Weird starting problem - 4.9L
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New User
Joined: Sep 2003
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Weird starting problem - 4.9L
Truck: 90' F-150
Engine: I6 4.9L w/ Man. Trans. Fuel injected.
The only way to get it to start is to feather the throttle back n' forth until it starts (I know fuel injection, but it won't start without moving the throttle some, maybe TPS sensor?) and even then, you have to rev it past like 1000 rpm to keep it running, then after like 30 seconds of that, you can let go of the gas and it will continue idling like a champ. And after that, if you rev it, it runs solid - so it doesn't appear to be anything mechanical. It does this hot or cold, so I ruled out the IAC sensor. Also fuel pressure checks out ok without leaks as well as spark. Maybe the TPS? I've seen that sensor do some crazy things on GM cars, but it's not throwing the check engine light after we get it started. Can I still scan it and get a code if the Check engine light ain't on? Thanks in advance.
Engine: I6 4.9L w/ Man. Trans. Fuel injected.
The only way to get it to start is to feather the throttle back n' forth until it starts (I know fuel injection, but it won't start without moving the throttle some, maybe TPS sensor?) and even then, you have to rev it past like 1000 rpm to keep it running, then after like 30 seconds of that, you can let go of the gas and it will continue idling like a champ. And after that, if you rev it, it runs solid - so it doesn't appear to be anything mechanical. It does this hot or cold, so I ruled out the IAC sensor. Also fuel pressure checks out ok without leaks as well as spark. Maybe the TPS? I've seen that sensor do some crazy things on GM cars, but it's not throwing the check engine light after we get it started. Can I still scan it and get a code if the Check engine light ain't on? Thanks in advance.
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Joined: Jan 2003
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From: Magrath
I just bought a TPS from the local ford dealer for $30. If I recall right, it did not trigger any codes when the neighbor ran it on his little computer, but it didn't get any readings from it either.
Hope this helps, but for $30, I would just replace it and try it. Can't hurt.
Hope this helps, but for $30, I would just replace it and try it. Can't hurt.
Posting Guru
Joined: Oct 2002
Posts: 1,301
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From: Dededo, Guam
I would put my money on a bad TPS. Yours probably has dead spots in in and whenever you feather the throttle you revive it long enough for the computer to see it and start the truck. A good way to test it is to put a voltmeter on its connector. You should see a nice linear transition the more you open the throttle plates. Full open reads about 4.6 volts. BTW I like your avatar, that little character is hilarious on TV.
New User
Joined: Oct 2003
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Hey, PhatCaprice, my truck is doing the exact same thing. You mentioned you replaced the EVR or EGR solenoid controller. Would you be referring to the EGR Valve? If not, could you be more specific as to what the part was.
Senior User
Joined: Feb 2003
Posts: 141
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From: North East
Same here, I was thinking IAC or TPS. What exactly did you replace? I am having the exact same problem, I would love to get it fixed without lobbing parts at it till it's fixed.
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New User
Joined: Dec 2003
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TTT
Any word on what the fix was?? I'm having same issue. Starts fine cold, but when it's warmed up a bit it turns over 5 seconds before it will start.
Any word on what the fix was?? I'm having same issue. Starts fine cold, but when it's warmed up a bit it turns over 5 seconds before it will start.
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