Weird Boosting levels...

[Jspec7m88]

Well, I've had 3 different turbo's on my car. The first, which was a .57 Trim, I bought it with it on there, and not until the last few months that I had it on there did I notice that I would get what I think would be called "boost spike". From searching, I've found that boost spike usually occurs by the MBC all depending on a spring that will sometimes spike up the boost instantly. I have no boost controller...However, After putting a stock turbo back onto my car...It still did the same thing...
"80% of the time, if I went WOT from a roll, after about 3-5 seconds of being WOT, my boost would be at 11psi or so...then within a split second, it "spikes" to 15, hits fuel cut, and then I back off. I thought it was the turbo itself...so after installing my 60-1 CT26 tonight...Going on a test run, I've found that (driving at a normal 9psi)...it will spike up to 15...AGAIN.
I thought it was the turbo/wastegate causing the problem...so what could it be. I am stumped. I thought it could possibly be my AFM which has been through hell and back because my filter sits under my headlight and it's seen some very wet days...:icon_conf

 

[Joel W.]

It sounds like a crack/split/leak in the waistgate actuator vacuum/boost reference line to me?

 

[Jspec7m88]

Well see, this problem has occurred over 3 different Turbo/Wastegates...
Vacuum/Boost...I don't know...I'm pretty positive the lines are ran just fine.

 

[Joel W.]

Yes, but did you use the same vacuum line for all three turbos? The one going between the outlet nipple on the turbo to the actuator port.

edit: I call it a vacuum line but it is really a boost referrence line in this application...

Just trying to help.

 

[Jspec7m88]

Hey first off, I appreciate your help! 2nd, Yes, I used the same "vacuum line". This one has really got me stumped. I'm really hoping I'm not the only person on the face of this earth that hasn't experienced this yet. Tomorrow, I will go out and record a video of what I am talking about and record the boost gauge while doing so...(If I remember). Thanks for the help though, Joel!

 

[Joel W.]

Your not the only one, I had a split in my line and it would do the same thing. It would not leak under vacuum but it would over 10psi and it caused spikes.

Try a new line (it's cheap and good insurance) for a test...

 

[Jspec7m88]

I think I will just replace all my vacuum lines...Hopefully that helps...because I hate hit...It only seems to do it sometimes...and it does it while I'm holding boost for a few seconds...First gear, it never does it because it doesn't get as much boost...so...maybe I do have some sort of vacuum leak...

 

[92turbo4life]

i think its a vacumm leak but yeah jeff change al ur lines and see if that does it. thats some strange shit........

 

[Jspec7m88]

Well, an update. It doesn't go to fuel cut off(15psi on mine)...

It did this when I had my stock CT26 on there..and it does it now...but instead of fuel cutting at 15psi...it does it at like 10.....
Here is a vid to explain what's happening. BOTH times that I let off and it blows off, I was at WOT both times and it was fuel cut and my check engine light came on both times that I let off the petal.

http://smvideos.suprapics.com/index.php?fileid=9de656c0f124d30f368196b1250adb50

I'm lost guys...I can't do a damned thing...Something just isn't right.

 

[Joel W.]

That could be because the new turbo is flowing the same amount of air at 10psi compared to the stock CT at 15psi.

Is it still spiking like it was? It does not look like it..

 

[Jspec7m88]

Okay, I'll break it down and explain.

My 1st Turbo: .57Trim CT26
I was running about 13.5psi in 2nd, 3rd & 4th gear...
If I went WOT in any of those gears, after it shifts into that next gear, IMMEDIATELY after it shifts into the next gear, then my check engine light kicks on, car jumps(fuel cut)...I recorded a vid of it doing that and it spiked to 15psi and then dropped down.

2nd Turbo: Stock CT26.
It was at 10-11psi in 2nd, 3rd & 4th gear...
At WOT, it would hold a strong 10-11psi...then sometimes even before shifting, it would do the same thing as explained above...But it still spiked to 15psi instantly then jumped back down to 10-11 and check engine light came on, blah blah blah.

3rd Turbo: 60-1 CT26 10* Clipped, the works.
At about 8.5-9psi in 2nd, 3rd & 4th gears.
Going WOT, it will hold strong for about 4-5 seconds, then it feels like hitting an invisible wall(check engine light comes on) and what I am explaining right now is what you just saw in the video(posted above). In the video, It doesn't seem like it, but when it looks like I'm letting off, It's hitting an invisible wall and CEL comes on, etc.

I hope that was clearly explained enough...

 

[blk91]

My car did the same thing Everbody said it was a boost leak or a vacum leak and i replaced all of the vacum lines the IC and IC pipes And i could never get it to go away The system would even hold 15psi pressurized with a compressor. And it kept happening lower and lower until I had Fuel cut a about 8psi. I never could fix it......

 

[Allan_MA70]

is it an oiled air filter?

 

[Jspec7m88]

My car did the same thing Everbody said it was a boost leak or a vacum leak and i replaced all of the vacum lines the IC and IC pipes And i could never get it to go away The system would even hold 15psi pressurized with a compressor. And it kept happening lower and lower until I had Fuel cut a about 8psi. I never could fix it......

Well that's what I'm afraid of...Because It was cutting off at 15psi...now it's cutting off at like 10...:icon_conf

 

[mkiiSupraMan18]

I'll let you try my AFM to see if thats your problem Jeff.

 

[Jspec7m88]

Cool. I think it really is though...because there was that flooding that I got stuck in and it just DRENCHED my filter in water...car wouldn't start for days...then I pulled off the AFM & Filter, cleaned the filter and put the AFM in the freezer(yeah, I know)...so it would dry...then it started...I bet my AFM is just on its' last leg...

 

[mkiiSupraMan18]

In the freezer to dry? lol Thats fun. Just let me know when ya wanna come down and try it.

 

[Jspec7m88]

LOL...I was pissed at that point...I thought it was done with so I just tried putting it in the freezer for a couple hours...then I took it out, put it on my car, and it fired right up! Stupid, Yes, but did my car start? YES. Now...I'm HOPING it's my AFM that's messed up.. (well, not really) lol

 

[blk91]

When I tried Swapping AFMS it fixed the problem right away... but within a week it was doing it againl, My problem was never really solved. Wish I had some more info.

 

[Jspec7m88]

Welp...Got a boost controller put on...I turned it up, and (obviously) I knew I was going to hit FCO...but 1. wanted to make sure it worked, 2. see if my lines were bad. I have no leaks in the vacuum lines. I cranked up the boost pretty high and normally in 1st gear, I would only get about 7.5psi (with the way my turbo is right now)...but at not even 3300rpms, It went to 10psi and wah-lah, FCO. So...Obviously, my FCO is dropping...First, 16, then 15, now 10...so whatever the problem is, it's just getting worse now.

I have noticed that there are people on here who have experienced this problem, but sadly enough, nobody figured out the problem. Unless a genius of the MKIII Supra wants to chime in on what they think...I am going to narrow it down to my AFM on its' last leg.:icon_conf