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Jerry, Master Mechanic
Category: Dodge
Satisfied Customers: 1751
Experience:  ASE Master tech, 30 years exp. troubleshooter, driveability tech
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I have a 1990 dodge ramcharger 4x4 , it had a holy

Customer Question

I have a 1990 dodge ramcharger 4x4 , it had a holy aftermarket fuel pump installed inside frame rail . I took this out drop the tank and installed a new Bosch fuel pump , I can hear the pump spin when I turn the key to the on position but when I try to start the vehicle there is no gas getting to the carb . I disconnected the line where the old holy fuel pump was , and can blow through the hose in here bubbles in the tank. And can actually suck gas out. What can be the problem . ?
Submitted: 9 months ago.
Category: Dodge
Expert:  bill replied 9 months ago.

if you spray carb cleaner in the throttle body does the truck start or try and start?

1990 ramchargers should have a fuel injected engine NOT a carburated one are you sure you have a carburated engine?

Customer: replied 9 months ago.
It had TBI originally it now has a 650 Holley carb On it . if I don't gas in the carb it will run till the gas is gone. It had an aftermarket holy blue fuel pump mounted in the frame rail , it was leaking badly so I removed it spliced the steel line back together, installed a new fuel filter, drop the tank and installed a Bosch fuel pump . When I turn the key to the on position I can hear the pump run for a second or two but when I crank the engine it is not pumping fuel. I checked by disconnecting the splice underneath and I can blow through the line and here it bubble in the gas in the tank, I also sucked on the hose and got a mouth full of gas. LOL that kind of sucked
Expert:  bill replied 9 months ago.

are you sure you have the pump wired correctly?

if you have the wires reversed the pump will run backwards and never pump fuel, try reversing the wires on the pump and see what happens

Customer: replied 9 months ago.
That's the thing the wire connection and the pump connection can't be reversed it has one larger prong and one smaller prong . It's kind of full proof
Expert:  bill replied 9 months ago.

who says the pump is wired correctly from bosch, while a well known brand they do have quality control issues, you also said there was an aftermarket pump installed i assume someone split the wiring at one time and it needed repair was it repaired correctly?

remember a DC motor will spin in reverse if wired in reverse, if you hear the pump run and NO fuel is coming from the line then either it is wired backward or installed incorrectly and feeding fuel back to the tank instead of from the tank

Expert:  bill replied 9 months ago.

what is the part number of the pump you installed?

Customer: replied 9 months ago.
I'll drop the tank again , and check that. With the after market pump the ran a new power wire and ground. I can't think of any thing else it could be , or would a air leak cause this maybe in a line or the module seal ?
Customer: replied 9 months ago.
Bosch 69306
Expert:  bill replied 9 months ago.

that's a universal style pump, be sure your wires are correct a fast check is simply reverse your wires and see waht happens BEFORE you drop the tank again,

there could be a leak at the line that goes from the pump to the hanger or you could have the feed and return line reversed as well, back then we used 2 lines on ALL injected vehicles, also that pump will need a regulator to reduce it's pressure to something the carb can handle

Customer: replied 9 months ago.
I'm not sure how I would swap the wires as I didn't pay any attention to the colors of them as they were at a plug , all I remember is 2 were gray and I would assume these were ground . How and where would I swap them ? Also I don't see gray wires under the hood at the relay , thanks
Expert:  bill replied 9 months ago.

you have 2 feed wires on the pump right?

1 is power to the pump the other is ground for the pump the other 2 would be for the sending unit swap the power and ground for the pump feed, use your test light to see which is power and which is ground, if you ran new wires you should know which is power and which is ground the power will be from the fuel pump relay and the ground needs to be attached to the chassis.

simply SWAP your power and ground wires.

unfortunately your truck is too old for me to pull factory wiring diagram for the fuel pump circuit