boost control issues

[kjizzle]

im having a weird problem with my new boost controller. with a stock style wastegate actuator, i had no problems pushing the 17 PSI that i wanted, but it wasnt very solid. usually, it would spike to around 21-22 PSI before dropping back to 17. i picked up a hallman pro mbc off a buddy who just got a new electronic controller for a good price.

installed tonight. i capped off the ends of the stock solenoid, ran the stock vacuum lines from turbo and actuator to the controller, then turned down my adjustable actuator to almost as low as it would go, still had to pull it about a 1/4" though.

took it on a test run, (turned all the way down). it hit about 11 psi. i figured, fine. pulled over, turned it up. still 11. weird. turned up some more, spiked at 15, then dropped to a steady 11. it really likes 11. firgured f it right? turned up a bunch, spiked 20, dropped to 11/12 and held solid. what is going on here?!!

i thought a boost controller would help me out, but its only causing a stranger problem? or could it be something else?

 

[Fuelie600]

Turn your controller down, and shorten your wastegate rod to get where you want your base boost, and then use the contoller to adjust up. I believe you do not have enough tension on the wastegate rod to hold it closed---causing your boost spikes.

 

[kjizzle]

i'll try that and make a run tomorrow. base police hang around here way too much this weekend to make loud noises. dui patrol and all...

 

[kjizzle]

tried that, shortened the actuator rod up to about stock levels, but it still spikes with the boost controller in line. what gives?

 

[Fuelie600]

Well it sounds as if your wastegate spring it weak, or the lines to the controller are not connected properly. You have had the same issue with both stock and aftermarket controllers, so those could most likely be eliminated from the equation. Please explain where both vacume lines come from and are attached to. You might also want to tighten your wastegate rod some more, and see if the problem lessens. Brian

 

[kjizzle]

the line from the compressor goes to inlet of the controller (the end with the check valve ball in it). the line from the boost controller on the bypass end (the other line) goes from boost controller to the stock wastegate solenoid.

i tightened it up also an hour ago and the problem doesn't seem to subside. it still spikes high enough for me to feel the timing retard kick in for a split second then recover.

i ordered a new downpipe that i haven't installed yet, so if i can't troubleshoot this before that gets here, i'll just throw that on. i wasn't planning on doing my dp yet, but i have an aftermarket one sitting here, so maybe i'll put that on this weeekend.

 

[Dreamcar86]

To test your actuator run the hose from the compressor housing directly to the actuator and see what happens. If you cannot control it that way then the actuator is bad.

 

[kjizzle]

i'll try that.

 

[Dreamcar86]

i'll try that.

Be sure to let us know your results.

 

[kjizzle]

OK...

(2 Days ago) direct line from compressor housing to actuator got me better then before through the stock setup and WAY better than with the MBC.

(tonight) Borrowed a buddy's electronic boost controller left over from one of his projects (1992 civic hatch). Works beautifully. once i got the gain and junk all dialed in, no spikes in lower gears, no creep. awesome. rock solid all the time.

but i have a new problem. The reading in my boost gauge doesn't match the greddy units reading. the TT chip i have is for 15-17 psi, so i dialed the old boost up to 17 on the boost gauge i have (not the stock dash one, its pillar mounted). After hooking up the greddy, it says i'm running 19.5.

i always noticed that my stock gauge and the aftermarket one never jived (the stocker always read higher), but i figured that it was just the standard old crappy electronics not working right. but now i wonder if the aftermarket one doesn't read right? i noticed that i can hear the squirrel that lives in my turbo chatter after the aftermarket gauge says 0 in hg/0psi. the greddy unit/stock gauge says 2-4 psi before the pillar gauge shows anything.

sorry for the long post, should i throw this new question in a different thread? i try to give more information than not enough.