Issues with boost controller

[foxdie]

Hi all, got an issue with my HKS EVC 3.. the boost seems off.

I started learning how this infernal little box worked and attempts to program it yield unusual results.. the boost is offset.

Example, I'll put the boost controller into manual mode and set the boost to 0.8, boot it and the boost readout will peak out at around 0.5 (which I believe is the default boost for a VR-4).. but things get stranger;


Set Value / Actual Result
--------------------------------
0.80 / 0.50
0.85 / 0.57
0.90 / 0.61
1.20 / 0.85

Any ideas?

[AderC]

Have you still got the stock BOV? Mine didn't hold the set values til I'd ditched it for an EVO VIII BOV. I wouldn't bother trying to set up a boost controller with the stock BOV as it wasted several hours of my life and gallons of V-Power.

aDe

[Nick Mann]

I used to have an EVC IV and that needed to go through a learning cycle before it would control properly. (It always controlled slightly low though, but not as low as that.) Maybe your unit needs to do that again?

It could be that you have developed or are developing a boost leak somewhere too. Maybe in a control pipe rather than a main pipe. Is your tail pipe sooting up more than normal?

[Kenneth]

Where are you taking the boost reference from?

If you take it from the plastic elbow, you may find that there is a pressure drop across the throttle body which accounts for the difference.

Also, how have you setup the boost control solenoid? Is it bleeding the pressure off the wastegate line, or is it (like a dawes device) inline with the wastegate?


er, i guess the first one depends on you reading a different boost value from a gauge or something, rather than it being read out from the EVC...

[foxdie]

Sorry Ken I'm not sure, I'll try and find out though.

[Kelly&Ben]

you'll find boost controllers are all stupid in design.. the set value wont actually be the boost level. you basically have to have a boost gauge and set it up from that by keep turning it up

[foxdie]

Sorry I forgot to update this thread. Resetting it and putting it through a learning cycle fixed the boost level reporting issues.

A problem I'd been having recently though was the unit was refusing to give me extra boost above stock until the engine had gotten warm and a few heavy dumps of pressure would get it working again, at which point it would work fine until the whole lot cooled down again (ie. overnight).

Today I felt I'd had enough, so I removed the valve assembly from the engine bay and stripped it down... It was totally caked up inside with oily sludge!

5 minutes of cleaning all the sludge out (including cleaning down the rubber seals) with some kitchen roll and after refitting it to the car it's as good as new, reliable boost again! /woot