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The Best Nutter Bypass Advice

Jeep Wrangler Nutter Bypass

This article will walk you through doing the Jeep Wrangler Nutter Bypass. I wrote this article several years ago and decided to rewrite it and post it again. Yes I am still obsessed with Jeeps. My advice is don’t be afraid to do it. The mod is easy and reversible.

I can tell you for me it was worth it. You Should see better performance and easier starts. I can use my fifth gear on the highway where it is generally flat. Even with my 33-inch tires. I decided to create this post so it might help someone out. It can be confusing reading some of the posts written by the techies that get into the fine details of the Jeep Wrangler Nutter Bypass. So here are some pictures and a description of the steps involved. This is just for the bypass. I am not going into many details regarding carburetor adjustments and the like.

Note: your vehicle may vary slightly, due to modifications, different carburetors, etc. Feel free to contact me and I will be happy to help if I can.

jeep Wrangler Nutter Bypass

The photo above shows the purple and orange wires that you read about in most posts about the Jeep Wrangler Nutter bypass. You do not have to do anything here. I am just showing you these wires so you can see where they are located (By the Distributor). This is helpful if you want to use a multimeter to check out the wires and make sure you have the correct pair at the ICM end of the harness.

The above photo shows the harness wires pulled from the wire loom.

Notice the twisted orange and purple wire. This is where they come out of the wire loom and go down through the firewall.

Here is what you need to do

  • These are the wires you need to cut and splice into, the orange and purple.
  • You will be cutting them just about where the arrow indicates.
  • Cut the orange wire and strip the end.
  • Then cut two lengths of new wire that will reach from your splice to the ignition control module.
  • The ICM is usually located behind the windshield washer tank on the firewall.
  • Attach your two new wires to the newly cut and stripped orange and purple wires from the side that comes from the distributor not the wires that go down the harness through the firewall.

Important Note:

Be sure that you are attaching the wires to the side that comes from the distributor, not the wires that go into the firewall. You will not be using the wires that go down the loom into the firewall. You will be connecting the wires from the distributor side orange and purple to the ICM with the extra wire you are providing.

  • Strip the other end of the wires that you just ran to the ICM.
  • Cut the orange wire at the ICM connector.
  • Strip the end of the orange wire.
  • Cut the purple wire at the ICM connector.
  • Strip the end of the purple wire.
  • Attach the two wires that you extended earlier.
  • Orange to orange.
  • Purple to purple.
  • Put all your wires back into the loom and tidy up.

Adjust the timing

  • Connect your timing light.
  • Start the engine.
  • Warm up to operating temp.
  • Turn off the engine.
  • Loosen the distributor Lock nut.
  • Remove and plug the vacuum line from the distributor.
  • Start the engine.
  • Adjust for 8° BTDC
  • Stop the engine.
  • Tighten the distributor lock nut.
  • Start the engine and check to make sure nothing has moved.
  • Reconnect the vacuum line to the carburetor.
  • Stop the engine.

Jeep Wrangler Nutter Bypass – Additional Notes

  • You want your distributor vacuum line connected to the ported vacuum, not the manifold vacuum (Off the carburetor, not the manifold)
  • Adjust your carburetors idle mixture screws for the best lean running setting you can achieve
  • Don’t be confused by my photo showing the ignition control module on the Fender. I put it there. It was under the washer fluid reservoir and was hard to get to.
  • The Nutter Bypass is for Jeep Wrangler Years 87-91 with a 4.2L straight six engine

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