OK guys, I just got my first RX7 A few days ago, its a 93 with a single turbo setup, HKS standard series wastegate, FC Commander & Apex AVCR boost controller. When I got the car it ran like nothing I have ever been in before, it was a monster @ 14-15 PSI!! All of a sudden it starts overboosting into 20-25 PSI and runs like s**t. I started poking around underneath and found the vacuum nipple on the top(end) is just open, the other nipple goes to boost controller solenoid. Should the top nipple just be open?? Once again Im a newbie so let me know if im not specific enough or you need more info.

 

If it has a boost controller on it, dumbfuck previous owner installed it wrong.
Do a search for "boost controller external wastegate", and that should pop up tons of hit on how to install a boost controller on an external wastegate properly.

I would cross my fingers that your motor is still okay.
Pushing that kinda boost on pump gas is scary!

Remove the boost controller and just run the wastegate line straight to the bottom fitting.
And leave the top fitting open...
This will be safer for you for now.


-Ted

 

Yeah I was worried about the motor too, the good part is that as soon as I see it overboosting I get of the pedal, because immediately I know thats not right. Also it is running rich on the A/F meter even when overboosting so hopefully that saved me. I just dont understand why all of a sudden it started overboosting like that it was pegging out at 15 before, from one day to the next it started having this problem.

 

did you switch it to the hight boost setting on the controller?

 

No, I hadn't touched the boost controller. It just started over boosting.

 

I tried this and it seems to still be doing the same thing boosting to 20+ PSI. What does this mean, is the boost controller solenoid possibly bad?

 

Personally, I think the 40mm HKS wastegate is too small.


-Ted

 

What would you recommend?

 

Just a suggestion before you decide that it is in fact the wastegate (which is always a possibility): check your vacuum lines both at the boost controller solenoid and also at the wastegate. Make sure none of them have cracks anywhere. If the lines are close to the downpipe or manifold, it's fairly common to see a busted line and this is a sure-fire way to end up with an overboosting issue.

 

I checked all the lines and didnt find any cracks or areas that seemed like they would be a problem. Is there a way to test the wastegate?

 

Make sure their aren't any holes in the vaccum line running the the WG. I run the same gate and I never have problems.

 

I checked for holes/cracks and didnt find any. I am going to double check though.