Fuel pump pressure issues

[CCCC]

Finally I have been able to get enough real gas to keep some in all of the trucks, but ethanol too long has caused several problems - one of which is that it seems to eat mechanical fuel pump innards. Have quite a few old Chev/GM trucks here - standard trucks - only one is powered up a bit.

Seemingly related is that I am experiencing unusually elevated fuel pump pressure from two or three pumps - leading to the carb problems one would expect. After a while, pumps supposedly built for no more than 6psi are running beyond 10psi - past the gauge top. Never before experienced this. Will a dying pump send higher pressure before it goes out? If so, why?

Two related questions:

What is the best simple fuel pressure regulator for the money - is the Mr. Gasket with the round dial a good one (1 to 6 psi) and will it still work as intended if a pump goes nuts and makes pressure above 10psi?

Is a guy better off going to electric fuel pumps in these conditions - are they consistent with advertised pressures and are they more durable/dependable than mechanical pumps while sitting unused?

Thanks for any info and advice.

[toolboxchev]

I would say you are on to something as the specific gravity of fuel has most likely changed in the past 40 years.

I would think that if the above is true there may be some differences in fuel pressure. How much is yet to speculate and a mathematician would have to work some numbers.

[mattfranklin]

Maybe the ethanol is fiddling with the check valves inside the pump. Like as in, maybe there is something that is supposed to be leaking down a little that is corroded or plugged.

[68gmsee]

I don't know if the problems you are having are related to the change in fuel but most of these parts are made overseas and the quality is not what it used to be.

The way I understand it the pump pressure is regulated by the diaphragm spring tension and a weak spring or one that loses it's tension will increase the pressure of the pump. Maybe there's a difference in viscosity that caused the increase in pressures.

[verdell]

CCCC-

I had one of those Mr. Gasket round dial regulators to fail on me a week after installing it. Was spraying 93 octane all over the engine compartment running down the interstate. I think its garbage. Replaced it with a Quick Fuel regulator and was good to go.

[cadillac_al]

I go through a lot of sbc fuel pumps. I just figured the quality was crap nowadays. Maybe it's the ethanol. I always buy Carquest pumps and they are always in spec. I never had one over 6 psi. I think they are bought out by Advanced now so I don't know if the fuel pumps changed.

[CCCC]

Well guys, thanks for the replies even if not pointing to some particular conclusion on the fuel pressure probs. I went ahead and got two of the Mr. Gasket regulators after talking to a tech on their phone line and knowing that they may spew fuel if the input pressure is above 9 psi. So, they do have a narrow working range, but am ready to try one because this flooding on freshly (and correctly) rebuilt Quadrajets is a nuisance. Yes, the adjustable Holley may be better but it has input pressure limitations as well and it has to be anchored to something. I'm going to try the Mr. Gasket inline.

Your comments about problems from spoiled check valves and weakened springs in fuel pumps seem to be on the mark, because the pressure did shoot up on three of these older pumps.

The worst case was worked on last night - 69 SB had A LOT of fuel pumped into the crankcase (surmised that it had to be a cracked/ruptured pump diaphragm), which happened AFTER I installed a Holley regulator to control pressure to a Carter AFB (which seems more sensitive to input pressure). And, the soft fuel lines were simply shot due to that fuel type. Once I get new motor oil in there today we will see how the fix worked.

Am not a violent guy, but would like to punch a few of those politicians/lobbyists who pushed the ethanol mess.

Thanks again. Any comments/suggestions on electrical pumps?

[68gmsee]

Originally Posted by CCCC

....Am not a violent guy, but would like to punch a few of those politicians/lobbyists who pushed the ethanol mess...

Yep, but you'd have to wait in line.

I read some years ago that it actually does not save anything by using ethanol-either in dollars or fuel. The transportation costs starting with the farm and the delivering to refineries eats up a lot of the savings. On top of that the drop in mpg for automobiles by using ethanol is about 3%. The problem is that farmers and large farming coops are being subsidized big bucks for planting corn for fuel and they don't want to lose that...