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Discussion Starter · #1 ·
Hi,
My aero is doing someething exciting yet disturbing... and I am trying t find an explination...
When I bought it, the boost was stuck at base boost, so i removed the "W" hose from the APC solenoid, and got overboost cutout. So i then swapped the 'C' and 'R' hoses (so that hose C was on R and vice versa) and i got propper boost control back. now the strange thing is, that the 'C' and 'R' hoses themselves are on the correct outlets ie. R is on the intake pipe before the turbo, but i have it hooked up to C on the solenoid.
Question 1. -
HOW IS IT ABLE TO CONTROL THE BOOST PROPERLY!?!?! it cuts boost when knock is detected and holds peak boost pretty stable. It does waver between 2700 and 2500 RPM, but it is only a slight waver....

Question 2. -
Boost in the right conditions goes just off the end of the guage... past the red. I thought it would have a max boost level and not be allowed past that no matter if the conditions are right. Oh, this only happens between 2500-3200rpm... like a little overboost allowed in this rev range.

Question 3. -
Why doesn't pressing on the brake pedal go to base boost?


Thanks in advance!
 

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Hi there,

I recall looking at a separate post recently on this site & someone was experiencing a similar set of experiences as you. It turned out that the problem was one of the solenoids going open circuit within the APC Solenoid.

I recall that measuring the resistance between the centre & driver side, and then centre & passenger side pins on the unit showed 2.9 ohms on one & off scale on the other. If you have an Avo, it could be worth testing this out as it's a very easy thing to do & might (dis)prove this unit.

Hope this helps & regards,
Mally
 

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Discussion Starter · #3 ·
The thing I found is, why is it working properly with the hoses on back to front??? i think it may be a dead APC solenoid, (will check tonight) but how is it able to cut boost when it detects knock like it shouuld, when i have the hoses on the wrong way
 

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Originally posted by Grentarc:
[qb]The thing I found is, why is it working properly with the hoses on back to front???  i think it may be a dead APC solenoid, (will check tonight) but how is it able to cut boost when it detects knock like it shouuld, when i have the hoses on the wrong way          [/qb][/b]
Because the APC works by using 2 electromagnets to open and close the c-w and r-w ports using a 90Hz square wave with varing duration of the high and low portions.

If one of the coils is dead and it was the c-w one and you swapped C and R pipes, you are now using the lower rather that higher portion of the square wave on the working port to give a semplance of C-R control.

Andrew
 
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