engine hesitation

[philmcw]

Jusr recently taken ownership of a lurvelly copper cascade tuscan 4.0 L and had the opportunity to take in on Bruntingthorpe proving ground last weekend for a couple of blasts down the 2 mile straight.

Great acceleration in 1st 'n 2nd but in third & forth there is a bit of engine hesitation around 6K rpm. The engine is still pulling but it feels like somebody turned the torque off Engine revs sort of creep to 6.5K when I up shift. The car immediately surges until aroundish 6K rpm in forth and the same thing happens. I up shift to fifth and off we go again until around 6K rpm. Not sure now whether its engine hesitation now 'cause I'm doing around 160mph where it appears i've now hit vmax...

Any views greatly received

[basil brush]

Might be worth doing an archive search for de throttle chip. I'm not sure if this is the problem but it sounds similar.

[T66ORA]

Change the HT leads and clean up the coil pack or get your dealer to do it, thats your problem i reckon, well it was on mine

[J.T.]

basil brush said:

Might be worth doing an archive search for de throttle chip. I'm not sure if this is the problem but it sounds similar.

I had exactly the same symptoms iin my S6 Cerb - factory supplied the de-throttle chip (somewhat erroneously named I believe) and fitted FOC by dealer - no problems since. It could also be that your throttle bodies are worn/need adjusting but I would go down the chip route first.

Try this thread as a starter www.pistonheads.co.uk/gassing/topic.asp?t=133357&f=5&h=0&hw=de%2Dthrottle+chip

JT

[ecosnige]

Mine was like this cats had collapsed and plugs changed had her decatted.

[philmcw]

Thanks for the replies.


Car off to dealer tomorrow with copy of your diagnosis

I'll post what they did

[philmcw]

Hi All


Plugs & Leads Changed.

All OK Now, Yippeeee

[dvs_dave]

Funny thing same thing happened to me after a trip to Bruntingthorpe. It developed an intermittent misfire and was generally running rough after doing a few fast laps and then going and doing some low speed slide control sessions.

Took it to TVR Gatwick who whacked a new coil pack and HT leads in. Sorted it out.

I think the reason this happens is that when the leads get a bit old and deteriorate, they become much more susceptible to heat in the engine bay. A track session will raise engine bay tempertaures considerably to levels where old leads may be tipped over the edge.

BTW Phil.....didn't take you long to get back into a Tuscan. T55 K** is going a treat. Just had TCS put Nitrons on her with a full geo set-up. Amazing difference!! Next job is a de-cat. Hope she doesn't make my ears bleed