Sean needs Help
- Thread starter sjpitts
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All of this sounds like a vacuum leak. It could be external, manifold, hose (there are what 7 miles of hose on that rig?
) gasket, etc, or internal like a vacuum switch stuck open all of the time, open at the wrong time, etc. Ether way it's sometimes hard to find on the 80's vintage rig with all of the junk that they have. The "book" way to find it is to test everything, but that can take forever, I prefer to cheat. First look for external, I prefer propane, modify a propane torch, remove the tip, add a hose, adjust the valve so it will delivers a low flow, set the carb so it's running on the idle jet and lean as possible. Then go over the system and note anywhere that idle speed increases. If there is no big changes start looking for internal leaks. My first test is to use needle nose pliers and pinch off hoses, note which make a difference, then research in the FSM to see what that hose supples, when it needs to be "on", etc.
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All of this sounds like a vacuum leak. It could be external, manifold, hose (there are what 7 miles of hose on that rig?
The "book" way to find it is to test everything, but that can take forever, I prefer to cheat. First look for external, I prefer propane, modify a propane torch, remove the tip, add a hose, adjust the valve so it will delivers a low flow, set the carb so it's running on the idle jet and lean as possible. Then go over the system and note anywhere that idle speed increases. If there is no big changes start looking for internal leaks. My first test is to use needle nose pliers and pinch off hoses, note which make a difference, then research in the FSM to see what that hose supples, when it needs to be "on", etc.
I like the propane idea. Can it also be used to find an intake leak-- such as a leak between the head and the manifold?
Jared
Yes it should work there also.
Howdy! If the smog failure is high on CO, isn't that a "rich" condition, not a "lean" condition that would be caused by a vacuum leak? On the heat problem, I don't remember, does the FJ60 have a clutch fan? John
- Joined
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Yes, it will find most any external leak. Most use carb cleaner, most any flammable spray will work. The issue I have with liquid is that it runs all over the place, making pinpointing the problem much harder. With a gas I first give it a pretty good flow, find an area that increases rpm, then turn the flow down and pinpoint the exact spot. I find it much easier.
Most leaks aren't even across all cylinders, so one (a couple) starve, run way lean. To make it idle you have to set the carb rich to make those cylinders fire, making the average of all cylinders way rich.
