Engine cut-out when revs drop

[chris_tivver]

My Tuscan suddenly developed a tendency to cut-out when the right foot comes off the loud pedal. The garage have had it for 2 weeks but have admitted defeat.

I can keep it going by heel & toeing on every change, which is fine when on the track or being exuberant, but frankly gets tiring when in town (and all that revving can give the wrong impression!)


Any ideas of anything the garage might have missed?

[lucozade]

idle speed?

[lady topaz]

I had this soooooo many times. Without sounding sanctimonious you do have to keep on at your dealer. It is a matter of fine tuning Mine used to cut out all the time. Usually they adjust idle speed but you really need to get it on diagnostics to get it right.

Di x

[chris_tivver]

Cannot tell you what the idle speed is now because it drops till it stops. It only does it when it is warm.

I suggested the idle speed, so why would they not have managed to fix that?

[NCE 61]

Throttle pots could need replacement, or could be valve clearences closing up. Adjusting the idle speed could just be covering up another problem.

[lucozade]

Just out of interest what should the idle speed be for a Tuscan S (07 plate) - since mine came back from it's 1000 mile service the idle speed has been raised. Maybe a little too high but it is running very well.

[orangecar]

Hello. My Tuscan II had a similar problem last year. It wouldn't always stall but if it didn't it would then show up an EFI fault on the dash as low oil pressure. My dealer informed me it was the oil pressure switch (which was a common fault) and replaced it with the latest upgraded one. From cold the idle is 600-650 once warm it stays around 850-900. Good luck

Regards Stu

[chris_tivver]

Now I have the car back I can give more info. One bank of the cylinders are running lean which is causing a slight mis-fire which apparently is causing the cut-out. I have to admit that whilst I notice the mis-fire sometimes I do not always notice it before cut-out.

That help anymore?

[nelly1]

Sounds like it could be a fuelling problem for those cylinders.

Could be the coil, plugs or the lambda probe.

I assume these have been thoroughly checked?

[glow worm]

Heath Briggs told me the low idle speed is an ECU fault which TVR knew about...Current Fix is to idle at 850 revs...Even worse if you turn Aircon on and revs drop, since Tivs don't make a compensation.

[chris_tivver]

nelly1 said:

Sounds like it could be a fuelling problem for those cylinders.

Could be the coil, plugs or the lambda probe.

I assume these have been thoroughly checked?

By coincidence I had asked for coil and HT leads to be replaced just before this problem hit, but they were actually replaced after it occurred so I know its not them.Plugs have been checked

I will ask about the lambda probe

Thanks

Edited by chris_tivver on Wednesday 9th May 22:30