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[ 14 posts ] |
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Rox Crusher
Official CCB Member
Joined: Sun Oct 10, 2010 5:36 pm Posts: 3980 Location: Roxborough Park, Colorado
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Stumble stumble
My new 351w now has 6000 kick ass miles on it. It runs very nice and I love the sound and feel.
Meanwhile, I continue to have an irritating stumble that I can't solve.
It only happens between 2900 - 3300 rpm. I have a digital tach which I have been watching very close and the stumble is very consistent and predictable within the range I mentioned. I'm not sure stumble is the right word. It's more like a series of dead spots within that range. When it "stumbles" it's kind of like the ignition goes completely dead for a nano-second and then right back to good.
I have good fuel pressure and the spark plugs look good. No codes on the computer either.
I thought it could be dead spots in throttle position sensors but I swapped in my spare tps sensor without solving the problem.
So, let's hear your ideas and recommendations and actions !
_________________ 1977 Sport, 351w OBDII EFI motor, 4R70W auto, 4:88 gears, ARB lockers, 3.5" suspension, 33" tires.
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Thu Feb 16, 2017 9:58 pm |
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landshark
Official CCB Member
Joined: Fri Oct 14, 2011 12:16 am Posts: 3942 Location: Denver, Wash Park Area
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Re: Stumble stumble
Coyote
_________________ 1976 Bronco "Green, Yellow, whatever", 1969 Bronco "Red", 1972 Bronco Stocker "Kind of Blue/Grayish"
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Thu Feb 16, 2017 10:05 pm |
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horseplay
Official CCB Member
Joined: Mon Jan 21, 2013 8:24 pm Posts: 408 Location: Grand Junction CO
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Re: Stumble stumble
Sounds like a possible pickup sensor
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Thu Feb 16, 2017 10:13 pm |
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Rox Crusher
Official CCB Member
Joined: Sun Oct 10, 2010 5:36 pm Posts: 3980 Location: Roxborough Park, Colorado
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Re: Stumble stumble
_________________ 1977 Sport, 351w OBDII EFI motor, 4R70W auto, 4:88 gears, ARB lockers, 3.5" suspension, 33" tires.
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Fri Feb 17, 2017 3:06 am |
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Digger
Official CCB Member
Joined: Fri Jun 21, 2013 8:53 pm Posts: 1276
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Re: Stumble stumble
Do you have a Knock Sensor?
_________________ Cummins R2.8 diesel, ZF5, AtlasII, HP44/BB9, ARBs, coiled / linked suspension, 37" KO2s, full cage, bumpers, etc. Build Thread:
Average 23.5 mpg, Best tank: 25.1 mpg
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Fri Feb 17, 2017 9:27 am |
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ZOSO
Moderator
Joined: Mon Nov 15, 2010 5:58 pm Posts: 3906 Location: Henderson, Co
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Re: Stumble stumble
_________________ Rob
74 Ranger EFI351w, 4r70w, ARB 5.13 9in, ARB 5.13D44, and a bunch of other goodies. Best of all the family memories.
04 Mustang Cobra, KenneBell 2.2 feeding a lot of boost on E85. Tire shredding machine
New project: 77 Bronco Ranger, body work and more body work.
Very little left of a 72 durango tan explorer sport
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Fri Feb 17, 2017 11:07 am |
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Rox Crusher
Official CCB Member
Joined: Sun Oct 10, 2010 5:36 pm Posts: 3980 Location: Roxborough Park, Colorado
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Re: Stumble stumble
It's all Explorer stuff.
So no knock sensor that I'm aware of.
_________________ 1977 Sport, 351w OBDII EFI motor, 4R70W auto, 4:88 gears, ARB lockers, 3.5" suspension, 33" tires.
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Fri Feb 17, 2017 11:39 am |
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horseplay
Official CCB Member
Joined: Mon Jan 21, 2013 8:24 pm Posts: 408 Location: Grand Junction CO
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Re: Stumble stumble
I would check the integrity of all the cam position assembly from connector to drive gear.
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Fri Feb 17, 2017 5:10 pm |
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ZOSO
Moderator
Joined: Mon Nov 15, 2010 5:58 pm Posts: 3906 Location: Henderson, Co
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Re: Stumble stumble
these are the same injectors that were on the 302 right? I wonder if you have a bad one somewhere.
_________________ Rob
74 Ranger EFI351w, 4r70w, ARB 5.13 9in, ARB 5.13D44, and a bunch of other goodies. Best of all the family memories.
04 Mustang Cobra, KenneBell 2.2 feeding a lot of boost on E85. Tire shredding machine
New project: 77 Bronco Ranger, body work and more body work.
Very little left of a 72 durango tan explorer sport
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Fri Feb 17, 2017 9:14 pm |
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Rox Crusher
Official CCB Member
Joined: Sun Oct 10, 2010 5:36 pm Posts: 3980 Location: Roxborough Park, Colorado
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Re: Stumble stumble
_________________ 1977 Sport, 351w OBDII EFI motor, 4R70W auto, 4:88 gears, ARB lockers, 3.5" suspension, 33" tires.
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Fri Feb 17, 2017 9:16 pm |
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ZOSO
Moderator
Joined: Mon Nov 15, 2010 5:58 pm Posts: 3906 Location: Henderson, Co
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Re: Stumble stumble
_________________ Rob
74 Ranger EFI351w, 4r70w, ARB 5.13 9in, ARB 5.13D44, and a bunch of other goodies. Best of all the family memories.
04 Mustang Cobra, KenneBell 2.2 feeding a lot of boost on E85. Tire shredding machine
New project: 77 Bronco Ranger, body work and more body work.
Very little left of a 72 durango tan explorer sport
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Fri Feb 17, 2017 9:18 pm |
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Rox Crusher
Official CCB Member
Joined: Sun Oct 10, 2010 5:36 pm Posts: 3980 Location: Roxborough Park, Colorado
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Re: Stumble stumble
_________________ 1977 Sport, 351w OBDII EFI motor, 4R70W auto, 4:88 gears, ARB lockers, 3.5" suspension, 33" tires.
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Fri Feb 17, 2017 9:25 pm |
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ZOSO
Moderator
Joined: Mon Nov 15, 2010 5:58 pm Posts: 3906 Location: Henderson, Co
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Re: Stumble stumble
If it does stick a timing light on each plug wire. Then also open the injector harness and do each injector. It should pick it up if it's one of those.
_________________ Rob
74 Ranger EFI351w, 4r70w, ARB 5.13 9in, ARB 5.13D44, and a bunch of other goodies. Best of all the family memories.
04 Mustang Cobra, KenneBell 2.2 feeding a lot of boost on E85. Tire shredding machine
New project: 77 Bronco Ranger, body work and more body work.
Very little left of a 72 durango tan explorer sport
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Fri Feb 17, 2017 9:29 pm |
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Rox Crusher
Official CCB Member
Joined: Sun Oct 10, 2010 5:36 pm Posts: 3980 Location: Roxborough Park, Colorado
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Re: Stumble stumble
Just getting back to planet Bronco after two long weeks of business travel.
I wiggled all the cam position wiring / connectors and problem remains.
Sounds like I need to check gear and then move on to plug wires and injector wires, etc
_________________ 1977 Sport, 351w OBDII EFI motor, 4R70W auto, 4:88 gears, ARB lockers, 3.5" suspension, 33" tires.
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Mon Mar 13, 2017 3:32 pm |
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