View Full Version : 1994 ford f150 will crank but no start.
zman58
Aug 13, 2014, 04:48 PM
My truck will crank but will not start. It has a new fuel filter and it is getting spark but it will not run. When I turn the key on I can hear the front pump run then stop after a few seconds. And the rear pump does the same thing. But when I go to start the truck it does not run. It is almost like it is not getting fuel. The schrader valve just leaks like it does not have any pressure. Anyone know what could be going on?
TxGreaseMonkey
Aug 13, 2014, 06:29 PM
Using a fuel gauge, connected to the Schrader valve, compare fuel pressure to spec. If it checks out okay, I would next focus on the distributor--it's common for the Ignition Control Module (ICM), which Ford calls Thin Film Ignition (TFI), and the ignition pick-up coil to prevent these older Fords from starting.
zman58
Aug 14, 2014, 08:51 AM
Using a fuel gauge, connected to the Schrader valve, compare fuel pressure to spec. If it checks out okay, I would next focus on the distributor--it's common for the Ignition Control Module (ICM), which Ford calls Thin Film Ignition (TFI), and the ignition pick-up coil to prevent these older Fords from starting.
Well the schrader valve barley has any pressure. We checked to see if the fuel filter was clogged and it was clear almost like gas is not even making it that far. We reset the inertia switch and then it ran for a second then stopped again. Also the truck has been sitting for a couple years. But it ran perfect the day it was parked
TxGreaseMonkey
Aug 14, 2014, 09:17 AM
The old gas has likely deteriorated and started to gum-up. I would empty and clean the fuel tank, and, in all likelihood, replace the fuel pump and fuel filter. The fuel rail needs to be fully pressurized, in order for the injectors to work.
zman58
Aug 14, 2014, 11:36 AM
The old gas has likely deteriorated and started to gum-up. I would empty and clean the fuel tank, and, in all likelihood, replace the fuel pump and fuel filter. The fuel rail needs to be fully pressurized, in order for the injectors to work.
We got some of the gas out of the tank and some leaked out when we took the fuel filter off and turned the key on but it still does not try to start... we are stumped I appreciate you helping and if there is anything else you can think of let me know
TxGreaseMonkey
Aug 14, 2014, 01:42 PM
Is the Schrader valve good? You mentioned that it leaks. The fuel rail needs to be able to hold pressure.
zman58
Aug 14, 2014, 02:31 PM
Yes it is. When we push the valve down to see if it has pressure it just leaks out instead of shooting out like it has pressure. We do not have a pressure tester.
TxGreaseMonkey
Aug 14, 2014, 03:01 PM
Sounds like you need a new fuel pump.
zman58
Aug 16, 2014, 08:35 AM
Sounds like you need a new fuel pump.
We found that the inertia switch does not have power. All the fuses are good so we don't know what powers the inertia switch or where to look to fix it
TxGreaseMonkey
Aug 16, 2014, 09:12 AM
Check the fuel pump relay--they often go bad. If you find an identical relay, usually located in the under hood fuse/relay box, try substituting it. If it now works, buy a new relay.
zman58
Aug 19, 2014, 11:41 PM
Check the fuel pump relay--they often go bad. If you find an identical relay, usually located in the under hood fuse/relay box, try substituting it. If it now works, buy a new relay.
All the relays were good but the inertia switch still didn't get power from them is there anything between the two that could cause it to fail?
TxGreaseMonkey
Aug 20, 2014, 05:32 AM
Try resetting the inertia switch. How did you determine all the relays were good?
zman58
Aug 20, 2014, 05:21 PM
Try resetting the inertia switch. How did you determine all the relays were good?
We already reset it and it does not have power and we swapped them around and everything still worked like the horn relay , etc.
TxGreaseMonkey
Aug 20, 2014, 07:05 PM
Basically, if the fuel pump fuse, fuel pump relay, ignition switch, PCM, and inertia switch are good, focus on the fuel pump wiring, connections, and pump. You need to establish a "baseline" of known good items.
zman58
Aug 20, 2014, 07:47 PM
Basically, if the fuel pump fuse, fuel pump relay, ignition switch, PCM, and inertia switch are good, focus on the fuel pump wiring, connections, and pump. You need to establish a "baseline" of known good items.
Well everything that you said is good the only thing that could be wrong is a connection somewhere. But we do not know where. The one thing we know is that the inertia switch is not getting power and we don't know where to look to see if there is a bad connection.