I have 93 R-1 and I drove last week it was totally fine but yesterday when I dove it, the car only got 5psi of boost so I downshift to thrid on freeway and do a full throttle just to test it and turn out my car has no boost at all.
I open up the hood when I got home I found that the intercooler piping connection was came loose (the one that connected to the lower portion of the intercooler.)so i reconnect it and the car still got no boost.. I have arc intake, trust top mount intercooler, dp and catback.. I replace all the hose to silicon hose like a year ago and everything was fine. I also did a search but seems like nothing quiet like my case tho. Will there be another hose came lose or something else happen? No smoke or smell or anything like that. Any help will be appreciate. Thanks in advance guys~!

 

What other mods do you have? ECU?

If you have a rough idle, first check the two pressure hoses to the pressure tank that is next to the intake plennum, then the MAP sensor vacuum hose.

 

Its a stock ECU, nothing else on the engine....the idle is normal.

 

I just had the same problem and I found that the turbo inlet duct of the front turbo had a broke nipple and the line that the vacumn line that went to the prge control was broke off. I also had a broke line which was under the airpump release tube, before the actual dump tube, is a large line that connects two pipes, one off the back of the airpump, about 4 inches long. I have no idea what it was called but I replaced it and now all is well. Sorry for my stupidity but I took my car apart today and that was my culprit, as well as my lower I/C tube was unhooked as well.

 

I have the exact same problem and i have a rough idle. Where are these hoses atihun? and what is the intake plennum? Thanks.

 

thank you so much for your help, I will take my car apart this weekend and see what can i do...hai....

 

Sorry, it's the intake manifold.

In front of the manifold there is a plastic box with two hoses going to it. It is a pressure holding box and sometimes it may pop off if they're not secured. The other line that goes to the MAP sensor, or called the boost pressure sensor. It is located behind the manifold on the firewall in front of the driver. It may come off under heavy load, and will result in a really rough idle, poor driveability and sometimes some black smoke.

 

so the boost sensor thing on the firewall (driver side) is the MAP sensor? I checked that and all the hoses were secure. Havn't check the other thing u said, but i will tomorrow. Thanks for the help and I will post my findings. If nothing is wrong..off to the shop.. =(