I have an stock 81 CJ5 that I have to CA smog on monday and I'm trying to get it running in peak condition before I do. Today, I set the idle mixture until I got the strongest vaccum and an RPM of 700. It idles SMOOTHLY (if you can believe that!), and even ran fine on the road. Spark plugs where cleaned, gapped, oil changed, ran around the block, running great. Then a couple hours later, I go to start the Jeep again. Still idles smoothly... then I begin to drive it after warmup, and it starts to bog down heavily and looses serious power and seems like it wants to die on me. I'm clueless??! any ideas what happened while it sat doing absolutely nothing? I have noticed that the carb was "sweating" gas around the gasket areas, could this be a sign of a sticking float causing fuel to spill over? I observed, and it didn't seem to be burning rich or anything like that. When looking through the carb the fuel looks like a extremely fine (invisible) mist at idle to mid accel, to very light spray (visible fuel) when heavy accel. I have the distrubutor advance hooked up to direct vaccum, should I re-route it elsewhere? I have heard this could be a problem sometimes, but it was configured this way when it was running fine. Does anybody have suggestions? I just need help with this situation, its driving me nuts.

Also, anything I could do to help get my Jeep to pass? My ECU & electrical sensors no longer work, however, it had passed before when I took it to a carb shop for adjustments (very expensive!). And since then I have upgraded my ignition to the ford TFI (should burn better, right?). I also made my own smog system to compensate for the inop-sensors. It still works the way it would have from the factory, just no longer dependant on sensors, or the stepper motor. I have heard of using a bottle of alchol and filling up with gas to help get it burning cleaner. Anybody know the validity of this "trick?"

Any help or suggestions will be greatly appreciated!!

Thanks,
Rob

Rob

You never stated which carb you were using. The bogging down sounds like it is fuel starved. Check the obvious, make sure the fuel is flowing, check your fuel filter, kinked fuel return line, etc.

You stated that you set the "idle mixture" to get the strongest vacuum at 700 RPM? I believe you should use your timing to pull the strongest vacuum - and at a higher (1600 -2000) RPM. You may have the mix set too rich(sweating fuel) or too lean(bogging down).

I believe that your vacuum advance hose should be hooked up to ported (increased rpm - increased vacuum) not manifold (continual) vacuum.

BTW, welcome to the board. Hope this helps.

Scott

Welcome. I agree with Scott, hook distributor to ported vacuum. This will make the advance work as it was designed. Check it after the change. Also sounds like fuel starve to me. We are talking about the 258 right? Good luck with the inspection. Sounds like you've made some upgrades they may not like. [img]images/graemlins/grin.gif[/img]

I can't say that I have any personal experience with the alcohol trick but have had smog guys tell me that it doesn't work. That's also what common sense also tells me. If it makes any difference, it's probably so small that it won't make you pass when you would otherwise have failed. About the distributor, I would look at the vacuum diagram to find out whether it should have ported or manifold vacuum. If you don't have one, go to the library and look at the Mitchell manuals. My 71 Ford LTD should take ported vacuum according to the diagram but I have run it on manifold vacuum for about 80,000 miles. It idles smoother and gives me better mileage that way. Back in the days when I had to smog it, I switched the vacuum back to what it was supposed to be before I took it in and then changed it right back. I love having old cars that are smog exempt!

Thanks for all the replies. I forgot to mention it is a 258 engine with the 2bbl carter carb. I came home today and drove the jeep, same problem. Then I blasted it with carb cleaner again (I neglected to mention I did this before adjusting carb). Now it runs strong just like before. What gives??? It just had a carb cleaning, sits for a couple hours, then it runs like terrible again until it gets another cleaning? I also added a fuel treatment previously (after I filled up the tank) before any problems. Could this be a clue? I plan to change the fuel filter, spark plugs & wires tommorow (sunday), before my smog on monday.

About my idle, the book said 700-900rpm? I couldnt get it any higher adjusting the carb, but I can using the little screw that pushes the throttle forward. Should I move it up to 1600rpms as my usual idle?

Also, where can I hook up the distributor to ported vaccum?? The way I have my vaccum hoses are slightly different than stock. The distrubutor goes directly to carb, 2 lines from carb go to the CTO and the EGR, smog pump & evap canister purge line hooks up to the CTO, and 1 line from carb opens up vaccum to allow smog pump air to go to the cat. My TAC system is a "dummy" there are hoses and sensors, but they connect to each other in a loop, so essentially they do nothing but look good. It all looks stock, just that it isnt. It fooled test only guys before [img]images/graemlins/smile.gif[/img]

Thanks again. I'm so glad I got so many quick responses!

Even though Wisconsin is not near as nazi as California when it comes to emissions... I have used the alcohol trick it does help, how much and in what areas I couldn't tell you, all I know is I was happy to pass. Run the smallest tires you can make the engine work the least amount possible, also I didn't see you metion an air filter in your list of replacments this is a must.
John
[email protected]
P.S. Napa sells a product called guarrenty pass or something along those lines I don't know what it contains but I've heard it works.

Still sounds fuel starved to me. (air/fuel mix)
Your ported vacuum from carb to dist is fine where you have it now.
DON'T set the idle @ 1600 - this is more of a timing RPM.
Set the idle to factory recommended settings(700 -900 seems high).
How are you setting the idle speed? You said you couldn't get it any higher adjusting the carb but you could by using the adjusting screw. The adjusting screw IS what you should be using to set idle speed.
While it is idling, spray carb cleaner around any vacuum fittings, base plates, anywhere that there could be a leak. If your idle changes- that is where you have a vacuum leak. You will have to fix the leak if you have one as it will mask your other problems that you may be having.

Scott

I'm happy to report that my Jeep passed! It didn't at first though. The smog guy suggested that a little carb adjusting could help fix the problem (it was rich). I cant afford a proffesional carb tunning right now, and today was the last day I can do my smog (without having to go to the dreaded DMV for permission slips) So I came home and fiddled with the internal adjustments of the carb. I adjusted the screws to see how the engine reacts. I managed to get it where it was very lean. I could tell just by looking at the fuel going into the intake that alot less gas was going through at the same RPM as before, so I took a chance on it and re-tested it. Passed by a very comfortable margin.

Now my second problem [img]images/graemlins/smile.gif[/img] The jeep is definately fuel starved now. It doesnt hesitate badly, but that nice powerful acceleration is now gone and has flat spots. I tried re-adjusting the carb like before, but it doesnt want to go rich again. Does anybody have experience adjusting the 2bbl BBD carter? My ECU doesnt work, so I had no problem with it trying to compensate. I can drive it like this, after all my main headache (smog) is now gone. Any kind of advice to richen the carb again would be great.

I still dont know what my original problem was. I cleaned the carb again yesterday, changed the fuel filter, air filter, plugs, & wires, and it ran great ever since. I also checked for vaccum leaks, there where none, except from the evaporation canister (which I already knew about and disconnected until I siliconed the leak lastnight), other than that, I have no clue why it was acting up like before.