85 Ranger Throttle Response Issue

[ISX_15]

Down to the nitty gritty on getting this truck running, for some reason going from 0 - 100% throttle, the motor would hesitate, as if its not getting fuel, then rev up. However if im on the gas smoothly and slowly it does not happen. Could this be my accelerator pump? New fuel filters, etc.
Basically at full throttle, my fuel will cut out for less then a second, then rev up like normal.

 

[Curious Hound]

Sounds like a Microsoft carburetor. You go to wide open throttle and it says “Are you sure?”

I’m no carb expert. But isn’t there another part that is supposed to open when you get close to wide open throttle (secondaries?). Sounds like that isn’t adjusted right. So you’re not really getting wide open when you ask for it.

 

[ISX_15]

Sounds like a Microsoft carburetor. You go to wide open throttle and it says “Are you sure?”

I’m no carb expert. But isn’t there another part that is supposed to open when you get close to wide open throttle (secondaries?). Sounds like that isn’t adjusted right. So you’re not really getting wide open when you ask for it.

ill do a bit more research on it, im not a carb expert either. but what i do know there is a part that is supposed to supply extra fuel before going full throttle to eliminate that lag response. some part that puts fuel in the jets if im not mistaken.

 

[rusty ol ranger]

Classic acclerator pump symptoms.

It gives the engine that intial "jolt" of fuel when you quickly mat the pedal.

 

[ISX_15]

Classic acclerator pump symptoms.

It gives the engine that intial "jolt" of fuel when you quickly mat the pedal.

yup, would you agree that i should change that out?
steps to do so?

 

[rusty ol ranger]

yup, would you agree that i should change that out?
steps to do so?

Im not super familar with the feedback carbs, but if the pump is similar to the old 70s 2150s its directly on the front of the carb.

Pop the top of the carb off (6 screws), remove the pump (front of the carb body, youll look directly at it with air cleaner off, right side as your looking), undo 4 bolts, remove from throttle linkage, REPLACE PLUNGER BEHIND IT (thats why you pulled the top cover off the carb)...reassemble.

Its pretty easy

 

[Curious Hound]

Classic acclerator pump symptoms.

It gives the engine that intial "jolt" of fuel when you quickly mat the pedal.

 

[rusty ol ranger]

#4 in pic.

 

[Curious Hound]

I think this requires the OBD”0” scan tool. It looks like this.

 

[rusty ol ranger]

I think this requires the OBD”0” scan tool. It looks like this.



View attachment 46098

Best OBD there is

 

[ISX_15]

View attachment 46097

#4 in pic.

got it, ill get er done when i feel like it.
arizona heat can kiss my ass.

appreciate the help!

 

[franklin2]

If you still have the feedback carb, you probably have the accelerator pump with the vacuum line going to it. There was a control switch that applied vacuum or didn't apply vacuum, and that varied the output of the pump. If you want full output, just disconnect and plug the line. That's how I am running mine with no problems. When it applied vacuum, it redirected part of the fuel shot back to the pump inlet, reducing the amount of fuel that went into the engine. What a complicated mess that engine system is (was on my engine, I took it all off).

 

[ISX_15]

bump,,
i checked the accelerated pump, and there is fuel going into the jets, heres a video to get a general idea, this was from last year, gotten a lot worse now. You can hear it lean out in the beginning when hitting the throttle. Maybe a vacuum issue?

 

[ISX_15]

If you still have the feedback carb, you probably have the accelerator pump with the vacuum line going to it. There was a control switch that applied vacuum or didn't apply vacuum, and that varied the output of the pump. If you want full output, just disconnect and plug the line. That's how I am running mine with no problems. When it applied vacuum, it redirected part of the fuel shot back to the pump inlet, reducing the amount of fuel that went into the engine. What a complicated mess that engine system is (was on my engine, I took it all off).

oo yes i will give that a try, thank you

 

[kimcrwbr1]

Sounds like your classic dead spot on a cold engine? Does it improve after the engine comes up to temp? Is your electric choke working properly? I also put in a power valve that opens when the vacuum drops below 8.5hg. Sounds like a choke issue to me do you know what size main jets are in the carb?