Intake Runner Leak

[wolfej1]

Well I found a vacuum leak at the intake runner gasket (if that is the correct terminology). Looks like it can be replaced without pulling the engine. Am I correct?

Here is some additional info in case anyone is interested:

I have been struggling with a poor idle for a quite a while and was pretty certain that it was vacuum related.

I thought my leak at the throttle shaft was causing my idle issues but a squirt of carb cleaner at the juncture of the intake runner and the head at number one cylinder confirmed the leak very quickly. The idle shot up very noticibly.

It all makes sense now. When cold the van started easily because the Aux Air Valve was helping it maintain a high idle. However, once the van began to warm up and the AAV closed up the idle became very low and hunting and would almost stall. Then after driving and getting the engine hot it would idle OK because the heat would expand the intake runner gasket and the leak would stop or be very nearly stopped.

This was a frustrating situation because I would try and adjust the idle when the engine was warmed up - and it would be fine. However, the next day the van would not idle at all without utilizing the gas pedal - because the leak was back in play. Then in order to get the van to idle when cold I had to turn the idle screw up - but once the engine got hot it would be idling way too high because the leak was not there.

Just thought I would share this in case some other poor sap like me happened to be struggling with this situation. I had checked for vacuum leaks everywhere except there so make sure you check there as well.



Thx
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1982 Westy
2004 KDX200
2008 Kawasaki KLR 650
1979 Yamaha DT 175
1995 Toyota 4Runner

[Gauche1968]

Would a leak where you describe cause a vacuum leak or an air leak?
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1984 Vanagon GL
1984 Vanagon Westy

[wolfej1]

I am not certain of the terminology, however, it would be unmetered air entering the system and screwing things up.

As an aside, I tightened up the 2 nuts in the affected spot and the leak was lessened somewhat and my vacuum reading increaded to about 17 at correct warm idle speed - where previously the vacuum was 12-14 at correct warm idle speed.

That gasket has to come off and be replaced. Hate to pull the motor for that
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1982 Westy
2004 KDX200
2008 Kawasaki KLR 650
1979 Yamaha DT 175
1995 Toyota 4Runner

[Gauche1968]

Do you mean the gasket underneath the intake runner as they enter the cylinder heads?

There should be no need to drop the engine for that. Remove the airbox. Then you are going to have to take out the injectors and unbolt the coolant pipe that runs across the top. Then you should be able to take the runner out by loosening the bolts where it enters the cylinder head and then disconnecting it from the intake plenum. Then simply replace the gasket. At least that is how it went on a 1.9.
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1984 Vanagon GL
1984 Vanagon Westy