Loss of boost when hot

Mikeyt5 · Post by **Mikeyt5** » 09 Jun 2016, 03:56

Morning all.reight here goes.
Firstly no engine or fault lights etc
2.4t s60 2001 petrol.
When I been driving round a bit I intermittently lose turbo which is getting annoying now. It can run fine for ages then all of a sudden decide not to play ball. If I leave it to cool down a bit then start her up she's fine again. Once hot again it struggles. Now to me it's like the turbo isn't kicking up. I've cleaned sensors and tcv and that hasn't really made much difference. I read a post on another site which said that it could be the maf. Not so long ago I clean that with some egr spray which didn't change anything. So would anyone suggest anything else or would a new maf be on the cards?
I'll just add I got tiptronic box too so feels a lot worse as the box doesn't like it lol...
Please be gentle as I'm no mechanic ..
Cheers.mike

Post by **jblackburn** » 09 Jun 2016, 07:18

Before shutting down the car, scan for codes. You may have an "overboost" condition or something of the sort occurring, which puts the car into a temporary limp mode.

Mikeyt5 · Post by **Mikeyt5** » 09 Jun 2016, 07:33

Might have to get a code reader then. Any recommendations on a cheap basic one

Post by **jblackburn** » 09 Jun 2016, 09:52

https://www.amazon.com/Autel-MaxiScan-MS ... 1_5&sr=8-5

I had one of these and it worked fine for what I needed it for.

Mikeyt5 · Post by **Mikeyt5** » 09 Jun 2016, 14:49

Cheers I'll look into it

Mikeyt5 · Post by **Mikeyt5** » 13 Jun 2016, 13:37

Just a quick update while I'm waiting for my code reader to come. Got home tonight and the engine wasn't boosting again. So left it ticking over and disconnected the maf and unsurprisingly the engine cut out. So I left it unplugged and tried to start the car and it started straight away no problem at all. Seemed to tick over just fine. I didn't go anywhere just left it running for a couple of minutes. So my question is this.... Should it do that or should it struggle to start or tick over rough?

Hopefully my code reader will come tomorrow but thought I'd ask now...
Thanks again

Mikeyt5 · Post by **Mikeyt5** » 19 Jun 2016, 06:52

Hi guys.
Right code reader came and nothing no codes at all. The app for it showed coolant temperature at -41 so got a replacement and still shows -41. Not been out long enough to see if I still have an issue as yet. The wires for the coolant sensor are fine if I unplug it I then get a code. Plug it bk in reset code and it's ok again but still -41. I'm at wits end now. I'm thinking about resetting ecu and see if that helps but really concerned about doing it properly. Any guide to do this would be helpful...

Spuddog · Post by **Spuddog** » 20 Jun 2016, 13:58

I have exact same problem, mines OK when cold but as soon as it gets to temp boost goes and it sounds a bit like a "Waarrpp" sound (think thats how you spell it) almost like the control valve is letting boost out from wrong place, can't see any leaks in intake/hoses and my stfc & ltfc indicates no air is leaking as they are about 0%. I'm using torque pro and a Bluetooth obd2 connection which also shows my engine coolant temp is -41c but I have replaced ect sensor with no change + I have checked resistance of sensor which is dropping as engine temp increases therefore I believe its working and problem must be something else. Running out of ideas now, I tried cheapo MAf sensors but don't last and give wrong readings so bought a second hand Bosch one which appears to give correct air volume measurements at different RPM... If you find out the solution to this problem please post as its driving me mad now

Mikeyt5 · Post by **Mikeyt5** » 21 Jun 2016, 00:03

Spuddog wrote:I have exact same problem, mines OK when cold but as soon as it gets to temp boost goes and it sounds a bit like a "Waarrpp" sound (think thats how you spell it) almost like the control valve is letting boost out from wrong place, can't see any leaks in intake/hoses and my stfc & ltfc indicates no air is leaking as they are about 0%. I'm using torque pro and a Bluetooth obd2 connection which also shows my engine coolant temp is -41c but I have replaced ect sensor with no change + I have checked resistance of sensor which is dropping as engine temp increases therefore I believe its working and problem must be something else. Running out of ideas now, I tried cheapo MAf sensors but don't last and give wrong readings so bought a second hand Bosch one which appears to give correct air volume measurements at different RPM... If you find out the solution to this problem please post as its driving me mad now

That exactly like mine mate, next step cat cleaner I'll let you know what happens. I had some "incomplete" reading on torque app on the cat bit which is ok when it's cold. I'll try the cleaner and shout you bk matey

kevinwalter · Post by **kevinwalter** » 21 Jun 2016, 03:15

Here it was the VVT solenoid when hot.
It threw an error code with Vida.