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Some concerns Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Mon, 14 Aug 2006 12:05:35
In Reply to: Boost cut off, TheAck, Mon, 14 Aug 2006 10:04:00 Members do not see ads below this line. - Help Keep This Site Online - Signup |
The first big concern is that the boost is going to the end of the red. It shouldn't do that. Boost should go to the end of the yellow/beginning of red in an unmodified engine. Something is severely amiss here.
The first thought is that your wastegate actuator isn't working for some reason. As the pressure builds up in the intake plenum, a thin hose brings it from there to the C (charge) line on the APC solenoid. From there it is ported to the W (Wastegate) line, which goes to the wastegate actuator. As the pressure increases, it pushes on the wastegate actuator (it's just a spring-loaded piston) - the arm moves out, and this opens the wastegate on the turbo. Under base boost, the APC solenoid is de-energized, and all the flow goes from C to W. At full boost, the APC solenoid is powered, and it ports some of the pressure off to the R (return) line. That means it takes a little more pressure in the intake in order to get the piston to move.
First thing, I'd make sure the wastegate actuator isn't stuck. You should be able to pull the plunger out a little - not a lot - about 1/4 - 1/2 inch or so. Then, I'd make sure that the hoses on the APC solenoid are right - C to the intake manifold, R to the hose before the turbo, W to the wastegate actuator. I'd blow into the hose to the wastegate actuator and make sure it holds vacuum - a bad line there, and the pressure goes to the air, not to move the actuator. I'd check the APC solenoid (energized, C connected to W, not to R; denergized, C, W, R all connected. I'd double check that the C hose isn't blocked.
Something is quite wrong if you're going into the red. Also DO NOT adjust the wastegate actuator. You only adjust that if something has been changed, or you are installing a new wastegate actuator. It shouldn't be adjusted to compensate for something else wrong in the system.
posted by 192.249....
, Mon, 14 Aug 2006 12:05:35 <-- Viewing This Message, Tue, 15 Aug 2006 10:50:22, Mon, 14 Aug 2006 12:55:29
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