Al_Camaro

I'm new to this and I have an 86 Camaro berlinetta with a 305 5.0l v8 it has a carburetor and no fuel is coming out of the mechanical fuel pump into the carb. My tank is filled half way and I just installed a new mechanical fuel pump. What could be the problem?

NoEmissions84TA

iTrader: (1)

You got the lines reversed, or it needs to be primed.
Or the fuel pump pushrod fell out when you weren't looking.

//<86TA>\\

iTrader: (14)

Did you leave the bolt in that holds the pushrod while you change the pump?

Al_Camaro

How do you prime it? And I made sure the fuel pump pushrod was in. The smaller line is the return line and the bigger one is the feed line.

Al_Camaro

I don't have those bolts in could that be the problem?

ironwill

A number of things:
1)the fuel line has a hole either chafed or rusted through it at some point.
2)the fuel pickup in the tank is rusted out and fell down inside the tank.
3)incorrect installation.
4) the 'new' pump is defective; check to see if it produces vacuum at it's inlet, and pressure at it's outlet.

If I were a betting man, I'd put my $$$ on #1.

//<86TA>\\

iTrader: (14)

You need the bolts or it will drip oil.

Also, if you didn't use the bolt to hold the pushrod in place, you probably dont ha e the pushrod sitting on the pump arm, and that's why you have no fuel.

tealman92

Did your old pump work before you swaped for the new one? This a new to you car?

zed-028

Lets pump the brakes a bit, why did you change it in the first place? was it:

• a weak pump
• fuel flow stopped completely
• felt like an upgrade

Speaking from experience, the first 2 can be caused by the occasional chevy vapor lock inclusion of an in tank pusher pump along with the mechanical. its 50/50 whether a mechanical can suck through a dead tank pump. Maybe confirm whether its present. Your car is one of the years where it was present.

Al_Camaro

The guy who sold the car to me said it had a bad fuel pump and I changed it. The car before I bought it was not starting but was cranking.

Al_Camaro

I used a hacksaw blade to push the rod up while I installed the pump. I'm going to check it agian.

Al_Camaro

The guy who sold the car to me said it had a bad mechanical fuel pump so I put a new on but the lines are still dry.

zed-028

Cranks but doesn't start, no fuel at the carb even after a pump replacement. guess you're either looking at a filter obstruction (total obstructions arent that common), a line obstruction (rarer), or a possible dead tank pump (seems to pop up more frequently than youd think)

Odd theory, but get someone to put an ear near the filler cap whilst you grab the feed hose of the mechanical pump (attached to the larger line) and blow some air through it with your mouth, youll quickly feel if its blocked, but hopefully the helper can hear bubbles at the other end.

NoEmissions84TA

iTrader: (1)

You need to inspect the fuel lines (esp. the supply line) all the way back to the tank.
If you are really lucky, the fuel filter is plugged. It's underneath, by the drivers side back seat.

Before you remove the new pump, connect a line to the inlet and run it to a separate gas can.
Crank the car and see if the carb gets fuel. It might even start.

tealman92

Also dont forget that the cam lobe for the pump might also be ground down from use and not push the push rod enough for the pump to work. Make sure you add that to the check list if all other areas reveal nothing. Had it happen on my k10 4x4.

dlinger

iTrader: (4)

I have never been able to get a mechanical fuel pump to pump fuel out of the fuel line with the starter. Prime the carb. I like to fill the bowl by the vent tube. You can also pour a small amount of fuel directly into the carb while someone is turning it over. Be careful and not spill fuel. Have fire suppression at hand in case of back fire.

naf

iTrader: (7)

no filter under the car for a V8 carb'd car

you can check your fuel lines, tank and pickup by pressurizing the tank with an air line through the return hose, fuel should flow out of the supply hose (with gas cap tight). you should also hear the pop-off of the over pressure valve in back as you pressurize it, another check.

you can also place the fuel pump pickup into a container with fuel with the supply line from the pump into another. should be able to observe pumping while cranking.

zed-028

I'd say you've had some other problems then. Mechanical fuel pumps (especially a modern replacement) are more than capable of pulling fuel with only the starter, there will be a lag obviously but within about 12 cranks max there should be fuel at the front of the line. Even when the carby bowls are bone dry you should still be able to get fuel up to the carby just with the starter.

Always quicker with a bit of starter spray or 1oz of fuel down its throat though :P

gt4373

Have You Inspected The Fuel Filter Check Valve, The Rubber Can Get Distorted And Stop The Little Plastic Plunger From Opening And Stop The Fuel Flow To The Carb,It Happened To Me..

NoEmissions84TA

iTrader: (1)

OOOH. Good one. That or the filter could be installed backwards.