Low boost pressure

[oblark]

When I brought my car a few years ago the BCS had been unpluged, this was done because the previous owner didn`t like the fast acceleration. I reconnected the BCS and all was fine. I`ve now fitted a boost gauge, new vacuum hoses and found I`m only getting 7psi of boost. I`ve looked in to this and found that if the BCS is unplugged the ECU goes into "limp home" mode so today I had the fault codes checked - all clear. could it be down to the fact that after 194k things are wearing out ?

[p fandango]

the normal boost pressure on a T-5 is only 10psi, so 7psi isn't far off. I'd say the 3psi loss is possibly due to the actuator ageing & possible air leaks in the system

[M-R-P]

As above, check all pipes and connections, then try tightening the W/G :)

[Kingsford G]

Could be a tired recirc valve aswell.

[M-R-P]

Could be a tired recirc valve aswell.

Good point, worth removing and inspecting.
Also, is the boost gauge you're using any good? it may be giving a false reading.

[oblark]

Good point, worth removing and inspecting.
Also, is the boost gauge you're using any good? it may be giving a false reading.

I`m using a brand new Tim 2 bar boost gauge.

[shrekblackR]

try turning actuator in 1 full turn could just be old

[oblark]

try turning actuator in 1 full turn could just be old

I took the actator off tonight and tested it, it started to move at 1.2 bar, I think someone has already " adjusted " the actuator.

Hopefully this month I`m going to fit a 16t with a RIP kit, if the boost is still low I`ll either fit a MBC or try a get a second hand ECU.

[p fandango]

I took the actator off tonight and tested it, it started to move at 1.2 bar, I think someone has already " adjusted " the actuator
thats 17.6psi?

[mitchyboy01]

I took the actator off tonight and tested it, it started to move at 1.2 bar, I think someone has already " adjusted " the actuator.

Hopefully this month I`m going to fit a 16t with a RIP kit, if the boost is still low I`ll either fit a MBC or try a get a second hand ECU.

You have a big boost leak if your actuator is set to 17psi! That psi will give you boost cut!

[T4Rick]

thats 17.6psi?

Wish i could get 17.6psi lol you lucky sod

[p fandango]

Wish i could get 17.6psi lol you lucky sod
i used to run at 20.8psi lol

[mitchyboy01]

Hi mate. If your actuator is set to 17psi, then this is the minimum pressure you can run, with or without boost control. If you're only seeing 7psi, you must have a leak. When you find the leak you also need to turn your actuator base pressure down unless your car is mapped for it.

[oblark]

As I`m only producing 7 psi I will never get to point when the waste gate opens, so I don`t think the waste gate is letting by.

When the RIP kit is fitted I going to use silicone hoses so if the boost pressure comes up then it was the pipe work, if not then I hope the boost pressure will come up when the 16t is fitted as my 15g is a bit tired.

[mitchyboy01]

As I`m only producing 7 psi I will never get to point when the waste gate opens, so I don`t think the waste gate is letting by.

When the RIP kit is fitted I going to use silicone hoses so if the boost pressure comes up then it was the pipe work, if not then I hope the boost pressure will come up when the 16t is fitted as my 15g is a bit tired.

That's what I'm saying mate. The reason you're not getting enough pressure is a boost leak. The minimum boost you can run is actuator pressure if you have no leaks. 17psi. Unless you have a boost leak.

Even a tired 15g will still boost more than 7psi.

[mitchyboy01]

Was the actuator still connected the wastegate when you tested it?

[Dan850r]

If you've tried everything else, your gonna need to pressurize the system and find leaks that way, either by smoke or other means, it'll save you a lot of time and money replacing things you don't need to. Every week theres another boost leak thread

[glock19]

Pull out the hose to the actuator and see what happens. If you are still on the standard map, you'll experience fuel cut going past 1.2 bars. Be careful though, not to plant your foot down, just gradual acceleration will confirm the following. I believe your previous owner might have plugged the hose from the compressor snail straight into the wastegate actuator. Was the BCS electrical connector the one you fitted back or was it the hoses ?
CAUTION : Pulling off the wastegate hose will be like running with a tightly wound MBC and the wastegate can only be opened by the pressure in the turbine. This is mainly to test leaks or verify the BCS' integrity.

[oblark]

The BCS was plumbed in as per the diagram in the haynes manual, the BCS was electricaly unplugged.

I`m having some blanks made so I blank off either end of the hoses and pressurize the system.

[oblark]

I've now fitted my RIP and she is now boosting to the correct boost pressure of 10 psi. When you look at the old hoses there look ok but they are very soft, not bad for 16 years of use.
Just the 16t turbo and the blue injectors to fit next week end.

[cherry1809]

Cool. Good cheap upgrade that. :)

[nottsgreent5]

mine old car went very well with 16t and blues and map bit thirsty tho lol