chimaera 450 keeps cutting out

[collingbroon]

I was wandering if anyone could give me some advice. I have owned my chimaera 450 98 for a few months with no problems but a couple of days ago it has started cutting out when i come to a halt and dip the clutch. It only seems to happen in the first 15 mins or so but the engine is hot and it only does it once or twice the rev needle seems to just drops to low. Also the speedo is sticking at 0 until about 10 mile is covered when it comes alive and works fine but it does seem to drop down at about 10 mph. I have tried cleaning the senser but no change.

[WOO5IE]

Hi Kev

Have you tried cleaning the stepper motor as this unit often is the cause of tickover problems.

What are the revs at tickover should be 800-1000rpm ish

There is article in Chimaerapages that goes through this process

I think that with regards to the speedo that 'most do that'

Trev

[GreenV8S]

The first thing to do is clean the stepper motor.

[collingbroon]

Hi

Thanks for the reply, ye the tickover is about 800-1000rpm Im afraid i not that good when it comes the mechanics im a smart repair tech so when it comes to bodywork its fine but not so good under the bonnet. I will have a look at cleaning the stepper motor but im convinced the two problems are related. is this poss?

[WOO5IE]

Hi giles

Try this link

http://www.tvrcc-south-wales.co.uk/stepper.asp

This could be the problem as when you dip the clutch you do put an additional strain on the engine although very small and if you had a weak tick over then it could stall.
Is it any different when cold or hot

Trev

[collingbroon]

Thanks for that Trev,

I have already cleaned the stepper motor as it turns out i just forgot the name ( told you i was crap ) it was spotless anyway but the reason i ask about the two being related is because it seems to stop cutting out after the speedo comes on also both problems started at the same time. I heard that the speed senser may be conected to the ECU somehow.It is fine when choke is on its once the engine is warm.

Cheers

[mt10argyll]

I had this problem a while ago also an erratic speedo turned out to be
the transducer I replaced it and no more cutting out as I came to a halt.

[jaxdanjo]

Transducer?

Is that a posh name for mass air flow sensor?

[mt10argyll]

jaxdanjo said:

Transducer?

Is that a posh name for mass air flow sensor?

never heard it called that
The speedo transducer on the rear axle half shaft

[GreenV8S]

collingbroon said:

im convinced the two problems are related. is this poss?

Unlikely, the two systems are not connected.

[collingbroon]

Cheers guys i will focus on the speedo senser then apart from that i love the car better than any modern jap car i ever owned.

Ta Kev

[GreenV8S]

Second thoughts they are connected in that the ECU has a road speed input which affects the idle speed control above a certain speed. The intended behaviour is that above the threshold speed the engine is held at fast idle, so you come to a stop and wait a few seconds and eventually the revs would drop back. Only rarely worked with mine and working or not I wouldn't expect it to cause the engine to cut. That suggests to me that the stepper is sticking closed.

[RedCabbage]

GreenV8S said:

Second thoughts they are connected in that the ECU has a road speed input which affects the idle speed control above a certain speed. The intended behaviour is that above the threshold speed the engine is held at fast idle, so you come to a stop and wait a few seconds and eventually the revs would drop back. Only rarely worked with mine and working or not I wouldn't expect it to cause the engine to cut. That suggests to me that the stepper is sticking closed.

Of course, mine will hold a steady 1200rpm if you dip the clutch while on the move, but quickly settles down to 1000rpm once stationary.