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post #1 of (permalink) Old 10-18-2002, 01:21 PM
JeepJohn
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doing the nutter bypass need help

ok I'm sick and tired of no idle and the crappy emisions I've decided to NUTTERISE !!!!
I do have a couple of Q's though.

1. it will not idle @all right now. I'm looking @vacume lines, and after the bypass can I just cap most all the vacume lines? I'm also gonna try to clean the idle tubes with some carb cleaner, do not want to open the carb up if possible.

2. in the directions it says while running, to screw in the idle jets, ok well are the idle jets the two "mixture screws" at the bottom front of the carb? and if I can't get it to idle can I just do it when it's not running, or set the idle up higher?

3. when setting the timing on one website http://home.sprynet.com/~dale02/home.htm it said to disconect the mercury switches. After doing the bypass They would be talken out of the loop and would cease to function correct? just plug the vac line and move the dist. to 8deg BTDC and clamp it?

any and all info is gonna be greatly appriciated by the Jeep chick and me TIA

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post #2 of (permalink) Old 10-18-2002, 05:56 PM
**DONOTDELETE**
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Re: doing the nutter bypass need help

I haven't done or needed to do the Nutter bypass... but have you done an extensive search on the board yet? Well I think the mixture screws are not the Idle Jet Screws... Just bringing your post to the top to help you out.
post #3 of (permalink) Old 10-18-2002, 06:32 PM
 
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Re: doing the nutter bypass need help

1) The vacuum lines:
Yes, you can cap/pull them out/set fire to them..whatever.
The computer received inputs from various sensors and then used the vacuum lines for various fucntions. With the ECU not in the loop anymore, the lines are not serving any function.
1a) The idle tubes: To get them completely clean, you will have to at least remove the air cleaner holddown, the choke plate, and the choke linkage. I can do this in about 3 minutes. I'll post some pictures later to show you what I'm talking about.

2) Essentially the "idle jets" are the mixture screws on the front and the reason the "directions" tell you do do it while it's running is so that you can tell when the RPMs drop. Ones the RPM's drop, you're supposed to turn the screws back out (enrichen the mixture).
I have access to a narrowband exhaust gas sensor, and I set mine with that then set the idle like you normally would with a fully functioning engine.

3) You will want to remove the vacuum line from the vacuum advance port on the distributor when you're setting the timing. You don't have to remove the 4" and 10" lines from the firewall, but I usually do it anyway.
Then you can set the timing to spec.

I would recommend setting the timing first, then doing the idle because the timing will affect the idle.
If the timing is at something like 12* it will idle higher than if the timing were at say...6*.

EDIT: Here are the pictures...

This one shows the carb and components that need to be removed to get the venturi cluster/idle pickup tubes out.
Red: Are you will be working in.
Green: Air cleaner holddown.
Blue: Choke linkage.
Pink: Choke plate (vertical in the picture).
Light Blue: Two venturi cluster screws you'll need to remove.


And the same picture without any colors on it so you can see what everything looks like.


This image shows the venturi cluster removed.


This one is the idle pickup tubes removed from the venturi cluster.





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post #4 of (permalink) Old 10-18-2002, 09:23 PM
MaineJeep
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Re: doing the nutter bypass need help

I just wanted to add that the reason for screwing inthe idle mixture screws was to lean out the engine so that the stepper motor will move the metering pins to the full rich position, forward. You need to look down in the throat of the carb when you turn them in to make sure they move forward. On My YJ they seemed frozen, or maybe the motor or computer was bad, I had to take the stepper motor off and turn it out by hand. This worked ok and was pretty easy to do.
post #5 of (permalink) Old 10-19-2002, 03:52 PM
 
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Re: doing the nutter bypass need help

Just a word of caution.....

The Nutter Bypass is not a cure for carb ills. If you have something that is wrong with the carb or a bad emissions control device (like a leaky air switch valve or the EGR -- which would kill your idle), it will not help fix that. What it will do is keep the computer from fooling with the carb and timing settings.

Find whatever is already wrong before you do the Nutter or you will be chasing down both problems from the mods and problems that were already there.

The other word of caution is watch out for what emissions hoses you pull off of it. The carb is jetted and calibrated for the emissions control devices you have on there. Sometimes removing them will make the carb act funny if you don't re-jet the thing at the same time.... but sometimes it works just fine too.

One thing that will help is breaking out your FSM and reading how all those stupid vacuum controlled emissions devices work. It will help you to figure out the best way to disable them and if you can or not.

Best regards

John
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post #6 of (permalink) Old 10-21-2002, 07:44 AM
JeepJohn
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Re: doing the nutter bypass need help

hey guys thanks for the replys and info!! Unfortunatly I was doing B-days all weekend so no work on the jeep [img]images/graemlins/frown.gif[/img] I was looking at the carb and I DEFINATLY need to clean out the idle tubes. gas was just drippin and sloshing out when I was able to get it to idle. on drilling the idle tubes what sise drill bit should I use? I think the smallest I have is 1/16" but all the write-ups I've seen say .035" well what would that convert to? Again thanks for the picks and info from all of you.
post #7 of (permalink) Old 10-22-2002, 08:42 PM
 
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Re: doing the nutter bypass need help

DON'T DRILL THOSE THINGS

They are specially calibrated tubes. If you drill them, it will throw all the idle calibration all out of whack.... not to mention fill the carb bowl with trash chunks and metal shavings. That is very bad.

Spray carb cleaner through them. That should dissolve 97% of the trash in there. My favorite stuff is that cheap generic Autozone carb cleaner. That stuff dissolves anything. Yellow can with red letters.

If they are clogged so clogged that carb cleaner won't penetrate even after you soak it for a couple of hours, pull the carb and clean it good all the way through. The trick is to find something that won't scratch those tubes or jets. Most every metal tool will dent or deform those brass orifices.

Best regards

John
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post #8 of (permalink) Old 10-25-2002, 02:47 PM
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Re: doing the nutter bypass need help

JeepJohn,

I was in your shoes recently and sick of the BBD issues. However, rather than Nutter alone I also chose to install the MC (Autolite) 2100 carb. I was amazed at the results the instant it was installed my CJ idled better than ever, even without dialing it in. Total cost of a junkyard carb and rebuild kit was $55. Depending upon any emissions tests in your area you may be much better off doing the 2100 swap than Nutter alone. There is tons of info on this board about it. Or I would be happy to give you specific help as well. Just a thought. Try it and you will become a 2100 apostle like me.
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post #9 of (permalink) Old 10-25-2002, 03:50 PM
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Re: doing the nutter bypass need help

Hi jeepjohn,
I just went though all this stuff. It was running so bad I had to drive an auto trans jeep with 2 feet at every stop, just to keep it running. I found out, If you see fuel driping in the carb. CLEAN the idle tubes it is very easy and should get things running a lot better for you. After you clean the tubes and have it kind of idleing. Try this look down the carb at the metering pin, it will be moving back and forth trying to keep the thing running. If it's not moving something is broken. But I'll bet it moves. Now turn the mixture screws on the front of the carb while looking down the carb and try to get that metering in the center. Try to get both idle screws turned out about the same. After you get it to idle which after cleaning the idle tubes will be so easy you'll be jumping up and down. Adjust your timeing @ 1600 rpm's. Also you need to make sure that the door in your air cleaning horn works, mine was stuck shut. I have 150,000 on my jeep and it now idles so well I have to stick my head out the window to make sure it's running! [img]images/graemlins/grin.gif[/img]
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