5.0 motor help
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Freshman User
Joined: Aug 2003
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5.0 motor help
Have a 89 f150 with a problem. It has a 5.0 automatic. Truck starts and runs ok until it hits operating temperature; then motor starts to break up. Have checked egr and it is ok; have checked pvc and distributor all ok.
Any ideas on what to look for next
Thanks, Tom
Any ideas on what to look for next
Thanks, Tom
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Freshman User
Joined: Aug 2003
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5.0 motor help
By break up I mean a bad miss. Feels like not all spark plugs firing. Blowing dark smoke out of tail pipe. Stalls/ can smell cat converter cooking. Until it reaches operating temperature truck runs ok; once hot the truck runs like cr*p
Tuned
Joined: Jan 2003
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5.0 motor help
Check your O2 sensor. Your truck only uses it in closed loop which occurs at full warm up. While it is warming it is in open loop and uses all the other sensors to determine a pre-programmed injector duration, but the O2 sensor does not take over until it is warmed up.
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Freshman User
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5.0 motor help
Not o2 sensor. Have also eliminated egr and pvc valve. Problem only occurs after truck has reached operating temperature. Truck runs very rough, stalls at idle. Seems to be getting a very rich mixture. Cat converter appears to be overheating,(excess fuel being dumped form cylinders?)
Any fresh ideas??
Thanks Tom
Any fresh ideas??
Thanks Tom
Post Fiend
Joined: Nov 2002
Posts: 9,987
Likes: 7
From: Memphis, TN
5.0 motor help
Read this thread and post the code definitions.
Also, see if you have gasoline in the red vacuum line to the fuel pressure regulator.
Also, see if you have gasoline in the red vacuum line to the fuel pressure regulator.
Freshman User
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I had similar problem ended up being fuel pump losing pressure after running engine for 15 or so minutes
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New User
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Check your MAP sensor on the firewall by the heater box. Check the vacuum connections to it also.
I had a similar problem and found a bad hose going to the MAP, it would run good the first few minutes then start blowing black exhaust out and running rough.
I had a similar problem and found a bad hose going to the MAP, it would run good the first few minutes then start blowing black exhaust out and running rough.
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I'd check your O2 sensor again...how did you check it? They are only good for about 50K mi also.
Then maybe the coolant temp sender for the computer. I believe it is a little black thing with 3 wires running to it.
Then maybe the coolant temp sender for the computer. I believe it is a little black thing with 3 wires running to it.
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