Calgary Jeep Association

4x4 Related Groups => Tech Talk => Topic started by: hatchtyler on July 21, 2011, 09:57:19 PM

Title: 1990 YJ 4.2L Sputtering Problem
Post by: hatchtyler on July 21, 2011, 09:57:19 PM

Hey Guys!  I'm a new member, and this may have been asked before, but my search didn't turn up anything helpful.

So, I recently bought my 1990 YJ with the 4.2L I6.  It starts REALLY rough with a ton of sputtering and won't hold an idle until about 5 minutes later when it's warm.  I recently did a good tuneup with new plugs, wires, dist. cap, rotor, fuel filter, oil change.  I tried to do the timing by traditional methods (timing gun) but ended up adjusting until the engine ran the best.  It runs better when it's warm, but I still have problems on startup and a little sputtering. 

I'm thinking a MC2100 Carb is the next step, what do you guys think?

Thanks for the help!

Title: Re: 1990 YJ 4.2L Sputtering Problem
Post by: LukeDuke on July 22, 2011, 08:58:23 AM

Nutter Bypass. It makes all the difference in the world.

http://jeeps.hallbergs.com/nutter.htm

Title: Re: 1990 YJ 4.2L Sputtering Problem
Post by: Dagoose on July 22, 2011, 09:54:52 AM

I would nutter and get rid of the Carter carb. I run an MC2100 on my CJ and it was a huge improvement. I could never get the idle or tune correct with the Carter.

Also check your choke, I'm assuming it's electric. It might be stuck open.

Title: Re: 1990 YJ 4.2L Sputtering Problem
Post by: hatchtyler on July 25, 2011, 04:21:24 PM

thanks for the advice you guys!  I just discovered a burst gas line and fixing that seemed to help A LOT, but I'm still going to switch the carb.

Title: Re: 1990 YJ 4.2L Sputtering Problem
Post by: binare on July 25, 2011, 06:49:53 PM

There's a lot of things that mask as a carb issue. The Carter really ain't that badlet me know if you need a hand with it. Money on the Weber is better spent elsewhere if your willing to show the Carter some love.