Regarding my STOCK 87 T2

Boosted fine this morning while it was cold (first couple minutes of my drive)

I sat in traffic for about 1 hour, the car ran and drove fine but once traffic cleared the car refused to boost. It would hover over the 0 mark on the stock boost guage, and not go any further. The car idles great, but drives like an N/A. It will accelerate smooth all the way to redline, but just isn't boosting today...

Here are my thoughts- the car was just vacumme checked and it was all good, no leaks, no idle issues... The car boosted for a few minutes while cold.. (opposite of most peoples issues)

How possible is it that the wastegate is stuck open? I can't even hear the turbo spool, but when I remove the intake the turbo spins freely with no shaft play to speak of...

Any help would be great.. i am daily driving the car right now.. Oh also this is my fist "unmodified" rx-7.. I am getting around 17-20mpg.. is that pretty normal?

 

I'd check out the bypass valve.

 

Think I found it. The vacumme hose from the intake to the pressure sensor had a crack in it... I am on the way to the store to buy about 10 feet of hose to replace all the vacumme lines.. They are a little brittle...

 

I bet sitting still at idle for an hour cooked the hoses that are already 21 years old.

 

Weird.. After disecting the brittle tube that was cracked i found a small black plastic peice inside the hose (about 1/8 of an inch long with a large hole on one side and a small hole on the other side... Anyone know how needed this is or what it is?

 

I'd bet it is a restrictor in the hose going to the waste gate - part of the boost control system. If you don't have the restrictor you probably will not hit full boost.

 

The restrictor pill in the boost sensor line has nothing to do with the wastegate. It's just there to smooth out pressure transitions, so the ECU gets a smooth stream of data with no abrupt spikes.

Pull the BOV and make sure you can't blow air through it without applying vacuum. Then inspect the wastegate actuator/arm, which is unfortunately hidden by the heat shielding. Make sure the arm didn't come off of the flapper door or something. I've heard of people making small amounts of boost with problems with either of these, so it is strange that you have 0 PSI at any throttle level/rpm.

 

About to drive home.. We'll see how the fix did..

 

Yeah that fixed it... Something simple.. All I did was replace the vacumme hose going to the pressure sensor, and put the restrictor plug back in... Boosted great on the way home.. Yee HAw!

 

nice,

17-20mpg is pretty good for a turboII

 

Pretty funny.. This is the only rx-7 I have owned that wasn't modified... Makes fixing things really easy when it's as MAzda intended..lol