Are these symtoms limp mode?

[mudski]

Hi ya'll. Happy fathers day...
Recently my Troll has been acting wierd. Every now and then, mostly when the car is cold or just reach temperature, under acceleration the car will lose power and my boost will drop from 16psi to around 10psi. I then let off the pedal and back on and its just fine.
Strange thing is, I can really give it a boot full and accelerate quickly with the boost topping out and nothing happens. I slowly get the revs up whilst keeping the boost up at 16psi and at around 3000 rpm I get this issue.
The only things i have done as of late is by-pass the vacuum canister and moved the dawes onto the firewall therefor having a longer vac line to the VNT and from the vac pump also.
When I have time I am going to get some more vac hose and put the canister back in and try it out. If that dont work, I will move the dawes back and see if having shorter hoses causes it.
Also my needle valve does leak. I can hear it hissing quietly, I have it mounted under the dash. the leak is coming from the adjuster knob, not the fitting itself. I pressure tested the valve and there is no leak, but vacuum testing I have not done. Also this leak has been happening since I got the valve so I don't think this is causing the said issue.
Cheers.

[threedogs]

Yo Mudski I have heaps of red silicon 3mm vacuum hose, bring a beer over.
We can double check each others fittings, I recently fitted needle valve and that stopped your problem.
Needle valve may need smeer of silicon grease to keep the seal

[Sir Roofy]

i would say yes to limp mode
i ran mine at 16psi but found it was causing issues as well
i dropped mine back to 12psi and found it better no limp
and egt,s a lot cooler220c-250c crusing and 300c-350c with the trailer
on with wood

[mudski]

Yo Mudski I have heaps of red silicon 3mm vacuum hose, bring a beer over.
We can double check each others fittings, I recently fitted needle valve and that stopped your problem.
Needle valve may need smeer of silicon grease to keep the seal

If I bring a beer over I won't be driving anywhere :D Anyhow I know its not the needle valve, as this issue has only just started and I've had a needle valve fitted for months. But I think i will change my needle valve as I know its NOT supposed to leak. No point in sending it back to dependable. They'll just say it my fault or something. Plus this valve can't be pulled apart, its a sealed unit.
I just strange how its acting though, because I can really give the car a boot full and floor it and the boost will top out and I get no limp mode, but if i slowly drag out the gears and keep the boost up, even though its not full throttle, I get limp mode. I'm gonna reconnect the vac canister first just to see what happens.

[nomadTech87]

It's not so much a proper limp mode as an inbuilt protection. Mine had this problem when I bought it due to the dawes valve being adjusted up too high,
the ECU steps in to protect the engine from overboosting. It generates no fault code and resets if you take your foot off the throttle.

[threedogs]

After your model there was no Vac cannistor, there's pics in archives with dawes set up

[mudski]

I'm not convinced yet I'm "over boosting". As I opened up the dawes a quarter of a turn and the boost now goes up to 17psi and I still get the same issues. I get this limp mode effect ONLY if I gradually wind up the revs whilst keeping the boost up to maximum. If I quickly get the revs up whilst keeping max boost it does not happen. As my needle valve is leaking I'm wondering if this may have some effect. I'm waiting on some silicone vac hose to arrive so I can put the vac canister back in the line, and if this does not help I will shorten the length of the vac hose from the VNT to the valve. As before it was only about 3 inches in length, now its about 18 inches. I did notice one thing, I get this symptom more from a cold to just operating temp engine too. I think i will have to get a gauge to see what the vac pump is doing...
Why I haven't lessened the boost yet? Is because I wasn't getting this before. Its either something I've done i.e bypassed the vac canister and lengthened the hose from the VNT to dawes, or the something else is amiss. Like my leaking needle valve or maybe a bit dodgy vac pump.

Good old Trolls, there's always something to do on them.