Please help!
 

Hi all, my rx-7 now creates unusual sounds (making sound like "PO" "PO" and the engine is shaking sometimes too) when idle...also when around 4500 rpm, boast drops to 0.5 bar, before 4500 rpm has 0.8 bar
I have taken it to a maintenance shop and have replaced the two turbos, all the gasket and the symptoms still occurs...
any idea which part may go wrong? upper intake manifold? the exhaust?

:confused:

Any suggestions on how to diagnosis which part is leaking? manifold? downpipe? :confused:

Thanks a lot in advance....

What your entire boost pattern?

http://www.scuderiaciriani.com/rx7/boost_test.html

My boast pattern is :
get 0.8 kg/cm^2 when around 3000rpm, then manage to hold it until 4500 rpm, which it will instantly drops to 0.5 or 0.6 kg/cm^2 and then hold the same (0.5 or 0.6) until redline....whenever the rpm is above 4500, I always get 0.5 or 0.6.....
when idle my car sounds like having a gasket leak and the engine is shaking a bit too, the repairer has changed all the gaskets and problem still persists, same sound as before when idle....

Thanks a lot in advance!!

Try talking a look at the check valve under the pressure chamber. You should only be able to blow through it one direction.

What is your vacuum reading at idle and what RPM does your car idle at?

Do you have any mods on the car or is it all stock?

my car is all stock, and for the readings, I can't anwser it now as it is still in the repairer's shop....
I will go to the shop and take the readings down and post them tomorrow....

Thanks a lot for your helps, Mahjik. ;)

btw, my car idles at around 800 rpm and quite stable there. only problem is when come to stop with a/c turned ON and shift the gear to any gears except neutral, rpm most likely will drops around 500 rpm to around 300 rpm, and then slowly get itself back to 800 rpm. Sometimes, it just stalled....get worse when in summer....