Howdy and thanks for any help/suggestions! I'm in a '87 yj with a 258 and ax15. Today I did a fluid change in the tranny and finally did the nutter bypass. I was amazed at the world of difference. The only problem is now my carb seems to be running super rich and idling at 1600 rpm. It's a weber 32/36 and I can't seem to find a diagram that says which screw is which. any ideas?
And also while i've got a thread going, Team rush mod or whole new ignition system? My springs are flat right now but I want my heep to run before I fix the ride quality.
Thanks for any help, these forums are great!
I have a Weber 38/38 so I don't know if I can help you. On my carb the idle adjustment is in the throttle linkage at the back of the Carb, the screw head faces the left towards the battery. On my carb I have two mixture screws, I believe yours only will have one located at the base of the carb facing right. Team rush upgrade is cheeper to do [BUT] if I had the $ I would upgrade to an MSD ingnition system including a new distribitor. After the nutter by pass did you reset the timing?
I did reset the timing, it's amazing what ten degrees will do to smooth out the engine. Last night when I was trying to adjust the idle though it seemed like no matter what I did to that screw it didn't change. Could that be caused by vacuum issues?
Well I've been messing with it some more and I got the idle to go down to 1000 rpm but its still not right... I'm to the conclusion that it's not jetted right but I'm broke at the moment. Guess that's another thing to put on the "Jeep to do list"
This maybe more than you had in mind, but this is what I did to my 87 258 to help performance. I installed a holley 470 TA 4 barrel, offy intake, comp cam, rollor rockers, 4.0 head, header, hei distributer, MSD, and 4:10 gears. Needless to say, it romps. I'm so impressed with it, I could care less about a stinlin V-8. It makes peak torque at around 1,800 rpm's, awesome on the trails, it boogies down the highway and light the tires. The holley TA 4 barrels are made for off road and will take extreme angles without flooding or fuel starvation. I've had a lot of jeep I-6's over the years, but this is the first one that I've built like this, truely impressive. The 258 in an awesome engine with it's lowend torque, any upgrade just makes it better.
1987 wrangler, 258 I-6, 5-speed.
2007 liberty sport 4X4, automatic
2009 ford ranger 4x4 FX4 OFF/ROAD, 5-speed
If you don't have a Fuel Pressure Regulator in line IMHO you're chasing your tail and will always run rich. You're pumping too much fuel. The stock Fuel Pump runs at about 8-9PSI. The max recommended fuel pressure for the 32/36 is 3.5PSI. I put a quality Holly FPR and guage in-line and run it at 3PSI and got rid of all the carb problems. Here's the one I got: Holley 12-804 - Holley Fuel Pressure Regulators - Overview - SummitRacing.com
I'll check that when I get back home. I remember putting the regulator on but I can't remember what it's set at. If I remember right, the first carb was starving the engine so I had to set it way high, maybe at 5 or 5.5 psi.
Wendell, I'm jealous of your rig but I'm just a broke college kid. I have a 4.0 sitting in my shed that I'm hoping to turn into a stroker this summer so I'm holding off on using my head. For three hundred I got the motor, tranny and a rear end out of a 95. Best deal I've ever made.
I'll post up this evening after I check the pressure. Thanks!
PD, I've got an '88 YJ w/ the 258. Did the weber 32/36 conversion, nutter, and msd box/coil. Below are some links to the data I used for carb install & adjustment. Mine's running great now. You need to ensure that you don't have any vac leaks or you'll just be wasting time trying to adjust carb. With regard to timing, mine is now set at 8deg. at 750rpm. Is yours set at 10deg at idle? I'm thinking of bumping mine up to see if it makes a difference. Anyone know the max base timing? Or do you just go up until you hit detonation?
If your still idling high make sure that your main cable and linkage is not holding keeping it high. If the carb idle screw is not touching the idle lever, then your linkage may be keeping the idle high.
Okay, I've been messing with it a lot since my last post and I'm pretty positive it's just a vacuum issue now. The psi is now set at 3 and it seems to run a lot better but it's still idling high and no matter what I do to the mixture screw it stays rich and I can't change the idle because the screw won't even touch the throttle if I disconnect all the linkage and throttle bracket.
So tomorrow I'm going to pick up all the stuff for the team rush mod and vacuum hoses and connectors. So here's the list I've made so far; please correct me if anything seems wrong:
plugs for a 95 yj (4.0 of course)
rotor, cap, & dizzy adapter for an 82 F150 I6
plugs while I'm at it
Vacuum stuff: (not sure about some of this and I plan on replacing the hoses since they're old)
line for ported vac, from CTO & dizzy to EGR port on carb, 2 T's for this
line for manifold vac, from PCV valve to ??? on carb and then to Charcoal canister, 1 T
No idea on the carb vent
I have a second PCV valve at the back of the valve cover? what about that?
Also, according to the research I did for the carb swap, make sure your dist. advance is hooked up to a ported vac. source (not manifold vac). Here's the JF thread I used: Weber 32/36 Install Write-up
That, unfortunately, seems to be the issue in most cases, including mine. The PO of my YJ left a bird's nest of lines with everything from golf tees as line caps to electrical tape melted on other lines. I'm no expert by any means. I followed the diagram for the major lines. Then I carefully traced each line and first made sure there were no vacuum leaks. As I found a leak I plugged it and noted it's effect on the engine and RPM. Then I got rid of the modified "Dead End" lines that went nowhere. These lines were shortened and combined in some cases. I'm still not sure it's correct but it runs quite well. I wish I could help more.