Very rough idle at start up

[Red's FSJ]

Hello all, my '88 Grand Wagoneer has a real rough time getting to a normal idle when I start it up cold. I have garaged it in a warm place but that doesn't help. It varies from time to time, but for the most part, the engine just wants to shut off and there is plenty of shaking and black smoke. At times, the more I accelerate, the more the engine wants to shut off. The smoke is enough to kill someone. It seems to be quite rich. I have recently installed an MSD 6 Ignition kit, including the module, coil, and distributor. I also just added dual exhaust with a free flow cat and flowmaster muffler. The problem was there before all of these upgrades, but I think it was due to the timing which I hadn't fine tuned. A few days ago, I set the timing right, but that did not help. Once it has warmed up, the truck idles perfectly without a hitch. Power is excellent and the engine is extremely smooth, more so than my 2000 Grand Cherokee. What have I done wrong? What do you think I need to do? The more your reply is for a novice, the better. Sometimes I don't understand the terminology. Thanks for any help!
Red

[brad_fsj10]

Red,

Sounds like icing in the carb to me. Does your wag still have the stock air cleaner assy? Do you still have a hot air tube running from the exhaust manifold to the air cleaner. There's a temperature controlled vacuum valve (not sure if it's in the air cleaner or intake manifold for your year. If this valve is bad you won't get warm air to the carb during warm-up and icing will occur when humid with temps below about 55 degrees.

[jc turtle]

HI RED, CHECK YOUR CHOKE TO MAKE SURE IT IS OPEN A LITTLE WHEN THE ENGINE IS COLD. IF NOT, IT WILL RUN VERY POORLY. GOOD LUCK, JOHN

[Bombadier]

Black smoke is plenty of un-burnt fuel.
Your carb might be running too rich. Your choke might also need an adjustment as J.Cooke mentioned, Haynes manual shows the proper gap between the edge of the choke valve and carb wall...
Does the smoking go away entirely once the truck is warmed up?

[ March 11, 2003, 11:44 AM: Message edited by: Bombadier ]

[Red's FSJ]

Thanks for the responses. Yes, the smoking does go away after the truck has warmed up. I think there is a small hole in one of the emissions tubes if that matters? I will apply your suggestions and see what happens. Thanks once again!
Red

[Bombadier]

if the smoke goes away, then it's most likely just a choke adjustment. Which tube has a hole in it? A slight vacuum leak can cause our beasts to run funny.
Good luck.

[The Anti-Chrysler]

Do you mean the smog tubes connected to the exhaust manifolds? Those won't give it the condition you speak of.

Your choke is likely sticking or out of adjustment. Along with checking the adjustment, make sure you have +12v to the electric heater on the choke, as well as the choke vacuum pickup to the intake manifold being connected properly. Without either of these, the carb would have to heat soak to weaken the choke spring enough to turn off the choke - and run rich as heck until it does.

[SoCalCruiser]

I have the exact same problem. Smokes, smells and shakes for the first few minutes, then smoothes out. When warm, it's clean enough to pass CA smog.

Craig

[Bob Barry]

I bet it's the choke pulloff. It has a 1/4"-head adjustment screw on the back; pull back on the rod coming out the front of it, then turn that adjustment screw so the choke-plate opens a little more.

Then start up the rig when it's cold with the air-cleaner lid off, and verify that the choke pulloff opens the choke a little once the engine is running.

My truck was doing this very thing until I made the adjustment, and the difference was like night and day. It's only a 5-minute adjustment.

[xc_xtc]

Hehehe... mine can sound like a heli-rotor sometimes. Thump....... Thump.......Thump......thump.....thump....thump..t hump..thump.thump.thump

And the smell .... well, i'm glad i don't get hangovers, cause its enough alone to make one puke.

[Red's FSJ]

OK, I have checked it out and it seems that it may have been open too far? Is this possible given the condition of start up? Should I actually then close it some? Thanks again! Haven't started it up because I don't want it to warm up! So I'll just wait and see if somenone answers soon.

[The Anti-Chrysler]

If it's open too far, it would be lean rather than rich. You're looking for it being too closed. The purpose of the pull-off is to use engine vacuum to slightly open the choke plate.

Were is Lexington? The CT guys were looking to get together somewhere in NW CT, and I was hoping to include some western Mass guys - is Lexington in Berkshire county, or is it on the other side??

[Blackjack]

AC,
Lexington's about 10 miles west of Boston.

There's a few of us Massholes in the eastern part of the state.
We need to do a NE get together when (if) the weather gets nice.

GFD

[Red's FSJ]

Well first of all I realized that I wasn't doing it right, I forgot to pull the accelerator cable to set it into place and then do the choke adjustment. I think the carb is defective though because it keeps shutting all the way, I have to manually open it every time I start it cold so that it works right. At least I think its defective, I am probably still doing something wrong.

About getting together to do some off-roading, I don't care where it is, as long as its in New England, let me know when you guys are going. I may be in eastern Mass, but I am willing to go wherever!

Agqainm thanks for all your replys!
Red