Lack of power

[coz_g40]

Im getting a lack of power below 4000rpm on my G40. I can bury my foot to the floor and it goes, but not as quick as it should, when it reaches about 2500rpm it goes abit quicker, then when you reach 4000rpm it goes like foook. Its starting to do my head in now. With me being so busy at work i dont get much time to work on my own car i just spend all day fixing everyone elses.
Any help or advice would be much appreciated.
Cheers Coz

[hayesey]

well there's quite a lot of things this could be.  Have a read through this:

http://www.polog40.co.uk/forum/index.php?topic=214

Start off by getting the basics sorted out.  Check the ignition timing, +5° BTDC (+/- 1°).  Get the engine up to temp and then unplug the blue temp sender.  The revs should rise slightly, then set the timing.  If the revs drop a lot or the engine cuts out when you unplug the blue temp then it's a sure sign the ECU is not getting a reading from one or more sensors.  Make sure you then plug the sensor in before turning the engine off.  

Also check all vacuum pipes for leaks.

Is the ECU map stock or have you got an aftermarket chip installed?  If so which one?  What other modifications have you got?

[Alexiskayak_7]

I had the same problem with you.I had a boost leak and while i was revving i heard shhhhhhh... there is a hose between servo and the manifold (it's hard in the side of servo and it has a hose in the manifold... Take a look if it is blown...

[coz_g40]

Cheers for that. The cam and ignition timing are spot on, we were quiet at work this afternoon so a had an hour on it. Elimenated the lambda probe and co pot as well. I think it is down to my Ebay chip, plugged my scanner in today at work and intake air temp is reading -40 degrees. C0 pot was bought new about 3 months ago. Trying to get another chip on ClubPolo.
Mods:-
Jabba stage 4 charger
65mm pulley
De-wedged TB
Ebay chip
Full stainless (no Cat)
Induction kit
Chip has been in for about 6 months but only had problem for about 3 weeks

Thanks again for the help any more opinions are more than welcome
Coz

[hayesey]

the crazy air temp is a red-herring, they always seem to read that at the ECU, check out the FAQ on VAGCOM I wrote.  Do you know what the ebay chip is?  Is it a Poloace one?  If so then it should be OK, Alan Laurence who makes these chips knows what he's doing.  Otherwise I guess it could be suspect.

You can quickly check for boost/vacuum leaks by disconnecting the boost return valve linkage, then with the engine running briefly close off the BRV (keeping the throttle closed since the linkage is disconnected) the pipework will quickly pressurise and you'll be able to hear any obvious leaks hissing out.

[coz_g40]

This is the chip i bought.  [attachment=51] I found my origional chip at work today so i slotted it in and it seems to have sorted the problem. Even feels to have the same power and torque.
Thanks again for all the help.

[coz_g40]

How big!!!!!!