ok, hopefully someone can help me out.

93 rx7
jdm swap
5spd
bone stock, all i have is a 3in downpipe to atmosphere, koyo and a 19 row oil cooler.

ok so i just finished my swap a couple nights ago and i ended up with 6 trouble diagnostic codes.

5 - knock sensor
6 - speed sensor
30 -split air bypass
39 - relief 2
42 - turbo precontrol
43 - wastegate control

today i fixed everything except the speed sensor, no more check engine light.
idles fine, sounds fine and derives fine but my boost gauge is only reading 10 in. of vacuum and if i try to boost it cuts off like boost cut but right before it boosts.

it doesnt even wanna go pass 1 psi.

Vacuum was at around 19 before i added the turbo control, wastegate control, turbo precontrol solenoid and fixed the knock sensor. also added resistors to the split air bypass and relief 2 solenoid clips.

any one have this problem before or have an idea of what it could be?

 

would a bad check valve do this or maybe having the wastgate control and turbo precontrol sensor plugs switched.

 

A check valve issue won't cause that... Did you check to make sure you have:

* CAS connectors correct?
* Fuel and coolant connectors correct?

 

Yea, I triple checked all the vacuums and sensors, except the wcs and tpcs wich ima do tomorrow when I have light, but im sure they are correct

 

Just keep in mind, that the sensors I mentioned can have the connectors 'switched' which would be a problem. i.e. they may be connected, but with the wrong connectors. However, if you are pulling less vacuum, you have a vacuum leak somewhere (if your idle rpm is the same).

When you say JDM swap, I'm assuming just the engine (short block) or did you use more than just the engine?

 

i have a full JDM swap minus harness and ecu

 

if i have the CAS switched would the car run still? i will check everything again right now, run some more test then ill come back with results. thanx mahjik

 

Yes, it will run and idle with the CAS connectors swapped. It just won't really accelerate well or boost at all.

 

Are you trying to run sequentially or non-seq? I read that you are using the turbo precontrol but something just isn't right with the whole situation.

If the system is set up for non-seq or is tricking itself into thinking it's non-seq and the vacuum line for the air control valve in the y-pipe is still hooked up i.e. not capped off, as soon as the y pipe sees positive boost pressure, the valve will slam shut and choke the engine. I've experienced it not all that long ago and saw no more than 1-2psi at WOT and completely bogged down with incredibly slow acceleration.


Double check the CAS as Mahjik said. It's completely possible. I'm just offering other thoughts if the CAS is correct. CAS hooked up backwards wouldn't cause the engine to create less vacuum though... right? Double check the vacuum source you are using and make sure the line is not cracked, brittle or pinched anywhere.

 

Did you disconnect the battery after fixing the knock sensor code? If not it will stay into limp mode. Also, if you went from -19 vacuum(im assuming around 1200 rpms) to -10 vacuum at the same idle speed you have one hell of a vacuum leak which would be obvious or a compression issue. Is the vac needle bouncing rapidly at idle?

 

ok, ive tried everything, its to late now but tomorrow ima disconnect the vacuum lines from the wastegate and see if i can get it to boost that way if not then i guess ima just have to rip everything out.

its sequential by the way, pretty much as if it was a bone stock us 93 fd

 

sorry, dbl post

 

map sensor hose connected to the UIM?

 

yea, i have made some videos of what my car is doing and how it drives, i will post it as soon as i get home, thanx

 

I had a similar problem that took months to find and minutes to fix but I'll wait on videos.

 

found the problem, took everything apart and while i was taking the downpipe of i felt something loose under a heat shield, it was the butterfly for the primary turbo wastegate.
it was missing the c clip that holds the wastegate rod in place with the butterfly.
it was unhooked making the butterfly stay open.

Now its boosting,,,,,,,BUT now i have a new problem.
i will check everything tomorrow and if i cant figure it out i will post my problem.

it has to do with it boosting only 5-7 psi all the way through most of the time but sometimes it jumps from 5-7 to about 12-13 at around 4500 rpm, you can feel the pull and hear the change in sound.

ill be more specific tomorrow when i can check it and have some light, i will also take video and post it.

and thanks everyone for all the help.