Thread: D4 Red triangle restricted performance

Originally Posted by Eric SDV6SE

Or the o ring that sits between the plenum and the throttle body. Not sure if it's the same on 2.7 and 3.0 variants.

Also, I believe the mass flows sensors cannot be swapped between the intake.

They can be swapped. I’ve done the same experiment and I think mine might still be swapped. I believe I checked and the part numbers are identical.

Both sensors are exactly the same.numbers are all the same,so can't see an issue changing to either side.
Anybody know an easy way to check if there's an air leak seen a guy use a smoke machine to check for air leaks and he found as the smoke was coming out of the leak.
Dont have a smoke machine so anybody got any ideas?
Thanks to everyone for their replies and input.

I made my own. An air compressor, a tin can with something to generate smoke, and a plug to block the intake. Hose from compressor to the tin can, hose out to the plug with a hole in the middle with the hose feeding into that.
Short runs of the compressor force the smoke into the engine and you can spot the exit. Works a treat. I used mosquito coils as my smoke producer. Filter on the outlet to stop any large particles.

What a great idea DiscoJeffster ,that is going to be my next plan of attack.
Will keep you all updated as I go hopefully if I solve the issue later on down the line it helps someone else when this happens to them.

Thanks Dec.

Have you removed the engine cover and looked for traces of oil on the inlet manifold/cam covers?

Have you cleaned the MAP sensor (the sensor behind the throttle body)? Don't poke it with anything - use a spray cleaner only!

That's going to be the next job Graeme,just read an old thread clean out you hold and it discusses the map sensor and the y piece manifold to be taking out and cleaned , slowly getting through the process of elimination hopefully one of these fixes the fault 😀

Originally Posted by Declan

That's going to be the next job Graeme,just read an old thread clean out you hold and it discusses the map sensor and the y piece manifold to be taking out and cleaned , slowly getting through the process of elimination hopefully one of these fixes the fault

My money is on a leak, sorry.

Agreed. A dirty MAP sensor can dull performance but restricted performance is because something is amiss with airflow - split/cracked manifold or hose, sticky isolation valve, faulty isolation valve solenoid, faulty variable vane mechanism of primary turbo etc.