hello all, name is kenny from charleston, sc. Just picked up a 93 rx and have never really messed with cars much, motorcycles have always been my way of life. got a chance to purchase this car from my boss for $13900.00, had only 18000 miles on it and is cherry. lucky me. either way it sounded like a good deal so i took it and the car is great. straight and clean. well i'm told that the car is normally to run at 10 psi and i can't get more than 3psi to register on the defi boost gauge. the gauge was installed by rotor sports in north carolina. i'm assuming was installed correctly, they seem to be "in tune" with everything. well i called them for info and they seem to think that there may be a vacuum leak of some sort. okay, that sounds simple enough (thinking bikes of course) then come to find out there are 70 vacuum hoses!!! any starting points?? maybe a certain hose that tends to have problems? any help is appreciated. thanks in advance.

 

hey there, I had similar problem could only get 4 psi of boost, and it turned out to be on of the big pipes connected to the intercooler was split straight down the middle, you will have to take the pipes off to check them, which is easy, just a chose clip on either end. , does your boost gauge have a vacuume reading as well as boost?? if so what is the vac reading at idle ?? that should tell you if its a boost leak or a vac leak hope this helps

Mark

 

Welcome to the wonderful world of FD's. This won't be the first time you have a boost leak.... Just to answer your question, there's not a real starting point. Just replace all the rubber lines with one of the hose kits from hosetechinques.com or something similar.

If you're tired of all those vacuum lines, perform a non-seq. or poor man's non-seq. conversion on it, and replace all of the vacuum lines.

As for your major boost leak, it sounds like a coupler that is completly ripped in half as schwass as said, or it could be the y-pipe and coupler. Something is not hoseclamped on correctly.

Good luck to you.

 

thanks fellas, much appreciated. that's where i'll start!!

 

That's kinda the problem with such a low mileage car. It was never driven and just sat around forever. All the hoses, o-rings, seals, couplers, etc. dry out, crack, rot, etc. But definately sounds like a boost leak. Start checking your hoses and couplers. If you could find a way to pressurize them with shop air and a blow nozzle, hmmmm. Might could help find a leak.

 

Check the FAQ thread, there is a link to a page about Boost Troubleshooting
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/faq-3rd-gen-other-useful-links-68640/


-s-

 

Well other people are going to chime in about vacuum hoses and solenoids. So I will leave that work up to them. What I will contribute is this:



I have highlighted the area of interest. Make sure that a C clip is still on there and that linkage is attached. Note it may look attached so wiggle it to make sure. You can acces it from under the car rather easily. Passenger side, right under the airpump, can't miss it.


If that linkage is not connected. You will only boost about 3 psi. I speak from experience.

 

yes and its at -20 to22. hopefully that may narrow the search down somewhat. please excuse my ignorance in this. when i accelerate it will go past 0 and no further than 3psi.

 

It is just a shot in the dark here but my cause of the 3 psi only was due to the precat. when I replaced it with a 3" downpipe it worked perfectly... 10-9.5-10 boost pattern. If all else fails give this a try.

 

still searching, if all else fails, where is the nearest shop/mechanic that i can trust to work on my new baby.

 

I think I know your problem because about a week ago I had the same problem 3-1-3 boost pattern. Have you checked your intercooler piping....especially on the back of the rubber tubing that is hard to see by just looking in the engine bay. You probably have a huge slit in the intercooler piping. Once I changed that my boost pattern went back to normal 12-10-12. If not that try changing your checkvalves because that also helps in your boost response.

 

Is it building boost down around 2200 and then just keeping 3 pounds all the way to redline?? If so that is generally a loose coupler or busted IC line. Its usually the lower intercooler line that busts.

If it isnt building boost up until late in the rpm range then check the turbo actuator as suggested above.

 

that's exactly what it does!! i'll check there again. i really appreciate the feedback from this forum. by far one of the best if not the best that i have been on. thanks guys.

 

Most of the time the rip/tear in the Lower IC line is not visible unless you squeeze the piping. Even then it is still dificult to see. It doesnt take much of a tear to show the symptoms you have.

 

let you know what i find tonight. thanks again.

 

12-10-12 is "NOT" normal and if your running that kind of boost on the stock ECU what will be normal is an engine replacement.

 

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

Very good bathroom reading material...

This was how I fix my own boosting issue.

 

FOUND IT. big crack on the piping to the turbo. 9-10 pounds now. finaly got home from work with some energy to actually take things apart. noticed it immediately, fixed it and man is this thing freaking fast! like a whole new car!!!! thanks guys.

 

Your boss needs a ride.

 

might **** him off.......

 

man, not to bring back a dead thread but I now own this rx7 that he was talking about. 37K miles and still cherry!
Thanks Kenny for the car.
Chad