Boosting issue with Greddy Profec B

[DSMGUY420]

so this may be a dumb question but im new to the turbo world and im having a problem i have a 95 eclipse gs-t with a 16g turbo with a internal wastegate and a greddy profect-b boost controller now no matter what i do with the controller i wont boost more or less then 10lbs and sometimes out of nowere it will boost 15- 22lbs and i have no clue why even if i turn down the boost on my controller, i just wannt to know how i can controll my boost can anyone give me some input please and thank you

 

[Calan]

Where are you taking the boost source for the controller from?

 

[DSMGUY420]

im sorry what like were am i getting my reading of my boost gauge

 

[90moneypit]

Yeah, that's what he means. Depending on where you're tapping into the vac/boost line, it can affect what your profec is seeing vs what your boost gauge is reading. Other factors include possible boost leaks, if you're still using the stock boost solenoid (it bleeds boost off), what rpm you're seeing the problem... Lot's of things. List your mods and what you've checked so far.

 

[DSMGUY420]

at around 4500 to 5000 i havent checked anything but the down pipe witch was loose so i tightned that up and im still having the problem um as for mods to the actual turbo none other then big injen high flow intake and i think its 3inch down pipe all the way back to a 5 1/4 inch muffler i was thinking that maybe it was a bad spring but like i said im still very new to the turbo world and have no idea how to trouble shoot alot of things i do appreatiate your help though any input i will take and try my best to check

 

[snowborder714]

Thread moved, title changed, and grammar/spelling warning issued.

 

[90moneypit]

First/cheapest thing to do would be to check your vacuum line from the wastegate actuator. If that's not cracked then I would use a mityvac to check your actuator and make sure it's consistently opening at the same pressure every time. Make sure all the mechanical aspects are working right and then check the electrical connections. All this is assuming you've already done the boost leak check first. It seems weird that a boost leak would make you spike but it might not be leaking all the time and when it doesn't, it'll spike.

 

[uberswede]

I've definitely got a similar problem. I bought a pre-modded '97 Talon a week ago, with a GReddy boost controller, I think mine's a little older of a controller though...

Regardless, it seems like no matter where I put the setting, it still boosts around the same points.

1st gear 7-8lbs
2nd gear 13-14lbs
3rd gear 15-16lbs... it's so strange.

I'm thinking I'm going to rip it all out and put in my AEM boost controller from my last car...

 

[enos1010321]

Things to check:
1. Do a boost leak test. If you have a huge leak you will not be able to pressurize your intake. Here is a good write up on how to do that here

2. Check that the controler is plumbed properly. Eg. The sensor portion of the controler needs to get its source from the intake, alot of people use the same line that runs to your FPR (Fuel Pressure Regulator)

3. Check all the vacuum line to the sensor portion. Check all the vacuum lines from the turbo pressure side to the solenoid. Check the vacuum lines from the solenoid to the waste gate actuator.

4. Check that the electronic portion is working. Leave your controller on when you are doing a boost leak test, set the controller to something like 10psi. When you pressurize the system to 10 psi your waste gate actuator should open. If it isn't then you might have a bad boost controller. Check the solenoid wiring.

5. Check that your waste gate actuator is not getting stuck. I had an issue with my T25 where somehow the arm on the actuator was bent and hitting the side of the turbo. Some times it would work just fine and the car would run like mad, other times it would get stuck open and I would get no boost.


Good Luck!

Let us know what you find!