Not making expected boost?

[Brit-Car-Nut]

Is there any chance your exhaust or cat are partially clogged? Seems to be a common cause of boot failure.

[saska]

Is there any chance your exhaust or cat are partially clogged? Seems to be a common cause of boot failure.

The only other thought is to remove the vacuum pipe from the EGR and then plug the end of the vacuum pipe.
This way the EGR valve is closed so if the top hat diaphragm is leaking exhaust from the exhaust manifold the valve being closed should stop the leak.

[JonT]

I'll try and check the exhaust. AFAIK the SE doesn't have any sort of cat, and it's just had a new backbox so I don't think that can have collapsed.

Blocking the EGR vacuum pipe is another good idea.

[surfboardfiller]

Sounds like the waste gate is stuck open slightly.

[JonT]

Is the default state of the wastegate open or closed? Does the positive pressure applied through the capsule open it or close it?

[surfboardfiller]

If the engine is off I think it will be closed and open when you start up until you put your foot down and open the throttle (maybe 70%?) and then the turbo spools up /on boost. You can accelerate gently up through the gears without boost.
Have a look at the controller and pipes see if they are perished, if you need one you can have mine to test if you like.
See if you can open and shut the wastegate by hand.

[saska]

Is the default state of the wastegate open or closed?

Closed

Does the positive pressure applied through the capsule open it or close it?

Opens it.
The way the wastegate is actuated is via a take-off directly from the turbo, this goes to both the wastegate actuator and the boost control solenoid which operates as a controlled leak to 'fool' the wastegate actuator.
The wastegate actuator would open the wastegate at about 0.41Bar except that if higher boost is required the boost control solenoid opens and vents the pressure to atmosphere (back into the air cleaner outlet). This prevents the actuator from operating the wastegate. When target boost is achieved the BCS closes allowing the pressure to open the wastegate. The BCS operates this cycle several times a second.
See;
http://ealanach.co.uk/elanchips/index.p ... 2&Itemid=3
along with Pages 29 & 30 EMK3 of the Engine Management Manual
One of the things they suggest in EMK3 is to ventilate the WG actuator line to prevent the actuator from opening the wastegate and then checking to see if it makes expected boost.
If you try this to see if it will go above 0.6Bar then please be careful -- it may boost to 0.98Bar and fuel cut with an Everest and you'll eat some steering wheel.
If it does boost higher than the fault is either in the wastegate actuator piping, Boost control solenoid piping, BCS or ECU.
If doesn't boost any higher then exhaust blockage would be next thing to check IMHO

[JonT]

Haven't got time to drive it properly until later in the week, but having just run the test rig again it appears I can't have tightened the jubilee clip on the large rubber pipe from the wheel arch (intercooler outlet) to the intake manifold.

Wastegate is definitely freely moving - checked again with a footpump.

Saska - thanks for that suggestion - I'll try that next Caveats suitably noted.

Jon

[JonT]

One of the things they suggest in EMK3 is to ventilate the WG actuator line to prevent the actuator from opening the wastegate and then checking to see if it makes expected boost.
If you try this to see if it will go above 0.6Bar then please be careful -- it may boost to 0.98Bar and fuel cut with an Everest and you'll eat some steering wheel.
If it does boost higher than the fault is either in the wastegate actuator piping, Boost control solenoid piping, BCS or ECU.
If doesn't boost any higher then exhaust blockage would be next thing to check IMHO

Woohoo. Progress (of a sort). Quick run with the WG actuator line disconnected, and I've now got no problem getting above 0.6 bar. Takes a very gentle right foot to control things when there's no boost control

So a few thoughts
1) The BCFV has dodgy electrical connections. I've now cleaned the contacts with contact cleaner - not sure how else to check this - even if I borrowed an oscilloscope from work I don't think it would show anything unless boost was being generated
2) BCFV pipes are the wrong way round - don't think so looking at the manual (vertical pipe to intake, horizontal pipe from wastegate actuator)
3) BCFV is knackered.

Not sure if there's any way to test 3, although it must be doing something as I can get above 0.41bar normally. All of the piping was replaced while I was trying to chase the problem, so I don't think it's that. I don't think it's ECU as the symptoms were the same whether I was using the Everest or just the standard ECU?

Anyone got a spare BCFV - even if just to test with?

Jon

[surfboardfiller]

Anyone got a spare BCFV - even if just to test with?

Jon

I did offer before.......

[saska]

So a few thoughts
1) The BCFV has dodgy electrical connections. I've now cleaned the contacts with contact cleaner - not sure how else to check this - even if I borrowed an oscilloscope from work I don't think it would show anything unless boost was being generated
2) BCFV pipes are the wrong way round - don't think so looking at the manual (vertical pipe to intake, horizontal pipe from wastegate actuator)
3) BCFV is knackered.
Not sure if there's any way to test 3, although it must be doing something as I can get above 0.41bar normally. All of the piping was replaced while I was trying to chase the problem, so I don't think it's that. I don't think it's ECU as the symptoms were the same whether I was using the Everest or just the standard ECU?

Have thought about this one for a while. When you say you replaced all the piping, do you mean 'all' ? Specifically, the BCFV outlet hose to turbo intake at airbox. Apologies for questioning what you've already written -- it's not meant in a disparaging way. I suppose it is also possible the wastegate actuator capsule is duff (spring weak and actuating the wastegate too soon) but this smells more of a hose restiction/blockage to me. I can't recall an instance of anyone replacing the wastegate actuator and solving the fault. I also tend to think the BCFV isn't faulty as it either works or not and the fact you get more than 0.41 indicates it works -- seems more likely the pressure isn't being successfully vented to atmosphere which means the hoses.

[JonT]

Have thought about this one for a while. When you say you replaced all the piping, do you mean 'all' ? Specifically, the BCFV outlet hose to turbo intake at airbox. Apologies for questioning what you've already written -- it's not meant in a disparaging way. I suppose it is also possible the wastegate actuator capsule is duff (spring weak and actuating the wastegate too soon) but this smells more of a hose restiction/blockage to me. I can't recall an instance of anyone replacing the wastegate actuator and solving the fault. I also tend to think the BCFV isn't faulty as it either works or not and the fact you get more than 0.41 indicates it works -- seems more likely the pressure isn't being successfully vented to atmosphere which means the hoses.

No problems with questioning - it's always worth asking "stupid" questions as it's all to easy to overlook the simple explanation. Yes, I have changed that pipe from the BCFV to the intake, and run some welding wire through the inlet where that pipe attaches to the intake corrugated hose just to be sure it's not blocked. Phil has kindly sent me a spare BCFV - I'm hoping to have time to fit that tomorrow evening and see whether it makes any difference.

[JonT]

Woohoo. I have full (controlled) boost

Very big thank-you to Phil (surfboardfiller) for the spare BCFV . No elanscan - I wasn't holding out hope that this time it would actually be fixed so I didn't bother logging, but will do another run before long and log just to check everything is as expected, but gauge now sits above 0.75 at full throttle and the car feels more sprightly than before

Jon

[surfboardfiller]

I wasn't happy having sold you a car that's not performing 100% and glad I could help, and pleased I figured out what it was.

I took it off the Fast cat. It's going no where fast at the moment, so I'll have to buy a manual boost controller now.