Fuel pump questions

[Blitz]

You guys got me thinking... ( seriously... everyone DUCK !!! )

1st about the electric fuel pump not shutting off in an "incident", then the vapor lock issue.

It seems that GM made an oil pressure sensing switch, that shut OFF when the oil pressure hits 4 PSI, through a relay controlling the power to the fuel pump.
NICE. I gotta get me one of those.

Of course, I'm running 24 volt oil pressure and 24 volt fuel pump, so there might be an issue there, but I will keep working on it.

Just food for though... I think I want one now.


For the Vapor lock issue, Barrman is the man, but it seems that the new ethanol based fuels have a lower boiling point than the "real gas" that our trucks were designed to run on.

There seems to be 3 potential fixes...
1st is try a fuel additive, of varying brands until you find one that raises the boiling point of the fuel.

2nd is to insulate the fuel lines with "insulative wrap" much like exhaust header wrap.
This wrap is designed to protect metal lines that sit next to RED hot manifolds.


3rd is an easy try... and it sounds strange... but probably worth a try.... here we go...

Go to the dollar store and get a package of wooden clothespins.

Yep.

clamp them onto the fuel line at multiple places where you think the heat is the greatest.

For the fuel to boil and vapor lock in the lines, the fuel line must get to a certian temp, and by putting the clothes pins on the fuel line in multiple locations... the wood cannot be heated quickly enough to allow the fuel line to get hot enough to vapor lock.

Essentially a Heat Sink.

I hope Barrman chimes in tomorrow... but it seems the real culprit is the cheap A$$ "fuel" that they feed us now a days.

Some suggested aviation fuel, as it has been known to force aircraft down in the past, and they added additives to it to prevent that.

best I can do...
But I want a fuel cut out switch now.
I guess a 24 volt relay would handle it and solve the voltage problem... but the sensor is probably 12 volt design.

Conundrum.

[militarypotts]

That was some pretty interesting ideas their Blitz. I thought about the wrapping of the fuel lines near the manifold, also a fuel additive. Basically I'm looking for an additive that raises the boiling point of the fuel, correct? Is their an additive out their that is more recommended than another?

[Blitz]

From what I read briefly, no recommendations were given for a particular brand.

Also, it seems that going with something like 104 octane boost would be the ""Wrong"" way to go... from my undersanding... becasue the higher the octane the more it wants to vapor lock and would boil off faster ??

that was my understanding... at 11:30 pm.
I could be wrong but it made sense when i reead it.

what surprised me was the Avgas suggestion... becasue AVGAS is usually higher octane, but the additives they put in it obviously are designed to prevent vapor lock...
So its not an octane thing, its an additive thing.

I have to go here in just a few minutes, but searching for that additive that will raise the boiling point "on line" will probably produce some results.

I just didnt research it farther.. due to a limited time and the late hour.
Pressed for time again, but wanted to reply.

In the long term, wrapping the lines will be the best answer... becasue you might not be able to get Your additive in the future.

I would try the clothes pins first though... for 3 bucks.
Cheap and dirty, but it might work.

I will have more time here later and will look into it in depth.
It helps me too.

[Blitz]

Millitarypotts,

While I was out I stopped at O'rileys auto parts and looked at all of their fuel treatment addidives.
They had literally 50 on the shelf.
Yes 50.
I counted them.
About 8 of those were for diesel only, and the remainder were for gas/ethanol.

It seems that ethanol over 10 % in the fuel causes a lower boiling point, among other issues and is what is causing our problems with "new and improved" fuel.

Without looking on the internet, I read almost every label there and found four that I would try first.

All four of these stated that they help with "stumbling and hesitation", or "phase seperation" of the fuel. Absolutely none said anything about vapor lock.

The first is "RED LINE" SI-1 and is 15 oz for 6.99
It stastes that it reduces octane demand and helps in hesitation and stumbling.

The second is 'STAR TRON' Enzyme , a clear blue formula that states it prevents "phase seperation" of ethanol fuel.
It is 8 oz for 8.99

The third is "Lucas Hyper Fuel" with MMT "Maximum Octane" ( an octane booster, only legal "off road" ) but it states that it helps with stumbling and hesitation.
I forgot to write that price down. I'm sure it was 10 to 14 bucks.
Several of the brands contained this MMT, and it seems to be a common active ingredient in the higher quality fuel additives. Once again, for "off road use only" which immediately gets my vote

The fourth is " NOS Octane Boost" Racing Formula.
It is an Octane booster, but it also states that it helps with stumbling and hesitation, it was 12 oz for 13.99. "Not street legal" ( thumbs up )

Most of the others were simple cleaners, lead substitutes, alcohol based fuel dryers, or for fuel injection systems.
The Royal Purple looked interesting, but it did not state it was for hesitation.

Literally 50 to choose from on the shelf.
This is my best guess, with out being a chemist and fuel delivery specialist.

I dont know the best way to test them, except add a small amout into a small amount of fuel and drive it like its in a parade.
When that is gone, try another brand.
One gallon at a time...
Bummer.

Major PITA and time consuming, with out a LAB to do controlled temp tests, and recording the actual boiling point with out blowing up the tool shed.

If I find anything else out on the net I will let You know, but those seem to be the best, even though two of them are actually octane boosters as well.
They seemed to address the "hesitation and stumbling" which... to me anyway... could be related to vapor lock.

By the time you try 3 or four of these, you could wrap the lines with the best insulative cover available , for the same cost.

An Ice Bucket with a coiled fuel line running through it is a last ditch effort... Much like the old racer air conditioning for the helmets... inducted air run over and through an ice bucket to cool the driver wearing a helmet.

another PITA ^^^

I'm starting to think AVGAS myself. 100 LL or higher ...for parades

but I'm sure its up over 7 bucks a gallon now... Been I while since I had to top off a Cessna 172 or a Piper Cherokee 140.

[wantapinz2]

For the holley 2300 carb I have yet to put on I bought a1/4 inch phenolic riser. They say it helps performance and helps insulate against boiling the gas. It might be the easiest solution .

[Blitz]

Well...

here we go...

It looks like My bendix 24 volt fuel pump is going out.

It comes on, pumps fuel, goes to about 5 psi, shuts off... ( engine is running at the time )

kicks back on... ( after the fuel psi dropped to zero for a few minutes ... engine still runing)

psi goes up... pump shuts off.

lather , rinse , repeat...
Till i starved the engine for fuel and it died...

Left it off, disconnected the batts... and started looking them up on line , AGAIN....



I'm gonna have to make THE decision.


I have a 12 volt pump, pre wired, plumbed, hose clamped and ready to mount...


BUT... I really like the 24 volt bendix pump.

I guess its time to find a rebuild kit and give it a go...
Installing the 12 volt version temporarily...

Total bummer.... but it was expected and accounted for.

It looks like this:

I will pull it and get the part number again...
Pretty sure its off an M 38

add it to the list...

at the TOP





BTW I like the phenolic riser idea for the Holley 2300.
I have seen them... and thought about them...

Maybe its time to revisit that concept.



In the mean time...

Yep...
Need a rebuild kit

more research and just too tired to do that right now

[Barrman]

Have you removed the in tank sock filter? Mine when I ran a gas engine would loose fuel psi and starve the engine every few months to a few years. All it would take was blowing air into the tank through the fuel line to clean it off and I was good to go again. I had the tank cleaned and the problem went away. I also converted to diesel. However, writting this I am wondering if my bad road performance this weekend might be that stupid tank sock coming back into my life?

It reads like you know the pump is the problem. However, what if the pump is just creating a vacuum and shuts off from that? Something else to think about I guess.

[Blitz]

Thanks For the reply Barrman.

yes, I replaced the sock puppet in the tank about a year and a half ago, when I vatted and red koted the tank.

The red kote was done properly... There is none in the clear large filter before the pump, and nothing red anywhere... So I'm pretty sure the red kote is holding.

I HAVE been using stabil.... Marine grade for ethanol.


Could be the problem...

But the pump 'clicks" when I turn on the "Super Secret Server Switch", like always it has...

But now those clicks are fewer and farther between...

and now even sometimes stopping completely.

Could be gummed up.
Needs taken off and cleaned and inspected.

I have seen rebuild kits for them...

I just dont want gas running on me today...

Threaded fittings at 90 degree angles.
I have the technology to "cap them" and not drown.

Just exhausted...

would rather source a new one and the rebuild kits and have spares.

It looks like this inside... and i have to say I'm HIGHLY disappointed to see electronics inside there !!!!

Solid State.... yeah... ok but I hate electronics.

It seems that Facet bought out Bendix ?

I already found some Aircraft FBO's that will service it, but still researching.

many were used on Cessna's and Piper Cherokee's other Low and high wing aircraft... but in 12 to 14 volts.

More research needed.
NOS ones are 185 smackers, but in 24 volts.

any suggestions for repairing/ sourcing parts for this one?
I checked all my old saved files...
Somewhere it seems I mis-categorized the data I had saved as its now on Hillary's E mail server somewhere and hence "vanished".

Yes I can go 12 volts...

Dont really want to , as the World is still holding together... and the internet and Credit Cards still work :")



When I pull it I will still blow air backwards through the lines...

Thanks for that Tip

[chimesickle]

I apologize for stating the obvious, I really do not want to insult you. But I did not read that you tested the wiring to your electric fuel pump. I hope you tested the switch? The connectors could be corroded, but the first and most common thing is the ground.
The only reason I am chiming in is that my fuel pump in my Ford was not working well. I was preparing to replace it tll I saw the corrosion on the harnesses terminal. I have it hot wired for now. It works much better.

[Blitz]

Now that You mention it,

When I pull it I will hook up My vacuum pump and a gallon bottle and try to "PULL" gas through first....

And see is it is "locking" as you describe...


covering all the bases that way....

Thanks again for the Good Idea and comm.

Good time to put in a new clear filter before the pump also.

I have anther clear glass filter right before the carb too, but its perfect and new looking still.
Clear and white...
a little Yellow form the gas is all...
No debris, no red, no particulate matter.

No Air either, when the pump "cycles" ON and is "clicking"