This is my first post here so I'd like to say hello everyone. I haven't really done any of my own work on this truck until the past year or so. I can't afford to pay mechanics to work on it anymore and the past couple times I went to a shop all they did was rip me off and tell me they couldn't find the problem. This truck is now my only vehicle so I need to to be back in good condition so I can actually depend on it. So I appreciate any assistance you all can offer.
Truck currently has 102k miles
No modifications to original factory specs
The problem: I can only get 2-4 successful starts in one day. The truck doesn't have a problem maintaining an idle, but if I have to take more than a few trips in a day it will randomly not start. When this happens the engine will rotate but will not turn over. Occasionally I will pull these four fuses for 10 minutes: fuel pump, pcm memory, pcm diode and pcm maxifuse. Then the engine may start, or will start and then die after a second (throttling doesn't maintain the idle, it causes the engine to shut-off immediately).
My only solution when this happens is to abandon the vehicle for 8-24 hours and return, and usually it will start.
The last shop I took it to told me they found codes for a failed IAC. They were also a bunch of bumbling morons, but I'm not going to get into that now.
Fixes I have tried:
Replaced IAC motor and IAC gasket
Replaced EGR valve and gasket
Replaced PCV valve
Replaced alternator (the post had melted off the previous alternator which had only lasted a year)
Replaced drivebelt (sched maint)
Replaced spark plugs and spark plug wires (sched maint)
Cleaned throttle body
Cleaned MAF sensor
Replaced TPS (had no effect on incorrect throttle position reading)
Checked for vacuum leaks with carb cleaner, none found
The only problem I could find doing my own diagnostics with an engine scanner is that the throttle position when the engine is off or idling is 18.4%. I replaced the TPS and it shows the same reading, however after running the truck with the new TPS it settles at 19.2% now. I tried a volt test of the signal coming out of the new TPS and instead of smoothly moving between .1ish and 2.3ish V, it just sticks at .33. However, if it fails this test wouldn't the PCM not be able to receive a signal? I could be performing the test wrong. Watching the engine scanner the throttle position moves smoothly between the 19.2% and 93ish% both on the old and new TPS. There is a good 11.5-12.5v running to the unit so that isn't an issue.
I'm about to replace the fuel filter soon now that I've learned how to make the clamshell tool out of a sharpie cap (lol).
I appreciate any help you guys can offer! A family friend of mine who has done a lot of work on Ford 3.0 and 4.0's told me it could be the fuel pump, but that is a job I'm on the fence about doing myself.
Thanks in advance.
Truck currently has 102k miles
No modifications to original factory specs
The problem: I can only get 2-4 successful starts in one day. The truck doesn't have a problem maintaining an idle, but if I have to take more than a few trips in a day it will randomly not start. When this happens the engine will rotate but will not turn over. Occasionally I will pull these four fuses for 10 minutes: fuel pump, pcm memory, pcm diode and pcm maxifuse. Then the engine may start, or will start and then die after a second (throttling doesn't maintain the idle, it causes the engine to shut-off immediately).
My only solution when this happens is to abandon the vehicle for 8-24 hours and return, and usually it will start.
The last shop I took it to told me they found codes for a failed IAC. They were also a bunch of bumbling morons, but I'm not going to get into that now.
Fixes I have tried:
Replaced IAC motor and IAC gasket
Replaced EGR valve and gasket
Replaced PCV valve
Replaced alternator (the post had melted off the previous alternator which had only lasted a year)
Replaced drivebelt (sched maint)
Replaced spark plugs and spark plug wires (sched maint)
Cleaned throttle body
Cleaned MAF sensor
Replaced TPS (had no effect on incorrect throttle position reading)
Checked for vacuum leaks with carb cleaner, none found
The only problem I could find doing my own diagnostics with an engine scanner is that the throttle position when the engine is off or idling is 18.4%. I replaced the TPS and it shows the same reading, however after running the truck with the new TPS it settles at 19.2% now. I tried a volt test of the signal coming out of the new TPS and instead of smoothly moving between .1ish and 2.3ish V, it just sticks at .33. However, if it fails this test wouldn't the PCM not be able to receive a signal? I could be performing the test wrong. Watching the engine scanner the throttle position moves smoothly between the 19.2% and 93ish% both on the old and new TPS. There is a good 11.5-12.5v running to the unit so that isn't an issue.
I'm about to replace the fuel filter soon now that I've learned how to make the clamshell tool out of a sharpie cap (lol).
I appreciate any help you guys can offer! A family friend of mine who has done a lot of work on Ford 3.0 and 4.0's told me it could be the fuel pump, but that is a job I'm on the fence about doing myself.
Thanks in advance.