406oc.co.uk

Hey guys and girls, looking for some advice on a Peugeot 406 1800cc from 1999 its done about 86k.

Been a great car but lately there seems to be a problem starting it. Turn it over and it will try to fire . Turn it over with a bit of throttle and it will start up, but as soon as you let off the gas it starts to sound like a misfire then dies.

Once the car has done about a mile or so its absolutely fine and if you start it up after a short rest its fine, but after a couple of hours it still struggles until its warmed up again!

I know a little about mechanics but not a huge deal, I thought perhaps there is a leak in a fuel line, which when it isnt used causes a leak in the fuel line and thus fuel starvation. Dont think its a blocked fuel filter as it would struggle to run normally, or electrical as again it would always show this problem.

Also with my head under the bonnet earlier, it did sound like an air hose or something might be cracked as it did sound like there was too much air being sucked in, but i cant see anything suspect.

Any advice would be greatfully recieved, just trying to get an idea of what it could be so i can plan on fixing or getting someone else to do it!

What does the stepper motor actually do?

When it's activated by the engine ECU, it lets air into the engine. Generally this is when your right foot isn't holding the throttle butterfly open

So it looks like i have my next day off planned then... Is there likely to be anything else not covered in that guide?

If you remove the throttle body, remember that there is a rubber gasket on it, which you should check for wear, and replace if needs be. My throttle body was clean as a whistle, and the butterfly valve in it was able to move no problem - but with a perished gasket, I found the engine would idle strangely - anywhere between 750 RPM and 1800 RPM.

Even worse, it would occasionally stall, even in motion (albeit at low speeds), resulting in the inevitable "ANTI-POLLUTION DEVICE DEFECTIVE" warning on the MFD and the engine management light coming on.

Ok, past 2 days the car has been fine, started it up absolutely fine!

Anyhow i have taken the stepper motor out, covered in carbon, so cleaned up and put back all seems good so far, be interesting to see when it warms up if it happens again!

One thing i did note there was a small amount of oil on the inlet of the throttle body where the air box joins the throttle body. Wondered if this had perhaps come from a breather that runs in that direction from the engine? Cleaned that out so ill leave it for a week and see if it re-occurs!