Hesitation at or below 2500

[coach]

Hi

My 450 (R) hesitates or judders noticeably but not violently on a partial throttle loading at or below 2500RPM.

Clears up straight away when I press the loud pedal a bit but then I am coming too close to traffic in town and have to back off. Endless cycle!

Any ideas what this is?

Regards

Coach

PS - Someones nicked me jack and spanner - AND my cigarette socket dont work to power the compressor that complements the tyreweld kit....busy mechanicing weekend coming up!!

[Big Al.]

Hi coach, before you get a flood of hails,

Altogether boys and girls have you cleaned the stepper motor?

Quick clean and a squirt of WD40 inside and out, seems to cure most of my tick over / throttling eratics.

Ciggy lighter, shot fuse or wire dropped oft.

[coach]

Big Al

Bugger! sorry for the thickness!

I thought the stepper was just for idle issues. I shall add it to the list of weekend greasy monkeh type things to do....

Coach

[GreenV8S]

Might start to get a bit lump somewhere between 1500 and 2000 rom but should be OK up at 2500 I would have thought. Could be fuel/ignition slightly out, or dirty plugs. Is it coming due for a service?

Also, on mine, the cigar socket is only live when the ignition is on.

Cheers,
Peter Humphries (and a green V8S)

[Big Al.]

coach said: Big Al

Bugger! sorry for the thickness!

I thought the stepper was just for idle issues. I shall add it to the list of weekend greasy monkeh type things to do....

Coach

Sorry coach, didn't mean it to sound derogatory.

Your probably right but if it’s clean, it's just one less item to rule out of the equation.

[apache]

I have had exactly the same problem and it got progressively worse. Eventually diagnosed by Mark Adams and Power Engineering as number 7 and 8 inlet valves not seating and leaking like crazy. Mark explained that this will cause the ECU to make 3 readings per cycle as air comes in, gets blown back on compression and exhaust (hot gas and not good for hot wire sensor)
TVR cut the valve seats back quite drastically apparently and if not done well will cause probs as later.

edited to add, above 2000 ish rpm the incoming pressure overcomes the backpressures

>> Edited by apache on Thursday 12th June 00:50

double edited cos tonight I 'ave bin mostly drinkin' a nice Sauvignon Blanc

>> Edited by apache on Thursday 12th June 01:09

[madhatter]

I get the same problem with my 450 only it happens all the way upto 3000rpm. Real pain in the in town traffic.

Hawthorns TVR have been looking at the problem but nothing shows up on their diagnostic equipment. They've also apparently got another 450 with an identical problem. There only thoughts todate have been electrical issues.

One intersting point though is that it wasn't a problem when I test drove the car. Only once I picked it up and they'd replaced sports exhaust with a regular one (sad I know).

[coach]

Right

Looks like we got us a mini trend here with the "450 shunt n Shuffle".

I will Update this thread when I have been to team pro-active a week tomorrow.

Hope it aint valve seats - sounds REALY expensive.

Mine didnt do it on the test drive either!

Bottoms!

Coach