Induction

BiggestNizzy · Post by **BiggestNizzy** » Mon Jul 16, 2007 11:32 am

hmm after reading your suggestions I had a good listen and it only seems to happen between 1500 - 2500/3000 Revs (my wee flat spot) are the 2 things connected ?

does sound kinda

though

robin · Post by **robin** » Mon Jul 16, 2007 1:07 pm

If you run it up to say 6,000 RPM somewhere where you can let the car coast down in 3rd (i.e. an empty motorway) it should be very clear what's happening.

If it then pops and bangs at anything above 2,000 RPM I would suspect TPS is away or needs reset (though usually, resetting it doesn't fix it properly, it just delays the inevitable).

Reset procedure is ignition on, lots of quick pumps (not sure of number but 10 should be more than enough) of the throttle pedal, ignition off, wait for the clunk from the rear (or just wait at least 30 seconds). Job done.

Cheers,
Robin

robin · Post by **robin** » Mon Jul 16, 2007 1:12 pm

The flat spot between 2,500-3,000 RPM exists on all non-VVC K's running on a plenum, to some extent. Porting and cams with more overlap accentuate this somewhat. The fact that the extent of the flat spot varies from car to car makes me think it's cam timing specific, so a vernier on the exhaust or inlet is a possible solution (to trim out some of the overlap).

Once your TPS is sorted (assuming anything is even wrong with it) you may well find that driving the car on part throttle below 3,500 RPM gives you better acceleration.

Cheers,
Robin

BiggestNizzy · Post by **BiggestNizzy** » Mon Jul 16, 2007 1:52 pm

Will try that on the way home tonight. and let you know.