V70R 'surging' under full acceleration

[Jod T5]

furthermore there is no way your map will allow your car to "overboost", i would be certain you, like the hundreds before you have a boost leak, regapping the plugs may help you but the fundermental issue is that you have a leak...
be it thru the vacuum hoses or intercooler piping you have a leak...
cheers
jod

[Jod T5]

Originally Posted by jod t5

furthermore there is no way your map will allow your car to "overboost", i would be certain you, like the hundreds before you have a boost leak, regapping the plugs may help you but the fundermental issue is that you have a leak...
be it thru the vacuum hoses or intercooler piping you have a leak...
cheers
jod

another thing is to carry out a stage 0 tune up..see maintenance section...
cheers
jod

[jongs]

Hi guys,

Thanks for the all the input. Last week I took the new plugs out (from Volvo) and it seems that I forgot to check the gapping of them before they were fitted..... I adjusted them all and the exhaust popping went away but the surging was worse, this time stuttering at 60 mph plus under acceleration - This time it put the engine light on though - I had the fault codes read and it was the Lambda probes showing faults. Replaced both of them (they were very black and gunked up) and it is now a lot better although it still does not feel like 270bhp........

Thanks again for your input - I have a friend with an 850R so I think it is time to put them side by side and see if it goes as hard as it should!

[s60ben]

Possibility of it being the TCV

Oscillating torque/low performance on T5 petrol turbo engines

Cases have been reported of oscillating torque during acceleration or low performance on petrol turbo engines. The symptoms are that during hard acceleration at high speeds, an impression of holding back is given.

The root cause has been identified as a sticking Turbo Control Valve (TCV) due to the Crankcase Ventilation gases, which causes rubber components inside the TCV to stick. TCV with improved resistance against Crankcase Ventilation gases is now available under P/N 30670448 for the following models within chassis range listed below:

V70 MY02-MY04 within chassis range 0171000-0395666
S60 MY02-MY04 within chassis range 0092352-0365357

Admittedly it's not within the date or chassis range, however thats not a surprise given the source.

Hope that may assist.

[THOMO]

Try Shortening The Gap On Your Spark Plugs

[jongs]

Hi again,

Thanks to everyone for their suggestions so far but now I have just got one more problem which somebody might be able to shed some light on! Now the new Lambda probes are in (from Euro car parts) and the plugs are correctly gapped the power feels like it should but the fuel comsumption has gone down the drain!! I was averaging around 23mpg in mixed but moderately hard driving before but now it is only averaging around 16.5 mpg....!!! I can't imagine that this is all it should be doing!

Does anyone have any idea please?????

[Clan]

Popping in the exhaust is a classic symptom of an air leak in the exhaust manifold somewhere, maybe loose nuts or a distorted flange or even a crack? It shouldt affect performance too badly thouigh . as you can't hear a blow ..

[theador]

I had the cut out problem before, and I've now got it again. For me, the fix is simple. On the drivers side there is a fuel breather pipe that runs I think back to the tank, it has a push fit connection near the subframe at the front. it can quite easily get knocked loose when doing work; then after a while I guess some sort of vacuum builds, and under hard acceleration, it feels like the Rev limiter is kicking in around 4000rpm.