Tuscan over revs at take off

[14TerryB]

Hi, Has anyone had experience of over engine over run on TVR Tuscan Str6 when changing from 1st or 2nd when moving of or stuck in traffic. Throttle valves closing pedal box lubricated and does not appear to be sticking.
Any help welcomed as meant to be going away this weekend. Bugger

[smighall]

Not sure i understand what you're saying? Feels like throttle sticking when changing into 2nd, and only 2nd?

[14TerryB]

Hi, The problem seem to happen when miving of or when stuck in traffic and it’s stop start. The engine carries on reving when coming off throttle to change gear. Ok once up and away.
I have removed throttle box and checking cable and that cable not sticking, butterflies are closing ok. Checked pedal box and that’s not sticking eitherWhen I had my Griff this used to be a throttle pot issue.

[Oneball]

What about an air leak around the manifolds/throttle bodies or a broken throttle return spring or badly adjusted linkage between the throttle bodies.

[14TerryB]

Hi, Not sure about an air leak but when just parked on drive and engine receding slowly or fast the problem does not seem to happen.
Checked spring and linkages and all seems ok.

[nawarne]

Ultimately, increasing revs indicates more air passing through the throttle (bodies).

I'd double check the "SMOOTHNESS" of the throttle cable and the linkage at the 'crank' on the common shaft/spindle for throttles. If everything else is operating within range....then something is holding the butterflies open??

I've had instances where the clevis pin/R clip assembly was catching on the adjacent flange of the air box, preventing the cable/throttle from closing completely. I've spaced the clevis with washers now and cured the problem..


Nick

[14TerryB]

Nick, Thanks for this information, I will have another look tomorrow. I did think I had checked these linkages but could have missed after refitting air box.

[MPETT]

Could be throttle body bushes or lack thereof. Sounds similar to what I had on mine. No bushes, just steel on alloy and slight wear in throttle body, causing small vibrations and all kinds of weird behaviour.