Carter feedback carb & EEC-IV
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Mountain Pass
Joined: Mar 2011
Posts: 110
Likes: 0
From: Willow Grove, PA
Carter feedback carb & EEC-IV
'86 F150 with a 300 has a Carter YFA-1 feedback carb, model 7665S. I took it off and disassembled it per a rebuild kit's instructions. Currently the carb body, jets, float bowl, and accelerator pump housing are soaking in carb cleaner.
Unfortunately, I'm working on a "black box" in some regards. This isn't the first carb I've rebuilt, but I am at a loss for understanding how the feedback part of this feedback carb works. EEC-IV reads info from the O2 sensor & can manipulate the mixture of the carb via a 2-wire sensor??
Also, why does the feedback solenoid have four ports on the carb - what is it doing, essentially?
The dashpot makes no sense to me either. That has four wires and a rod which contacts the throttle ... why does that have four wires?! I'm really confused about this little thing
Unfortunately, I'm working on a "black box" in some regards. This isn't the first carb I've rebuilt, but I am at a loss for understanding how the feedback part of this feedback carb works. EEC-IV reads info from the O2 sensor & can manipulate the mixture of the carb via a 2-wire sensor??
Also, why does the feedback solenoid have four ports on the carb - what is it doing, essentially?The dashpot makes no sense to me either. That has four wires and a rod which contacts the throttle ... why does that have four wires?! I'm really confused about this little thing
Thread Starter
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Mountain Pass
Joined: Mar 2011
Posts: 110
Likes: 0
From: Willow Grove, PA
Hi Grubbworm,
thanks for the reply - actually I stumbled upon those documents before, hehe. Distributor-mounted ICM failed this summer which was my introduction to TFI-IV. (Unless I missed something in those documents, in which case, excuse me)
This solenoid, this is the one which confuses me. I started to follow the ports on the carb airhorn to see where they lead, but not long enough to discern how this solenoid affects mixture. Some other things have been causing confusion and arising questions in the saga of this carb rebuild. Namely:
The main jet looks way too huge for the metering rod. How can it be, that the rod never blocks off the main jet completely?
Someone's been inside this carb before. The float has a solder blob on it - remedy for a puncture, I guess. Another clue: there is a plastic spacer provided in the rebuild kit which was missing between the accelerator pump assembly and the pump housing.
Sorry to bombard with multiple inquiries, but here is one final question: I lost my reference point for where the idle mixture screw was. Where do I start as a baseline for this setting, and how do I adjust from there?
thanks for the reply - actually I stumbled upon those documents before, hehe. Distributor-mounted ICM failed this summer which was my introduction to TFI-IV. (Unless I missed something in those documents, in which case, excuse me)
This solenoid, this is the one which confuses me. I started to follow the ports on the carb airhorn to see where they lead, but not long enough to discern how this solenoid affects mixture. Some other things have been causing confusion and arising questions in the saga of this carb rebuild. Namely:
The main jet looks way too huge for the metering rod. How can it be, that the rod never blocks off the main jet completely?Someone's been inside this carb before. The float has a solder blob on it - remedy for a puncture, I guess. Another clue: there is a plastic spacer provided in the rebuild kit which was missing between the accelerator pump assembly and the pump housing.
Sorry to bombard with multiple inquiries, but here is one final question: I lost my reference point for where the idle mixture screw was. Where do I start as a baseline for this setting, and how do I adjust from there?
Cargo Master
Joined: Apr 2010
Posts: 2,936
Likes: 9
From: Acworth, GA
I ended up having my carburetor rebuilt professionally many years ago (right out of warranty). They screwed it up so bad that they had to take it to another professional (an actual professional carburetor rebuild shop) to do it properly. I also had it replaced with a new one a few years later by the Ford Dialogue Program. I have not had to fool with it since then (knock on wood). My truck still has all of the emission/ EEC IV/ TFI IV on it and functioning properly. It is not all the original parts that came on it from the factory, I have replaced some of them with new when they wore out, but the system is still in tact and working like a charm. If you plan on keeping your truck and working on it yourself, I would recommend getting a shop manual for it from Service Manuals, Owner Manuals, Wiring Diagrams, Service Bulletins - Helm Incorporated
It will prove to be the best investment you could make.
Also, if someone else has been inside the carburetor and not done it properly or screwed things up, I would save some money and take it to a professional carburetor shop. Buy a re-manufactured or rebuilt one from them and give them yours as a core. That way you can get a good core back. Just a thought.
On another note, I have rebuilt many carburetors before, just not this one.
It will prove to be the best investment you could make.
Also, if someone else has been inside the carburetor and not done it properly or screwed things up, I would save some money and take it to a professional carburetor shop. Buy a re-manufactured or rebuilt one from them and give them yours as a core. That way you can get a good core back. Just a thought.
On another note, I have rebuilt many carburetors before, just not this one.
Thread Starter
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Mountain Pass
Joined: Mar 2011
Posts: 110
Likes: 0
From: Willow Grove, PA
Grubbworm,
unfortunately I operate and live at the intersection of stubborn & frugal, and surely someone with a truck as splendid-looking as yours (yes, I looked through your album :P) can understand my bullheadedness. I wanted to buy the EEC-IV emissions booklet from Ford a few times, and I still might wind up doing it ... then again, I'm not dead-set on having the original equipment on this truck.
What I do want is a functioning & reliable 300. I did a full-on rebuild of my '96 Saturn, which I now have no questions about the condition of. I'd like to get the Ford to the same state within the next year.
Here's wishing I didn't flat-out remove the idle mixture screw. D'oh. Maybe if I poke around on the web long enough I'll find someone else's record of how many turns out from fully seated theirs was to start with.
Yep. D'oh.
unfortunately I operate and live at the intersection of stubborn & frugal, and surely someone with a truck as splendid-looking as yours (yes, I looked through your album :P) can understand my bullheadedness. I wanted to buy the EEC-IV emissions booklet from Ford a few times, and I still might wind up doing it ... then again, I'm not dead-set on having the original equipment on this truck.
What I do want is a functioning & reliable 300. I did a full-on rebuild of my '96 Saturn, which I now have no questions about the condition of. I'd like to get the Ford to the same state within the next year.
Here's wishing I didn't flat-out remove the idle mixture screw. D'oh. Maybe if I poke around on the web long enough I'll find someone else's record of how many turns out from fully seated theirs was to start with.
Yep. D'oh.
Cargo Master
Joined: Apr 2010
Posts: 2,936
Likes: 9
From: Acworth, GA
Grubbworm,
unfortunately I operate and live at the intersection of stubborn & frugal, and surely someone with a truck as splendid-looking as yours (yes, I looked through your album :P) can understand my bullheadedness. I wanted to buy the EEC-IV emissions booklet from Ford a few times, and I still might wind up doing it ... then again, I'm not dead-set on having the original equipment on this truck.
What I do want is a functioning & reliable 300. I did a full-on rebuild of my '96 Saturn, which I now have no questions about the condition of. I'd like to get the Ford to the same state within the next year.
Here's wishing I didn't flat-out remove the idle mixture screw. D'oh. Maybe if I poke around on the web long enough I'll find someone else's record of how many turns out from fully seated theirs was to start with.
Yep. D'oh.
unfortunately I operate and live at the intersection of stubborn & frugal, and surely someone with a truck as splendid-looking as yours (yes, I looked through your album :P) can understand my bullheadedness. I wanted to buy the EEC-IV emissions booklet from Ford a few times, and I still might wind up doing it ... then again, I'm not dead-set on having the original equipment on this truck.
What I do want is a functioning & reliable 300. I did a full-on rebuild of my '96 Saturn, which I now have no questions about the condition of. I'd like to get the Ford to the same state within the next year.
Here's wishing I didn't flat-out remove the idle mixture screw. D'oh. Maybe if I poke around on the web long enough I'll find someone else's record of how many turns out from fully seated theirs was to start with.
Yep. D'oh.
Although I did buy my truck new, I only took care of the mechanicals through the years. Now, I find it is time to address the whole truck in order to bring it back to a semi-new state.
Having worked as a mechanic before, I have found the shop manuals to be invaluable. That being said, I always buy a shop manual for any vehicle that I purchase.
And I do understand where you are coming from. If all of your EEC IV/TFI IV parts are not there or not working properly, you could always do a DSII conversion like many people here do.
Thread Starter
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Mountain Pass
Joined: Mar 2011
Posts: 110
Likes: 0
From: Willow Grove, PA
Shop manuals are incredible. I found a .pdf of a 1998 Saturn SL2 factory service manual, which was extremely helpful for certain niggilly little measurements like release fork travel, hydraulic lifter travel, valve guide protrusion above cylinder head surface ... that project was involved
Lucky me - found an online copy of instructions for a YFA rebuild, which specify to set the idle mixture screw 1 1/2 turns from being bottomed out. At least I have a baseline now.
Unfortunately, I'm not sure what's wrong with the pump lifter assembly - as it's hooked up now, when the throttle is rotated, the accelerator pump doesn't move until the last 1/8 of throttle travel. That's not how it was when I took it apart - it was linear
Gotta figure this out. Maybe there's a reason the spacer between the accelerator pump diaphragm & pump housing was left out
PS - long live Saturn. Watch out for stuck oil control rings - that's why they burn so much oil. '95 means you have an aluminum valve cover gasket - lucky. My plastic one took some sanding down to get level again. Leaked onto old clutch & ruined it (well, after 212k).
PPS - your truck is an example of owner excellence. Top stars
Lucky me - found an online copy of instructions for a YFA rebuild, which specify to set the idle mixture screw 1 1/2 turns from being bottomed out. At least I have a baseline now.
Unfortunately, I'm not sure what's wrong with the pump lifter assembly - as it's hooked up now, when the throttle is rotated, the accelerator pump doesn't move until the last 1/8 of throttle travel. That's not how it was when I took it apart - it was linear
Gotta figure this out. Maybe there's a reason the spacer between the accelerator pump diaphragm & pump housing was left outPS - long live Saturn. Watch out for stuck oil control rings - that's why they burn so much oil. '95 means you have an aluminum valve cover gasket - lucky. My plastic one took some sanding down to get level again. Leaked onto old clutch & ruined it (well, after 212k).
PPS - your truck is an example of owner excellence. Top stars
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Laughing Gas
Joined: Nov 2010
Posts: 924
Likes: 4
From: Johns Creek GA
I wish I had better advice to offer you...but it's been a while since I was inside my carburetor, and I don't remember all the details. The only picture I have of the lifter assembly (keeping in mind my carb isn't a feedback) is the one you've probably already seen:
For some reason I can't find the instructions that came with my kit (I'll look more tomorrow when it's light out), or I'd post the exploded view of the lifter in there. All I can suggest at this point is to be sure you've got all the various little clips and plates and thingamabobs in there, and in the right direction; I seem to recall that some of them could be put in upside down, and that could affect how things work.
What brand rebuild kit are you using? Mine was a GP Sorensen, and it was very satisfactory.
For some reason I can't find the instructions that came with my kit (I'll look more tomorrow when it's light out), or I'd post the exploded view of the lifter in there. All I can suggest at this point is to be sure you've got all the various little clips and plates and thingamabobs in there, and in the right direction; I seem to recall that some of them could be put in upside down, and that could affect how things work.
What brand rebuild kit are you using? Mine was a GP Sorensen, and it was very satisfactory.
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Thread Starter
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Mountain Pass
Joined: Mar 2011
Posts: 110
Likes: 0
From: Willow Grove, PA
Thanks for chiming in Dorsai; I have the same kit. Also I tried to reference both your photo and a youtube video of someone rebuilding a similar one, heh. Contrasting that against what I remember, something is definitely not right.
video
I have a copy of the GP Sorensen instructions that are floating about and teasing you. Rest assured: Chicago carburetor has a slightly different version of the GP Sorensen kit's instructions. Doesn't that just put your mind at ease?
Maybe something is amiss with my reassembly. Referencing this pdf, part 45 (spacer between the pump diaphragm & accel. pump housing) was not in the carb during disassembly. I put that in there on reassembly because the kit mentions it; do you remember if you have that spacer in there or not?
video
I have a copy of the GP Sorensen instructions that are floating about and teasing you. Rest assured: Chicago carburetor has a slightly different version of the GP Sorensen kit's instructions. Doesn't that just put your mind at ease?
Maybe something is amiss with my reassembly. Referencing this pdf, part 45 (spacer between the pump diaphragm & accel. pump housing) was not in the carb during disassembly. I put that in there on reassembly because the kit mentions it; do you remember if you have that spacer in there or not?
Laughing Gas
Joined: Nov 2010
Posts: 924
Likes: 4
From: Johns Creek GA
Maybe something is amiss with my reassembly. Referencing this pdf, part 45 (spacer between the pump diaphragm & accel. pump housing) was not in the carb during disassembly. I put that in there on reassembly because the kit mentions it; do you remember if you have that spacer in there or not?
Stupid question...your new pump and old pumps have the same length shaft, right?
Thread Starter
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Mountain Pass
Joined: Mar 2011
Posts: 110
Likes: 0
From: Willow Grove, PA
Not stupid question. Do you know how many times I've relearned the lesson of comparing new parts to old parts?
The depth of checking is shallow. No biggie to retreat a few steps
The depth of checking is shallow. No biggie to retreat a few steps
Post Fiend
Joined: Jul 2004
Posts: 8,786
Likes: 28
From: Northern California
The Feedback solenoid operates in an rapid ON/OFF way.
Power is applied to the solenoid and disengaged rapidly by electrical pulses. The EEC-IV controls the fuel mixture either lean or rich by how fast or slow the pulses are sent.
Power is applied to the solenoid and disengaged rapidly by electrical pulses. The EEC-IV controls the fuel mixture either lean or rich by how fast or slow the pulses are sent.
Thread Starter
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Mountain Pass
Joined: Mar 2011
Posts: 110
Likes: 0
From: Willow Grove, PA
Gotcha. I guess this affects vacuum in ports on the carb?
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I wasn't meticulous taking this carb apart, and am now paying for it I'm not sure that the pump lifter, metering rod, and accelerator pump are going to function at all correctly. Although I followed what the diagrams depict, this doesn't look right to me. It's as if a spacer or clip is missing, because nothing depresses the accelerator pump. Am I missing something obvious?
Also ... (here goes ...) I have a metal washer & a small rounded-edge collar that I can't remember where they came from. I know how dumb this is The rounded-edge collar looks like it'll sit well on the accelerator pump shaft, but this is a crapshoot unless someone knows.
_______________
I wasn't meticulous taking this carb apart, and am now paying for it
I'm not sure that the pump lifter, metering rod, and accelerator pump are going to function at all correctly. Although I followed what the diagrams depict, this doesn't look right to me. It's as if a spacer or clip is missing, because nothing depresses the accelerator pump. Am I missing something obvious? 
Also ... (here goes ...) I have a metal washer & a small rounded-edge collar that I can't remember where they came from. I know how dumb this is The rounded-edge collar looks like it'll sit well on the accelerator pump shaft, but this is a crapshoot unless someone knows.
Laughing Gas
Joined: Nov 2010
Posts: 924
Likes: 4
From: Johns Creek GA
Something's definitely not right there.
You're certain you have the right kit for your carburetor? I don't know about the feedback carb, but there are a number of variants of the standard version of the YFA, and many of them take different kits. If you've still got the metal tag attached to the outside of your carb, is that part number listed as one of the ones your kit applies to?
Other than that, all I can suggest is that you look very closely at the diagram in your kit, and verify that each and every piece shown in the diagram is present on the shaft of your accelerator pump, in the right order and in the right orientation. I think what you said is right, it looks like you're missing some kind of clip somewhere.
You're certain you have the right kit for your carburetor? I don't know about the feedback carb, but there are a number of variants of the standard version of the YFA, and many of them take different kits. If you've still got the metal tag attached to the outside of your carb, is that part number listed as one of the ones your kit applies to?
Other than that, all I can suggest is that you look very closely at the diagram in your kit, and verify that each and every piece shown in the diagram is present on the shaft of your accelerator pump, in the right order and in the right orientation. I think what you said is right, it looks like you're missing some kind of clip somewhere.