aggressive hissing and occasional dumpvalve sound

[volvod570]

volvo v70 d5 185bhp 2006, car is only boosting a bit and sounds really aggressive when it does (hissing then loud dump valve noise, wont rev all way up either, and sometimes it will constant try and make the dump valve noise with out changing gear with whats like a misfire, have recently replaced the boost resonator pipe which was blowing of, now with the silicone one that doesnt blow of now, but thought i heard another blow the other day, but the pipe was still on, chucking lots of back smoke and burning a lot of oil to

[volvoid]

hissing+dumping - great - park it outside halfrauds with a for-sale sign, it will be snapped up

[volvod570]

😂 sure someone would, if it wasnt for the fact how i still keep trying to remember how it used to drive 😒 can there be a problem with the wastewater, its been remapped for a while and i had no problems until it first blown of the boost resonator pipe

[volvod570]

wastegate not wastewater lol 😂

[davebb]

Originally Posted by volvod570

�� sure someone would, if it wasnt for the fact how i still keep trying to remember how it used to drive �� can there be a problem with the wastewater, its been remapped for a while and i had no problems until it first blown of the boost resonator pipe

Hi there will not be a problem with a wastegate as it has not got one,
it is a vnt turbo,
I would say that the vnt is not working as it should, and the car is over boosting, so it has now gone in to limp mode,
Dave

[AndyV7o]

Modern engines use a boost solenoid valve to vent pressure as the ecu sees fit, so unless its stuck open I doubt its that. It could be inoperative also causing excess pressure, blowing pipes off or bursting something.
Sounds like you have a big leak, have you checked intercooler? They are known for failing and if youve been running higher boost from a remap its even more likely.
Other thing could be overboost if turbo vanes are stuck, with ecu constantly venting the excess pressure, though that is often routed back into induction system rather than vented to atmosphere but I suppose you might hear it still.
Either way you'd expect ecu to throw a code, and light up the eml.
MAP sensor could be faulty giving ecu spurious readings making it think/do things wrong related to the above. Again you'd expect ecu to realise something wrong from the whole array of readings and throw a code/eml.
You dont always get eml though, so get it scanned for any codes...

[volvod570]

thanks dave, at least its not that lol, yeah that all makes sense, what can i look for if its the intercooler, is it worth cleaning the turbo valve solenoid, just the engine service system has come on, sometimes it will boost but sound like theres air escaping, then later turn the car on again, and it will be pure limp mode and no boost, and it will keep doing that all day, it was running so nice after the remap for the first few months, so annoying, ill try to mess with stuff on the car myself, but think this might have to be a garage job??

[volvod570]

could the weird deep rumble noise in limp mode be to do with the induction system

[AndyV7o]

If youre losing boost you will get limp mode, if theres variability of leak causing variability of pressure you can get intermittent poor running/limp, this was how my dads vectra was with a split pipe.
Overboost usually runs ok until overboost then limp, switch off, back to normal until overboost, repeat. Usually. Could still be your prob.
Intercooler tends go bow, look underneath front bumper, intercooler is sandwiched between radiator and condenser. You would generally expect it to be oily too if leaking, cos I've never known a TD without -some- oil in induction system no matter how healthy.

[volvod570]

yeah thats what its pretty much like, will boost a bit, but not all the way around town, then when i go over 40mph thats when a deep sound in the exhaust appears and limp mode, ill check the intercooler tomorrow and all the pipes, will let you know, thanks for your advice