I am feel extremely lazy right now so I really dont want to read through 50 pages on boost issues. Just got new motor and car was checked over. At idle I get about 16-18 vac at 750 rpms, but at full throttle I just get a solid 6-4-6. Is a solenoid bad? I dont really think I have a hose unplugged since I am getting good vac at idle. So...

 

your mods? Do you have stock dp or main cat? One of those could be plugged up.

 

Yea I do have the stock cat on the car. I had a mp on the car before the engine went and I got boost up fine. Should I try and just run open dp for just a bit and see if the boost goes up?

 

I don't think the secondary kicks in unless 7lbs of boost is reached by the primary. If a new motor was just put in. You are probably looking at a vaccum hose misplaced, misconnected, or busted. Go through the basics.

Efini Y pipe and the IC hoses.

If you ran fine with a mid pipe and bad with a main cat on. It's probably that. Is your air pump connected and running to your main cat?

I once had a boost problem like that. It was my main cat that caused it. Gutted it and now it's fine.

 

I am positive the secondary boost is coming on. I can feel it. It could be 7psi on first turbo.

I checked ic hoses and the y-pipe already.

No the airpump is not plugged in, would that make a difference in boost?

 

The main cat will clog VERY quickly if it doesn't have the air pump connected feeding it air. So if it's disconnected 99% chance it's clogged already. i mean they can clog up fast say a 3 to 4 digit miles. Either connect the air pump with the main cat on or go mid pipe. If you want you can leave the cat on like my friend did and have it explode. =)

 

It didn't fully explode ..... just everything inside the cat exploded. Made a really weird noise too.

 

Wish I was there!

 

I am glad I gutted that cat. My car feels much more responsive.

 

I drove it without the airpump hooked for about 300 miles. If I plug it back in will it slowly but surely unclog it?

Could I just test it, by just running a open dp for a bit and see if boost goes up?

 

Tried running open dp, that didnt help still got same boost pattern. What else could it be?

 

Did you replace any of the vacuum hoses during the rebuild? maybe the boost pills did not make it back into the 2 hoses. that would explain the boost problems, although it would be about 7 psi. across the board. If you are using an autometer boost gauge, It could be off acouple of psi.

 

My friend's car does this same thing... I checked for the pills and they are in there on his car. I was suspecting his cat also but haven't had a chance to check it out.

Brian

 

The hoses were replaced recently with silicon hoses before the rebuild, I was getting boost fine before. I called up the rotary guy that did the rebuild and he said to check all the solenoids.

I have a autometer guage so maybe that is why I am only reading 6 psi.

Where are these pills? I could check that out.

 

TTT

 

I just changed my vacuum hoses too and I threw out the two pills so maybe you did the same. On some cars, the pills aren't in the hoses but are in the two nipples on the primary turbo housing. If that's the case, you need to drill those restrictors out.

The pills are in the two hoses from the primary turbo housing to the wastegate and pre-control actuator. Check out the link below.

Rob's Site

 

Are you absolutely positively sure the y-pipe coupling isn't damaged. I think it's impossible to tell without removing the coupling and examining it closely. Low boost at all rpms is a symptom of a bad y-pipe coupling.

If that's not it, be sure and check the bible of boost troubleshooting:

http://www.autosportracetech.com/RX-7/rx7stuff.htm

 

Just posting so I can find this again.

 

Did the problem ever get resolved?

 

Actually, the car is in the shop right now. Hopefully will be done today. Tito @ Alamo Rotary said that he is all a solenoid problem. I will ask him what solenoids it was when I pick the car up.

 

yeah Tito says a bunch of ****.

 

Check the pills! I had the same problem and that was my fix.

All you gotta do is take out the stock air box, and down on the primary turbo there are 2 hoses side by side. One is about 3 inches long the other is probably 7 or so. There should be restrictor pills in both those lines. If not, you need to get some. You can get jets from NOS size 59 and 61.

 

I HATE dealing with Tito. I think next time my car needs work I am going to take it to Gotham Racing. Steve Kan seems like alot easier guy to work with.

I should have checked the lines before it went out, but I didnt. Hopefully Tito will check that if the solenoids dont work.

 

IF YOU DISCONNECT THE PRECONTROL SOLENOID AND WASTGATE SOLENOID OR SWITCH THE CONNECTORS YOU WILL GET A STABLE 6-4-6 PATTERN. THEY ARE THE TWO RIGHT NEXT TO EACH OTHER UNDER THE PRESSURE TANK

 

I Second that. Try to do what sirjury mentioned. It worked for me when I was having stationary 7psi secondary boost. Now it's a perfect 10-8-10 . Good Luck!!