couple of questions does anyone have the how to for an 87 and up nutter by pass. as I understand there is a colour difference in the wiring somewhere. can someone give me the modified protocol for the wiring bypass using a the newer wire colours for an 87 and on. and how much do I turn in the idle mix screws just until it starts to miss? Thanx to all. Scott
I just did one on an 87 YJ. The wires colors (Orange & Purple?) are correct at the distributor, and also correct on the control module. They are different inside the harness going to the control module.
As far as adjusting the mixture, I leaned it until the RPM dropped, and backed off 1/2 turn.
I think the best is to just add 2 new wires so you don't have to mess around inside the wiring harness.
You should read the thread on Jeep CJ 258 acceleration issues.
Here are a couple good links on tweaking the 258's:
formatting link
formatting link
And before you attempt to mess with the mix, the mix must work so here is a good link on that:
formatting link
Before you start, a carb kit is only about $20.00 at CT and is easy to put in. You really need that carb working or it will 'never' set stable.
When you set the mix, you need to turn the screws 1/4 at a time with a rev between each turn. When it starts to miss, back them out 1/4 turn or just until the burble goes away. The 'sniffer' likes a slight burble.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
ha their dyno hard drive broke going in on Monday now. they did acknowledge that the emission standard for a 4.0L and 4.2L is different so I get a free redo on my first test
Ya I ment the wiring, I actually replaced my carb with the older CJ model, same thing only no emissions stuff.
Like mike said, add the wires it's a lot cleaner and faster and as he's said before it can be romoved fast....I sound like a parrot, but I dont wanna take credit for Mikes sound advice
ok so this is what I'm doing,,,,,,,, I want to clarify as I seem to be getting confused( don't ask) Orange wire at distributor connects to orange wire at ignition module, Purple wire from distributor connects to purple wire at ignition module......SOOO cut and run new wire as out lined above.? leaving the other wires disconnected from the system.
Yup. All except for the purple which has to go on the module side of the plug, I do the cuts on the wiring harness side of the plugs so the parts can be replaced easy if needed. I always stagger the cuts by a
1/2" or so, so there is no danger of the wires you left shorting to each other or cap them with heat shrink.
CT has some wicked doubled walled heat shrink with a heat activated glue inside to weatherproof them. Works great.
I've got a late update for everyone on this.... I just did this on my 89 YJ 258. The wires are the same except....DC did something really funky. Not used to DC motors... The wires that come out of the ignition module are correctly color coded, but then there is a wiring harness plug, and most of them change colors...Why in the world they would do that is beyond me... The colors at the distributor are also correct... Strange, very strange.... All went well thought..... Thanks ALL Seattle WA Robb S 89 YJ 258 Build in progress... ps... tomorrow I install my 4 1/2" Rubicon extreme Wish me luck
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.