DIY - problemas de arranque e de andamento (apenas motor 2.0i)

Retirado de um fórum inglês de Peugeot 406:

"I HAVE MANAGED TO RECOVER THIS GUIDE FOR ALL OF US TO USE

Now Edited for turbo models

Mods could you please sticky this guide i have made, but do not lock it so members can post there comments

thanks


406 D8 petrol (Excluding V6) running and starting problems

as this subject comes up quite a lot i thought i would make a guide on the fixes for D8 petrol running and starting problems, this doesnt cover the V6 as i have never had the honor of working on the V6 and i am demonstrating on my car, which is 2.0 16v XU10J4R RFV, all petrol 406's execpt the V6 have XU engines hence why it applies to all the models!
Right first on the list:

Stalling, rough/harsh gearchanging (manual only) and high idle

the most common cause of these problems is a faulty or lazy stepper motor, usually cleaning and re-synchronsing it can cure all of these problems
the stepper motor can be found on the throttle housing
see the pics below
NOTE: turbo models are slightly different !

turbo 8v




non-turbo 16v




going by the second photo -
for the moment ignore the blue circle
the pink circle indicates the throttle housing on the first pic and the red circle on the first one
start by removing the airbox as shown below





please ignore the green circle, the red circle is the stepper motor, it should have AMC printed on it, some have phillips also
undo the connector with 4 wires on it
the undo the two torx 20 screws and pull it out




this is what you should have
the red area indicates where the carbon buildup occurs, clean this with brake cleaner or carburretor cleaner, dont worry about getting it inside it, this helps to a certain degree
now refit everything, taking note to put back all the various vacuum hoses and electrical connectors
now 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 seconds, now go for a drive for about 20 minutes and all should be well!

Running Problems

remember i told you above to ignore the blue circle, now this is what we are concerned about, if you have a rather annoying hesitation between 2000 and 3000 rpm at part throttle when the engine is warm, then you will most likely have a faulty oxygen sensor, they are also often refferd to as a lambda probe
the picture below is a close up of the blue circle in the first picture above





the red circle indicates the plug for the oxygen sensor, lift the red part up with a screwdriver, and pull the front part out leaving the red part where it was, now go for a drive, the car should now drive faultlessley and it WILL NOT trigger the K light as the engine management is too stupid to know somethings not right
you can drive arround like this without a problem, untill your MOT then you will need to have the sensor replaced

Starting Problems

if your car is refusing to start and the keypad/immobiliser is functioning accordingly then most likely the TDC sensor, or Top Dead Centre sensor is faulty, its often called a crank angle sensor, crank position sensor or engine speed sensor, it basically informs the engine management of the position of the crankshaft so it can time the injection and spark correctly, what usually happens is the thermostat housing, positioned directly above the sensor developes a leak and shorts the sensor internally rendering it usesless, i will now demonstrate how to test the sensor





airbox removed for clarity
ignore the red circle
in the green circle is where you will find the connector for the TDC sensor
its a brown color
now i have removed the sensor for clarity here, but to test it, you need to un-plug it
BUT LEAVE IT FITTED!!





the pins i have circled above are the ones we are concerned with
now grab yourself a multimeter like so





you dont need a very expensive one like mine, i use it for work everyday, anyone will do
now set it too A/C voltage, or Alternating Current, this is ESSENTIAL otherwise this test is pointless

now attatch the leads to the sensor plug, NOT the harness plug as shown below





taking note again, i have the sensor removed for clarity, you still need yours fitted to the car

now with the multimeter attached and set to A/C voltage, get a friend to try and start the car, a good sensor can read anything between 1.5v to 3.5v, BUT as a general rule 1.0v should be ample enough to start, if this not the case, then leave the pins attached, and turn the multimeter to measure resistance in Ohms, now generally anything above zero is good, if you have very low voltage and open circuit or low resistance, then the sensor is almost certianlly faulty, now the good news is they only cost about £22+VAT from pug
and if you follow the cable its bolted into the top of the gearbox with one 10mm bolt, undo this and it simply pulls out, BEFORE fitting the new sensor take not of what i mentioned above, these sensors only usually fail if the thermostat housing leaks directly above the sensor, which is quite a common problem, so make sure you remendy the leak before fitting the new sensor otherwise you will be looking at needing another new one pretty soon!"