[BB6SE]

When i floor my car.. boost starts to build around 2k
then around 3k my boost drops to 0psi..
then starts building again around 3500rpm

according to my dyno graph, im running very lean at 3k
my mods are dp, intake and exhaust

will a safc or other type of fuel controller help me?
what is causing this?
THANKS GUYS!

 

[MaliCali]

sounds like you have a major boost leak....

 

[Jaxx]

sounds like you have a major boost leak....

I would agree with this. What psi are you hitting when boost does build and what are your egt's?

 

[BB6SE]

im hitting 14 psi and it holds till redline..
are u sure it's a boost leak?

i don't have an egt gauge

 

[cwtt]

I know this is going to sound funny, but I am dead serious..... does your cruise control work ?

If not I know exactly what your problem is.
I used to have the same problem, at 3000rpms my car would hit a wall and boost would go to 0.

 

[BB6SE]

cwtt!!!! help me out man!!!
my cruise doesn't work
damn im glad u know why.. now u just gotta tell me how to fix it
THANKS!

 

[michaelvanle]

I know this is going to sound funny, but I am dead serious..... does your cruise control work ?

Yea, that does sound wierd lol.

 

[Guest]

I also loose boost at 3K...but only in 1st gear. Cruise control works fine........I think... :dunno:

 

[cwtt]

cwtt!!!! help me out man!!!
my cruise doesn't work
damn im glad u know why.. now u just gotta tell me how to fix it
THANKS!

LOL
I knew you guys would think I am crazy, but here is the problem.

Your ecu is not getting the VSS signal (VSS= Vehicle speed sensor). It is a common problem on supras for the solder on the back of the odometer to go bad. This is where the vss signal is located. So basically the ecu is not getting a speed signal.

Here are the steps to correct/ test the problem:
Here is how you can TEST to see if you are having a problem with your VSS or something else. If this jumper did solve the problem, then splice the 5 & 6 wires together on the back of this plug.

Since I am such a nice guy I will even include a picture for you... :bigthumb:

Here is a picture:

You can find more info by searching for "vss" or odometer + vss or anything simular to that.
like:
http://www.supraforums.com/forum/showthread.php?s=&threadid=20583&highlight=odometer+jump


Basically once you fix the problem everything will function correctly. You will have a better rock solid idle, and smoothe boosting!

K, now im off to have some beers with the ladies, hit me up if you have any more problems.

 

[Project-SupraDupra]

i had the same problem
just convert it into TTC then it will be solve

 

[Jaxx]

^^

I don't think a lot of people would want to go TTC just to fix this problem ya know?

 

[BB6SE]

PROBLEM SOLVED! Thanks to cwtt!

 

[Guest]

I have researched the VSS problem A BUNCH and know a LOT about it, but I never knew it caused boost problems. Thanks cwtt!

 

[cwtt]

I have researched the VSS problem A BUNCH and know a LOT about it, but I never knew it caused boost problems. Thanks cwtt!

Yeah, actually effects a lot of things like : boost/sequential operation, idle, cruise control, false rev limiter etc.

Glad I could help you guys.

Now give me some rep points +1 haha :bigok:

 

[Guest]

Also causes funny shifting in an atuomatic car while driving slowly, and a flashing O/D light. Weird how just a simple signal could cause so many problems.

 

[michaelvanle]

Yea I did that jump the wire shit and it still ain't working. My cruise is still dead.

Also, when I turn on the cruise, the light will go on, then it blinks off. Then it'll go on randomly a few secs later.

 

[brian_k03]

i have resoldered my points on my board only to have cruise control work when it wants too. When the overdrive is not flashing i can use cruise control.

I will try splice #5 and 6 together to see if that fixes that blinking light.

 

[IcedSuPrA]

sorry to bring back an old post but

i wanted to say that i did splice the 5 and 6 wires and it worked...my cruise control works again and my turbos boost the way they are supposed to...


thanx to cwtt...

Ant

 

[SupraSonic]

I'll try to test sometime this week. I'll let you guys know my findings.

 

[michaelvanle]

:lol: