Can someone give me the rudiments of how the vacuum system to the waste gate works?? Replaced the plastic
flex line when I found it melted a couple of years ago, using 1/4 " copper tubing. Worked ok until now; I hear a slight intermittant ticking sound and no boost. What's AFC?
Any help sincerely appreciated. Clutch1, whaddaya think ???

'98 12v Manual, all stock. Thanks.........

 

Oh my, I just went through that. My problem was the same - no boost, no power. It turned out to be a fuel supply problem caused by a jimmied up AFC. Read the thread below titled 'Still No Power / Boost'. Several people responded with possible causes.

If the '98 is the same as the '97 (and I believe it is), the plastic line you replaced carries pressure, not vacuum, to a tee. One branch of that tee leads to the AFC, the other to the wastegate actuator. When boost is present the wastegate actuator diaphram opens the wastegate, and the AFC diaphram allows more fuel to the injector pump.

You mention a ticking sound: check the overflow valve located at the fuel return line on your injector pump. Use either a stethescope or screwdriver to see if that is where the ticking noise originates.

Good luck. Hope it's something simple and inexpensive.