6.9L violent jerking during decel
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Freshman User
Joined: Jul 2010
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6.9L violent jerking during decel
I am working on an 87 F350 6.9L IDI with a 4 speed manual transmission that runs pretty good, except at lower speeds. Whenever trying to maintain speed or decel it starts jerking pretty violently, like you are blipping the throttle. Only way to get it to stop is to either press in the clutch or step on the throttle. I am at a loss, fuel pressure is good with about 5-7PSI. I am using an electric fuel pump (Airtex E8090)
Any suggestions appreciated!
Any suggestions appreciated!
Senior User
Joined: Dec 2010
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well me personaly i think that it could be air. what i mean by that is that you know how when you start to decel like goin down a hill and the truck is supposed to let out an deep kinda roar kinda like an exhaust break does. well im thinking that there is a flap underneath your air filter that works off the throttle the harder the throttle is pushed the mor air is let in the less push the less air because it doesn't need that much fuel to run at the idleing speed when you are decelling. take your air filter off and take the throttle that is under the hood and throw it like your flooring the motor and you will see and this flap work if it is propperly. im kinda new to working on diesel motors but i know quite a bit for age of 16 haha
Thread Starter
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Freshman User
Joined: Jul 2010
Posts: 26
Likes: 0
well me personaly i think that it could be air. what i mean by that is that you know how when you start to decel like goin down a hill and the truck is supposed to let out an deep kinda roar kinda like an exhaust break does. well im thinking that there is a flap underneath your air filter that works off the throttle the harder the throttle is pushed the mor air is let in the less push the less air because it doesn't need that much fuel to run at the idleing speed when you are decelling. take your air filter off and take the throttle that is under the hood and throw it like your flooring the motor and you will see and this flap work if it is propperly. im kinda new to working on diesel motors but i know quite a bit for age of 16 haha
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