continued improvement

[Jeepzilla]

The saga of the bezoar's motor continues. I have cleaned out the carb idle jets. Now it idles where it would not before. I have replaced the cap, rotor, wires and plugs. It now idles smoothly and does not miss anymore. I have replumbed the emissions vacuum lines and found three errors and an open port (service manuals are great!!). I now have a closed system. Now I am on a check ride and am still puzzled by lousy throttle response in any gear. Stumbles and coughs. I get a thought as I think this through, this is a mixture problem and carb while not rebuilt is at least clean and jetted right. I pull off the road and check the main damper in the air cleaner--still closed!! It is supposed to open when the engine is warm. I wire it open with a coat hanger (doesn't everyone carry some?). MAJOR improvement (oh, surprise) in driveablity now that it gets enough air. I suppose my reason for writing this is to ask how many of us with the Thermac system have checked that damper for operation as a fix for mixture/driveability squawks?

[ April 21, 2002: Message edited by: Jeepzilla ]</p>

[andy d]

uhhmn, not intimate with that particular carbatater, but thats the choke and its not opening up. check the linkage for binding. does it have a thermostat? (runs cold) if not then you 're gonna hafta fiddle with the adjustments. you want it to be closed to start the engine when cold and to back off when the engine warms. sounds easy, but can be a pita. before fiddling, id make sure all the stuff is in place and that the linkage is free.

[Jeepzilla]

Thermac is a damper system in the air cleaner snorkel, not a carburetor. On cold start, one damper opens that silver tube from manifold muff to give warm air and therefore richer mixture (in addition to choke) and faster warmup. When warmed up, that damper closes and the other opens to admit cool outside air to the carb thru the snorkel. Mine was staying closed all the time, starving the engine of oxygen.

[ April 21, 2002: Message edited by: Jeepzilla ]</p>

[LRRH]

I'm confused....I think you're talking about the vac lines that run into the air cleaner. I've never check that for opening, but it troubleshooting an 82 chero we had to rewire a keyed 12 volts to the choke....

[Jeepzilla]

The dampers are vacuum operated, you are right. There is an temperature sensor in the air cleaner body which operates a valve that opens/closes the proper vacuum line. The one that is electric is part of the Exhaust Gas Recirculation (EGR) system. When the sensor is cold, no exhaust goes into the combustion chamber. When the sensor is hot, a valve opens and admits some exhaust gas. That injection of gas cools the charge somewhat and makes it burn slower thus making fewer NOx emissions.

We are talking about two different things here. I understand chokes and their operation. The choke is in the carburetor itself. I am talking about the damper system in the air cleaner snorkel, those two silver (maybe rusty) pillbox-like Thingies on the top of the snorkel are vacuum operated doors that change the routing of air into the carburetor depending on whether the engine is hot or cold.

[ April 21, 2002: Message edited by: Jeepzilla ]</p>

[RustyJeep]

Although not a Jeep, I had that same thing happen to my 258 powered AMC Eagle. I wired it open and it alieviated most of the problem.

[Ernzo]

Great Heads Up, Zilla. Also, an easy fix, usually a vacume line and/ or one of the numerous PITA "one way" valves, which have, of course, to be lined up corectly etc. etc. etc.

SMOG!! It's whats for Dinner!!

[Lindel]

You can replace the vacuum motors on the air filter box, but I don't know that you'll be able to find new ones.

You might have to salvage some off of a junker, or get the whole air filter assy.

To replace, you'll have to drill out the rivets, and either pop-rivet, or bolt the "new" motors in place.