406 1.8 Petrol tickover

[killjoy]

The tickover on my 406 increased to about 3000rpm, I have replaced the stepper motor as I knew it was knackered from earlier problems ~ however my tick over is now about 1800rpm rather than 1100rpm.

Whilst the tickover is high it is steady with no sign of hunting (which it had before I changed the stepper motor.)

[Captain Jack]

Maybe the throttle cable is too tight? I suspect you checked this but you never know!

[highlander]

Could also be the Mass Air-Flow meter - if the ECU reckons there's too much air getting in to the engine, then it'll add more fuel to the mix, resulting in a higher-than-normal idle.

If the MAF isn't buggered, check to ensure there's a good seal between the throttle body and the inlet manifold. There should be a gasket between those two parts. If not, or if it's not a good seal, then regardless of the position of the butterfly valve in the throttle body, there'll be more air getting to the MAF than there's supposed to be.

[killjoy]

Sorted - I Think


I went back to jameslxdt's post:

viewtopic.php?t=3489

and repeated the initialisation routine - starting by switching on the ignition with the stepper motor disconnected.

once all is together, get in the car and turn the ignition on for 30 seconds, then switch it off for another 30 seconds, repeat this 3 times, on the 4th time you turn the ignition on DONT touch the throttle, start the car and alow it to idle for another 30 second

The tickover is now 1100 rpm, just got to take it for a spin now.

[killjoy]

It looks like I spoke to soon

Start from cold and the tickover is steady at 1100 rpm as should be, however once the car is warm the tickover drops to about 800 rpm, which means I have a 50% chance of it cutting out when I shift into neutral when stationary ~ any suggestions.

[Captain Jack]

Isn't 800rpm the ideal tick-over speed?

[mjb]

800rpm should be about right once warm.

However, it shouldn't cut out. Make sure you haven't left something unplugged like the stepper or throttle pot

[killjoy]

It always used to tickover at 1000rpm, I just find that if it drops below that 800rpm level into that lowlevel marked on the rev counter it cuts out ~ I will go and try the connections, again.