Okay so don't shoot me, I just spent an hour searching the forum with to many results that didn't help.
So if anyone has a link please toss it in here.

We have a 1993 RX7 touring.
It's in great running condition.
Everything is stock except the exhaust.
There is an HKS downpipe and a Racing beat muffler.
Well everything is in order under the hood. I mean absolutely everything.
All the old rubber lines have been replaced with silicone lines and we always use mini zip ties on the ends of all the hoses to ensure a proper seal and no popping off.
Well the car drives well and it can go to redline but it doesn't boost.
Yes, I know what boost in a 3rd gen feels like, I've had a few myself already in life. There is a boost gauge installed in the car and it will zero out under acceleration and occasionally hit 1lb but it just doesn't want to cooperate.
Where do I start with this???
So what could it be??? Is there a write up on this somewhere??

The car has 78K miles on it and nothing smokes. Turbo and engine are original.

HELP!!!!

Thanks in advance.

 

Start here:

http://www.autosportracetech.com/RX-...leshooting.htm

 

Start with looking for boost leaks. Take *off* all rubber couplers between the turbos and throttle elbow, and stretch them to show any cracks.

Dave

 

If you have the stock intercooler (which your post indicates that you do), check to make sure that the end tanks have not separated from the core of the intercooler. If it has separated, this can result in a big loss of boost. There are a lot of possibilities, but you want to first make sure that you are not blowing boost into the atmosphere.

 

1 psi? if it's a leak...must be a really big one.

but let's back up a little...so car was running/boosting fine at one point...what changed?

 

I agree with the boost leak diagnosis. These cars can have a variety of problems, but almost none of them can cause essentially zero boost under all conditions, except for a MAJOR boost leak (dislodged or badly torn boost coupler is most likely).

Dave

 

I had the same thing happen. Turned out I didnt have a IC tube hooked up well enough and it came off. I was not getting any of the boost into the engine.

Hope its something as simple as that.

-Derek

 

check for big holes in intercooler couplings, my car was only boosting 1-3 lbs and i couldnt find the problem and then i took one of the original intercooler couplings off and it had a hole about the size of a quarter in the side.

 

Well the car was running fine then it sat for about 4 months. Then it turned into a daily driver again and that's when this lack of boost problem became evidant.
The first thing we did was look for leaks.
We took off the elbow and it seemed fine.
I didn't find any damage to the piping pieces coming from the turbos.
The first thing we did inspect was the stock IC. I took it to have it pressure tested at a radiator shop and it was fine.

It's a mystery as of now.
We are rather good at troubleshooting cars and finding gremlin problems but this one has us up in the air this week. LOL.


Majik, thanks for the link. That's some good stuff.
I'm going to have my buddy go over it with me today. Maybe I just missed something.

 

Check the hose to the charge relief valve to make sure that it has not split in some dramatic way. If it splits on the inside of the elbow, it can be difficult to see. Also make sure that the y-pipe flanges are all bolted down tight.

 

You should be able to hear a boost leak of this magnitude. Try boosting again with the windows open.
If your Air Bypass Valve is stuck open, though, the airbox would mask the sound. You could temporarily disconnect it from the airbox and then try boosting again.

 

I'd examine the wastegate actuator.

 

I've repaired a lot of boost leaks over the years. I'm familiar with hearing them as I am driving.
But these twins just aren't boosting.
I'm pulling them off tomorrow to inspect the wastegate, actuator and the turbos and manifold itself.

I've worked on these cars for years, many of them with low or no boost problems but I have always found the culprit.

This one is ticking me off though.

Since everything else has been inspected I am guessing there might be something wrong with the wastegate system.

I'll be back tomorrow to post my findings.

Thanks for all the great advice so far.