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- Not a feedback carb - those have a solenoid at one of the corners - so no matter what the computer is doing, if anything, it can't be doing anything that affects this.
- The head has the pumped-air inlets blocked off, FWIW.
- That looks like a grey push-start TFI ICM on the distributor, so unless the computer is controlling timing, there's no advance. I'm under the impression that those were first used with EEC-IV systems, but don't actually know.
- Is that a (broken and unconnected) knock sensor to the right of the (non-machined) fuel pump boss in reply #7? Did the EEC-III systems use those? If not, to have a knock sensor then the block is from at least an '87.
- The valve cover has the mounting bracket at the rear for the TAD, TAB, and EGR solenoids, though none of them are there - did EEC-III have those?
A clear, readable photo of the entire vacuum diagram there to the left of the hood latch would clear up some of those issues.
A guess: this is an 87+ donor engine with the TFI-mounted distributor, but a log intake & exhaust and an aftermarket (non-feedback) carb, and a partially wired up '86 ECU. Dr Frankenstein may not have put any effort into tuning the carb (jets, whatnot). If the computer isn't doing a passable job of controlling timing, then maybe swapping out the dist and ICM with a DSII ignition system (or equivalent, as previously mentioned) would be better - or whatever the aforementioned 'computer delete' thread recommends. The computer might still be controlling important things like a fuel pump relay, which would complicate just removing it; an '86 engine-to- ECU wiring diagram would be useful, or even just the '86 ECU pin list.
How did '83 or earlier systems control the EGR valve - some mix of temperature & vacuum doohickeys?
Ok I hate to pick this apart but here goes.
That dose look like a feedback carb just the "feed back" parts have not been taken off the old carb and installed on this one.
You can see the plate held on with 2 screws where the solenoid would bolt to.
Also if you look at the throttle shaft where the red cap is, end of throttle shaft, is where the TPS would bolt to.
Now being the carb looks new I would keep it but can cause a problem with timing down the road.
That distributor is used on the feed back system and the computer controls all timing adjustments.
Now as I said if the computer sees a fault with say a bad or missing sensor the computer goes into "limp" and locks the timing so no adjusting at all and that makes for low power and bad MPG.
To fix this get a HEI distributor from Ebay and drop it in and use the wire that power the coil now.
Now this little problem down the road with the carb you have now is it dose not have a vacuum port to the distributor for vacuum advance and this can hurt a little with power but mostly MPG.
Once the distributor is changed out and the timing can be adjusted by mechanical advance that should help power & MPG and we can see what you get for MPG and go from there.
Oh you dont believe me about the timing and that it is locked put a timming light on it and see what you get at idle and at 2500 to 3000 RPM.
I bet it will be what idle is and that is not good.
Dave ----
Oh 1 last thing throw out the gas filter as it is a fire starter.
The glass between the metal ends breaks and gas sprays all over a hot engine and POOF FIRE!
Get one of the normal plastic fuel filters you get from the auto parts store as you can see fuel in them if that is why you bought that one and they will not melt unless it gets in fire.
Dave ----
Ok I hate to pick this apart but here goes.
That dose look like a feedback carb just the "feed back" parts have not been taken off the old carb and installed on this one.
You can see the plate held on with 2 screws where the solenoid would bolt to....
Many of the aftermarket YFA replacements have that plate - it was used for things other than a feedback solenoid by makers other than Ford. For example, some AMC's had these things:
Leaving the blank plate bolted in place makes it a suitable replacement for applications that don't use some accessory there, feedback solenoid or otherwise.
[QUOTE=BlueWaitNoGreen;21655066]Many of the aftermarket YFA replacements have that plate - it was used for things other than a feedback solenoid by makers other than Ford. For example, some AMC's had these things:
The Ebay carb I got for my 81 F100 did not have that plate and none of my 232 / 258 AMC's had that plate on the carbs either.
I would think for carbs marked "altitude compensator" it was doing the same thing as the Ford carb, making the carb rich or lean.
I thought the plate was just for shipping to keep crud out of the port.
Lets see what happens with the HEI distributor for power and MPG as it gives us things we can work with and no computer.
If you want more information on this feedback swap go up to the 80 - 86 truck area as there is a lot of information on it.
Dave ----
I have installed the HEI distributor and it definitely runs differently. I can't seem to get the idle to be less rough through the timing, but I'll take a look at that once I'm able to hook up the vacuum advance. Now the question is, do I need a different carb or does this one just need some different fixtures for the vacuum advance? More photos included.
You don't have to change the carb, it would not be cost effective, I never did.
It would not have been my first choice, I would have went with an older style carb, but I would use what you have.
I don't believe you current carb has ported vacuum as an option. This is an issue for some people.
As far as how rough it runs, it might be a good idea to do a compression check to see if you have any dead cylinders.
It doesn't have to have good compression, numbers in the 80's will still work OK.
You don't have to change the carb, it would not be cost effective, I never did.
It would not have been my first choice, I would have went with an older style carb, but I would use what you have.
I don't believe you current carb has ported vacuum as an option. This is an issue for some people.
As far as how rough it runs, it might be a good idea to do a compression check to see if you have any dead cylinders.
It doesn't have to have good compression, numbers in the 80's will still work OK.
I am with Jim on doing a compression test so you know that all holes are good to start with because if you have a low or dead hole it will never run smoothly.
As for ported or manifold I like ported but that is me but I tell people for you to know what your motor like is try it both ways ............... if you can.
Lets test the ports bt I think that is a feed back carb with out the solenoid where the plate is up top.
That RED cap up at the top / air filter base is the hot air choke asst. fresh air inlet. Keep plugged
The BLACK large cap to the right is a float bowl vent that went to the charcoal canister under the battery. Keep plugged
I see a BLACK (lower left) and a RED (lower right) caps. You will need to start the motor and pull each cap off and see if you have vacuum on either one.
Now if 1 dose not have vacuum at idle bring the RPM up to say 2000 RPM and see if you now get vacuum.
If you now have vacuum that would be ported vacuum and what I run to the hose to the distributor from.
If you dont have ported vacuum it is not the end of the world, just dont run it with vacuum but may want to check timing curve.
Do the compression test and vacuum check and get back to us.
Dave ----
Snip... The BLACK large cap to the right is a float bowl vent that went to the charcoal canister under the battery. Keep plugged
The float bowl does need to be vented, I am not sure if there's another vent. Try running with the large black cap removed.
Make sure the hot air choke tube is drawing hot air, or to say, look at where the tube connects to the manifold. It's usually rusted off and hanging in the wind, drawing cold air. You can wire the choke full open for testing.
I never found a ported vacuum source on my feedback carb, I just used a connection near the throttle plate and is seem to work OK.
Snip... The BLACK large cap to the right is a float bowl vent that went to the charcoal canister under the battery. Keep plugged
The float bowl does need to be vented, I am not sure if there's another vent. Try running with the large black cap removed.
Make sure the hot air choke tube is drawing hot air, or to say, look at where the tube connects to the manifold. It's usually rusted off and hanging in the wind, drawing cold air. You can wire the choke full open for testing.
I never found a ported vacuum source on my feedback carb, I just used a connection near the throttle plate and is seem to work OK.
Good luck, Jim
The carb is still vented so you dont need to run without that cap and if you do you may get a gas fume smell.
All modern carbs are vented in the air flow opening of the carb so if the needle / seat did not stop the gas flow the gas then goes down the carb throat flooding out the motor killing it so you have to check why and fix it.
Sorry to say I dont have any pictures of this bowl vent but pull off your air filter and look at the air inlet and you will see a tube coming from the bowl area that is the vent.
And pre-smog carbs did not have that external vent on the bowl so how do you think that vented?
His carb did not look like it has any of the hot air choke parts and why the cap at the air horn. I think the hot side had a dash pot blocking where the tube went to the choke housing.
Yes feed back carbs DO NOT have ported vacuum but I also see some ports on his carb that might be ported and why I said he should test them to see and if not no big deal ATT.
Dave ----
Here a photo showing the vent tube you referenced.
This is a feedback carb, 1985 I believe, pre TPS.
You can see the place i connected the distributor vacuum advance.
The orange tube is the "fresh filter air" for the hot air choke, which loops though the manifold and out the top of the manifold, entering the carb choke next to the orange tube.
On a non feedback carb, the entry point for the hot air choke is on the other side of the carb.
The electric assist, (see wire on choke) only works when it is warm, like 70 degrees.
This is supposed to pull the choke faster in the summer time, and to help pass emissions testing.
The point is ... if the hot air choke isn't working as it was intended, you will be driving around with the choke partially ON... Until the air around the carb hits 70 degrees.
Jim
I will do the compression test and check those ports for vacuum and get back to y'all. Luckily enough, my father in law has a lot of auto specific tools.
A true feed back carb, maybe factory? dose not have a ported vacuum nipple but I see yours and his have more nipples and why I wanted him to test them.
He like you might get lucky and have a ported vacuum nipple to use for distributor vacuum.
My 81 F100 non-feedback carb has the hot air coming in on the other side but yes the hot air side should be hooked out so the choke works right.
Because I run EFI exhaust manifolds there is no hot air tube hook up so I had to take copper tubing and wrap it around the manifold and then cover with header wrap to trap the heat to get my hot air asst. choke to work right.
Dave ----
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