you took off?
Put that pump back on

 

No. The problem started with the old pump then one of the first things I did was swap out that old pump.
Greg

 

Quick way to tell if its an obstruction or other fuel line issue would be to add a tee in the fuel line just before the pump and run a long enough hose to mount a vacuum gauge on the cowl outside the windshield. See if vacuum reading spikes or drops when the issue happens.

 

Well, I ordered the Spectra Premium Stage 1 pump from a Canadian Online autoparts place as they had 2 in stock. I just waited 2 weeks for it and it showed up. They list it as the Stage 1 pump and show pictures of the Stage 1 pump in all their info but when it arrived it is just the standard pump. It has the correct part number on the pump and box. I thought I was lucking out finding a pump. Nope. What a piss off. I am going to try one out anyway. If that doesn't do the job I am probably going to go electric.
Greg