82 CJ7 258 Timing Help

[82Laredo]

It's an 82 AMC 258 i6 / 4.2l with a new weber carb, cap, rotor, plugs, wires. The 'nutter bypass' has not been performed to my knowledge (at work so I can't inspect the wiring). I'm having a bad bog with slight popping only at WOT and want to make sure I set the timing correctly before beginning carb diagnostics/adjustment. It runs fine other than wide open throttle (but overall seems a little sluggish)

Being an 82 I set the timing at 8 degrees @ 1600 rpm with the vacuum advance disconnected and unplugged. At this setting the total advance with the vac advance connected is right at 36 total at 2500rpm free revving.

Does this sound correct? I can set sbc timing in a flash but am new to the AMC 258 i6 / 4.2l , and all this computer controlled timing and stuff is throwing me off.

Thanks for any help

 

[Lumpy Grits]

Did you disconnect the 4 & 10 inhg switches?
That bog sounds more carb than anything else.
LG

 

[82Laredo]

I'm assuming those are idle control vacuum switches? If so I disconnected and got rid of all that when I put on the weber, but haven't changed any wiring. Only vacuum lines I have are to the distributer advance, PCV and brake booster. Sorry for not clarifying that in the first post.

Yea I'm guessing its a carb/fuel issue but want to iron out timing before proceeding.

 

[82Laredo]

Does an 82 need to be set at 1600 RPM or just at idle? I'm finding all kinds of mixed information. The most notable is that the 'nutter bypass' rewires 83+ models to be like 82 and older models, leading me to believe I should set it at idle???

 

[Torxhead]

Since you have installed the Weber, your emissions system is pretty much disconnected. I think you should verify that Nutter by-pass for proper ignition timing.

 

[Lumpy Grits]

Double ck to be sure you are read'n the scale 'rite'.
This might help w/info.
Ignition and Timing

LG

 

[82Laredo]

Thanks for the reply. I understand the basics of setting timing, advance curves, etc. but 82 seems to be an odd year without a lot of info, a transition year if you will. I know it doesn't have a computer in the dash on the passenger side like the 83+, but it does have some kind if module on the passenger front fender. I am going to trace the wires from this to see if is the early version of the engine management comp. My concern is the proper way to set timing on this model year - does an outside system (other than the ignition module) have any control over the timing?

I'll look deeper into after work and report back since there's not a clear answer!

Thanks again for the replies!

 

[Lumpy Grits]

How did it run before the carb change-over?
LG

 

[82Laredo]

How did it run before the carb change-over?
LG

I have only owned it for a couple months and it ran like with the carter so I swapped over. It has been running good with the weber but seemed down on power (would only go about 60-65mph up top on 31" tires). This is my first cj but that seemed odd so I had a friend floor it while I looked at the throttle blades and sure enough, not getting WOT. I adjusted the linkage last night and reset the timing and now it bogs badly and pops a little at WOT whether under load or free revving. Drives and idles fine except for that last 20% of throttle. Adjusting the timing did smooth out the idle.

 

[Torxhead]

On the '78 thru '90 Jeep CJs and Wranglers there was an ignition control module located behind the radiator overflow bottle. I think 36 degrees is a bit much for a AMC 258 i6 / 4.2l engine, I would say more like 28. I would assume your issue is ignition timing related. I would also suggest looking into the "Team Rush" upgrade which is a larger distributor cap conversion found in this forum.

 

[Lumpy Grits]

When was the last time the dizzy cap, rotor, wires and plugs were changed?
When you disco the vac line on the dizzy to set time'n. Do you plug that line?
LG

 

[82Laredo]

The plugs/wires/cap/rotor are all new.

I'm an idiot btw, got home and right there on the sticker in front of the radiator it said 5 degrees btdc +-2 at idle with vac advance unhooked and plugged. I checked it and was only off by one degree. Didn't fix the wot bog problem though so it has to be carb/fuel related. I'll start a new thread on that at some point.

Thanks for all the help on this!