3.8 v6 Carb Questions, Options?

Topic: 3.8 v6 Carb Questions, Options? (Read 3264 times) previous topic - next topic

3.8 v6 Carb Questions, Options?

November 20, 2021, 11:33:45 PM

So i had some time to go work on the tbird today, hoping to swap the carb and get this thing driving reliably, but got stopped by some differences between the one that came with the car and the remanufactured replacement i bought for it.

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The replacement has a mixture solenoid on the back that mine doesnt, i was expecting that to be there on the original and bought the replacement on the assumption it would be. We all make mistakes sometimes and i should have known better than to buy something without being certain about it.
The original one has no bucktag for some reason and the sticker on it was too faded to make out any numbers. There wasnt any numbers stamped on it i saw but it was dirty and dark in there i could have missed something.
It may not be original for all i know.
There is also a problem with the linkage being different between them, the replacement didnt have the kickdown stuff on it and the original carb parts are to be honest looking in such poor condition i dont believe i could get away with swapping them over to make it work.
The replacement one has what looks like a nice hairline crack going thru most of the airhorn(not casting flashing or anything like that) so now im in doubt about that as well.

Any advise on what course should i proceed with here on this mess?

Send out the original one that came with the car to get rebuilt since it likely needs more than just gaskets?

Purchase another carburetor and try again?

I only bought the other as it was advertised specifically for the 3.8, so many choices out there for these 2150 carbs for less than 100 bucks but they were much larger and didnt want to get into making things work i wanted bolt on and go for now.
The only other one i was eyeballing was a pricey holley im reluctant to shell out the money on yet.

Re: 3.8 v6 Carb Questions, Options?

Reply #1 – November 21, 2021, 11:11:29 PM

Pic of the linkage difference.

What the original looked like on the car.

Now, after doing a little searching i find out that the carburetor has to match the transmission of the car when searching for replacement, since these AOD cars have different throttle valve linkage that sometimes cant just swap over.
I never saw anybody mention the trans in their listings.
Ugh, Wish i knew an oldhead local mechanic i could bother about this, i get the feeling this is stuff they would be more familiar with and could point me in the right direction.

Re: 3.8 v6 Carb Questions, Options?

Reply #2 – December 14, 2021, 12:34:46 PM

After going thru 2 carbs that dont work, the second one looked like it was rebuilt with a can of spraypaint, im just going to rebuild the old one when im on vacation at the end of the month.
Atleast my replacement baseplate came with new gaskets for everything instead of just the base.

Re: 3.8 v6 Carb Questions, Options?

Reply #3 – December 28, 2021, 05:13:45 AM

Nice, no slots to remove the choke so gotta remove the whole thing. Thats gonna be fun putting back together.

Wonder what im gonna find inside.

:Enhance:

Low mileage aint always a good thing.
Well, guess i can see why it wouldnt run right now.
When i removed the carb i saw rust and silt in the fuel line and figured the filter probably caught most of it. Nah.
Atleast nothing was seized and it came right apart for the venturi stuff. The air screws are covered in crud and im not going to be able to get them out untill i clean it enough to disassemble the covers and clean them with spray.
Now tomorrow i gotta find some dip and hope i can get this cleaned and back together before my vacation ends. Ill have to go over the tank, pump and lines later, i have a new pump and waiting for a tank, i hope its correct. The carb rebuild kit i got might not be correct either(it was advertised as such) after comparing parts in them, hope thats not going to be an issue.
Got other stuff i promised i would do while i had off so i got to get to scanning that as well.
Busy busy busy.

Re: 3.8 v6 Carb Questions, Options?

Reply #4 – January 02, 2022, 06:33:53 PM

So im sitting here waiting for another carb to arrive and had some thoughts and observations.

First, since the carb tag is missing i didnt know what kit is correct without disassembling it and ordered one based on the year, the kit was federated kit #10852. Its not correct, the power valve and gasket is wrong for the carb that came with the car. It may work for one of the other carbs i have so its not a total loss yet.
What i do not know is if you can figure out what kit you need by the part number on the airhorn/base gasket, since its the only thing i see that has an actual part number on it.
Im holding off on its rebuild untill im sure but its getting fixed regardless.

Second, according to the literature i have my carb that came with the car, if original, should have had a spring on the float shaft but doesnt.

Not sure whats going on there.
I dont think the kit came with one either.

Third, bought a new gas tank to replace the original but not going to throw that or the new pump in right away untill i fully sort out under the hood and empty the tank. Im going to install another inline glass filter before the fuel pump to observe whats flowing thru it. Got to paint that so it looks all nice and pretty first anyway. It has no baffle in it but i dont know if the carbed ones are supposed to, im not familiar with that stuff and i couldnt find anything noting those differences. I wont know untill i yank out the original.

Sucks my vacations over, but hopefully ill be driving before the gas goes stale.

Re: 3.8 v6 Carb Questions, Options?

Reply #5 – April 08, 2022, 06:49:34 PM

So got the car running last week with a new carb.
Unfortunately it idles so high(not high enough to sound like its going to explode but revved up indeed) that when in gear it pushes on the brakes at every stop making staying put at a red light a c. After shutting down the car and restarting it idles relatively what i would consider "normal"(i didnt hook up a tachometer to it yet to verify rpms, i have something i hope will work for that) and put it in gear and it will put along like its supposed to, untill i press down on the gas pedal and then the idle stays up and it builds up speed on its own. Its not something stuck in the carb holding the throttle open a crack i had that happen to me before because of a spray can straw falling down in there which was enough to completely overpower the brakes on it.

This is all when up to operating temperature, i havent tried to do what the emissions sticker said yet about idle since i didnt have a tach to verify rpms but i think this is related to something i did.

When i was there i tried to check the throttle cable and its not sticking and binding but my time there ran out so im going back, hopefully tomorrow, to figure this out.
The choke definately works but i made no adjustments to it out of the box, the idle soleniod plunger might not be correctly adjusted. It also might be sticking but im eliminating everything else before i start thowing parts at it.

I cant find anything in my literature about adjusting those things so ill just
Any input from those more familiar with carb stuff would be appreciated.

Re: 3.8 v6 Carb Questions, Options?

Reply #6 – April 14, 2022, 01:02:14 AM

There are a lot of variations of the 2150 2-V carburetor. If you can post pictures of all sides of it maybe I can help figure out what you have.
Does the car have a mechanical fuel pump?

Re: 3.8 v6 Carb Questions, Options?

Reply #7 – April 15, 2022, 02:16:57 PM

The throttle kicker shown in your picks looks like it is for a non A/C car.
This is probable an anti dieseling solenoid, needed with a mechanical fuel pump.
It should extend with key on and is adjusted with a warmed up engine for curb idle. Check fan shroud decal for details.

The 83 EVTM shows the A/C throttle kicker solenoid is a vacuum valve. so the kicker would be vacuum operated.

Re: 3.8 v6 Carb Questions, Options?

Reply #8 – April 15, 2022, 02:48:14 PM

Have you looked at the throttle position while the engine is racing?
The cold engine high rpm cam can run the rpm up pretty high. It is a three step cam.
The vacuum pull down should move it off the highest step when the engine starts and you step on the gas to remove the throttle return spring tension.
The electric choke should move it through the next two steps until it drops off the cam.

Re: 3.8 v6 Carb Questions, Options?

Reply #9 – April 15, 2022, 03:09:03 PM

IF THEY WANT THE TRANSMISSION IN DRIVE FOR CURB IDLE ADJUSTMENT, HOLD OFF ON THAT UNTIL WE GET THIS FIGURED OUT. WE DON"T WANT A RUNAWAY CAR.

Re: 3.8 v6 Carb Questions, Options?

Reply #10 – April 16, 2022, 12:19:42 PM

Fast idle control diagram.

Re: 3.8 v6 Carb Questions, Options?

Reply #11 – April 16, 2022, 01:12:19 PM

The choke heater (thermostat) is powered by the alternator S "Stator" output. This voltage is only available after the alternator is running. The voltage is lower than battery voltage, 7-9 volts.
Your stock alternator is a 1G with an external voltage regulator. If it has been upgraded to a newer alternator with an internal regulator they may not have reconnected the choke heater.
Check the voltage at the electric choke.

Re: 3.8 v6 Carb Questions, Options?

Reply #12 – April 16, 2022, 04:14:59 PM

Thanks for the replies.

Quote from: softtouch – on April 14, 2022, 01:02:14 AM

There are a lot of variations of the 2150 2-V carburetor. If you can post pictures of all sides of it maybe I can help figure out what you have.
Does the car have a mechanical fuel pump?

When i go back to the car ill grab some pics of the carb on it, all the carb pics i have are of the old one and the ones that were not compatible for it.
I was supposed to go do this today but i spent all day yesterday working on my fox mustang vert and i got alittle beat up from having to attack some things from both under the hood and under the car. Off topic but I have no idea how you could cleanly remove and reinstall the turbo on those things without a lift what a mess that was.

Quote from: softtouch – on April 16, 2022, 01:12:19 PM

The choke heater (thermostat) is powered by the alternator S "Stator" output. This voltage is only available after the alternator is running. The voltage is lower than battery voltage, 7-9 volts.
Your stock alternator is a 1G with an external voltage regulator. If it has been upgraded to a newer alternator with an internal regulator they may not have reconnected the choke heater.
Check the voltage at the electric choke.

The alternator is the original 1g, no modifications have been made to it(although i have been looking for a higher amp 1g solution for an electric fan later down the road).
Ill check the electric choke voltage but i think i either didnt position the idle solinoid correctly when i installed it on the new carb and its pushing a little too hard on it or the cam on the choke is binding/hanging up on the detent.

Re: 3.8 v6 Carb Questions, Options?

Reply #13 – April 16, 2022, 04:26:25 PM

Quote from: softtouch – on April 15, 2022, 02:16:57 PM

The throttle kicker shown in your picks looks like it is for a non A/C car.
This is probable an anti dieseling solenoid, needed with a mechanical fuel pump.
It should extend with key on and is adjusted with a warmed up engine for curb idle. Check fan shroud decal for details.

The 83 EVTM shows the A/C throttle kicker solenoid is a vacuum valve. so the kicker would be vacuum operated.

The pictures in this thread are of the original carb that came with the car and of one that i bought but couldnt use because it wasnt for an AOD equipped car. Nothing is what is currently on the car, ill update what is currently on it when i go back there and take some pics for clarity.
The car has a mechanical fuel pump.
From what i understood the idle stop solinoid has nothing to do with a/c on this, although common sense would imply it does. Raise idle to accommodate extra load at engine idle so you dont stall.
There is some kind of bimetal tab vent thingy on the carb i thought was relative to a/c.
I dont want to pretend i understand all of it right now, havent got my hands dirty working on this stuff in years and need to hit some books to get up to speed on it.

Once again, thank you for your input.

Re: 3.8 v6 Carb Questions, Options?

Reply #14 – April 17, 2022, 01:46:48 PM

From the 83 EVTM:
The A/C throttle kicker solenoid has LG/P H (Light Green/Purple Hash) and BK (Black) wires.
The anti-diesel solenoid has two BK (Black) wires.