Turbo problem?!

[Evo8.Rob]

Originally Posted by kikiturbo

boost plot at a minimum, but you really want a log from the ecu... like ecu load, WDGC, WDGC error,

basically, evo's will usually overshoot their boost target. What happens is that when you load up the car at low rpm the boost will shoot up, and the base waste gate duty cycle (WDGC) will be too high, esp with 3 port solenoid. When the boost readches the desired level the ecu will start lowering the duty cycle, but depending on the settings in the map iit will not pull it fast enough. Also, evo ecu looks at ecu load, which is measured at MAF and not boost directly (depending on model)... so ecu will sometimes be too slow to react. As a result you will overshoot the target boost. Now, in the ecu you have some load limits in the map, and if you overshoot those you will have a pretty hard limit that you will hit and will sense it, like a hard RPM limit..
if you do not hit that limit, and overshoot boost, you can have knock, and then the ecu will pull timing and add fuel. As a result you can feel the engine boost up hard, then loose power for a while....

if you look at your boost you will probably see boost go up, spike and then drop down.. that is what is sounds to me... In any way you will need a good log of it happening to see what is going on.. maybe a look in the map too..

That is all way over my head.. i've screen dumped it to my mapper. Hopefully he can shed some light on it all for me. I know the mapper put waste gate duty to 0 and it was still spiking.

With regards to seeking a log.. is there something i can plug in to read it?