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My car just died when i was driving her. the 30 amp fuse blew changed it . still no power i put the meter on the wires on the bottom of the sending unit. i then changed the fuel pump relay. know i have power when iturn on the key and still have power when iturn the engine over . i then hook the pump back up nothig put the meter on the pump it read all 0's with the pump off it was reading in the 12.00's . i checked the pump on a car battery in the garage it was running . i thought maybe it was weak so i bought another pump same thing happens with the new pump. i tryed to trace the wire coming off the sending unit well i can follow it about 3' then it goes in the frame. i dont now what to do!!!
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NOT A RV ,right?
fuse # not told nor he AMPs rating. (hard job this)
on all cars, most fuse have not just one, load.
the fuse name is can only fit one name there, even up to 10 loads on 1 fuse. the service manual covers he wiring fully
scan the PCM so it can tell you what is shorted"? DTC errors.
F350 not superduty version (wild guess me)
I have trouble finding the 7.3L wiring in total.
ok found 35 pages of schematics on this. wowl
wish I knew fuse number F# that blew.
fuel heater means what?
Glow Plugs
intake induction heater MIAH
02 oxygen sensor heaters?
fuel filter bowl or water separator? heater?
fuel filter/water separator assembly., yes.
found it. I did, fuse 30/34 and 30 amps,in battery JB.
runs what you said and waste gate solenoid. bingo shorted
+ 2 relay coils only 86 pins, I bet are not bad. PCM and IDM.
bingo
There is a switch in the airflow meter that keeps the fuel pump relay closed as long as there is airflow. With the meter unplugged, the pump should not run except when the key is turned to start. It would seem to me that you have a wiring issue. Try jumping the fuel pump relay so the pump runs whenever the key is on. (Remove the relay and jump the pump wire to the accessory wire--see top left diagram.) This defeats the safety feature but will keep the pump running.
It's a short in the fuel pump circuit wiring. Were those damaged wires where the pump fuse is located? If so, that is where to start looking.
The circuit is not that difficult to follow. The pump wire runs from the fuse to the fuel pump relay (probably in the same location as the fuse). And from the relay the pump wire goes direct to the pump in the gas tank. Somewhere in that path, your wire is shorting out-touching metal or another wire with insulation stripped from it.
Techs use a multi-meter to help look for shorts. Checking a section of wire with an ohmmeter will tell you if the section is good or has a break. Good luck. Take another look at those damaged wires.
If the fuse and relay is good, and there is power AT the pump, then the pump is bad. Fuel pump power goes through the oil pressure switch but only after engine is running. So there should be power to the pump for approx 2 seconds when you turn key on. There is a RED wire (prime, it will be a single wire poking out near relay) at the fuel pump relay, if you put 12V on that wire the pump should run, IF the wires and pump is good. The GRAY wire powers the pump.
do you have a volt meter with a built in amp meter? if you do remove the fuel pump rely then put the leads into pins 30 and 87 this should start the fuel pump if the amp out put is higher than7 amps the pump is worn out. if the pump dose not start. if the pump is on the driver side rail bang on it if it starts its bad. if the pump is in the tank hit the bottom of the tank with a large soft mallet. if you still get no pump check to be sure you amp meter it set and working. then test for voltage to the fuel pump . the voltage comes from the battery to pin # 30 at the relay test for power there first.
You basically answered your question, there's no power getting to the pump when the factory harness is connected, so check the fuse for the fuel pump and also the fuel pump relay this could be the cause if there was a short in the wiring it would surely blow the fuse. As for the hose problem, are the hoses colapsing when running, if so its a air pocket or possablly a stuck open or closed thermostat.
Try changing the fuel filter first we always change them when servicing the fuel pump anyway,its easy and cheap,if that doesnt solve the problem you will have to perform an amperage draw test on the fuel pump to insure your not replacing a good pump. Check the fuel pump relay and inertia switch and wiring also.Although possible its unlikley the fuel pump would blow a fuse consistantly without displaying any driveability problems.There may also be another component running off the fuel pump fuse have your mechanic pull a wiring diagram to find out. Good hunting keep me informed
that fuse feeds power to fuel pump relay circuit that feeds pump could be defective pump,or damaged circuit wires that shorts out! and not a good idea to put higher fuse in circuit could cause more damage to circuit! but i know when your stuck, u do what it takes,so inspect circuit related to fuse,
well that sounds like you may have a short to power or a short to ground means you may have 2 wires rubbing against each other or you may have an internal problem with the cars computer.start by back tracking the wires leaving the box where the fuse is and if you have acces to a meter try to measure the draw of the short with meter on the highest scale of the amps side don't test for for more then 5sec at a time or may damage meter.back to checking fuel pump with out dropping out of tank is to self power the unit and run a hose from fuel line disconnected from motor or by the tank-if you can raise the car and let it run for 10min see what happens if not check relay
to see if you have ground at the relay and 12volt to relay and turn on volt from ignition or computer. listen for the click on and cliick off if ground is god and power then swop the relay another relay and run again for 10min P.S please check or replace fuel filter and I've had problems with mass air flow sensor on those cars computer doesnt know how much air is being monitored so computer doesnt know how much fuel to add to car
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