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Trouble shooting . . .

Spanky

Moderator
Staff member
Out for a cruise yesterday. Drove about 15 miles, and the engine sputtered and died. Scary feeling! Pulled off the road and checked things out. No loose wires visible; gas in the tank (about 1/4 tank); electrics seem to work (lights, horn, etc). Jumped back in, turned the ignition on and vroom, it started up and ran fine all the way home. What gives? Any ideas? I suspected fuel pump - Holley "Red" electric pump installed 3+ years ago. But wouldn't it quit altogether if it was bad?
 
Fuel tank vent. Is your cap vented or is there a line to a vacuum source? With alcohol in the gas a complete open vent is not a good idea. It collects water fast.
 
If you have a HEI distributor, if it does it again, check to see if the coil is getting hot. They cool down pretty fast and will let an engine restart and run until they over heat again.
 
If you have a HEI distributor, if it does it again, check to see if the coil is getting hot. They cool down pretty fast and will let an engine restart and run until they over heat again.

I have a conventional 'points-type' distributor. And . . . my tank has no vent.
 
Mine has done that about 4 or 5 times . Always out of gas. Jump in and go and not check gas guage. Wish my guage was in dash . It might not help.
 
A clogged fuel filter can do that. Secondly, you have no vent at all in the gas tank?
 
Does your point system have a ballast resistor? Possible bad connection or faulty ballast? Normally a carbureted fuel issue gives hints like poor acceleration or sputtering. Ignition issues normally give no warning.
 
Last edited:
Bill,

I am on my third Holley Mr Gasket 12S Fuel Pump. My T died several times and would come back a short while later. I have a fuel pressure gauge on the carb fuel inlet. If I hear a sputter, that is now the first thing that I check.

Several people have diagnosed my problem as running crappy (ethanol) gas. With the newest pump, I am trying just to run pure gas. In my area of NC, it is available everywhere. If I cannot get pure gas, I put Seafoam into the tank to offset the ethanol.
 
Could be water in the carb too. It will cause them to sputter and die, then as the water bubble moves away from the jets, will fire back up and run. It is amazing how small of an amount will cause it. I have never had great luck with any additives, just end up pulling it apart and cleaning it out. I actually installed a external water separator/filter in my boat for that exact issue... it has a Vortec 4.3 in it with a carburetor and it got old pulling the top off of the carb to get the water out
of it.
 
rbsWELDER,

If I could offer an opinion without offending you .....I finally retired my Holley RED fuel
pump after 30 years when I went to the Holley Blue pump and and a regulator with a return
line back to the fuel tank.

There might be a reason why the 12S pump only sells for about $40. Just upgrading to the
next level pump (No Regulator Required) is the Red pump, but it will cost $115. The upgrade
will move you from 35 GPH (Free Flow) to 97 GPH (Free Flow).

"What Size Fuel Pump Do I Need?" Your Top Tech Questions Answered! - OnAllCylinders
(350HP x .5 lbs) / 6 lbs =
175 lbs/hr of fuel / 6 lbs = 29 GPH

From the above calcs you would assume that you have plenty of room to grow, but ALL
manufacture's rate their pumps at free flow. Every fuel system has restrictions in the real
world, therefore 35 GPH is more like 20 GPH in reality. The more 90°, 45° connection
the more restrictive your system will be.

If you are only trying to get down the highway at 70 mph or going to get groceries at the
local store then you will be fine. But if you are about WOT acceleration then you will be
in trouble.

That has nothing to do with the reliability of the pump ..... at this point all I can say is
"You get what you pay for".

Mr. Gasket 12S Mr. Gasket Micro Electric Fuel Pump

Holley 12-801-1 97 GPH RED® Electric Fuel Pump
 
rbsWELDER,

If I could offer an opinion without offending you .....I finally retired my Holley RED fuel
pump after 30 years when I went to the Holley Blue pump and and a regulator with a return
line back to the fuel tank.

There might be a reason why the 12S pump only sells for about $40. Just upgrading to the
next level pump (No Regulator Required) is the Red pump, but it will cost $115. The upgrade
will move you from 35 GPH (Free Flow) to 97 GPH (Free Flow).

"What Size Fuel Pump Do I Need?" Your Top Tech Questions Answered! - OnAllCylinders
(350HP x .5 lbs) / 6 lbs =
175 lbs/hr of fuel / 6 lbs = 29 GPH

From the above calcs you would assume that you have plenty of room to grow, but ALL
manufacture's rate their pumps at free flow. Every fuel system has restrictions in the real
world, therefore 35 GPH is more like 20 GPH in reality. The more 90°, 45° connection
the more restrictive your system will be.

If you are only trying to get down the highway at 70 mph or going to get groceries at the
local store then you will be fine. But if you are about WOT acceleration then you will be
in trouble.

That has nothing to do with the reliability of the pump ..... at this point all I can say is
"You get what you pay for".

Mr. Gasket 12S Mr. Gasket Micro Electric Fuel Pump

Holley 12-801-1 97 GPH RED® Electric Fuel Pump
I use those universal pumps like the 12s on various off road machines. They are not the most dependable, from my experience. They are very convenient and I like them on things that sit between uses so I can pre prime the fuel system without over straining the starter and battery, but they seem to fail fairly prematurely, the old square vibratory pumps were more dependable, imho, but aren’t as available nowadays. I had one of those 12s on my boat when I replaced the engine, it would not deliver enough fuel to keep it running above about half throttle... it was pulling fuel through a check valve, but was mounted at fuel level or below and had a short delivery path to the carb... the Holley blue marine pump done the trick but cost MUCH more. Also, the ethanol blend fuel wreaked havoc on that blue pump... I was able to save it, but it was nasty... looked like it sat in water for years when it had only sat for a two seasons. I now store it dry.
 
No offense taken. The original builder put the 12S in, so I was just following his path. In actuality, the first two pumps were Mr Gasket 12s, but the third was a K&N: 81-0402. It looks just like the Mr Gasket, so I thought that it was the same Chinese manufacturer. I called K&N and they insisted that K&N made these pumps in the USA. So I figure with the same footprint, I would try it. So far, so good, but the pump does make a banging sound, when the ignition is first turned, but goes away in a few seconds.

Indy - I am always open to upgrades and improvements. I did look at Customer feedback on Amazon for the three pumps and found the following ratings on a five point system:

Mr Gasket 12S - 2.8
Carter - 3.4
Holley Red - 3.7

My assessment is the 12S is probably a poor pump. Unfortunately, the other two are only slightly better.
 
Hopefully this one will work out for you, it's no fun being stranded some where.
 
Yikeeessss !!! ..... I couldn't afford to drive a car that needed that!
 

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