Post chip problem

Like the weather "it does not rain, it pours". Having had the solenoid replaced my turbo boost is back but it has a new friend: shuddering or shunting under acceleration. It does not always happen but if the RPM is about 2,200 and I put my foot down I can feel a judder, almost like a very uneven road surface (although it is not). I am assuming it is as a consequence of the modification and that the transmission is struggling with the torque, any ideas? I have called the chip people and left a message asking for a call back so hopefully they will respond. In the meantime anyone else had a similar problem?

[Dan F]

Originally Posted by anthonyf

Like the weather "it does not rain, it pours". Having had the solenoid replaced my turbo boost is back but it has a new friend: shuddering or shunting under acceleration. It does not always happen but if the RPM is about 2,200 and I put my foot down I can feel a judder, almost like a very uneven road surface (although it is not). I am assuming it is as a consequence of the modification and that the transmission is struggling with the torque, any ideas? I have called the chip people and left a message asking for a call back so hopefully they will respond. In the meantime anyone else had a similar problem?

Hi.
Sounds like your spark plugs may need regapping or replacing. The high boost might even be 'blowing them out'.
I would say it is an ignition related problem one way or another though.
Later,
Dan.

Have spoken to the tuners, they have come across this problem before with their sport tune giving too much torque (never thought you could have too much) so I have to re-visit to lower the torque which should then sort the problem.

Hurrah.

[upv5]

I think I'd have to agree with Dan on this.
I can't think of any thing in the transmission (manual or auto) that would give the symptoms you describe which do sound like a minor miss fire.
High boost pressures can "blow out" the spark, my old Cossie with 1.5 bar boost needed plug gaps of 0.6/0.7 mm, down from std 0.9
Now you,ve paid for the "torque" or higher boost in other words it seems a shame to have it turned back down.
Have you got a boost gauge you can connect, it would be of help to know what you have and that your not getting overboost spikes.

Checking and modding plug gaps is something you can do youself for free and it's reversible.

John

[Aeroresh]

Sounds like boost spiking causing the ECU's safeguarding function to retard the ignition. The only way of sorting is by re-mapping.

Who was the tuner?

[Simon Linton]

Minor hesitations are often ignition related; I had what I thought were some hesitations post chip with my old leads and plugs, so I replaced them (with problems detailed elsewhere in the forums - tip, plug ALL the leads back when you reassemble!) and the hesitation appears to have gone.

My change could of course be placebo effect; but replacing the 10-year-old (and looking very shagged) leads can't hurt.

[Dan F]

Hi.
Was this ever cured? What was it?

Dan.

[imac]

What car was it?

If it was a D5 on a "Sport" tune, it was probably the driveshafts juddering?

The earlier D5's with the sport tune from RICA suffer from this at around 2k-2.2k rpm...

EDIT: As he drives an XC70 D5 163 I think I'm right! W00t!

[foggyjames]

Totally stupid question...it's not wheelspin is it? Assuming all XC70s are AWD, I guess not!

cheers

James

[Dan F]

Originally Posted by VolvoT5

EDIT: As he drives an XC70 D5 163 I think I'm right! W00t!

Never even thought to ask what kind of engine it was, just assumed it was a petrol.... lol.