I have decided to go carburated so I have a question about my fuel pump. I do not want to have to drop the tank and remove the electric fuel pump. Will I be able to use my fuel pump and use a regulator with a return. If so what is the best one to use. Thanks for an input.

 

you dont need to drop the tank. you can use a regulator with a return. dont know witch one. get one that regulates to around 5-10 psi.

 

Thanks for the reply. But, I am not sure if I have ever seen one that will regulate that low of a psi and still be able to return around 30-35 psi to the tank. I am still looking. If some knows of one it would be greatly appreciated.

 

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Do what everybody else does. Pull up the rear carpet a cut a access hatch door on the floor right over the gas tank.

Allows you to get in there are remove the tank pickup and re- work it. nice to add an extra pickup for NOS.

many times the fuel guage sender in the tank is about pouched, Good time to inspect it.

Just close the U shaped hatch you cut in the floor and seal it up with RTV and reistall the carpet.
No one but you will know the difference.

You can replace the in tank pump with a low pressure (7psi) replacement designed for a carb.
You can eliminate the in tank pump and rework the fuel pickup, then install either an electric 7psi inline pump over the rear axle on the drivers side and/or install a mechanical fuel pump on the engine.

A Carter 4594 electric pump make a nice replacement for a carb swap. No regulator is required.

The price is very reasonable.

 

now why would anyone want to cut a holw in thier floor? is it really that hard to drop the tank to do it right? and i would know it was there and thats bad enough. but if someone wants to do it like that its fine with me but i dont think i would ever do it that way.

im going to need to do the fuel pump on my 88 tbi if i go with a high flow pump that pushes 60 psi. will i have a problem regulating the pressure down to 13 psi with my stock regulator?

 

Why make trouble for your self by buying a fuel pump that has way way too much pressure. get the right TBI pump to start with.

If your Third gen was a perfect car, it wouldn't need to be modified at all, would it.

GM should have built the car with a fuel tank service hatch in the rear floor over the tank to start with. Makes life so
much easier and much safer to service the fuel tank.

Countless cars and garages have been burned to the ground needlessly when peole have to drop the gas tank on their car to fix something. If you've got any rust under the car you're going to hate dropping the tank,
Cutting the hole in the floor makes things real easy now and later on. The hole is small enough that wil will not compromise the structure.

Someone else previously cut the hole in the floor on my car and I've had to go in and mess with the top of the tank a few times since I've owned the car.
One of the best mods on the car.

 

ok but the correct pump for my car wont supply my new engine. iv been looking for a high flow pump for my car but most high flow pumps are around 60 -100 psi.

 

Run two stock TBI fuel pumps with two fuel lines to the TBI
Wire the second pump to only come on at WOT when its needed.
You won;t need it at all for normal street cruising.

You'll have double to fuel flow capacity available at the recomended friendly TBI fuel pressure.

You want to increase capacity, not pressure.

Double your fuel flow capacity with $$$stock parts$$$ and no headaches. (exessive fuel pressure.)

You can juggle the fuel pressure up and down a bit but the TBI injectors will want to operate within a friendly pressure window that they were designed for.
Larger simular injectors or a simular throttle body from a big block TBI may be nessessary.

how much power over stock will it be making?

 

stock tbi is 160hp. my engine is 300 - 350 hp. im still building the engine. but my pump is failing so im going to need to replace it and dont want to do it twice.

 

Have you flow tested your stock pump?

You'll need to disconnect the fuel line at the throttle body and rig up a pressure guage and adjustable restriction ( pepcock)
and flow the pump into a bucket and measure the volume its able to pump in a specific time while holding the pressure on the guage at what ever psi the TBI system operates at.

How much fuel volume (gallons/ hour ) will a stock TBI pump flow at its normal operating pressure?

I'll bet the stock pump is not maxed out by the stock motor at 160hp.
I'll bet two stock pumps will more than feed your 350+hp motor and maintain the stock designed fuel pressure.

I'll bet you can do this with stock parts and a little injinuity. for a lot less $$$ than a aftermarket pump. that has exesessive pressure and will cause you lots of tuning grief.

Usually the stock stuff is pretty reliable. Remember your pump is about 20years old. Its served a long life. probabily sucked up a piece of s*&^t from the tank or the pickup sock is plugged up.
You could try removeing the pump from the tank and back flowing it (reverse the power polarity) to get the junk out of it.
Install a extra junk yard pump and pickup while you're in there.

 

I am at this juncture right now. I have the pressure regulator along with a nice new carbed 355 to drop in. What wires should I look for and where is the relay located. I need to wire the pump to come on and work. Thanks.

 

You need to look at my setup then. I run 192LP{H ford electric pump feeding a mallory 4 port regulator and I run 6 psi to the carb and return to the tank. I calibrated the psi last sunday as a mteer of fact, it worked great! I love that regulator.

I have fuel in on one port, a line going to the carb on another port and my fuel pressure gauge on a 3rd port, the 4th is blocked off, then I have my return line at the bottom, it sounds means when the system is on. I did 100% custom wiring for everything in the car, so if u need help, let me know. I can explain it in detail, but get the regulator first.

 

I would really like to here more. You said it was a 4 port, then you said the return come out of the bottom. The bottom of where. Port 1: fuel in, port 2: carb, port 3: gauge, and port 4: blocked off. I am lost. i would appreciate some more info. Thanks

 

ok, the regulator has 4 input ports, then 1 bypass port, the 4 input ports is where u put the fuel in and fuel out to the tank. I also put my pressure gauge on a free input port, thus leaving 1 input port free, i had to plug it so fuel would not leak out. THEN I hooked up the return line to the by pass port that is ont he bottom of the regulator. You adjust the pressure with an allen head and what doesnt go into the carb goes to the bypass port and back into the tank. I will take some shots of this. Look for a mallory regulator on summit.

 

I appreciate it. I thought that it might have a bypas port but you did not mention it. I belive this is the regulator i am looking for. Thanks again.

 

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exactly what I bought, i love it. If I wanted, I could hook up a fuel cell to the empty port I have to run race gas. Seen that on a 9 second 69 z28, but maybe I should get it on the road first...

I mounted it to the firewall, I drilled a hole and used a self tapping screw. I dont have wiper motor, so I mounted it right under that hole the motor went into. I'll post pics tommorow.

 

Thanks. You have been a huge help. I am looking forward to seeing the pics. Thanks again.

 

355gta,
Not EVERYBODY else thinks that cutting a hole is a good idea!

IMPO - This is an EXTREMELY dangerous and VERY FOOLISH move. The pick-up assembly is very large... in order to avoid clipping the lines one would have to cut an ENORMOUS hole in the rear of the vehicle. Unless one has decided that clipping the lines and splicing them together with rubber hose or some other method was not a FURTHER COMPROMISE in safety?

The previous owner of my son's '82 cut a HUGE hole in the rear of the car... He still couldn't get the pick-up assembly out!!! In the end he (the previous owner) ended up clipping all the lines and splicing them back together with rubber hose. The cut ends did not provide a flare or ferrule to properly accept a hose without potential for leakage. My son and I spent an entire weekend fixing that mess! We dropped the tank, replaced the entire pick-up assy, sealed, and welded in a new section from a J.Yard vehicle. I now feel that the vehicle is "SAFE" to drive (photo attached)

I hope you are able to accomplish your task with a regulator... If not... IMPO DO NOT CUT THAT HOLE.... Pull the tank.!

If you have an extra set of hands you can most likely do the job properly in an afternoon! We all want our cars to last forever......and don't like to think about a potential accident but do you really want to be rear-ended if your car has had this modification?

Sincerely,
Kurt

 

I agree 100%, do not make a hole, that is very dangerous, and if you ever took it to a drag strip, i bet they wouldnt let you in if they saw it.

Here is a pic of my regulator setup.

1. Fuel line to carb (and inlilne filter)
2. Fuel return to tank (bypass valve)
3. Fuel line to my fuel pressure gauge (it sits in the engine bay, but I didnt hsow it)
4. Fuel in from the tank

The other port is blocked off because I have no use for it. Hope this helps

 

Just to clear up some misinformation here.

Pumps just move fluid, the fluid doesn't leave the pump at x psi. You only get pressure when you put a restriction on the line. Which is the job of the regulator. Any pump is capable of 90 psi or more, you just need a pump that can give you pressure at the required volume. So using a "60 psi" pump on tbi won't change the pressure a bit. Most people just use a walbro 190lph or 240lph pump which will work with almost any FI setup. Some people have noticed that the factory TBI regulator is too restrictive for the VOLUME of the 240 and can't get the pressure low enough, this shouldn't be a problem with any other regulator.

With that said the factory TBI pump will barely keep up with a stock 305, so changing to a high flow pump is the way to go. Of course while you have it out you might as well just replace the pump with a piece of line and use a cheap mechanical pump rather than an expensive electric one. I would do the electric if you ever planned on going back to FI.

 

thats right, PSI is due to restrictions in the line. However, i recommend using an electric pump just because you have less chance of getting air in the line. I dont know if that is a common problem any more, but I know that most the hard core drag racers I've met use electric pumps because when they launch, the fuel can get away from the pickup, same with rock crawlers, when going up a steep climb, they cut out. Of course that is if they are using carbs. But, if your looking for simple, a mechanical pump will work fine. My problem was I only had access to a tank that allowed for an electric pump.

 

An electric pump won't necesarily fix that problem. It has more to do with the extra baffling that most FI fuel tanks have. I retrofitted a frame mounted pump into my monte, and you can't hit a turn hard with less than a 1/4 tank of gas. For some reason once the motor stalls I have to sit for 5 min before the pump will purge the air back out of the line and run again. This is a TBI setup by the way. Carb'ed fuel tanks didn't need the baffeling because there is a bit of a seperator built into a carb when the fuel dumps into the fuel bowls. The air can then escape out the vent tubes, where in a FI setup you either have to spit the air out the injectors or back into the tank.

 

interesting, did not know that. I was told that the electric pump sock was always submerged in fuel

 

Yeah, kinda wierd. I have an carbed camaro tank, and a FI camaro and S-10 tank sitting behind my house. Both the FI tanks have what looks like a plastic box that the pum sits down in. The carb'ed tank doesn't have this. Neither does my monte. The trick with the G-bodies is to get a tank out of a vehicle that had a 4.3, being TBI'd it has the baffle. If you go to a parts store there are only 2 part numbers for g-body fuel tanks, the 4.3 and the non-4.3 tanks.

I found this stuff out the hard way. Just have to make sure your filled up before you go auto-xing.

 

Do you take your car to the track? I don't think you would get through tech with those rubber lines and hose clamps.

 

Umm....how else would I run fuel? I cant have 100% hard line, my V6 MPFI had rubber lines. They will be heat wrapped in the end.

 

Ok, I went with stainless hose and an fittings so I wouldn't have any problems with tech.

 

You're allowed a total of 12 inches of rubber fuel line throughout the entire fuel system.

 

I think it is 12 inches of non factory rubber fuel line right?

 

12 inches of non-OEM hose, yes.

 

Well, maybe I will get steel braided sleeves for the lines then. I certianly have more than 12" of soft line. I will be trimming it down once the car is on the road of course, just need it to fire up right now.

 

I don't know if a braided sleeve is legal, or if it has to be an integral part of the hose.

 

Doug, I have a Barry Grant regulator I can hook you up with.
It has 1 in port and 2 out ports and a smaller port to hook up a guage. Works well with in tank TPI pumps on cars converting to carb(I've done a couple ). I can hook you up.
It's new,never used. I picked it up when I had my GTA and considered going carb.
Expensive little sucker($93 and some change),I guess cause it's billit and annadised.
Picked it up at Zimmermans speed shop in Greensburgh,IN.
Also have a dual feed line for a Demon carb,factory built useing braided line and AN fittings.
If you need either,let me know.

 

I need a demon carb, LOL. I might be interested in the regulator. I will let you know. Thanks again for the headers.

 

Your welcome,Thanks for the intake and cam.
I didn't know your GTA was white,so was mine. I need to come up and check it out sometime.