1990 f150 no fuel issue
#1
09-29-2018, 03:33 PM
1990 f150 no fuel issue
Hey guys, PJ here. New to the forum as I recently got a 1990 f150 4x4 5speed with the 300 motor (inline 6)
long story short I got this truck as a project for tech school as I am in my 2nd year and pretty confident in my knowledge. Shortly after owning it and fixing the no spark issue one day it died in me. And basically I find out both tanks are rusted,front fuel pump doesn’t activate, getting about 3 psi to the fuel rail, and about 1 volt to each pump. So I replace both tanks,fuel pumps,sending units,relay, relay harness, switch harness. Before I replaced these parts I was only getting about 6 volts to the switch so I knew it was getting extra resistance at the relay. So I replace all these parts finally getting battery voltage to the pumps and bolt the tanks in. Make sure my wiring is correct and put 9 gallons in both tanks. Front fuel pump won’t activate (and I think it’s because the farmer who owned it messed with the wiring to the switch so I have to re arrange it with my teachers) and the back pump activated but I’m not getting any fuel to the rail or the filter (so I think the cause of this is my fuel lines are crossed?) what do you guys think about this situation and any advice? I work at an auto part store so getting cheap parts is not an issue and I did tons of diag to make sure the lines are not clogged, new filter etc. I’m really hoping it’s just some crossed fuel lines. Thanks guys for your help!
long story short I got this truck as a project for tech school as I am in my 2nd year and pretty confident in my knowledge. Shortly after owning it and fixing the no spark issue one day it died in me. And basically I find out both tanks are rusted,front fuel pump doesn’t activate, getting about 3 psi to the fuel rail, and about 1 volt to each pump. So I replace both tanks,fuel pumps,sending units,relay, relay harness, switch harness. Before I replaced these parts I was only getting about 6 volts to the switch so I knew it was getting extra resistance at the relay. So I replace all these parts finally getting battery voltage to the pumps and bolt the tanks in. Make sure my wiring is correct and put 9 gallons in both tanks. Front fuel pump won’t activate (and I think it’s because the farmer who owned it messed with the wiring to the switch so I have to re arrange it with my teachers) and the back pump activated but I’m not getting any fuel to the rail or the filter (so I think the cause of this is my fuel lines are crossed?) what do you guys think about this situation and any advice? I work at an auto part store so getting cheap parts is not an issue and I did tons of diag to make sure the lines are not clogged, new filter etc. I’m really hoping it’s just some crossed fuel lines. Thanks guys for your help!
#2
09-29-2018, 05:23 PM
#6
10-01-2018, 07:56 AM
Yes, jumping those 2 pins will run the fuel system continually vice the 1 second pulse when you turn the key on.
Remember to pull the jumper when done testing.
Check for pressure at the rail schrader valve.
Sure, if you have pressure at the schrader valve, try to start.
Ultimately put a fuel pressure gauge on the schrader valve to check for correct fuel pressure.
Remember to pull the jumper when done testing.
Check for pressure at the rail schrader valve.
Sure, if you have pressure at the schrader valve, try to start.
Ultimately put a fuel pressure gauge on the schrader valve to check for correct fuel pressure.
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