Help...Cerbera Ticking over to Fast

[Gray_101]

Hi. Ive just spent the best part of the day fitting ported and polished manifolds to my 1997 4.2 Cerbera. Every thing i took of the car has gone back on as it was, but now the engine is idleing between 1200 and 1800 RPM and car is nearly undriveable at low speeds

Before i swaped the mainfolds it idled at 800 RPM and was perfect, i am going to have the car re mapped but i want to go to chatsworth this week end , is there some thing i might have done wrong or any thing i can do to drop the RPM ?

I dont have a data cable to reset or check the sensors

[methodwares]

seeing as you had the manifolds off, I would guess the idle screw may have moved, just try undoing it to drop the idle.

[touching cloth]

Lambda sensor I would guess.

[ridds]

What are your throttle pot values and are the throttles shut?

Sounds like an air leak after the throttles.

[Gray_101]

Thanks guys for your replies.

ive got a feeling one of the banks is slightly open at tick over, im going to try adjusting the throtle linkage rod in the morning and the idle screw and see how it goes

[itiejim]

Did you port your own (known) throttle bodies or buy some already done?

I understand that the 4.2 throttle bodies are well known for wear and consequently air leaks which will increase the tick over speed.

[hoppo4.2]

as soon as the bodies are removed they must be rebalanced and the T-pot 's adjusted. even a slight movement in the settings makes a massive diffrence as i found out when i had mine off.

[Gray_101]

I cracked it, after quite a bit of fiddleing this morning i manage to get the RPM down to 800.
I had to keep moveing the throtle pot sensors just a fraction to get the engine to tick over with out staling or reving its head off.

im all set for chatsworth now , lets hope the rain stays away

[hoppo4.2]

did you get the car on the laptop when you did this?

if not you could just be maskin the problem my moving the T-pots.

when you get chance you should check it out you will prob find you need to balance both banks of bodies and then reset the T-pots. worth a check

[Gray_101]

Ive not got the cable as of yet , so all adjustments have been done physically, but your right about masking the problem .
took the car for a little spin to day and it seems gultless and want to stall from a standing start. but once over 1400RPM theres no stoping the savage power. and the extra noise due to the ported manifolds is awesome

but spoke to an indy TVR garage today about having it re mapped, so im hopeing it will all be sorted very soon