I have a 3-port boost solenoid setup with direct ECU boost control with an Evo X MAP sensor. If I get into boost before the motor warms up (eg, if I boost withing the first mile of driving), the solenoid is wide open and I overboost into fuel cut. After I drive another mile or so, boost functions normally. Any thoughts as to why this occurs?

 

I just noticed this as well, w/ my IX... Wasnt logging while it happened (twice) I attributed it, to the car not being fully warmed up, but after reading this post, maybe it is the 3-port, and Im hitting boost cut. I got a small lil pop each time it happened.
@ first I thought it was spark blow out, or something wrong w/ my plugs, pulled em, they were fine, checked the gap, all plugs @ .024...
I would say, just drive the car for a min. or so before getting into any boost...

did u log the occurance, by any chance?

 

Nope - I've never logged it. Usually when I log, my car is fully warmed up.

 

Wouldn't the % WGDC / coolant temp table address this?

 

Interesting to know
my car runs a bit lean when boosting at first bit then good and when fully warmed up

 

My table is stock. Max WGDC is 0 below 60 deg C. At 60 deg, the max WGDC is 50. At 70 deg, max WGDC is 100. In theory, I shouldn't boost at all when cold. I suspect what is happening is that the ECU sends no voltage to the BCS when the water temp is cold but the 3 port must default to be fully open, hence the overboost. I will try to put some numbers in this table below 60 deg to see if this works. I don't daily drive my Evo so I will post later.

 

Just wondering why the heck you guys are hitting full boost before the car is up to normal operating temp anyways? Not good on your engine ya know!

 

I'm not trying to boost a cold engine - because my BCS is wide open when cold, I'm unintentionally overboosting even at part throttle.

 

Why you gotta be sane and reasonable and spoil our fun!? I will booost whenever I want! Even if it's cracking cold out side and I just crank up!

 

Just go to your Max WGDC vs. Coolant Temp Table and adjust it lower.

 

My under 60 degree temps are already at 0%

 

Have you logged your coolant temps and WGDC while the overboost occurs? It shouldn't be able to exceed the max value in that table unless something is up. Your coolant temps may exceed 60* rather quickly, even when air temps are much cooler.

 

I have not logged this occurrence. Typically when I log, my car is already well warmed up.

 

Give it a try and we'll see if we can get to the bottom of it.

 

No datalogs yet but I have a new issue. I just installed a new BOV (Perrin - awesome BTW). Car boosts through the gears fine. If I do a low rpm, high load (like from 60-65 mph) pull in 5th, the car overboosts until I hit fuel cut (around 28-29 psi). What gives? This happens consistently in 5th.