vtecgsr95

I just purchased a 1993 RX7. I was reading on some sites and it said that boost should be 12 psi on primary turbo and 10 psi on secondary. I am getting 5 psi, then jumps to 10 when the second turbo kicks in, and at times the secondary wont kick in. The car was sitting for a while I believe and I am not sure how often it was started. Tha car is all stock.....so I am trying to figure out if I have a bad solenoid or vacuum leak or what. any help is appreciated!

frank

C's-7

iTrader: (3)

This is a good place to start:

http://www.fd3s.net/boost_problems.html

dgeesaman

iTrader: (7)

The correct boost is 10psi up to 4500, then a quick dip to 8psi, then again to 10psi the rest of the way. You should never have 12psi, even briefly. Run the test in 3rd or 4th gear starting at 3000 so you have a safe chance of watching it.

It's hard to say exactly what is causing the problem, especially since it's intermittent. Start by checking for vacuum and pressure - after running the car and making bad boost, remove a hose from the black tank at the top and center of the engine bay. If it's working ok, you should feel a rush of air coming out.

Then carefully pull a hose that leads to the vacuum tank - another black plastic tank that's hidden partway under the alternator. A long needlenose pliers works for this. You should observe a bunch of air getting sucked in.

Dave

vtecgsr95

Thanks ofr the update! I was unsure about the boost thing, but after doing more research I figured 12 was too high! After doing some investigating, I found an unhooked vacuum line, leaking coolant hose going to the turbos, and one line with a cap on it and the hose plugged with a screw-not sure why. I went ahead and removed the upper intake and found the solenoid in the rats nest closest to the front of the car also has a broken nipple on it. I am not sure which solenoid it is.....according to the diagrams I think its the air bypass solenoid, but I am still checking. I also ordered a silicone hose kit, so I am gonna just get them on and replace the coolant hoses and be done with it!!

Another question off this topic, I was thinking about installing a complete exhaust consisting of a megan racing dp/mp and apexi GT exhaust (using the megan parts for now assuming I will go single turbo later!), and I was told I dont have to adjust fuel control until I have 3 bolt ons.......is this true??

And one other thing........is there a place to get oem parts at a discounted price? I know hondas have places that cut a sweet discount on oem parts and figured maybe there was a place to get all your rx7 parts! I need weather strips for the doors and some trim pieces and what not, and was trying to find out where to get them at a reasonable price!

BUMP for info!

vtecgsr95

Couple more things!!!

Where is everyone mounting their EGT guages?? In the downpipe or in the manifold???

Where is the coolant thermoswitch?? I wanna swap in an FC piece and dont know where its at for sure?

Where can I get a factory service manual or is everyone buying the CD manuals on ebay??

dgeesaman

iTrader: (7)

1) Replace that coolant hose before taking the car out again. Leaking coolant is a Bad Thing on FDs.

2) The front/top solenoid on the rack is the charge relief solenoid - and it's very important for proper turbo operation. The front/lower solenoid feed the double-throttle and is less important. The good thing is these solenoids are interchangeable. I buy and test used solenoids and keep a few on hand for things like this. You can try to repair the solenoid by using superglue, but be very careful to not get any on the inside of the solenoid. So use a tiny amount of glue to reattach the nipple and then leave a thicker bead around the outside to seal and secure it.

3) The diagram to use for a manual tranny is this one: http://www.davidgeesaman.com/rx7/93v...lor.edited.jpg

A midpipe is a little more than your average bolt-on. While it adds about the same amount of power as most bolt-ons, it's usually the last exhaust mod and the extreme flow of a full exhaust often causes boost creep or boost spikes. So the 3 mod rule isn't too useful in this case. (Usually the 3 mods are cat-back, intake, and downpipe).

The better rule is 10psi - if you keep your boost at 10psi you won't need different ECU or fuel mods. With a midpipe you're probably going to have trouble keeping it at 10psi unless you port your wastegate and use a different boost controller.

IMO, it's simpler to not use the midpipe until you've got the other mods in place. But I live in an emissions state and I dont' like lots of noise or stench, so it's just an opinion.

Malloy. It's listed under 'M' of the FAQ.

Dave

dgeesaman

iTrader: (7)

It's time for you to start reading the FAQ and using the search. The manuals are linked in the first sticky thread. EGTs will die if you put them in the manifold - I think most people put them about 18" down the downpipe. The thermoswitch is the second-from-the-top sensor in the back of the coolant filler neck.

Searches will bring up lots better detail and pictures.

Dave