[nichols077]

Why havent i heard of this before? it sounds like it will solve all of my ignition problems. Has any one done this? The article says the symptoms of a malfunctioning ECM include surging or missing at idle, knocking or pinging, loss of overall power and/or an increasing inability to maintain freeway speeds. This accurately describes my jeep. any responses will be helpful. thanks

[Mike Romain]

Those symptoms kinds describe the ECM when it has gone into limp home mode because some emissions component has failed.

The most common failure for the surging at idle is the charcoal canister's (gas tank and carb vent) purge valve failure or it's air filter blocked with dirt. To test this quick, at idle pinch the line from the PCV line to the canister closed. If the idle changes, you have found most of your troubles.

How comfortable are you with manually tuning a carb? If that's no issue, a carb kit is recommended before doing the 'Nutter' so the carb will behave when manually tuned. A kit runs about $25.00.

It is super easy to nutter the thing. I just add two new twisted wires and hook the orange and purple at the ignition module up direct with the orange and purple at the distributor. This avoids messing in the harness. You then have to set the timing because it will have jumped. I set the distributor to 8 or 9* BTDC at idle with the vacuum off. The vacuum will now be coming off the 'ported' nipple in the valve cover side of the BBD carb.

The carb needs it's stepper pins set in the middle just like where the computer should have them when it's running right. 'Not' full rich like the directions say, that only works well for low speed running. This way it will pass emissions and get great mileage.

You then have to set the mix screws down front. You might have to cut or drill to get at those screws, so if yours doesn't have two obvious screws down on the front bottom plate or if you aren't used to setting a 'best lean idle' mix, post back.

The Nutter jumped my red line up to 4400 rpm. 3rd is my highway passing gear good to 75 mph, 4th buries the speedometer and well, I don't use 5th much with my 33's and 3.31 gears...

If I stay at 65 mph and under I get a nice 23 mpg.

[SuB8HaVeN]

Go ahead and nutter it as long as you don't have to pass emissions. It's easy, doesn't cost anything, gets rid of a lot of wire clutter (and that box behind the dash), and makes it run better and get better performance and fuel economy.

[Mike Romain]

Originally Posted by SuB8HaVeN

Go ahead and nutter it as long as you don't have to pass emissions. It's easy, doesn't cost anything, gets rid of a lot of wire clutter (and that box behind the dash), and makes it run better and get better performance and fuel economy.

We can still pass tailpipe emissions up here in Canada easy with nice low numbers when they are manually tuned up. I have done more than a half dozen. The carb gets set differently than John Nutter did. We set the stepper pins in the center of their travel just like it runs factory, then adjust the mix, not full rich like Mr. Nutter does. The sniffer likes it this way. The rest of the junk can be left on for the visual if needed.

[arfmel]

neuter bypass?

[HighCountry]

I highly suggest you not remove the stock wiring and other systems. None of it will cause you any problems afterward and you never know when "someone" might want to return things to original! I did my '86 like Mike R is promoting, I even spliced in the two new jumper wires on the Distributor Side and the Module Side of the connectors to keep from ruining my wiring harness. A little extra benefit is that I eliminate the possible corrosion at the stock connectors at the same time. I used round 'motorcycle style' plug in connectors so that I could pull the Distributor and Module later without cutting wiring.

There is also a BLACK ground wire coming from the Module all the way to the Distributor for grounding purposes. It is very highly recommended that you add an additional grounding source to this wire, as the distributor does not provide the best. The Module is what you are trying to help here not the Distrubutor, so bear that in mind.

Bruce

[nichols077]

The carb needs it's stepper pins set in the middle just like where the computer should have them when it's running right.

Thanks for the info Mike but i have some questions. Can you explain more about the above quote, im unfamiliar with this. and also how do i set a 'best lean idle' mix

[Mike Romain]

Originally Posted by nichols077

Thanks for the info Mike but i have some questions. Can you explain more about the above quote, im unfamiliar with this. and also how do i set a 'best lean idle' mix

Stock, the computer adjusts the final mix using a stepper motor that moves two pins in steps to adjust the air mix. These pins normally ride about the center of their travel which is where the high speed mix sets right.

For some reason the 'Nutter' directions want these pins all the way rich or full into the carb. It will idle ok there and run, but it is way too rich for top end or the sniffer.

The low speed mix is set with the two screws in the front of the base plate. You can set these up for the best lean idle. Basically you gently screw these in all the way counting the turns so you know where it 'was', then back them out about 5 turns.

With the engine warm preferably you move these screws in in 1/4 turn shots, then give the engine a rev, then turn them another 1/4 turn and so on. You might have to adjust the idle speed while doing this. You will reach a point where the engine starts to stumble a bit. At this point you back them off 1/4 turn to smooth it out and you are done. If it has to get emissions sniffed, it likes to be right at the stumble point, not backed off the full 1/4 turn for the best readings, but for the smoothest idle, slightly rich is best.

The finish point of the screws should be close to your starting point it was at stock.

[nichols077]

thanks Mike only one more question. Where are the stepper pins and how do i adjust them?

[Mike Romain]

Originally Posted by nichols077

thanks Mike only one more question. Where are the stepper pins and how do i adjust them?

The stepper motor is on the back of the BBD carb. You look down the ports and you can see one of the pins poking through the back half of the carb throat. This pin can be rocked and moved up and down steps with a small sharp screwdriver or the motor can be removed and the pins moved.

OK, I uploaded a photo to the 'odd mech stuff' album on my photo site. That will be there as the featured photo until something else comes along, then will just stay in the album. http://mikeromainjeeptrips.shutterfly.com

The red arrow points at the stepper pin and the blue arrow on the back, the motor.

My engine runs extremely well with the air mix set there with the needle's shoulder about 1/8" out from the back.

[Rollbar]

Hey Mike, I have mine set all the way in & from time to time I have to readjust the idle screws & use some carb cleaner, then it runs fine. If I push the pin to the middle (if the pin will stay) do I need to re time the engine or just re adjust the idle screws like usual.

Thanks,
Jim

[Mike Romain]

Originally Posted by Rollbar

Hey Mike, I have mine set all the way in & from time to time I have to readjust the idle screws & use some carb cleaner, then it runs fine. If I push the pin to the middle (if the pin will stay) do I need to re time the engine or just re adjust the idle screws like usual.

Thanks,
Jim

Just the idle screws. They only adjusted about 1/4 turn or so when I tested mine.

The pins move in steps so need to be rocked to jump steps.

The gas mileage difference is amazing. Pins all the way in and I needed gas at 250-275 miles max, pins back out and I get an easy 350 highway miles or 23 mpg.

I also blew black smoke at top end and didn't have much top end power at all. Fine for trails, just bad on the highway.

[Rollbar]

Thanks Mike, I'll try it & see.

[nichols077]

Hey thanks man im on my way outside to do this now. Ill let you know how it goes.

[Mike Romain]

Originally Posted by Rollbar

Thanks Mike, I'll try it & see.

You should check your plugs. They tell a story. If rich, they will be black, if lean they will be gray/white, if nice, a light tan.