Different stepper motors ?

[pac1uk]

I changed my stepper motor today. I thought a new one would smooth out my hunting idle. This was first replaced back in 2002.

Cold start and running was a lot smoother, once the engine was hot after a run, idle was ok for a bit then it would cut out, the revs would drop and cut out, it would restart but would have to give it some gas to keep the revs up.

I thought this would be just a straight swap! Am I missing something else to adjust?

I might have to clean the old one and put it back to see if I get the same symptoms. But it never cut out when idling.

[bobfather]

Not sure about set-up but I would suggest you clean the seat. It's a valve and all you've changed is the plug, you should also use a stiff brush to scour the valve seat ring as this will get carbon build up too. I use a fibre Dremel wheel

[blitzracing]

The low cost Chinese steppers you get on Ebay can cause problems- the shafts are the wrong length, and also can leak air.

[spend]

Do the base idle when you change the stepper motor, it may well have been 'serviced' to accommodate the wearing stepper during its life (as well as the effect of the bypass gallery / pipes clogging up?).

[spitfire4v8]

spend said:

Do the base idle when you change the stepper motor, it may well have been 'serviced' to accommodate the wearing stepper during its life (as well as the effect of the bypass gallery / pipes clogging up?).

^^ this .. go back to first principles and set it up from scratch. blitz's comments about cheap steppers would be worth noting if that's true .. buy cheap buy twice as they say.

[pac1uk]

Thanks for the advice. I got it from a TVR parts company I regularly use.

In the end I reset the base idle, runs fine now. That's one job crossed off the very long to do list.

[p5000ko]

blitzracing said:

The low cost Chinese steppers you get on Ebay can cause problems- the shafts are the wrong length, and also can leak air.

griff 500.. original stepper was starting to stick at 2k revs seemed to be beyond cleaning as made no difference. Purchased non lucas version from TVR supplier, popped it in and couldnt start without large amounts of throttle. was advised to kill ecu then start up and set base idle. All very well but after reset of ecu it still would not start so impossible to set base idle. Once fired and warmed to fan operation it started to work. tried to set base idle but adjusting screw didnt make much difference. I put the sticky lucas one back in and it started staight away and didnt stall but i know it is unstable. Found your link but there are two different types, could you advise which one i need please. The other non lucas one will be going back..............refund or not as it is no good IMHO.

[blitzracing]

I cant tell you part numbers- but the difference is just the connector locking tab is 180' different between the two types, so if you can get a picture just check the connector.

[Sardonicus]

There are a lot of variation on this style IAC/stepper as Blitz mentions even the Yanks used them on various cars (a Delco copy) http://www.ebay.com/itm/New-AC-DELCO-17111286-Idle...