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 !
Stumble stumble
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Rox Crusher
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Stumble stumble
1977 Sport, 351w OBDII EFI motor, 4R70W auto, 4:88 gears, ARB lockers, 3.5" suspension, 33" tires.
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landshark
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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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horseplay
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Re: Stumble stumble
Sounds like a possible pickup sensor
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Rox Crusher
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Re: Stumble stumble
horseplay wrote:Sounds like a possible pickup sensor
Cam position sensor ?
1977 Sport, 351w OBDII EFI motor, 4R70W auto, 4:88 gears, ARB lockers, 3.5" suspension, 33" tires.
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Digger
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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: http://www.coloradoclassicbroncos.com/viewtopic.php?f=3&t=5420
Average 23.5 mpg, Best tank: 26.3 mpg
Build Thread: http://www.coloradoclassicbroncos.com/viewtopic.php?f=3&t=5420
Average 23.5 mpg, Best tank: 26.3 mpg
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ZOSO
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Re: Stumble stumble
Rox Crusher wrote:horseplay wrote:Sounds like a possible pickup sensor
Cam position sensor ?
That doesn't do much. But it may be a possibility or the crank position sensor.
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
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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Rox Crusher
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Re: Stumble stumble
It's all Explorer stuff.
So no knock sensor that I'm aware of.
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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horseplay
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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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ZOSO
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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
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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Rox Crusher
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Re: Stumble stumble
ZOSO wrote:these are the same injectors that were on the 302 right? I wonder if you have a bad one somewhere.
Nope, this are different injectors. Refurbished 17lbs with returnless rail set up
1977 Sport, 351w OBDII EFI motor, 4R70W auto, 4:88 gears, ARB lockers, 3.5" suspension, 33" tires.
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ZOSO
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Re: Stumble stumble
Rox Crusher wrote:ZOSO wrote:these are the same injectors that were on the 302 right? I wonder if you have a bad one somewhere.
Nope, this are different injectors. Refurbished 17lbs with returnless rail set up
hmm. is it under load or does it do it free revving?
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
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
-
Rox Crusher
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- Joined: Sun Oct 10, 2010 4:36 pm
Re: Stumble stumble
ZOSO wrote:Rox Crusher wrote:ZOSO wrote:these are the same injectors that were on the 302 right? I wonder if you have a bad one somewhere.
Nope, this are different injectors. Refurbished 17lbs with returnless rail set up
hmm. is it under load or does it do it free revving?
I believe it does it free revving. I'll confirm it in the morning in front of my Prius neighbor's house
1977 Sport, 351w OBDII EFI motor, 4R70W auto, 4:88 gears, ARB lockers, 3.5" suspension, 33" tires.
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ZOSO
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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
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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Rox Crusher
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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
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.