I got the car mapped on Tuesday there and it wouldn’t make any more than waste-gate pressure, or we’re assuming that.

We seen anything 0.8-1.012 bar.......

So we decided the boost control solenoid was faulty.

Today I’ve removed the Mac 3 port boost solenoid and bench tested it - and t works. You can hear it clicking when voltage is applied and you can blow through the ports and it comes out the other port, then when voltage is applied it closes and you can no longer blow through the ports.

Thoughts?

I had actually ordered a new one but cancelled it after doing the tests, I’m thinking I might order it again, fit it and see then if no difference I can always sell it on. I don’t want to really waste money if I don’t have to.

 

Who mapped it lad

 

Yup

 

It’s nothing to do with the mapper as it was only making 1 bar before, in fact I was led to believe that it had been mapped to 1 bar and 1 bar only.

But after the mapper hooked up his stuff and accessed everything he was able to see that it was mapped to 1.6 bar, so my theory is the 2nd last owner before me had an issue and couldn’t resolve it and sold it on with the bull**** story that t was mapped to 1 bar only.

I might just order a new one again and try it and see what happens, then sell it on if it’s not that.

 

Having a mind **** here, can someone explain what actually happens from the hose that connects to the compressor on the turbo, to the bcs, and then to the wastegate?

How and why does this stop the actuator from opening the wastegate too early?

And what is the bcs doing at these different stages?

 

I’m fairly certain my WG port and Turbo port are mixed up.

After reading up online it would appear that this would cause the issue I’m having, tomorrow I’ll swap them round and hopefully it’ll make the 1.3 bar, then we’ll get it adjusted to 1.4 bar and take it from there.

I should notice the difference between 1 bar and 1.3 bar, I don’t have a boost gauge and I’m needing to switch via de-mister so I’ll never really know if it’s working

 

when the demister switch is used isn't there some special sequence of pressing or holding switch down for a certain length of time ?

 

full throttle press rear demister

 

Yeah that’s it.

 

which mac valve is it, some of them run at a different frequency meaning on standard settings the performance just isn't there. The way it's supposed to work is pressure comes from the turbo compressor and normally heads to the wastegate pushing it open to drop the boost. When the solenoid is activated it blocks pressure from getting to the gate and pushes it out the vent port (on a standard setup this goes back to the turbo intake pipe).

Should be easy enough to work out what way round the pipes go, also for what it's worth I've seen a few that will work fine on the bench but won't when attached to the car. They seem to be fine with single full 12v battery power clicking open and shut, but when cycled by the ECU it's just not happening.

If you have the kit you can probe the BCS connection in the engine bay (run some wire into the cockpit) and you should see it cycling on/off on/off once the revs get high enough for the ECU to start asking for boost.

Also, I wouldn't go swapping changing and playing with parts without having a temporary boost gauge hooked up. Doesn't have to be super mad specifications - just soomething to show you a boost reading that you can see changing. You *should* notice a difference in 1 bar vs 1.3 bar, but if the car couldn't generate that boost on mapping day then how can you be sure the timing/AFR is set right for that level as well? So you'd be wanting to get the boost working first then back to the mapper for a tweak up.

You can also test the wastegate as well with your compressor, put small amounts of pressure in (0.5 bar up to 1 bar) and you should see the arm opening/closing nice and smooth. If it opens and sticks open then it will need replacing most likely.

 

I swapped over the hoses so it was correctly routed and it made no difference, so I think you’re right about it working with 12v being applied but not working when asked upon by the ecu.

 

and you've checked to make sure it's not in limp mode yeh? Doesn't always cause an engine light to be on. Normally you'd get a code for the solenoid performance when it's like that as well.

 

Definitely not in limp mode, well I don’t think so anyway.

 

Check for restrictor pill for its existence and correct location...as it's built into the hose it often gets thrown away when some numpty fits fancy coloured hoses.

https://www.scoobynet.com/technical-...locations.html

 

Don't think mine will have one, fully built gt30 and has been mapped before, 3 port mac bcs so I'd imagine it was removed way back when set up.