NO START-Please tell me what im missing

[97-5.0]

intermittent no start issue for over a year

new fuel pump months ago from ford but stamped made in china
drove for a few hours around town - parked in driveway now it wont start

couldnt hear the pump buzz when i turned the key- removed and hooked it direct to battery and it runs fine

i only get 6 volts at fuel pump connector- no change koeo back and forth
12 volts @ switch at passengers right foot

fuel pump relay wouldnt click- saw something on net and added a ground wire to fuel relay in box under hood.....
sparked at relay when i turned koeo- removed wire

now NO CEL @ KOEO- will check bulb

.60 volts at TPS reference voltage...should be 4.0
removed evap sensor connector, fuel pump level sensor , dpfs sensor and still at .60 volts at tps

will clean crank sensor connector next....
how to i check voltage from pcm connector to check for 4volt reference?

PCM relay clicks still when koeo, cleaned and check all fuses, none blown

sprayed started fluid with no fire so NO spark also!

will check voltage at dpfs and evap now for 4 volts

unhooked batt for 10 min no change

i know im missing something.....searched fourms for hours till im dizzy and ready to set a match lol...please ANYONE!!!!!

sorry for typos as im on the edge of sanity!!

 

[ahodges]

dude, slow down. I think you have too many trouble shooting checks going on at the same time!

First, check to make sure you have fuel pressure. There is a shreader valve on the fuel rail on the right side of the intake just in front of the throttle body. Use a tire pressure gauge and check the pressure there right after you turn the key on. you are looking for 30-40psi at the rail.

If you have fuel move on to spark. I have a hard time believe this is a spark issue because there are 2 coils in each coil pack for a total of 4 coils that need to fail before the engine will fail to even try to start.

Forget about the DPF for now. If you don't have fuel pressure, swap out the fuel pump relay for another one (such as your wiper relay or something). If that doesn't work, reply back for more advise.

 

[97-5.0]

fuel pump wont turn on so i cant check for that, it only get 6 volts

i swapped all 3 relays around, the pcm relay will click with koeo but never the fuel at any time


i say no spark cuz it didnt fire with engine starter


just tried to look for codes and it says it cant connect, something is wrong with the pcm i think

 

[ahodges]

could be. My other suggestion would be to check the fuel pump inertia switch, I don't know if yours has one or not.

If a scanner won't connect I would say you have a PCM problem.

 

[97-5.0]

i get 12volts at the switch- hit it and reset it-no change- i was just going to run a wire from there to the pump.... splice into it....


but now the CEL wont come on @ KOEO - key on engine off
havent check the bulb yet but for some reason only 6volts are going back to the pump harness


the pcm isnt putting out the 4volts ref power to any sensors but the pcm relay will click and has 12volts

 

[deweyville65]

Voltage drop with key on engine not running is normal. I chased that same thing last year when changing fuel pump.

 

[97-5.0]

but still only 6 volts at pump and the pump wont spin

and my scanner wont talk to the pcm, connection error

12volts at fuel relay but it wont click, tried several relays, left side ground and bottom power


and 12volts at pcm relay and it will click every koeo


what slots do i check on the PCM harness for power?
1997 xlt 4dr 5.0 4r70w- ill get the code off the pcm

 

[2000StreetRod]

power first

I suggest that you solve your power issues before worrying about fuel pressure. Are you sure that you have 6 volts at the pump and not 0.6 volts? Check the PCM power relay fuse in the battery junction box. I don't have a 1997 wiring diagram but on my 2000 it's fuse 10 (30 amps). The relay clicks which may only mean the solenoid is being energized but there may not be power to the switched contacts (relay pin 30). The PCM power diode fuse in the central junction box (fuse 19, 25 A) provides power to the solenoid (relay pin 86). If you don't have battery voltage to the PCM then any unusual behavior is possible. If there is power to the PCM power relay then check the C115 main engine harness connector for being loose.

 

[tenny]

my suggestion....????

you need to track down the SHORT.

somewhere in the wiring, you have a voltage drop/shortage somewhere.

you need to completely pull the harness apart and check the wires.

this may take some time

 

[97-5.0]

has anyone ever seen the fuel tank ground strap?

Haynes shows it being attached above the left sway-bar link end


i have a mass of rust with a bolt in the middle, no trace of strap left.....fuel tank is rather far away

pic looks like the strap goes to rear sub-frame lip to some sort of "line\pipe" that runs along


there is the filler neck but its rubber in that section unless it just meant to ground the outer metal neck.....makes sense when filling up but it dosnt ground the tank

 

[koda2000]

i believe the ground for the fuel tank is supplied by the fuel pump/fuel sender wiring harness. the ground should be a black wire. while there are several "ground straps" (and they do tend to disintegrate over time) they're there to provide good ground connections between the body, engine and frame.

the black ground wire to the fuel pump assembly is connected to the frame somewhere and can be suspect. the wire can corrode, break, or no longer have a good connection to the frame. if this happens your fuel pump may not run at full speed or not at all. i suggest you trace the ground wire from the fuel pump assembly and check it.