Is cleaning the stepper motor part of a service?

[wolosp]

I have a 96 4 litre Chimaera which recently developed lumpiness when driving slowly. After reading about carefully cleaning the stepper motor to cure such problems, I checked this out and found that there was a tie-wrap around the throttle cable and the plug onto the stepper motor. It definitely looked like an original tie-wrap and as it was around the plug retaining clip it was preventing the removal of the motor plug. It occurred to me that the motor had therefore never been removed / cleaned.
If a build-up of crud is such a known problem with the stepper motor, should it not be part of the normal service routine to clean it? If so, several TVR dealers and one well-known TVR engine specialist have not been as thorough as one would expect.
After cleaning the motor valve, it definitely runs better - I was suprised at the amount of crud on the conical valve.

[zippy500]

They usually clean it if there is a problem with running, however if it is running well it usally gets left.

[P7ULG]

After reading about all the threads on cleaning stepper motors the last time I was at the dealers i asked about it and they reckoned it should be done at every service.

[wolosp]

Thanks for your replies chaps.

[sps]

Hello all,
What the hell is a stepper motor , what does it do and what is it's location?
I have a 4ltr Chimaera.
Thanks in advance.
SPS

[shpub]

quote:
Hello all,
What the hell is a stepper motor , what does it do and what is it's location?
I have a 4ltr Chimaera.
Thanks in advance.
SPS

It's covered in the Griff and Chimaera bible and I'm sure if you search the archive it will come up with the details. It basically controls the idleing and gets gummed up and starts to do silly things. Black thing at the back of the plenum.

Steve
www.tvrbooks.co.uk

[sps]

Many thanks Steve.
SPS

[JonRB]

Dave Batty has commented in the past that the Stepper Motor has now acquired near-mythical status in TVR circles such that some owners seem to be of the opinion that ANY engine-related problem can be cured by cleaning it.

He very tactfully and gently (as is his style) cautioned me against cleaning it too often as it is very delicate and fragile. He also said that it is just one of a number of things that can cause a lumpy idle.

[shpub]

quote:
Dave Batty has commented in the past that the Stepper Motor has now acquired near-mythical status in TVR circles such that some owners seem to be of the opinion that ANY engine-related problem can be cured by cleaning it.

He very tactfully and gently (as is his style) cautioned me against cleaning it too often as it is very delicate and fragile. He also said that it is just one of a number of things that can cause a lumpy idle.

Yes but it is also one of those things where if you don't clean it and spend hours looking for the other causes, you can guarentee it is the thing that is causing the problem! Sod's Law is universal. As for being fragile, well the fact that it spends its life with temperatures in the 100 C and subject to a lot of G forces through braking and accelerating and rarely breaks tells me that it is not that fragile. sure you need to take care and most damage is done when the thing is tightened up with a 6 ft scaffold bar but to say you shouldn't clean it regularly is a bit of a generalisation of the opposite kind.

Steve
www.tvrbooks.co.uk

[wolosp]

I agree with Steve in that as long as you are careful, then there should be no problem.
I can see that David is saying that the stepper motor is not the be all & end all of idling problems, but in the same way that if you had handling problems you would ensure the tyre pressures are within spec before you replaced the dampers or did any work on the suspension, checking the stepper motor for cleanliness when it is apparent it has never been removed (as in my case) made absolute sense.