About 1 year ago my 2002 Golf V5 (170ps) developed an engine rattle at about 2000 rpm followed, several months later, by pinking and poor engine performance. The engine management light came on and the local VW dealer eventually replaced both lambda probes which eliminated the pinking and restored performance, but the rattle remained and its cause could not be found.
Several months ago the pinking and impaired performance returned. After several visits to the garage the cause of the engine rattle was finally tracked down to a faulty device that was supposed to alter the position of the inlet manifold depending on rpm. This was duly replaced and the car now drives better than it ever did before and the mpg has improved by up to 10%.
Does anyone know whether the faulty inlet manifold could have been the cause of the original lambda probe failures and whether any latent engine damage (which will probably show up just after the 3 year warranty expires!) could have been caused by driving for over 10000 miles with this undiagnosed fault? Forewarned is forearmed!
{post amended to make use of drop down menus that weren't available at the time first composed.}
Edited by Dynamic Dave on 11/01/2009 at 21:04
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As I understand it, such variable length inlet manifolds simply allow a resonant shock wave to be generated, that can then be used to help the engine ingest air more efficiently. A bit like tuning a two stroke exhaust pipe, in reverse. Assuming the air mass meter and other devices are working correctly, I would therefore not expect a dodgy mechanism inside a variable length inlet manifold to cause the lamda probe failure you mention, as the amount of air being ingested would still be measured, and the fuelling adjusted accordingly. The same goes for knock on effects to the engine. So, reduced preformance, most likely, yes, damage, no.
For information, until last year I drove a Vauxhall Vectra V6 GSi Estate, and a suggested performance tweak was to swap over the two vacuum pipes that each control a butterfly mechanism in the inlet manifold. The effect is to change the inlet manifold configuration points, which reduces low-end torque, but improves that delivered at high revs. I tried it, subjectively and against the clock, and this was indeed the effect. Not living with a German Autobahn in my neighbourhood, I reverted to standard settings.
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Hi there I know this was posted a long time ago, but I have the same problem!!! its been a nightmare trying to get to the bottom of it!!! waht I want to know is what is the name of the part that was replaced in the above mentioned post that alters the position of the inlet manifold depending on the rpm. Anyones help is greatly appriciated as this is causing major headache.
thanks in advance
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I've had a look through my past invoices and can see that the following parts were replaced:
W066 133 203 D 05492/Column (£314 +Vat)
W022 133 237 B 005476 Washer (£4.81)
W066 133 237 005492 Gasket (£13.55)
These were the prices in 2004
The replacement lasted 9 months before the same fault occured so I got rid of the car after that! The car was a Mk4 Golf V5 Tiptronic.
Hope that is of some assistance to you.
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thankyou for the reply.
kind regards
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