hesitation

Today I discovered a problem and I need some suggestions.


Took my wife 4 wheeling this morning. Put it in 4-low and we climbed a rough road a couple thousand feet about halfway up Holston Mountain. She got carsick and I turned around and came back down. When I got to the bottom I unlocked the hubs, put it back in 2WD and started home. I immediately knew something was wrong when I noticed there was about a three second hesitation between pushing the gas pedal and the engine responding. This has never happened before since I bought the Jeep. I drove on home, let it sit for three hours and drove it again a couple miles down the road and back. No hesitation after the cool off.

Background: I've had the Jeep for about a month now, but only got the gas and temperature gauges working last week. Since I got the temperature gauge working (new sender, wire, and speedometer+gauges), I've noticed that the temperature climbs to "high" within five minutes of starting the engine. The radiator coolant is full. The hoses look old and worn. Thermostat is in unknown condition.

I've driven the Jeep to work and back home (62 mile round trip) twice at highway speeds (60 mph) without experniencing this hesitation problem. The Jeep always starts and has seemed to run fine up until now. I replaced the plug wires about two weeks ago.

I am guessing I experienced some sort of vapor lock or overheating problem. My question is, what to do next? Replace the thermostat? Radiator (unknown age)? Or am I on the wrong track alltogether? Engine is a 304.

 

Update:

Just got back from a fifteen mile grocery store trip this morning. The hesitation I experienced yesterday seems to be completely gone. Another thing both my wife and I noticed yesterday during and after the 4wd climb was what smelled like exhaust fumes inside the Jeep. We didn't smell it at all today, nor have I ever smelled it before yesterday. Yesterday was the first time I've ever had it any distance in 4wd.

 

Only time I had that kinda problem was when my tranny was low on fluid in the '66 Olds Dynamic 88 I used to drive. Had to wait a few seconds for the fluid to all drain into the pan for the pump to pick it up.

But looking at your jeeps profile, it's a manual so that won't be your problem.

Could be fuel starvation or maybe a temporarily clogged air filter?

 

Or the float hung up momentarily, causing you to have too much fuel and coming close to flooding it out.

 

That sounds like a possibility.

 

What type and model carb do you have? If you are smelling exhaust or the engine is running fat after being on a steep angle is typical carburator behavior as far as I know. The cooling problem that you've explained, sounds like a thermostat problem. I would start there.

 

Choke...plain and simple. I'll bet you have an automatic choke, which tend to stick, especially when changing altitude that fast. I've had the same engine problem off roading in the mountains in AZ, then when I get back down to PHX, the problem seems to vanish....even thought about putting in a manual choke one of these days but haven't gotten around to it. Try lubricating the choke and see if the problem persists.

 

As for the exhaust smell, what is your exhaust setup? Do you have duels that exit in front of the rear wheels? Straight out the back? Stock location?

If you don't properly set up the exhaust, you can actually draw the exhaust back into the Jeep as you drive. It's more noticble when you drive around fairly slowly........