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- it ran fine until things got up to operating temp and it went into Restricted Performance (RP) mode. I can only assume this was due to the temperature sensor (Bank 1 - sensor 1?) on the EGR pipe reading obviously low with no exhaust gases flowing through. There was no error code logged but clearing all ECUs took it out of RP mode.

Thanks yep that makes sense (about the MAF).

Yes I'm using IID Tool I wasn't aware of this setting - how do I enable it?

Under faults, select advanced. Mine has test failed, pending and confirmed with a green tick. IIRC confirmed wasn't set ex factory.

thanks - wasn't aware of that!

Another small update. Took the actuator arm off the primary turbo to check movement of the vanes - all is moving nice and freely.

I also bypassed the turbine shut off solenoid (so it had permanent vacuum) and can confirm from IIDtool that the shut off valve on the secondary turbo opens when it's given vacuum and there are no vacuum leaks (soon goes into RP mode so I couldn't test if the vibration still occurred @ 2400rpm). So I'm content the shut off valve isn't sticking.

Running out of options now

Whatever the correct "operating conditions" are at around 2400rpm - something isn't commanding the secondary turbine shut off valve to open until 3k.

Any help welcomed.

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This is a complete stab in the dark but do a you tube search for, pa6-gf30 turbo boost valve.

Hi Kevin, thanks....tested the boost valve today and its working fine...the light blue line refers but it's commanded 'late' at around 3k. The green line relates to the measured position which isn't long after.


It's whatever tells the valve (via the ECM) to open that I'm struggling finding

It's complicated stuff mate but there are three of them units in the system and I have no idea what they do to be honest. I've just sold a couple to a member on here.
Is the vacuum pipe definitely connected to the secondary turbo activator?

Yes mate, I bypassed the valve and connected the permanent vacuum to the turbine shut off valve and IIDTool shows the secondary turbo permanently active, so all hoses are fine.

When I connect it back up it still activates but at 3k rpm all at the same time as the recirculation valve and compressor shut off valve (and confirmed working by the airflow on MAFT bank 2 sensor).

The other pressure valve controls the compressor shut off valve and I know that is working as that is when the symptoms stop. Theres a couple more on the other side of the bay which don't control turbos.

It sounds like you know your way around things. Sorry I couldn't help. Hope you sort it .

no problem thanks for the input - it's a quiet post this one and as far as I can tell there's only me and Rambles with this issue so obviously not a common one! Trawling the internet hasn't helped either as it's such a specific setup on these engines.

Have you checked the harmonic balancer/front pulley and the belts for unusual behaviour as the revs go up and down through the rumble zone?

Thanks Graeme I couldn't see anything obviously wrong with the harmonic balancer/front pulley and the belts (the Mrs must be sick of revving the car for me )

I don't want to jump the gun, but I think I might have cracked it.....


Back on page 2 I mentioned I suspected the electro-viscous fan had failed as it was extremely noisy at all RPMs and had excessive lateral play. I wasn't convinced at the time it could be causing the vibration noise so religiously at 2.4k and stopped at 3k - especially as the EGR and secondary turbocharger operations happened at this point.

When the engine is cold, you cant shove a newspaper in the fan without it ripping it to shreds. IIDtool confirmed at the time that the electro-side of things weren't actuated so the viscous unit must be .

I've got no error codes relating to the fan. Unplugging it doesn't chuck up an engine management light but it does log a fault on IIDtool.

I removed the fan this afternoon and zip-tied it back to the radiator/charge air cooler enough so I could take it for a drive and.....


NO VIBRATION


It would also explain the excessive fuel consumption as it appears the fan was permanently engaged. I can't explain why it disappears at exactly 3krpm - maybe the electronic side of the fan activates/de-activates at this point; I'd had to do another log (racked up about 60 of them on this fault!!).

The fan part number is LR022732 so I'll be replacing soon, along with the pulley bearings and belt (luckily the water pump seems fine and wasn't changed long before I bought it; notice the obvious scars on the fan nut).

I'll report back once done to close this problem off definitively.


Interesting point, while the L322 workshop manual states:

"At engine speeds above 2400 rpm under load, the fixed vane secondary turbine comes into operation"

In practice, I don't measure this on the IIDTool which sent me down a blind alley.

Interestingly the L405 workshop manual (with the same engine) states:

"When the engine operating parameters approach the the limits (approximately 2800 rev/min under load) of the primary turbocharger, the ECM begins the switch to parallel bi-turbocharger operation"

So I think in reality this is what should happen, and does happen on my car; between 2800 and 3000.


One last thing if it helps anyone, the quickest way to check the secondary turbocharger turbine shut off valve and associated vacuum solenoid valve is to let it idle from cold for 3minutes and do a data log on the following values. Revving it immediately closes the value, and idling again brings it back open.

From the WM "If the engine idles for more than 3 minutes, the secondary turbocharger is actuated to ensure correct lubrication"

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It seems as though you've found the cause!

Mine's secondary turbo change-over operation has changed with pcm updates so the WSM could be out of date with regards to rev ranges.

Interesting to see that your fan connecting nut is a dull colour. I'm investigating a dull humming noise and was wondering if it could be coming from the fan. But my nut is clean and bright in colour so I'm suspecting it has already been changed.
Could be a common mileage failure item?

Interesting. My previous Indy had replaced those same pipes for the air con which run across the top of the shroud for the fan just before my problem started.
Maybe the shroud was moved / damaged in the process.
I will check on the weekend