4.9L intermittantly QUITS
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New User
Joined: Jun 2003
Posts: 14
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From: Jacksonville, FL
4.9L intermittantly QUITS
95 F-150 intermittantly just shuts off
My friend has a 95 F-150 w/122k miles , 4.9L automatic.
Lately, while driving, it will just QUIT. No warninig signs. Usually he could restart and go on his merry way. Last night, it did it again and we couldn't get it to start until it sat for about 25-30 minutes.
Any reccomedations as to where to start looking. We feel like it's an ignition problem.
Shawn
My friend has a 95 F-150 w/122k miles , 4.9L automatic.
Lately, while driving, it will just QUIT. No warninig signs. Usually he could restart and go on his merry way. Last night, it did it again and we couldn't get it to start until it sat for about 25-30 minutes.
Any reccomedations as to where to start looking. We feel like it's an ignition problem.
Shawn
Post Fiend
Joined: Nov 2002
Posts: 9,987
Likes: 7
From: Memphis, TN
4.9L intermittantly QUITS
The coil does the same thing - that's what mine was, and I'm also running a '95 4.9L in my truck. The Haynes manual tells how to test the whole ignition system with a multimeter.
Postmaster
Joined: May 2002
Posts: 3,241
Likes: 3
From: Broken Arrow, OK
4.9L intermittantly QUITS
Pull the coil wire off and check for corrosion. Also check the primary connections at the coil, mine were bad and my truck had a similar symptom. I found it one day when it quit and wouldn't restart until I wiggled that connector.
New User
Joined: Jul 2003
Posts: 8
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From: Oklahoma City
4.9L intermittantly QUITS
Moonen
I had essentially the same problem you describe in my '89 Bronco and it drove me crazy. If you are not getting any codes to help you out, then it is probably a fuel delivery problem. I ended up changing the in-tank and frame rail mounted fuel pumps, as well as lots of other expensive stuff, only to find out that I had a corroded wire and intermitant connection inside the wire harness for the high pressure (frame mounted) pump...I could have saved some money by having the fuel pressure checked, maybe. In the end, it happened so infrequently, and always fixed itself by the time I had it towed to the dealer, that I got tired of paying for an hour's diagnostics with "could not duplicate" as the action taken that I started replacing the most likely components one at a time each time it failed. Eventually I ended up replacing nearly every common component in the fuel system plus the ECM and it still had the bad habit of stranding me in some inhospitable locations.
Some checks you can do before you change anything:
1. In the morning when the engine has sat all night, .tTurn ignition key on without starting the truck. If you hear the fuel pump run and then shut off shortly, your fuel pump relay and fuel pump are likely working ok. Fuel pump relay is cheap and easy to fix, so you might have him buy one to carry with him.
2. Check the fuel pressure at the fuel pressure regulator using an in-line fuel gauge and the procedure for the '95. (sorry, don't have one for a truck that new) You need a fuel pressure gauge to check it, and if the engine is running, it will probably read good. To check it out, you will probably have to drive it and check the pressure under load. A big drop when you tromp it will indicate that your fuel pump is toast or your fuel filter is badly clogged with some loose icky-bits. (you already had him change the fuel filter didn't you?)
I fought that problem for years until finally, it stopped "fixing itself" and stayed broke so I could track down the problem. I think the reason I didn't find it earlier, was that every time I checked the voltage to the pump, I moved the wires around enough to temp fix the symptom.
I recommend a book by Robert Bentley publishers titled "How to Understand, Service and Modify Ford Fuel Injection & Electronic Engine Control" By Charles O. Probst, SAE. It is well written to a level most shade tree mechanics can understand, and takes some of the "new-fangled-ness" out of fuel injection for those of us raised on Q-jets and Carters.
I hope your friend's problem is easier to check out and fix than mine was. I think a good service manager at my dealer then could have helped me work through this problem a lot quicker (if not necessarily cheaper) than doing it myself. But on the bright side, I got to learn my fuel delivery system intimately.
I had essentially the same problem you describe in my '89 Bronco and it drove me crazy. If you are not getting any codes to help you out, then it is probably a fuel delivery problem. I ended up changing the in-tank and frame rail mounted fuel pumps, as well as lots of other expensive stuff, only to find out that I had a corroded wire and intermitant connection inside the wire harness for the high pressure (frame mounted) pump...I could have saved some money by having the fuel pressure checked, maybe. In the end, it happened so infrequently, and always fixed itself by the time I had it towed to the dealer, that I got tired of paying for an hour's diagnostics with "could not duplicate" as the action taken that I started replacing the most likely components one at a time each time it failed. Eventually I ended up replacing nearly every common component in the fuel system plus the ECM and it still had the bad habit of stranding me in some inhospitable locations.
Some checks you can do before you change anything:
1. In the morning when the engine has sat all night, .tTurn ignition key on without starting the truck. If you hear the fuel pump run and then shut off shortly, your fuel pump relay and fuel pump are likely working ok. Fuel pump relay is cheap and easy to fix, so you might have him buy one to carry with him.
2. Check the fuel pressure at the fuel pressure regulator using an in-line fuel gauge and the procedure for the '95. (sorry, don't have one for a truck that new) You need a fuel pressure gauge to check it, and if the engine is running, it will probably read good. To check it out, you will probably have to drive it and check the pressure under load. A big drop when you tromp it will indicate that your fuel pump is toast or your fuel filter is badly clogged with some loose icky-bits. (you already had him change the fuel filter didn't you?)
I fought that problem for years until finally, it stopped "fixing itself" and stayed broke so I could track down the problem. I think the reason I didn't find it earlier, was that every time I checked the voltage to the pump, I moved the wires around enough to temp fix the symptom.
I recommend a book by Robert Bentley publishers titled "How to Understand, Service and Modify Ford Fuel Injection & Electronic Engine Control" By Charles O. Probst, SAE. It is well written to a level most shade tree mechanics can understand, and takes some of the "new-fangled-ness" out of fuel injection for those of us raised on Q-jets and Carters.
I hope your friend's problem is easier to check out and fix than mine was. I think a good service manager at my dealer then could have helped me work through this problem a lot quicker (if not necessarily cheaper) than doing it myself. But on the bright side, I got to learn my fuel delivery system intimately.
