Hi again Guys. I posted a thread some time ago about boost problems on number 2 turbo(I think), at the time i had no boost guage but have fitted one this weekend. Weird one this i reckon, went out to test according to the troubleshooting thread i was given before and tried the recommended 3rd gear wide open throttle test. First run was spot on, 10 psi dipping to 8psi then beack up to 10 psi and slighty dropping to the redline back to 8psi. HOWEVER, thinking to myself great problem sorted, cause i has changed a few connections, went to floor it after turning round and back to normal. Repeated test run twice more with the same results, spins up to 10psi and then drops down at about 4500 revs to 5 psi and never returns. So guys, what deductions can i take from that, where do i look now!!!! Just a quick second question, what purpose does the air pump serve, would i f&*k anything up if i disconnect it, if you are wandering why i want to do this it is because i get and awfull induction groaning at around 30-35mph.
Firstly, you can disconnect the air pump - but you may have problems getting it though emissions? also it will start to backfire and carry on - which isn\'t such a bad thing :)
As for your boost problem, it could be a few things. Are all the turbo pipes etc. in good condition? it may be that one of them is collapsing under heat and boost/vacuum depending on where it is. This would be the main thing to check, if any of them look dodgy see if you can replace.
Also, you could have a collapsing CAT converter (unlikely - but never rule these things out).