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Re: Base Boost and messed up Cruise Control Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Fri, 13 Jan 2006 04:16:03
In Reply to: Base Boost and messed up Cruise Control, steve, Thu, 12 Jan 2006 19:03:06 Members do not see ads below this line. - Help Keep This Site Online - Signup |
In your '86, the APC works pretty simply. There is an APC solenoid on the radiator - the thing with three hoses (or should have three hoses). One goes to the pressure (output) side of the turbo, one connects before the turbo, and one goes to the wastegate actuator. It's an electrical valve. If it isn't powered, it's closed, and it shunts all the air from the turbo output to the wastegate actuator. That's base boost. When it's powered, the valve opens, it some of the pressure is also connected upstream of the turbo. This means that it takes more turbo pressure to move the actuator, so you get more boost before the actuator starts to open the wastegate.
So the APC is easy - no power to the solenoid, base boost; power - full boost. The APC solenoid can be turned off a few ways - by the APC box if it detects knock, if the brake lights are on, or if the cruise control is engaged. One of those little dohickeys on the right-hand fender by the CC pump connects to the APC solenoid. It's just a pressure switch. The CC works by applying vacuum to an actuator, and the actuator pulls on a chain and moves the gas pedal. So if there is vacuum, the CC is engaged. That little pressure switch is in series (electrically) with the power going to the APC solenoid. If there is vacuum, the switch opens, and cuts off power to the solenoid.
So what does this mean if you want to disconnect the Cruise Control? Find the pressure switch - it should be the one with two wires coming out. Tie the two wires together. Now it doesn't matter what the CC is doing, or if it even exists.
My guess is that something else is driving you to base boost, because it sounds like somebody did a little bit of butchering on this car. That makes it more 'interesting.' But it's a start.
posted by 192.249....
, Fri, 13 Jan 2006 04:16:03 <-- Viewing This Message
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