Fuel Pressure trouble?

[Bo Mows]

Anyone have a good fuel pump for a '71 GT motor? Or at least a online gettin' place. Can't find one in town (yet). I don't think i'm getting enough pressure to fill the bowl fast enough. With fuel line off and turning over engine, i get no fuel. This is my last resort to getting this thing running. Carb is rebuilt now but will not idle or run. I can spray carb cleaner into it and it will run good, but stop spraying and stops running.

Bo

[baz]

hi bo
try gil at
http://www.opelgtsource.com/

they will be quickest and have an online section to graze in

[Bo Mows]

Thanks Daz. I forgot about that site. Still learning!

Bo

[baz]

who ?

[Bo Mows]

Sorry, Fat finger syndrome!

[tekenaar]

Originally Posted by Bo Mows Anyone have a good fuel pump for a '71 GT motor? Or at least a online gettin' place. Can't find one in town (yet). I don't think i'm getting enough pressure to fill the bowl fast enough. With fuel line off and turning over engine, i get no fuel. This is my last resort to getting this thing running. Carb is rebuilt now but will not idle or run. I can spray carb cleaner into it and it will run good, but stop spraying and stops running. Bo

Check to see that you have fuel flow at the pump inlet first! Disconnect hose from FP nipple, fuel should run out freely . . . lower level than tank. If not, fuel sock in tank is probably plugged . . . most likely from rust particles from inside of tank due to sitting long time with mostly empty tank . . . water vapor condensation.

Have you replaced fuel filter between pump and carb? Do so!

[Bo Mows]

I'm using a large jar full of fresh fuel (fuel tank needs cleaning). I can fill the bowl full of fuel and still won't pump fuel into carb.

[baronbors]

Originally Posted by Bo Mows I'm using a large jar full of fresh fuel (fuel tank needs cleaning). I can fill the bowl full of fuel and still won't pump fuel into carb.

BOOOOMMMMMnnnnn

[Bo Mows]

let me rephrase the "jar" I made a large jar with a 6' hose and a sealed lid that has a vent tube that i use to rebuild lawnmower motors and use it when the tank is shot. If my wife smelled gas in the garage then it would be BOOOOMMM for me

[Wolf Spyder]

Don't forget to get the 2 gaskets for the pump spacer!

[Bo Mows]

How much trouble is it to go to an electric pump? Would i wire it to the engine run leg of ignition? Can i use almost any electric pump?

Bo

[baz]

you would need a low pressure pump (around 3 psi ) or a 5 with a pressure regulator a filter and an inertia trip switch or oil pressure trip switch incase of the worsed and it would shut off if you hit something or roll over
a vain type pump is quiet and you can mount it under the rear of the car near the tank

[baronbors]

Originally Posted by Bo Mows How much trouble is it to go to an electric pump? Would i wire it to the engine run leg of ignition? Can i use almost any electric pump? Bo

Got mine from Auto Zone- works great but make sure to get an inertia cut off switch

[john4856]

I have been shopping for a new fuel pump for my gt. I called opel gt source and they said all they have is an elec. pump. I called advance auto parts about 2 hrs. ago and they said they have 3 in warehouse and if i come and pay for it ( about 40 $ ) i will have it the next day. Hope this info may help.

[soybean]

Bo. Mows Check out this thread, http://www.opelgt.com/forums/showthr...tric+fuel+pump. I wasn't able to put the switchs' in as per Ottos, and others suggestions, but I found an inertia switch on Ebay from an MG. There is another thread about them around here somewhere.
I ran it all through a relay, hooked to a cutoff switch in the dash so I can manually shut it off. Another search will turn up many inovations on how people have done theirs.
If you do put in an electric fuel pump, you really do need some way to shut it down in case of wreck. That is a definite safety issue. HTH, Jarrell

[greensmurf20]

i got a really nice aftermarket fuel pump from napa 3 years ago for my GT. got about 25,000 miles on that paticular pump, with 3 different cars, and more than 3 different engines, LOL. its a federal mougal pump made in italy.

[Bo Mows]

I found an elect fuel pump at NAPA rated at 1 1/2 to 4 lbs. Is this too much for a weber without a pressure switch or should i get one anyway? I saw the thread in the previous post with the elect pump and the oil switch screwed into the block, does this use oil pressure or is this just a convenient placed to put it?

Bo

[namba209]

Bo, this could be a long explantion, but here goes: Carbed engines that have an electric pump from the factory have an oil pressure switch in the electrical circuit that grounds out the fuel pump if there's no oil pressure. EFI cars with a lot higher fuel pump pressure also have an inertia switch. Which means in the event of a crash the fuel pump is turned off so if there is a break in the fuel lines, there won't be fuel spraying all over. Both are safety issues, and if folks aren't aware of them, they can be a PIA. On the monza, if I don't drive it for a couple of days , it takes a lot of cranking on the engine to get fuel to the carb. HTH.

[Bo Mows]

Update on the carb not getting gas. Well, I soaked the carb in a degreaser (industrial at work) for a few minutes cause it's hell on aluminum. Then soaked it in top dollar carb fluid. Washed in extreme hot water then blow out all ports with air. Now the acc pump is pumping like crazy into the throat. Now gonna put back on the car and see. Is there a turn setting on the needle vavle that's just under the air cleaner platform? I posted on the downdraft section a question that pertains to this, sorta: How do you set the water choke? This is the last hurdle for the motor (just purchased the electric pump and switch and going back with that tomorrow) now i move on to the brake system.

Bo

[tekenaar]

Originally Posted by Bo Mows I found an elect fuel pump at NAPA rated at 1 1/2 to 4 lbs. Is this too much for a weber without a pressure switch or should i get one anyway? I saw the thread in the previous post with the elect pump and the oil switch screwed into the block, does this use oil pressure or is this just a convenient placed to put it? Bo Originally Posted by namba209 Bo, this could be a long explantion, but here goes: Carbed engines that have an electric pump from the factory have an oil pressure switch in the electrical circuit that grounds out the fuel pump if there's no oil pressure. EFI cars with a lot higher fuel pump pressure also have an inertia switch. Which means in the event of a crash the fuel pump is turned off so if there is a break in the fuel lines, there won't be fuel spraying all over. Both are safety issues, and if folks aren't aware of them, they can be a PIA. On the monza, if I don't drive it for a couple of days , it takes a lot of cranking on the engine to get fuel to the carb. HTH.

Not exactly, grasshopper. The proper safety switch (see below) is SPDT (Single Pole, Double Throw) electrically and connects its Common (Switching) contact to the EFP positive (+) terminal (EFP negative terminal is grounded at pump), its NC (Normally Closed) contact to the ignition switch "Start" contact and its NO (Normally Open) contact to any "switched (ignition key 'ON')" 12V source.

This provides 12V from the ignition switch "Start" contact via the safety switch NC contact to the EFP during starting and "switched 12V" via the safety switch NO contact (now closed by oil pressure) to the EFP once the engine starts and as long as there is oil pressure (engine running). This fills the carb fuel bowl VERY quickly, as the pump runs immediately upon key being moved to "Start" position. It does NOT require the engine to be turning over for it to function like the mechanical pump does. That's all there is to it!

[namba209]

True Otto, on later cars, but on the monza with the oil press lite on in the dash there's an open circuit to the pump. The pump is not grounded at the tank, there is a 3-wire harness from the tank sending unit/fuel pump assembly that goes forward up to the engine compartment. What I normally have to do is crank the motor to get the oil lite out, I can hear the pump in the tank running, when the lite comes on and the pump quits running, crank the motor again till the lite goes out and the pump comes on. And repeat until the engine will start. Usually about 3-4 cycles. It's one of the gonna do things, putting in a primer switch to bypass the need to get the oil lite out before the pump will run. Granted the pump will run during start, but I'm not too strong on cranking the engine that long, so I do the above to save wear and tear on the starter. BTW it's a fairly new pump in the tank with a new sock too. I don't have a problem once the carb gets fuel, it's just after it sits more than 3-4 days. Found all this out after I retired and wasn't driving every day.

[tekenaar]

Originally Posted by namba209 True Otto, but on the monza with the oil press lite on in the dash there's an open circuit to the pump. What I normally have to do is crank the motor to get the oil lite out, I can hear the pump in the tank running, when the lite comes on and the pump quits running, crank the motor again till the lite goes out and the pump comes on. And repeat until the engine will start. Usually about 3-4 cycles. It's one of the gonna do things, putting in a primer switch to bypass the need to get the oil lite out before the pump will run. Granted the pump will run during start, but I'm not too strong on cranking the engine that long, so I do the above to save wear and tear on the starter. BTW it's a fairly new pump in the tank with a new sock too. I don't have a problem once the carb gets fuel, it's just after it sits more than 3-4 days. Found all this out after I retired and wasn't driving every day.

I can only assume from this that your safety switch is electrically different?! My hopped up, 2.2 SSD GT fires right up, even after sitting for a month between starts.

[Bo Mows]

Thanks, tekenaar

No Problem. Napa has the pump and the switch. Which is best (if it matters) put the filter before or after the pump? I want to mount the pump at or close to the tank and the filter under the hood (easy access).

Bo

[namba209]

I'm gonna guess you're right Otto, I don't have a schematic for the car, dumb me, so for the switch it'll be by guess and by golly. tracing each of the wires from the tank to see exactly where they go. I presume this setup I have is U-KNEE-CUE-E, because there was no room for a mech pump when they stuffed the 5.7L V-8 in a hole originally designed for an inline 4. It seems all the wierd stuff just gravitates to me, just like Mr. A Murphy does on more than one occasion.

Bo, just for grins and giggles, why not two filters? They're so inexpensive, one in front of the pump and one in front of the carb, both opaque or transparent so you can see when they're dirty. No need to get trash in your new pump to screw it up. On Willit? I've got 2 filters, two pumps and two tanks, but only because of the high pressure SFI on the engine.

[tekenaar]

Originally Posted by namba209 I'm gonna guess you're right Otto, I don't have a schematic for the car, dumb me, so for the switch it'll be by guess and by golly. tracing each of the wires from the tank to see exactly where they go. I presume this setup I have is U-KNEE-CUE-E, because there was no room for a mech pump when they stuffed the 5.7L V-8 in a hole originally designed for an inline 4. It seems all the wierd stuff just gravitates to me, just like Mr. A Murphy does on more than one occasion. Bo, just for grins and giggles, why not two filters? They're so inexpensive, one in front of the pump and one in front of the carb, both opaque or transparent so you can see when they're dirty. No need to get trash in your new pump to screw it up. On Willit? I've got 2 filters, two pumps and two tanks, but only because of the high pressure SFI on the engine.

Your 'safety switch' actually has two separate switch circuits in it, a single terminal, internally grounded NC switch and a dual terminal NO switch. Both are controlled by oil pressure.

The OP idiot light is connected to the internally grounded NC switch which opens when there is oil pressure, extinguishing the idiot light. The two terminals of the NO switch has one side connected to a 'switched 12V' source, the other side connected to the + side of the EFP and will only run the pump when there is sufficient oil pressure to close this switch. That explains your longer starting time after the car sits for a while . . . a few days or longer.

As you said, Bo should put one fuel filter BEFORE the pump, with both mounted close to the tank in the rear of the car, and another between the pump and carb, this one can be underhood for easy access. M2CW