Adjust. Jets BBD Carb - Off-Road Forums & Discussion Groups
Jeep-Short Wheelbase All discussion of short wheelbase Jeeps: CJ, TJ, YJ and JK

 
LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 01-23-2001, 10:18 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Adjust. Jets BBD Carb

I'm wondering how can you disconnect the computer from a stepper motor bbd carb and then adjust the stepper motor manually or electrically with a dial? Could you then hook a voltmeter to the oxy sensor and tune your carb to exact stoich. fuel to air ratio? How do you do this?? Thanks

Sponsored Links
Advertisement
 
post #2 of (permalink) Old 01-23-2001, 01:55 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Adjust. Jets BBD Carb

I had the computer disconnected from my bbd carb. From my understanding thay disconnect the stepper motor ajust it to one positions and then just leav it. Then thay tune the carb to run it's best with out the cumputer. I didn't do it my self so I can't give you any more info. as for what your suggesting I don't know why you would want to do that? what advantage would there be from doing that.

[img]/wwwthreads_images/icons/cool.gif[/img]http://members.home.net/paul5696[img]/wwwthreads_images/icons/cool.gif[/img]
post #3 of (permalink) Old 01-23-2001, 03:15 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Adjust. Jets BBD Carb

Here's how I adjust a BBD,
First I do internal mods so I can chuck the stepper motor, but you can also keep the motor on the carb and run the pins all the way in, either manually or by leaning out the idle mixture. This eliminates the air bleed function of the stepper.
Next, I adjust the idle mixture screws the normal way, usually about 2 turns out.
Then I turn the metering rod adjusting screw counterclockwise until the engine stumbles off idle when you give it gas. I then turn the metering rod screw clockwise, to richen the mixture, 1/4 turn at a time, until the engine doesn't stumble when you give it gas.
Your done.
I have tuned many BBDs this way and it works fine for me, I am one of the few who think the BBD is a great carb.

CTjeepnut

Funny thing is, the more I practice, the luckier I get
Sponsored Links
Advertisement
 
post #4 of (permalink) Old 01-23-2001, 07:59 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Adjust. Jets BBD Carb

I took the stepper motor off and removed the needles. Then reinstalled the motor onto the carb. This way it looks stock, doesn't affect the computer because it still thinks its doing something and if by any strange chance I ever want to use the stepper again all I have to do is replace the needdles. No wiring no worries.

'88 Sahara, 4.2, auto.
post #5 of (permalink) Old 01-23-2001, 10:59 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Adjust. Jets BBD Carb

Stooby, if you remove the pins, without blocking the internal passages, then you are opening up the air bleed holes 100%. This means you are running your carb at full lean condition.
How do you tune it?
What you are suggesting is exactly opposite of what most people do with a BBD.

CTjeepnut

Funny thing is, the more I practice, the luckier I get
post #6 of (permalink) Old 01-25-2001, 02:53 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Adjust. Jets BBD Carb

where is the metering rod screw

post #7 of (permalink) Old 01-25-2001, 03:47 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Adjust. Jets BBD Carb

CTJeepnut, if you love the carter how come your vehicles have webers...I am about to go to a weber in the next day if I can't tune the carter reasonably. What do you do with the electric choke? Disable it and leave it wide open? My main problem is with inital idle...I have a bypassed computer with stepper needles completely in. With the choke closed when the engine is cold.. I can barely start the Jeep? Thanks for any help.

post #8 of (permalink) Old 01-25-2001, 06:18 PM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Adjust. Jets BBD Carb

I guess I should update my profile.
I currently run only 1 Weber, that's on my 85 4cyl. I thought that Webers were the only answer, until I started experimenting with an old BBD.I also thought that the HEI was a great ignition until TR gave us the TR cap upgrade and MSD box.
We are a big Jeep family here in rural CT.
Currently we are running 5 carbed 6 cyls., all of them have modified BBDs, they all have the TR ignition with TFI coil, and 2 have MSD boxes.
I'm not against changing directions, if there is a better road to take.
As for the choke, I just use the original choke wire.
I can think of 3 reasons for hard cold starts.
Choke not adjusted properly, the choke should close completely when the throttle is first opened, then move to a slightly opened position after startup, then slowly open all the way.
Accelerator pump not working, look down the carb throat while pumping throttle, you should see 2 steady streams of fuel. For cold starts you need to get some fuel injected into that engine.
Fast idle not right, for an engine to stay running cold it has to idle up to about 1500 rpm.
Hope this helps

CTjeepnut
BTW, I have a complete,like new Weber 32/36 forsale, with instructions, with fuel pressure regulator, $200, you pay shipping.
Oh yea, the metering rod adjusting screw is under the cover at the front of the carb, take out the 3 screws and you'll see the rods going down into the bowl, the screw is on top of the rod holder.

Funny thing is, the more I practice, the luckier I get
post #9 of (permalink) Old 01-26-2001, 07:39 AM
**DONOTDELETE**
Guest
 
Posts: n/a
Re: Adjust. Jets BBD Carb

thanks i found the screw last night that fixed it

Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome