ok tune up gurus

heres my problem, 1st im talking about my 85 cj with the 6 cyl and the carter carb oh yeah its an automatic. I always have had problems with the idle and after reading a post about the idle tubes I pulled them out and drilled them out to .032 with a dremel tool. Man what a difference I wished I did it a long time ago. It now idles just as good if not better than my 04 suburban. The problem I still have is Ive got great acceleration 1st and through 2nd gear but when that auto tranny hits 3rd gear I get a little hesitation, my acceleration in that 3rd gear is my problem. Now ive tried all sorts of timing positions too see if I could smooth it out but to no avail. The only way I can get smooth acceleration in 3rd gear is to have the choke slightly closed which I do with the Manual choke. I am stumpped how it can idle great and accelerate in the first 2 gears then hit 3rd and stumble is beyond me. What do you guys think?? thanx cw

 

Being an 85 your BBD should be computer controlled. This article may help you http://jeep.off-road.com/jeep/article/articleDetail.jsp?id=261400
You should check your connections to the stepper and your O2 sensor. Hope this helps.

 

Your running too lean under load at a certain RPM. You have a lean spot. I am in a rush right now. I'll give you some info on how to handle it when I get back.

 

Alright...I was in a hurry the first time and I did not click on Dave's link. Everything I would tell you to do will just be a repeat of the link he posted. Hope it works out for you. If not, come back and we can go from there.

 

thanx this gives me some direction ill start on it tmrw and let you know what I found. thanx again cw

 

My 73 cj5 has been having the same exact problem you described. Mine has a manual choke too. So how would you go about fixing a "lean spot" on a 73 model R)

 

I dont believe you have a computer on your 73 these guys on here should be able to straighten you out, as far as mine goes the arcticle that dave has on his post was excellent and I think I might try the ignition upgrade which bypasses the computer and see if that fixes it.

 

Well, I personally am not a big fan of the BBD and I have usually "fixed" mine by replacing it with something else. So I am not super familiar with every little trick involved with tuning the BBD. I can tell you this though...They (yours) works with metering rods. When the engine is under high vacuum (idle, light cruise, etc) the high vacuum keeps the metering rods pulled down into their holes to block off fuel flow. When you roll on the throttle and vacuum drops, the little spring on the metering rod now has enough force to push it up out of the hole and let fuel past. This is a MAJOR over simplification of what really happens....but what I am getting at is....if your metering rods get stuck, then no fuel can get past them, which would make you very lean under load. So a good cleaning may work wonders for you.

 

A '73 has a different carburetor, the 1V Carter YF. First year for the 2V BBD was 1977, and only on the 258 trucks and wagons. Both the BBD and YF are metering rod carbs, but the similarity ends there.

Carburetors can be funny - lots of little mechanical parts and hidden plumbing has to work together to control the fuel. Sometimes you can take them apart, find nothing obviously wrong with them, do some basic cleaning, parts replacement, and adjustment, and they work much better.

Then again, sometimes you'll hear of a carb that just refuses to work properly. Hard to tell if that's because of the owner or because of the carb. The BBD is one of those carbs that everybody seems to loves to hate though. They are commonly replaced with the Motorcraft 21xx or Redline Weber kit ... I have a 2100 on my truck, in place of the original BBD (now in a box in my basement).

 

Yeah...sorry, I was still stuck in BBD mode. Take the letters BBD and replace them with YF in my previous post about the metering rods.

 

I have the Carter YF too. I know my the diaphragm is bad in my EGR valve, and so I have a vacuum leak. I guess it definitely wouldn't hurt to get a rebuild kit, and clean it up.