problems boosting

[HRthirty1]

hello all ,
i have nearly got this rb25 det working properley in my hr31 however when i am driving it gets to about 4500 rpm then tries to boost but nothing happens. the engine does not go faster,does not gain rpm and sounds as if all the boost is just being dumped through the wastegate or blow off valve.
i have been told that this is due to the MAP sensor not functioning and i dont even think i have 1 wired into the ECU. i have purchased a MAP sensor but dont know how to install it can anyone help me with info or diagrams?

i would really love to get some enjoyment from my car finally.

[mmcleo11]

If your car has a stock computer in it, there is no MAP sensor that can be fitted. Whoever told you that should bury their heads BACK in the sand.

Three possible problems:
1. You have a boost leak between the turbo and the throttlebody. The air being leaked causes the motor to run really rich and lose power/no want to rev. This is the most likely culprit.
2. Your spark plugs and fuel filter are likely to need changing(if not already) and I would also recommend changing the timing belt if you have not done so already.
3. Check that the rubber intake pipe between the airflow meter and the turbo is not sucking itself closed when hot, as the massive vacuum causes the pipe to close shut and reduce air flow.

[HRthirty1]

Originally Posted by HRthirty1

hello all ,
i have nearly got this rb25 det working properley in my hr31 however when i am driving it gets to about 4500 rpm then tries to boost but nothing happens. the engine does not go faster,does not gain rpm and sounds as if all the boost is just being dumped through the wastegate or blow off valve.
i have been told that this is due to the MAP sensor not functioning and i dont even think i have 1 wired into the ECU. i have purchased a MAP sensor but dont know how to install it can anyone help me with info or diagrams?

i would really love to get some enjoyment from my car finally.

cheers mmcleo11 , your advise was right on the money.
there was 2 spots where the air was geting to the turbo after the sensor these have been blocked now.
there was also a little gold pipe ontop of the motor which has now been blocked ,is this for the boost guage hose?
A mate of mine also blocked the hoses running to the blow off as it wasnt working properly.
my car is now running very well and im very happy this little sleeper skyline has some real potential ,thank again

[mmcleo11]

The gold pipe should connect to your brake booster.