Fule Pump

[swamprat87]

Hi does anyone KNOW the correct voltages that the fuel pump should be getting? I have an 87 Blazer thats only gettig 9-ish...im a bit puzzeled here..my concern was that i was only getting 3PSI at the carb but now i get ZERO any help would be great...
James

 

[sweetk30]

12 volts.

check the grounds thay get corroded bad and make it hard for good contact.

also check wires for pin holes in insulation . lots of people stick them and then water gets in and corrodes the wire bad.

 

[TheBeast_88K5]

Fule me once, shame on you?

 

[British Slave]

Hi does anyone KNOW the correct voltages that the fuel pump should be getting? I have an 87 Blazer thats only gettig 9-ish...im a bit puzzeled here..my concern was that i was only getting 3PSI at the carb but now i get ZERO any help would be great...
James

Have you done away with the TBI?

 

[swamprat87]

ypu its got a 1984 383 under the hood...im trying to run a carb but its not getting any fuel to the regulator.

 

[British Slave]

Well then, I would guess fuel filter or pump. Very possible a bad ground to the pump.

 

[swamprat87]

ya im thinking that too...i jus really need to know for sure if the pump should be reciving 12vlots or not...i mean i could bypas the ECM an run a switch to the pump from the batt, but somthing about fuel and electiric dn sound safe..lol

 

[British Slave]

It should be getting 12 volts. Could be a ground, and could be the old wire. Do you hear the pump running?

 

[swamprat87]

i can. its really quiet tho, that why i was considering a jumper wire..bad idea?

 

[British Slave]

You were getting 3 psi? Do you have a fuel regulator? The stock TBI pump should have been putting up 9 to 13 psi.

 

[swamprat87]

ya 3psi...turned the reg both ways no change then it jus started to fdrop then....blah...0psi, i really think it may be pluged or bad pump...but 9 volts dn sound correct.

 

[sweetk30]

find the power up wire for the stock relay on the firewall from the computer. then hook that to a key hot & crank hot so when the key is on the pump runs.

 

[bensk5]

find the power up wire for the stock relay on the firewall from the computer. then hook that to a key hot & crank hot so when the key is on the pump runs.

Along with this ^^^^^

On the fire wall drivers side, at the harness plug below the wiper motor,if your looking at the plug straight on it will be the "tan with a white stripe" wire. BE ADVISED, there are (2) wires the SAME color in the same area. You want the thinner of the two. This is the direct hot to the fuel pump. If going carb, you will need to cap off the return and the vapor line from charcoal canister....AND add a pressure regulator.

 

[swamprat87]

Along with this ^^^^^

On the fire wall drivers side, at the harness plug below the wiper motor,if your looking at the plug straight on it will be the "tan with a white stripe" wire. BE ADVISED, there are (2) wires the SAME color in the same area. You want the thinner of the two. This is the direct hot to the fuel pump. If going carb, you will need to cap off the return and the vapor line from charcoal canister....AND add a pressure regulator.

sorry to sound stupied...why do i need to cap the vapor and return line? if my regulator has a return port?

 

[sweetk30]

ya why also my self ?

you want the tank to vent and need return line to tank for regulator if running intake pump still.

 

[bensk5]

sorry to sound stupied...why do i need to cap the vapor and return line? if my regulator has a return port?

Sorry dude, I was in a quick rush to type that message. My apologies.

DO NOT cap the vapor.....and only cap the return if you plan on NOT using a returnless system. Why I commented is because I am not using the return after verifying the stock pump put out 14 psi. and decided to cap my return and vent the vent tube.


Sorry for any confusion.

 

[swamprat87]

ok so this weekend i will put 12volts to the pump (cross fingers) and see if that gets the fuel PSI up...if not then replace pump...