Boost problem FD won't boost past 3psi.
 

Hi recently I noticed that my fd won't boost past 3 psi I think that the primary turbo is spooling but won't boost past 3 psi and when it reaches the 4500rpm the secondary won't boost and as rpm keep climbing boost keeps dropping till it hits zero. Any one know what it could be??? I really don't know what to do

Major Boost leak! Check the coupling off the Y pipe to the Inter cooler piping and see if it is split and all of the other inter cooler piping for major leaks.

You said you just noticed it. Was it boosting properly before recently? I just had the EXACT same problem. I couldn't find ANY boost leaks, but I did find several vacuum lines that had gotten hard and cracked and many that were split in half completely, making no
Connection. I am doing a full vacuum line replacement and solenoid replacement right now. Honestly, with as many broken and cracked lines/solenoid nipples, I cant believe the car drove as well as it did.

Trev

You just noticed that your car was down 75-100hp? :lol:

One of your intercooler couplers or pipes are ripped. The more boost it tries to make, the bigger the hole expands and lets more pressure escape. Check it out. A hole that big shouldn't be hard to find. Pull the piping from the y-pipe to the intercooler and the "S"nake accordion from the intercooler to the elbow. Move the flexible accordion in all directions and look for it and inspect the couplers.

Original stock intercooler pipes, couplers and stuff is just old and wore out. Upgraded aluminum piping and silicone coupler kits are inexpensive, work awesome and looks good, too. I think just about every FD RX-7 tuning shop/company has them.

The OEM rubber couplers get brittle and tear. Typically the one on the y-pipe goes first.

Other common cracked hoses are the BOV and CRV.

Also if someone has recently changed your oil, they could have removed the AWS hose at the throttlebody elbow to get to the filter.

The AWS hose is super noticeable as it will woosh and/or foosh when ever you're driving. I know I just did that 4 days ago "/ but I can't get past 5 psi, ever! On all new vac hoses, and a fresh build, the engine is solid, but I can't find any torn factory hoses. If our turbo control actuaries weren't opening and delivering pressure to the secondary turbos, would these symptoms result? I got annihilated by a friend in a z31 300z on my way home today, not cool when he has a SOHC 170hp motor

possibly tha cca being stuck open would cause turbos to fight eachother and not make boost. most likely there is a large boost leak. Have you actually taken all the flex pipes off to inspect them? I had a large boost leak for the longest of time and my hoses all apeared fine. i took off the flex pipe to the stock ic and it was ripped all the way down the seam but only visable when i bent the pipe. or make a home depot boost leak testor to trace all leaks

If you're only boosting 3 psi you will not transition to secondary. You need boost to make boost [kind of]. As everyone mentioned, step one is boost leaks. When my Y-pipe coupler split I could hear my boost leak [stock exhaust probably helps with hearing it :P]. Inspect all your components and then move onto the next portion of troubleshooting.

thanks guys it turns out the the coupler got loose and was letting all the boost out.

yeah i noticed that i couldnt keep up with a satur ls1. lol true.thanks guys for your help i got my boost back anyone know who tunes or how to tune a pf pink ecu.

To test our pressurized systems with one of those home depot boost testers, do we need to plug the secondary turbo inlet when charging the system? Or will the gate between the primary and secondary turbo hold the psi in the system? Just curious I'm going to build one tomorrow and if thats the case I'll buy a "plug" for the top inlet hose at the same time.