Strange boosting problem

[beansblacktsi]

Well i have a 92 laser awd, it has the 14b, mbc, exhuast, boost guage and airfuel guage. The problem im having is that my car will hit only 10 psi and in second it will go right to 10 and thenslowly creep up to 14 at higher rpms. Ive tried turning the mbc up and down but it doesnt change a thing, ive tried switching the wastegate line and j pipe line on the mbc, adn nothing changed. I would really appricate any coments or replys becuase I really need to get this car running good agian.
Thanks

 

[viprez586]

14psi isn't too bad of creep, you should be okay. Anyway take apart your MBC. There is a ball+spring in them, clean those, lightly lube them and reassemble. That should help with your adjustment.
Otherwise if you really want to just run steady boost do some searching on porting.

Also search for proper MBC controller hookup and make sure you have the lines right. Do NOT run them from your BOV line.

Also if you have a narrowband air/fuel gauge I wouldn't rely on that too much for tuning.

 

[numlock666]

I don't really understand your problem here. Are you trying to get 14lbs or is your problem creep?

If it's creep, look into porting.

If you are trying to get 14lbs, make sure your MBC isn't jammed open, take it apart, clean and lightly lube it. Also make sure your Wastegate acutator is pulling the flapper fully shut. Alos one last thing to check is make sure you have the bleeder fitting between your WGA and MBC, I just went through a weird boost problem and it turned out to be not having the bleeder that I didn't have for years until one day it caused problems.

 

[beansblacktsi]

well its a brand new boost controller and my problem isnt really boost creep it is that it wont go over 10 pounds or under when turning up and down the boost. it came with a breather but im not sure on which way it goes if anyone could show me a diagram or something to help. and how do i check to see if my Wastegate acutator is pulling the flapper fully shut? Thanks and here is a link to a similar boost controller http://http://cgi.ebay.com/ebaymotors/R-Manual-Turbo-Boost-Controller-240SX-300ZX-350Z-G35_W0QQcmdZViewItemQQcategoryZ33742QQihZ017QQitemZ270180342506QQrdZ1QQsspagenameZWDVW

 

[numlock666]

Link doesn't work. Is it a ball and spring type or bleeder?? If its a bleeder, throw it away and try again. How you can tell is the Ball and spring are sorta T shaped with a screw adjuster on one side with a fitting directly opposite of the adjusting screw and another fitting in between. Like this<pre>

Screw _______ Fitting <--this side to j-pipe nipple
|
Fitting<---this side to actuator (usually a small plasic fitting with hole in it between this fitting and actuator)</pre>

 

[beansblacktsi]

http://cgi.ebay.com/ebaymotors/R-Manual-Turbo-Boost-Controller-240SX-300ZX-350Z-G35_W0QQcmdZViewItemQQcategoryZ33742QQihZ017QQitem%20Z270180342506QQrdZ1QQsspagenameZWDVW

heres the right link sry

 

[numlock666]

yup thats a bleeder. Throw it away and try again. Or if money is an issue try this. Ive made one for a friend and sold it to him for 20 bucks http://www.geocities.com/chmwatson/FAQs/mbc.html

 

[beansblacktsi]

alright i will switch to my other one, but even with a ball and spring it wont boost over ten and i turned it up and down and both boost controllers do the same thing, i really need some help on this and as quick as possible, it has no boost leaks or anything, what could cause this? Thanks

 

[numlock666]

what RPM are you seeing 10lbs in 3rd gear? Is it really lagging? Could possibly be your wastegate flapper not fully shutting. I just solved this problem myself, just one day I was out driving at 15lbs let off the throttle, got back on it and it went to 7lbs and wouldn't go higher. And 7lbs came in at 4200rpms. That sucks!. Turned out it was because my actuator wasnt allowed to depressurize due to not having a 1/32" bleeder hole between the MBC and Actuator.

 

[beansblacktsi]

im not sure about 3rd but in 2nd it will hit 10lbs at about 2500 and then at about 4500-5000 it will slowly creep up to 14lbs. i have a breather for it but im not possitive on the way to install it i know where it goes but not sure on where the line comes out of the breather. Thanks

 

[beansblacktsi]

little update i put the breather on and went to test it and it hit 20 and i let of right away, i tried turning down the mbc all the way and it still will hit 20lbs so what do you guys think would be causing this. thanks

 

[beansblacktsi]

bump

 

[numlock666]

take a picture of your setup. It should go like this Boost Source (j-pipe) -->MBC In (opposite of adjusting screw, yes its possible to have it backwards) --->MBC Out --->Bleeder Fitting(has small 1/32" hole) ---> Wastegate Actuator.

From you telling me your getting 20lbs sounds like :

A) MBC screwed in too tight
B) Bleeder has way too big of a hole
C) MBC on backwards

 

[viprez586]

bump

Someone didn't read the rules, don't bump threads. Hope a moderator doesn't see this.
Look over the rules so you don't get a slap on the wrists, or better yet banned.

Anyway I'd just leave it how you had it, 14psi isn't terrible. A wise choice would be to purchase a logger to determine your air/fuel mixture, along with many many other features.

 

[beansblacktsi]

well the bleeder has a pretty big hole so could this be my problem and sry for bumping my thread.