Carburetor Help, please :)
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Carburetor Help, please :)
Hello, I am looking for some help or direction. I have a stock untouched (except for some smog errors, blocked inputs) 1986 ford F150 straight six, four point nine liters. Note: At the door opening it says it is a 9/1985, I bought it new. The carburetor, single barrel, and what looks like a solenoid on the right side, and a pot on the butterfly shaft. This carburetor has a tag on it that reads: motorcraft – E5IE – UA – A – 5 – D – 19. <O
</O
My fuel mixture is way too rich especially at low RPM, most likely due to the smog ports blocked. I am looking for a place where I can buys smaller jet sizes, gaskets, explanation of the solenoid function.<O</O
Thank you<O</O
logmode <O</O
</OMy fuel mixture is way too rich especially at low RPM, most likely due to the smog ports blocked. I am looking for a place where I can buys smaller jet sizes, gaskets, explanation of the solenoid function.<O
</OThank you<O
</Ologmode <O
</O
Fleet Mechanic
Joined: Jun 2010
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From: North Carolina
Welcome to the site. First, I would think that if you bought it new in 1986, and it only recently started running rich, then installing smaller jets in the carb probably isn't the best way to tackle the problem. After all, the jets it has have presumably worked fine for decades.
Your truck came from the factory with what is called a feedback carb (diagram below), it is partially controlled by your engine control computer. The solenoid you mention on the drivers side front of the carb is computer controlled. It's job is to vary the air/fuel ratio according to engine speed and readings received from the O2 sensor threaded into the exhaust manifold. It is a simple solenoid with only a few different set duty cycles (not a continuous range of fine tuning).
The "pot on the butterfly shaft" I am unclear about, but you may be referring to the Idle Speed Control or the Throttle Position Sensor (pictured below).
If you are suddenly running rich, you might consider as a first step replacing the O2 sensor and/or querying your engine control computer to see if/what problem codes it throws out at you (OBD1 system).
Your truck came from the factory with what is called a feedback carb (diagram below), it is partially controlled by your engine control computer. The solenoid you mention on the drivers side front of the carb is computer controlled. It's job is to vary the air/fuel ratio according to engine speed and readings received from the O2 sensor threaded into the exhaust manifold. It is a simple solenoid with only a few different set duty cycles (not a continuous range of fine tuning).
The "pot on the butterfly shaft" I am unclear about, but you may be referring to the Idle Speed Control or the Throttle Position Sensor (pictured below).
If you are suddenly running rich, you might consider as a first step replacing the O2 sensor and/or querying your engine control computer to see if/what problem codes it throws out at you (OBD1 system).
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Jets?
Thank you for the welcome, and your very well done answer, very helpful.
But there has been a temporary change to the intake manifold, all exhaust input have been blocked for testing purposes and I need to temporarily rejet the carburetor for testing purposes. Do you know where I can get the jets?
But there has been a temporary change to the intake manifold, all exhaust input have been blocked for testing purposes and I need to temporarily rejet the carburetor for testing purposes. Do you know where I can get the jets?
Fleet Mechanic
Joined: Jun 2010
Posts: 1,251
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From: North Carolina
Thank you for the welcome, and your very well done answer, very helpful.
But there has been a temporary change to the intake manifold, all exhaust input have been blocked for testing purposes and I need to temporarily rejet the carburetor for testing purposes. Do you know where I can get the jets?
But there has been a temporary change to the intake manifold, all exhaust input have been blocked for testing purposes and I need to temporarily rejet the carburetor for testing purposes. Do you know where I can get the jets?
Lead Driver
Joined: Jul 2009
Posts: 6,477
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From: Sheffield, AL
Welcome to the forum, logmode!
It sounds like you are doing something other than trying to get the engine "back to stock". There are several things which might account for the "way to rich" fuel mixture.
What are you testing for?
It sounds like you are doing something other than trying to get the engine "back to stock". There are several things which might account for the "way to rich" fuel mixture.
What are you testing for?
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Elder User
Joined: Jun 2010
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From: Casper, Wyoming
Carter YF series carbs were used for many years on many vehicles, so there are jets available. I can't recommend any specific source myself through experience. But here is one source I found in seconds using Google: Carter YF YFA Main Jets
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Hi ,
Ok I am now tiring to pulling out codes from the EEC-lV. I hooked up one wire from the signal return to the self test input. Then I connect a led from battery positive and self test output. I push down the clutch and turn on the ignition (KOEO). The LED lights up and stay lit no blinks at all. When I turn off the ignition 4 seconds later the LED turns off. Does anyone know what I should do?
Thank you logmode
Ok I am now tiring to pulling out codes from the EEC-lV. I hooked up one wire from the signal return to the self test input. Then I connect a led from battery positive and self test output. I push down the clutch and turn on the ignition (KOEO). The LED lights up and stay lit no blinks at all. When I turn off the ignition 4 seconds later the LED turns off. Does anyone know what I should do?
Thank you logmode
Fleet Mechanic
Joined: Jun 2010
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From: North Carolina
Here's some pretty good instructions: Fuel Injection Technical Library » How To Run a Self-Test
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Galendor thx for the jets info.
I look at the self test info, and found that those directions are different from the other I found. Instead of connecting sti to sig-rtn, yours say to connect the sti to battery negative which is the same thing. So why would the light not blink?
I look at the self test info, and found that those directions are different from the other I found. Instead of connecting sti to sig-rtn, yours say to connect the sti to battery negative which is the same thing. So why would the light not blink?
Fleet Mechanic
Joined: Jun 2010
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From: North Carolina
I don't agree that Signal-Return (SIG-RTN) and Self-Test IN (STI) are the same thing. They are different connectors on the testing harness so I think they may be different.
I recommend trying it your way, then turn truck off for a minute and try it following the fordfuelinjection directions. If you don't get any blinking lights using either method, then it may be time to begin investigating wires and components using a volt meter or test light. Your problem could be as simple as a dirty connection at the test harness, or as complex as an empty hole where your engine control computer should be.
I recommend trying it your way, then turn truck off for a minute and try it following the fordfuelinjection directions. If you don't get any blinking lights using either method, then it may be time to begin investigating wires and components using a volt meter or test light. Your problem could be as simple as a dirty connection at the test harness, or as complex as an empty hole where your engine control computer should be.
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Hi
Thank you for your response. I have been thinking and thought it may be that it’s not going into test mode. That is if the test light on the test plug is the same circuit as the service light in the dash, then the reason it is on may be that it’s in normal mode and telling me that there is trouble. Well ok then I will test it again with the battery negative.
Oh i did not say that the (sig-rtn) and the (sti) are the same thing. But i did say that the (sig-rtn) and Battery (negitive) are the same thing.
Thank you for your response. I have been thinking and thought it may be that it’s not going into test mode. That is if the test light on the test plug is the same circuit as the service light in the dash, then the reason it is on may be that it’s in normal mode and telling me that there is trouble. Well ok then I will test it again with the battery negative.
Oh i did not say that the (sig-rtn) and the (sti) are the same thing. But i did say that the (sig-rtn) and Battery (negitive) are the same thing.
Last edited by logmode; Nov 8, 2012 at 09:30 AM. Reason: forgot to say
Fleet Mechanic
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From: North Carolina
My mistake, I'm sorry.
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No my fault, I am sorry for the bad explanation.
Well I used the battery ground instead of the signal return and now it works. Him, I don’t understand. Does that mean signal return is not the same as Ground, or is something wrong with signal return circuit?
Well I used the battery ground instead of the signal return and now it works. Him, I don’t understand. Does that mean signal return is not the same as Ground, or is something wrong with signal return circuit?