i have a problem with fuel pumps not running as well as injectors not firering.
What is your question?
the truck will run if i induce fuel through the plentom. I have changed many parts all of witch were corroded or looked bad. i do to have low voltage at the inertia switch, i do have 12v at the relay, i changed the pcm,throtle position senser, eec guts in the distributor,air flow sensor, netraul saftey,map,and all relays. the truck ran then didnt when this all started, any help would bee nice
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you will only get 12 volts at the inertia switch,to the fuel pump, for a couple seconds when you turn key to on,not start,then it drops to around 6 volts.thats for priming the pump,then when you crank the truck,when the computer sees rpm it will fire the fuel pump and truck starts and pump runs all the time untill you turn truck off again.one thing you can check,when you turn key to on,can you hear the fuel pump prime(humm)for 2 seconds.try this and listen for the pump to prime,it will prime every time you turn key to on,if you have power to the pump from inertia switch,and if pump is good.
The pump is good I can jump it @ the inertia switch or the relay and it will run the truck will not the injectors don't seem to fire. If I spray w/ either the truck will run I did change all the injectors and flush the line with fuel the pump ran then, the truck ran fine the next day nothing. I will check in the am if the voltage is higher @ key first on .
but,did you also change the fuel filter?you said pump is comming on,but is it pushing fuel thru the filter and line?have you checked fuel pressure at rail?
I do have fuel pressure,I did change the fuel filter. I can run the pump by jumping it out until it returns to the tank. The pump does not run with key first on and the injector curcuit does not have power.
check and clean all the grounds,you do have a ground coming off of battery to chassis?clean em all up and replace fuel pump relay.check ignition switch.
Did that, and replaced both, both cables on the battery are new including the grounds to the frame cleaned the ground @ the pcm, inertia switch heater box,headlight harness and under the dash.
Ok I checked the voltage @ the inertia switch just the meter 12v add the test light for a load it drop's to 5v first on w/key and continuos no change .
if you got 12 volts on the wire going to the inertia switch(DARK GREEN W/YELLOW STRIPE)then it drops to 5-6 volts,now do the same test,but this time,check the(PINK WIRE w/BLACK STRIPE)on inertia switch,should get same reading,if not the inertia switch is bad.if same reading,you need to do same test at fuel pump harness,unplug harness on frame,should be a 4 wire connector.look for corrosion inside plug,if none,make sure the pins are not spread out on the female side.then check for power going to pump at connector.you will only get voltage on 2 of the pins. you will need a helper to do this.if no helper,pull the fuel pump relay,put a jumper(paper clip)from pin 30 to pin 87,that will give you power to inertia switch,then put a jumper in inertia switch,in both wires in the plug.that will give you constant voltage going to the fuel pump.
Only 5 volts @ the inertia @ key first on and constant, same @ the pump. I do have 13 v @ the power side of the relay. I have only 5 v constant @ injectors.if I jumper 12 into the curcuit the pump will run but I still only have 5v @ injectors
ok,your relays,fuses,etc are different on your truck,compared to mine.mine is a 2000 model. your wire colors are different.you should have 3 relays under the fuse box.the fuel pump relay is the 3rd one from the firewall,i think.now the ECC relay,do you have power on it?have you changed it?the fuel pump relay and the ECC relay work together.
Yes I do have 3 relays fuel pump and eec work in tandom both have 12 v I did install a new eec module @ the begining I did not have spark as well so I changed it w/gutting the dist and new relays now I only have spark. I'm stumped whatever happen happen over night the truck ran then it didn't. This truck sat for 16 years in a field and were trying to bring it back to life. When we got it I put a battery in it some gas and drove it 11 miles home with no brakes. I'm adding to this on 4-10-15 because I found my problem there ia a diode in the curcuit that was faulty I relaced it all systems working fine and the truck runns thank for your help
The pump is good I can jump it @ the inertia switch or the relay and it will run the truck will not the injectors don't seem to fire. If I spray w/ either the truck will run I did change all the injectors and flush the line with fuel the pump ran then, the truck ran fine the next day nothing. I will check in the am if the voltage is higher @ key first on .
but,did you also change the fuel filter?you said pump is comming on,but is it pushing fuel thru the filter and line?have you checked fuel pressure at rail?
I do have fuel pressure,I did change the fuel filter. I can run the pump by jumping it out until it returns to the tank. The pump does not run with key first on and the injector curcuit does not have power.
check and clean all the grounds,you do have a ground coming off of battery to chassis?clean em all up and replace fuel pump relay.check ignition switch.
Did that, and replaced both, both cables on the battery are new including the grounds to the frame cleaned the ground @ the pcm, inertia switch heater box,headlight harness and under the dash. Ok I checked the voltage @ the inertia switch just the meter 12v add the test light for a load it drop's to 5v first on w/key and continuos no change .
if you got 12 volts on the wire going to the inertia switch(DARK GREEN W/YELLOW STRIPE)then it drops to 5-6 volts,now do the same test,but this time,check the(PINK WIRE w/BLACK STRIPE)on inertia switch,should get same reading,if not the inertia switch is bad.if same reading,you need to do same test at fuel pump harness,unplug harness on frame,should be a 4 wire connector.look for corrosion inside plug,if none,make sure the pins are not spread out on the female side.then check for power going to pump at connector.you will only get voltage on 2 of the pins. you will need a helper to do this.if no helper,pull the fuel pump relay,put a jumper(paper clip)from pin 30 to pin 87,that will give you power to inertia switch,then put a jumper in inertia switch,in both wires in the plug.that will give you constant voltage going to the fuel pump.
Only 5 volts @ the inertia @ key first on and constant, same @ the pump. I do have 13 v @ the power side of the relay. I have only 5 v constant @ injectors.if I jumper 12 into the curcuit the pump will run but I still only have 5v @ injectors
ok,your relays,fuses,etc are different on your truck,compared to mine.mine is a 2000 model. your wire colors are different.you should have 3 relays under the fuse box.the fuel pump relay is the 3rd one from the firewall,i think.now the ECC relay,do you have power on it?have you changed it?the fuel pump relay and the ECC relay work together.
Yes I do have 3 relays fuel pump and eec work in tandom both have 12 v I did install a new eec module @ the begining I did not have spark as well so I changed it w/gutting the dist and new relays now I only have spark. I'm stumped whatever happen happen over night the truck ran then it didn't. This truck sat for 16 years in a field and were trying to bring it back to life. When we got it I put a battery in it some gas and drove it 11 miles home with no brakes. I'm adding to this on 4-10-15 because I found my problem there ia a diode in the curcuit that was faulty I relaced it all systems working fine and the truck runns thank for your help