What is the jeep Nutter bypass?
The Nutter bypass cuts out all of your emissions on the YJ and is for “offroad rigs only”. Oh and don’t get a Weber they are a pain. Go with a Motorcraft 2100, a bit less and way more reliable. Here is the write up about the Nutter explaining it! Nutter write up.
How does the Nutter bypass work on a CJ?
This modification will do two things. It will rewire the ignition wiring to be basically the same as that found in an ’78 to ’82 CJ (with the 258 engine, but without the computer controlled version of the Carter BBD carburetor) and it will make the stock carburetor with its computer controlled stepper motor work with the rewired ignition.
What are the steps to the Nutter bypass?
The following steps all apply to anyone keeping the BBD carburetor. Steps one and two may be skipped by those changing to another type of carburetor or to fuel injection. Warm up the Jeep long enough for it to be operating in closed loop mode if the ECM is still functional.
What causes the spark timing to go off on the Nutter bypass?
Any change to a different type of carburetor, or to a TBI fuel injection system such as those offered by Holley or Howell may confuse the ECM resulting in the the spark timing being off.
How much torque does a nutter bypass engine have?
It also has a bit more power below 3000 RPM and the low end torque is definitely stronger at 600 RPM than it used to be. I idled up a fairly steep driveway in 1st gear high range and it went down to 400 RPM and kept pulling, before the conversion the engine always died when I did this in this driveway.
This modification will do two things. It will rewire the ignition wiring to be basically the same as that found in an ’78 to ’82 CJ (with the 258 engine, but without the computer controlled version of the Carter BBD carburetor) and it will make the stock carburetor with its computer controlled stepper motor work with the rewired ignition.
Where is the purple wire in the Nutter bypass?
Cut the purple wire here as well . There is no purple wire coming out from the plug near the ignition module, so you will have to add a section of wire.
The following steps all apply to anyone keeping the BBD carburetor. Steps one and two may be skipped by those changing to another type of carburetor or to fuel injection. Warm up the Jeep long enough for it to be operating in closed loop mode if the ECM is still functional.
Any change to a different type of carburetor, or to a TBI fuel injection system such as those offered by Holley or Howell may confuse the ECM resulting in the the spark timing being off.