uncontrolable 14b boost?!?

[97fwdtsitalon]

well i guess i can say that i succesfully installed a 14b on my 2g. but i cannot control the boost at all. my boost controller doesnt do a thing and i also tried just using the acuator..no luck with either...can anyone tell me how to fix this? thanks in advance.













Drew

 

[SikRacing97GST]

Have you tried bypassing the boost controller all together, does it hold boost without the mbc?

 

[oldman]

Describe the boost behavior in detail, I suspect you are talking about boost creep.

 

[allgripnoslip]

what kind of install kit do you have? with my sbr kit, the lower radiator hose was pinching my boost feed, therefore the wastegate was recieveing no boost signal and boosting too much

 

[4CTP]

yeah man, if your wastegate is totally disconnected, it will NEVER open, and you will have as much boost as you will every want, to say the least. The actuator is not getting any pressure for some reason.

 

[oldman]

i also tried just using the acuator..no luck with either

I think he has already tried bypassing the mbc. Is the boost shooting straight up (a bad actuator, if you've already bypassed the mbc) or is it hitting a certain psi first then slowly increases with rpm (boost creep)?

 

[4CTP]

Yeah, test your actuator. Hook it up to compressed air-if it doesn't open at all, that's your problem. If you need a new one, look me up, I have a bunch gathering dust I can let go for cheap.

 

[97fwdtsitalon]

yes i tried just bypassing the mbc and going straight to the waste gate. the boost goes up to around 25 psi no matter what if i try to go full throttle. what psi is the stock 14b waste gate supposed to open? i will check later this evening to see if the waste gate is opening or not. thanks for your help.





drew

 

[oldman]

yes i tried just bypassing the mbc and going straight to the waste gate. the boost goes up to around 25 psi no matter what if i try to go full throttle. what psi is the stock 14b waste gate supposed to open? i will check later this evening to see if the waste gate is opening or not. thanks for your help.





drew

The FSM says 7psi but real world data seem to suggest 10-12 psi. If you are getting all out boost and you've already bypass the mbc, it's pretty clear that the actuator is not opening when it should. You can verified this by disconnecting the actuator arm and do a wot run. If you are only able to build very little boost, that means the wastegate swings freely and the only thing left would be the actuator. Good luck.

BTW Don't let it get to 25psi under any circumstances, shut down at about 20psi.

 

[JessesTalon]

If your arm on your turbo that holds the wastegate is being pushed on and not allowing it to move, or if your arm is seized somehow or stuck shut you would have this problem...

again double check all the vaccum lines and make sure they are correctly routed.

And please don't keep on the gas thinking the boost will go back down after its hit 20psi+... not a good idea!

 

[97fwdtsitalon]

ive pretty much decided that it is the actuator. do u think it would be alright use one of my t25 actuators on the 14b? i know it wont bolt up or anything, but i was thinking i could just cut the actuator rod on both of the actuators and weld the t25 actuator the the 14b actuator rod. do u guys think this would work? it sounds good to me. but im not 100% sure on it.

 

[97fwdtsitalon]

nevermind on that whole welding idea. i just looked at the 14b actuator and i dont think it comes off the bracket that holds it like my t25 one does. guess im looking for a new actuator now. who has one that works?

 

[Zexell]

Im having the same problem. My boost is stuck at 20psi and Unable to be controlled by my MBC.

 

[Below Ambient]

your actuator is done... go replace it... some thing happened to me... i grabbed one off ebay for aorund $30

 

[oldman]

your actuator is done

Not so fast, not until he does a test run bypassing the mbc. At this point it can still be the actuator, bad mbc or a incorrectly hooked up mbc.

 

[Zexell]

How do I test either one?? It was boosting at 20 psi even before I hooked up my mbc.

 

[oldman]

How do I test either one?? It was boosting at 20 psi even before I hooked up my mbc.

First, how is it boosting 20psi? Hitting 20psi immediately or hitting a lower boost first then slowly CREEPS up as rpm increases. If it's hitting 20 immediately then do the following.

Disconnect the pressure source from the mbc nipple and connect that directly to the actuator nipple. If you can hold around 10-12 psi, you have either a bad mbc or a leaky hose going from mbc to actuator. If problem persists, you have a faulty actuator.

 

[Zexell]

It hits a lower psi and creeps up to 20 psi.

I have the pressure source mounted a odd way. The original line from the BOV had to be changed in direction and teed off like an L instead of the running straight through.

The top of the T went to the intake manifold, the left went to the BOV, and the bottom went to the MBC. Im not sure if that matters.

 

[oldman]

It hits a lower psi and creeps up to 20 psi.

You have boost creep, different from all out boost or uncontrollable boost if you will. In fact, after reviewing this thread again, 97fwdtsitalon never really answered my same question concerning boost creep. It's possible that both of you have boost creep. I suggest doing a search on boost creep, there are a lot of good threads on this subject.

 

[Zexell]

But even if I set it to a lower PSI, it still goes to 20. At what RPM should I be hitting full boost? I'll try to post my settings.

I get fuel cut at 5500.

I was reading your previous posts, and you say that if I disconnect the actuator arm, it'll resort to stock boots? If so, why dont I just do this? Because I really hate fuel cut.

 

[oldman]

But even if I set it to a lower PSI, it still goes to 20. At what RPM should I be hitting full boost? I'll try to post my settings.

I get fuel cut at 5500.

I was reading your previous posts, and you say that if I disconnect the actuator arm, it'll resort to stock boots? If so, why dont I just do this? Because I really hate fuel cut.

Because when you have boost creep, the lower you try to set it the worst it's going to creep. Another words, if you set it to 15psi and it creeps to 20psi and you try to set it at 10psi (stock boost), you'll most likely creep to 20+psi or fuel cut, which ever come first. All out boost is a actuator/mbc problem, boost creep is a exhaust problem. http://www.dsmtuners.com/forums/showthread.php?t=166082&highlight=boost+creep There are many more if you just do a search under "boost creep", the more you read the better.

 

[Zexell]

I have stock everything from the turbo down. Im gonna see if I can play around with my MBC and WGA. If it is boost creep, i guess i need to get a new o2 housing.

 

[Zexell]

I hook up the BOV line to the waste gate and viola, boost is right on the mark. Full boost at 15-16psi, no fuel cut. Thx oldman.

 

[oldman]

I hook up the BOV line to the waste gate and viola, boost is right on the mark. Full boost at 15-16psi, no fuel cut. Thx oldman.

You're welcome. Sounds like you still have issues to sort out as stock actuator shouldn't run at 15-16psi, I would look into that more. At least for now you got it down to 15psi.

 

[Zexell]

Its actually at 9-10 psi, and around 4200k, it creeps up to 15-16. So yea I have boost creep, but not that bad. Ported o2 housing hopefully will take care of it.