Overboosting all of a sudden.

[sexytoy69]

I have a problem with either my Tial 38mm wastegate or my Hallman boost controller. I am overboosting big time. My boost gauge is going all the way to around 30 PSI. I have set my manual boost controller at 15 PSI, and it used to go to 15 and just stays there, but about a week ago I started to overboost all of a sudden. I'm not sure if it's my wastegate or my MBC that is causing the problem. How do I diagnosis this problem? Thanks.

 

[WOTDSM]

Sounds like your wastegate actuator lost its pressure source so its never opening. Check MBC/WGA vacuum lines

 

[sexytoy69]

I checked all the vacuum lines and they are okay. What else can it be?

 

[90talonfwd]

its the wastegate, get a new one

 

[sexytoy69]

This is a brand new Tial wastegate. I've had it for about 1 month.

 

[90talonfwd]

then im not sure whats wrong

 

[tqmx1]

Check the wastegate accuator to make sure the diaphram is not blown out when it blows it locks the wastegate closed. My GSX had it happen before I bought it and it blew the ring lands out of the pistons.

 

[sexytoy69]

Is there an easy way to check if the wastegate piston is stuck besides taking it apart? Because my wastegate is hooked up to a DNP manifold, and it's such a pain in the ass to remove the wastegate.

 

[unlmtdndeavor]

was this setup working correctly for a while. or once you installed the wastegate and mbc. what spring do you have in the tial

 

[sexytoy69]

was this setup working correctly for a while. or once you installed the wastegate and mbc. what spring do you have in the tial

Yes, it was working fine when I first installed the wastegate (which was for about 3 wks until the overboost problem). I have the 14 PSI spring from ExtremePSI.com. The mbc was installed over a year ago, and that was working fine also.

 

[tqmx1]

To check the accuator remove the hose connected to it install a longer one (about 3 feet should do) and install a vacuum scorce (your lungs will do just fine) if it holds a vacuum you are in good shape and if not you know what to change.

 

[sexytoy69]

This is weird, but all of a sudden the overboosting problem stopped. I'm back to 15 PSI. I didn't really do anything to fix the problem. All I did was recheck all the hoses and wiggle the BCS a little. Oh well, I'm sure the problem will occur again.

 

[delta448]

The MBC may be failing from being clogged with oil or dirt. BCS may be shot.
Personally I think the BCS is useless and run my MBC straight off the LICP to the WGA.

 

[sexytoy69]

The MBC may be failing from being clogged with oil or dirt. BCS may be shot.
Personally I think the BCS is useless and run my MBC straight off the LICP to the WGA.

I do run my MBC straight off the LICP to the WG, but my BCS is still hooked up to my intake. Should I just unplug the BCS? I just don't want a CEL to come on.

 

[lenny 15]

I have a problem with either my Tial 38mm wastegate or my Hallman boost controller. I am overboosting big time. My boost gauge is going all the way to around 30 PSI. I have set my manual boost controller at 15 PSI, and it used to go to 15 and just stays there, but about a week ago I started to overboost all of a sudden. I'm not sure if it's my wastegate or my MBC that is causing the problem. How do I diagnosis this problem? Thanks.

16G's cant boost 30 psi... what were your EGT's, and AFR's? or were you running lean at all? when i bought my car it had a T25 and the boost gauge showed it holding 20psi to redline.... when t25s can only spike at 15 psi, then ussualy come down to around 10psi near redline, the car had the cheapest boost gauge that autometer sold. it was always going haywire, reading different boost levels on every pull, so yours could have gone out.

Just thought i would throw that out there.

 

[zippyshoe]

I do run my MBC straight off the LICP to the WG, but my BCS is still hooked up to my intake. Should I just unplug the BCS? I just don't want a CEL to come on.

If you have an MBC, then you should not have any vacuum hoses connected to the BCS - once you remove the vacuum line between your BCS and intake, just cap-off the vacuum port of your intake. You may also want to cap-off the two vacuum ports on the BCS in case you ever decide to use it again. Be sure to leave the electrical connector plugged into the BCS to avoid a CEL.

 

[sexytoy69]

Just as I predicted, my car started overboosting again yesterday. I don't know what's going on. Please help.

 

[zippyshoe]

To determine whether the problem is a faulty MBC or a faulty wastegate, try running a vacuum line directly from your LICP (boost source) to your wastegate actuator (effectively bypassing your MBC altogether) - if your boost returns to a reasonable value, then this points to a faulty MBC. If you still experience overboost, then this points to a faulty wastegate.