BBD Metering Pins

[MDJEEPER]

Guys,

I am still trying to deal with various carb issues on my Jeep that I think ultimately will have to be fixed by Nuttering it. Before I do that, I want to know what you think about the current position of the stepper motor metering pins since they are not being controlled by the computer.

I thought they may already be in the full rich position, but looking at the pictures again, I think they may actually be lean. What do you think?

 

[Slydeco]

Rich!

 

[MDJEEPER]

Thanks! Then what I am seeing must be the end of the pin, rather than the shoulder that is supposed to be 1/8 to 1/4 of the way extended to be in the "neutral" position. Does anyone happen to have a picture of what this perfectly neutral position looks like?

I was going to attempt TDHofsetter's great idea of simulating an O2 sensor to move the pins...seeing as how the PO removed the O2 sensor when the manifold was swapped. However, I am not sure if this will work since I also don't have a coolant temperature sensor. So I don't know if the computer is operating in open or closed loop...or even capable of controlling the pins anymore.

Is there a purely electrical (i.e., no computer/sensors) or a manual way that I can move the pins??

 

[Slydeco]

Go to the Jeep forum and search for posts by Mike Romain he is the BBD Guru.All your answers are in those posts. I had the same probs and ultimately put in a non-feedback BBD and noticed a big difference.The stepper pins can be moved electrically,John Strenk I believe has a pic of this in one of those posts. The detailed diagram will show you what pins to Grnd and what pins to apply 12 volts to. Mike will also advise you to put a kit in the carb as well.Not that hard I did my first with ease following the Instuctions Good Luck

 

[MDJEEPER]

Go to the Jeep forum and search for posts by Mike Romain he is the BBD Guru.All your answers are in those posts. I had the same probs and ultimately put in a non-feedback BBD and noticed a big difference.The stepper pins can be moved electrically,John Strenk I believe has a pic of this in one of those posts. The detailed diagram will show you what pins to Grnd and what pins to apply 12 volts to. Mike will also advise you to put a kit in the carb as well.Not that hard I did my first with ease following the Instuctions Good Luck

Thanks!!

Do you happen to know about how old these posts are? I have searched the Jeep Forum and still haven't found the info...There are LOTS of posts by Mike Romain and John Strenk, but nothing yet that specifically talks about moving the pins electrically.

 

[Slydeco]

I,ll try to find the diagram for you

 

[MDJEEPER]

I,ll try to find the diagram for you

Thanks!

I also read on the Jeep forum that some guys simply have removed the stepper motor from the back of the carb and then moved the pins around by hand. Seems like the motor would provide resistance to do that and there might be a risk of breaking a pin. But, I guess it could be a back-up plan...

 

[Slydeco]

 

[Slydeco]

Have not tried to move by hand but I have one if you need it,Since I now use the Non-Stepper version

 

[MDJEEPER]

Thanks!!

The captions on this diagram have me confused. Extending the pins should cause a rich condition, but the diagram has "lean" next to it. And, retracting the pins should make the carb run more lean, but it says "rich". So, maybe the diagram is referring to the existing condition of the carb (lean or rich) that is to be fixed by moving the pins??

 

[Slydeco]

Just move the pins till you get the 1/8th shoulder

 

[MDJEEPER]

Just wanted to provide an update. I used TDHofstetter's oxygen sensor simulator to neutralize the metering pins. It worked great!! I was concerned it might not work since my project is missing nearly all of the computer inputs, but was perfect.

Thanks to him for such a fantastic idea!


His procedure can be found at the following link:

http://www.jeep-cj.com/forums/f2/shorten-throttle-cable-4836/index2.html

 

[Trapshooter]

Thanks!!

Do you happen to know about how old these posts are? I have searched the Jeep Forum and still haven't found the info...There are LOTS of posts by Mike Romain and John Strenk, but nothing yet that specifically talks about moving the pins electrically.

The needles can be moved both electrically with idle mixture adjustment and physically by removing the stepping motor and placing the needles in the desired postion.

The explanation on Jeep Forum was actually written by "luckycheesehead" with Mike Romain acting as editor.

Here is the link:

How to - Nutter Bypass - JeepForum.com

Another great article that I also found helpful can be found on 4X4Wire. Here is a link:

The "Nutter" Bypass

I was amazed how much better my AMC 258 i6 / 4.2l ran after performing this mod. I than performed the "Team Rush" upgrade to the ignition system which improved things even more. Lastly, I pulled the idle tubes out of my BBD as there was fuel drooling during idle. That old AMC 258 i6 / 4.2l has never run better.

I just did all these things within the last two weeks so if you need help just PM me. I could probably walk you through the mods.

Hope this helps............

P.S. If you remove your emission components after the Nutter Bypass hang on to them; their are people who will pay good money to get those parts.

 

[Trapshooter]

Just wanted to provide an update. I used TDHofstetter's oxygen sensor simulator to neutralize the metering pins. It worked great!! I was concerned it might not work since my project is missing nearly all of the computer inputs, but was perfect.

Thanks to him for such a fantastic idea!


His procedure can be found at the following link:

http://www.jeep-cj.com/forums/f2/shorten-throttle-cable-4836/index2.html

I should have read the entire thread. Glad to hear you where able to get the metering pins where they needed to be.

Maybe someone else can use the info.........

 

[MDJEEPER]

The needles can be moved both electrically with idle mixture adjustment and physically by removing the stepping motor and placing the needles in the desired postion.

The explanation on Jeep Forum was actually written by "luckycheesehead" with Mike Romain acting as editor.

Here is the link:

How to - Nutter Bypass - JeepForum.com

Another great article that I also found helpful can be found on 4X4Wire. Here is a link:

The "Nutter" Bypass

I was amazed how much better my AMC 258 i6 / 4.2l ran after performing this mod. I than performed the "Team Rush" upgrade to the ignition system which improved things even more. Lastly, I pulled the idle tubes out of my BBD as there was fuel drooling during idle. That old AMC 258 i6 / 4.2l has never run better.

I just did all these things within the last two weeks so if you need help just PM me. I could probably walk you through the mods.

Hope this helps............

P.S. If you remove your emission components after the Nutter Bypass hang on to them; their are people who will pay good money to get those parts.

Thanks! I have to agree that my project is working much better now....no knocking, pinging, or bogging down. The idle also seems smoother...BUT I discovered last night that the original problem that sent me down this road still remains.

For whatever reason, my project cannot hold speed (say 60 mph) when going up a hill in 4th gear on the highway. I just cannot figure it out. I have checked all the usual stuff (plugs, wires, cap, rotor, dizzy vac advance, etc.) and the engine is running incredibly smooth now so there is no indication of an internal problem. It's just like it runs out of HPs even at WOT.

Any ideas?

 

[Trapshooter]

This may have been asked earlier in the post but what axle ratio are you running?

With 31" tires you may have gears that are to tall for your bigger tires. Here is a link to an article on offroad.com showing where to find the code on you AMC20 to determine the ratio the axle came with from the factory.

Jeep Axle: AMC 20 - - Jeep at Off-Road.com

Make sure you drop down on the page to the wide track info. The stamp on the axle housing is faint. You will want a wire brush to clean things up to see the markings. If you have a "D" code then you are running 2.73's which maybe a little tall and who knows what a PO may have done.

Good Luck..........

 

[Cheepjeep85]

even with 33x12.50s and 2.73 gears he should be able to hold 60mph. maybe a little drop off but not much

 

[MDJEEPER]

This may have been asked earlier in the post but what axle ratio are you running?

With 31" tires you may have gears that are to tall for your bigger tires. Here is a link to an article on offroad.com showing where to find the code on you AMC20 to determine the ratio the axle came with from the factory.

Jeep Axle: AMC 20 - - Jeep at Off-Road.com

Make sure you drop down on the page to the wide track info. The stamp on the axle housing is faint. You will want a wire brush to clean things up to see the markings. If you have a "D" code then you are running 2.73's which maybe a little tall and who knows what a PO may have done.

Good Luck..........

Yes, I have the standard AMC axle with 2.73 gears. However, I thought the 31 inch tires were pretty common on CJs...

 

[Cheepjeep85]

man i pull a 15' 1500lb boat behind mine with 33s and 2.73s, its now torque monster with the boat but it pulls it decent, you definately got issues. have you ruled out all of the ignition parts? bad dizzy, bad ignition mod., coil? are you getting enough fuel press. to the carb? bad fuel pump? timing off? bad carb? have you done a compression check lately? low compression could cause your problem too. could just be time for a rebuild, or some head work. another problem could be a worn out cam. how far you are willing to go into it depends on how much this problem bugs you.

 

[MDJEEPER]

man i pull a 15' 1500lb boat behind mine with 33s and 2.73s, its now torque monster with the boat but it pulls it decent, you definately got issues. have you ruled out all of the ignition parts? bad dizzy, bad ignition mod., coil? are you getting enough fuel press. to the carb? bad fuel pump? timing off? bad carb? have you done a compression check lately? low compression could cause your problem too. could just be time for a rebuild, or some head work. another problem could be a worn out cam. how far you are willing to go into it depends on how much this problem bugs you.

Thanks! I have replaced all of the ignition components except for the module and the dizzy. However, I did check to make sure the vacuum advance on the dizzy was working. Timing is set at 8 degrees (per the Nutter procedure).

As far as I know, the fuel pump is original.

I have not delved into the compression or other serious engine issues. It also still has the BBD carb, with the metering pins now set according to the procedure.

Where would you start? What's most likely??