Doing the V6 to V8 swap and I dropped the fuel tank to remove the old V6 EFI pump. I left everything else in there so that the fuel level gauges will still work. Any how, I got to thinking about it and realized that if I try to start the car, and the wires touch the old pickup they could spark and cause a major problem. Is that possible? The old 12V power wire for the pump is just chilling in the tank. Can I just locate the 12V power wire to the pump and cut it? Or would it be better to just pull the fuel pump fuse? My main concern is that the fuel level gauge will work when I put the Autometer unit in. Thanks, Paul Moore

 

dont worry, liquid gasoline doesnt burn, the electric pump itself is creating tiny sparks while it runs.

 

look at the wire that goes thru the top of the tank to the pump figure out which one it is on the plug and cut it on top of the tank if it is bothering you ...LOL

its not a big deal just cut it off and forget about it ...

your fuel gauge is ran off of a different wire

 

Pull the fuse.

 

well you could do that too....LOL

 

under vacuum is doesnt....

 

so if i run a car with the gas cap removed and no internal vacuum it will explode?

 

Well, yes. Even with the gascap on. Although when its warm out and the cars been sitting most of the air is displaced by fuel vapors so usually there wont be enough oxygen to support an explosion. IIRC, the fuel pump actually uses an AC induction motor since its sitting in gasoline. It probably also has other safeguards to prevent it from causing a fire.

 

Coulda just left the intank pump alone and not have this problem to deal with.

 

not necessarily it has happened where the intank pump has restricted flow ....althou not to common but it can happen ...your always better off to take the pump out and throw it away ....

 

Of all the cars that I have seen it seems pretty damn common, LOL! Usually at the strip. Usually with a more than stock engine. I just cut my wire outside the tank and did away with it. Less wires = GOOD.

 

Exactly what I did

 

Im not talking about cutting wire and sucking through the intank pump. Im talking about a 3 port reg and still using the intank pump. Just to make sure everyone knows what i ment. :lala:

 

Thats all cool, but that leaves a few more spots for high pressure leaks, and the ever present "when will the pump die" question. I just like the old school reliability of the mechanical pump, and yank the other.

 

I've always favored the pusher electric/engine mechanical concept.

A 3-port return-type reg will keep the pressure down throughout the system.

 

Yes, I do agree that it would make it easier only because the electric pump is just one more part that you don't have to take out, but if the regulator fails, or the pump goes bad, or anything that causes fuel pressure to rise BEFORE the mehanical pump can cause the diaphrams in the mechanical pump to take a dump. A typical carb can usually only handle 7-8 psi of pressure before it floods it out.

 

ljnowell... Thats all cool, but that leaves a few more spots for high pressure leaks,

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What high pressure? The system is kept at the pressure set by the reg. Its no longer under the typical 40+ psi at which the tpi system uses.
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paulmoore .....Yes, I do agree that it would make it easier only because the electric pump is just one more part that you don't have to take out, but if the regulator fails, or the pump goes bad, or anything that causes fuel pressure to rise BEFORE the mehanical pump can cause the diaphrams in the mechanical pump to take a dump
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Mallory 4309 connected to the supply line, the return line with one line going to the carb and a fuel pressure gauge screwed into it. There ISNT a mechanical pump to fail in this story._
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What seems odd to me is how many people talk about "when will the pump fail" but some of these same people use electric cooling fans!? :lala:

BTW did you break anything during the swap? I hear alot of people hit the wiper motor box.

 

It is not the fact that everything electric fails, but some guy, Murphy or something implied something along the lines of "something that is very hard to replace will probably go bad"

I just took my entire car apart, so it really wasn't a problem, but just imaging having to get to the fuel pump while the car is my daily driver. Not fun.

On these cars you have to drop the entire rear axel and then the gas tank just to get to it. On my integra, it is behind an access panel held in place by 6 screws.

 

Thats why once you do replace it, like myself, youd be a jack *** to replace it with another in tank one.

 

Sure there is. The line from the tank still is, and its still running in your engine compartment, unneeded at that high pressure.

Also, the electric pump will fail. how long will it make it, who knows. But to liken the changing of an in tank fuel pump on a thirdgen, to an electric fan going out, well, i neednt say more. If you have a carb, you have provisions in the block for a mechanical pump, you may as well change it over. For the cost of the regulator you could have a reliable fuel system.

 

No the line isnt! The line pressure is now much less then it was with the typical FI unit. The line pressure is what the regulator says it is plain and simple. I had someone else look at my engine and try to tell me the same thing
"dude that high pressure line is gonna leak" So i said really?
I took off all the hose clamps with the engine running and the hoses still didnt leak.
With this type of regulator a huge amount of gas is being returned to the tank . The line pressure IS NOT high.

Sure one day the pump may die, but thats one of the pita's of owning these sheet metal wonders. Theres lots of things gm could have made it easier to repair on these cars.

And just because you "have a carb" doesnt mean you can slap a mechanical pump on and be done. Your cam will also need to have the lobe on it iirc...

 

Yes, the line coming from the tank is, otherwise you wouldnt need the regulator, unless you are running a deadhead regulator, thats just stupid to do anyway. If the line pressure coming from the tank wasn't high, then you wouldnt need the regulator, get it? As for the cam lobe, you are correct. In your haste to quote me, you even quoted my statement, "If you have provisions in your block" ie. spot for the pump, hole drilled for shaft, lobe on cam. Spend your 70 dollars on regulator, and then later on down the road when the pump fails, you can throw it away and go with a mechanical pump. I really am not sure why we are having this argument anyway, yes your way works, yes my way works.

firebirrrrd

 

Basics of what ive been saying...

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Yes, the line coming from the tank is, otherwise you wouldnt need the regulator, unless you are running a deadhead regulator, thats just stupid to do anyway. If the line pressure coming from the tank wasn't high, then you wouldnt need the regulator, get it? As for the cam lobe, you are correct. In your haste to quote me, you even quoted my statement, "If you have provisions in your block" ie. spot for the pump, hole drilled for shaft, lobe on cam. Spend your 70 dollars on regulator, and then later on down the road when the pump fails, you can throw it away and go with a mechanical pump. I really am not sure why we are having this argument anyway, yes your way works, yes my way works.
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You speak about a system you have no exp on. With a 3 port adjustable reg the fuel system IS NOT under high pressure all while still using the intank pump. plain and simple.

Post all the childish flags you like your still incorrect.

 

Pressure is produced by resistance to flow. A return reg regulates pressure by allowing all but what is required to provide the desired pressure to return to the tank. Therefore, the supply is only at the pressure to which you set the outlet to the carb.

If you set a return-type reg to 6 psi, no matter where you measure the pressure on the supply side (line loss excluded), it will be 6 psi.

 

I am also going to drop carbed engine into my car at some point. I was thinking of staying with an electric pump, but the kind that mounts somewhere on the outside.

Just because GM decided to do it this way, doesn't really mean you have to live with the fact. There can always be things that can be done better, especially if you are in there anyway.

The reason I was thinking of going with electric is because I read a post a while back with a guy who had a carb which worked fine accept at WOT. When he floored the pedal, it seems like carb would suck out all gas out of the bowl and judging by the plugs it looked like it would run too lean.

People told him his pump was too weak to deliver required volume of fuel. I wasn't sure if mechanical pump would be able to keep up if that ever happened, but you can always upgrade an electrical one. What's your take on this guys?

 

there are alot of high volume mechanical pumps out there also ....its all a preference when it comes to alot of hp ....but a stock engine will not out pull a stock mechanical pump unless you have a plugged fuel filter...or a crimped line

 

400hp engines generally wont need more than a stock style fuel mechanical pump. Too many people pay too much just to have a name on something.