89 F150 stalls when warm
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89 F150 stalls when warm
I've read a number of threads on here that appear to be similar problems, but few of them actually follow up with what the solution was so I'm starting a new thread.
(89 F150 300 CID)
Truck starts and runs fine when it's cold and at running temp for a while. After about 15 minutes of driving or idoling - it sputters and dies. If it does it while driving, I can keep my foot in it in gear (5 speed) and it will compression roll for 5 or 10 seconds and usually power up again suddenly.
If it stalls at idol, it will usually restart and idol fine for a while, but once the problem starts it will continue to do it intermittently and will often get gradually worse until I let the truck cool down completely. It does not increase in severity or frequency under load (towing etc) or at higher RPMs. It does appear to do it more in the summer as I've seldom had the problem in colder temperatures. It has been doing it for about 3 years - mechanics can't recreate it when I've taken it to them so they can't diagnose / fix it.
I have replaced the TFI and recently used liquid air to cool the TFI off when it was having an "episode" but it made no difference. It has dual tanks, but it does it regardless of the tank I'm on and the fuel pumps have always engaged and continue to engage even when restarting during an "episode." I haven't checked fuel pressure nor have I tested the relays since the problem is intermittent so I'm assuming those test would be unreliable.
Any thoughts - similar expereinces - solutions???
(89 F150 300 CID)
Truck starts and runs fine when it's cold and at running temp for a while. After about 15 minutes of driving or idoling - it sputters and dies. If it does it while driving, I can keep my foot in it in gear (5 speed) and it will compression roll for 5 or 10 seconds and usually power up again suddenly.
If it stalls at idol, it will usually restart and idol fine for a while, but once the problem starts it will continue to do it intermittently and will often get gradually worse until I let the truck cool down completely. It does not increase in severity or frequency under load (towing etc) or at higher RPMs. It does appear to do it more in the summer as I've seldom had the problem in colder temperatures. It has been doing it for about 3 years - mechanics can't recreate it when I've taken it to them so they can't diagnose / fix it.
I have replaced the TFI and recently used liquid air to cool the TFI off when it was having an "episode" but it made no difference. It has dual tanks, but it does it regardless of the tank I'm on and the fuel pumps have always engaged and continue to engage even when restarting during an "episode." I haven't checked fuel pressure nor have I tested the relays since the problem is intermittent so I'm assuming those test would be unreliable.
Any thoughts - similar expereinces - solutions???
Last edited by '89F150Spokane; Sep 15, 2009 at 07:49 PM. Reason: add pic and signature
Senior Member
Joined: Nov 2006
Posts: 5,495
Likes: 7
From: Memphis, TN 38135, USA, Earth
Get a Haynes manual & a cheap digital multimeter, and test the ignition system. Try chilling the coil when it stalls, but test it by Haynes before replacing it.
A fuel pressure test wouldn't hurt, and upgrading the relays is CERTAINLY a good mod.
BTW
It's "idle", and "idling". An "idol" is something that's worshipped.
A fuel pressure test wouldn't hurt, and upgrading the relays is CERTAINLY a good mod.
BTW
It's "idle", and "idling". An "idol" is something that's worshipped.
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Thanks, Steve - I knew the idol / idle thing didn't look right and I'm certainly not worshiping anything about my truck right now.
I'll replace the relays and do the tests if the relays don't solve the problem. And - I'll post the results. Thanks again.
I'll replace the relays and do the tests if the relays don't solve the problem. And - I'll post the results. Thanks again.