my xantia problem

joegood · Post by **joegood** » 12 Jul 2007, 13:54

hii..i'm from malaysia and newbie here ..
i've a few queston to ask expert here.My xantia engine sometime stall especially when the car going to slow down,for example at traffic light...but this problem only happen sometime.According to the mechanic, stepper motor should be changed.. i already changed my stepper motor but the problem still not resolve.
For further information, my RPM engine when idle is around 7-8 and never stall when the car is not moving..stall only happen between moving to stop(dunno how to describe properly).sometime K light flashing but this sympom happen very rare.. i can say about 2 month once.

is anyone here having expericnce the same problem? or anyone here know how to solve the problem.

Thank

Post by **admiral51** » 12 Jul 2007, 15:05

hi
what model/engine petrol/deisel
what year

colin

AndersDK · Post by **AndersDK** » 12 Jul 2007, 15:35

Hej Joe

Must be a petrol when stepper motor is mentioned.
I think your mechcanic could be right. But it can as well be the MAP sensor.

Depending on exact type/size of engine - plus the model year of your car.

Post by **admiral51** » 12 Jul 2007, 16:14

thanks anders must learn to digest what is on the screen in front of me

colin

joegood · Post by **joegood** » 13 Jul 2007, 05:15

hii..sorry,forgot to put car detail
Model : Xantia Petrol 2.0
Year : 1996

I already change stepper motor but the problem still persist..anyone here have other solution?planning to check MAP sensor ,anyone in here know how to check map sensor symptom?

Clogzz · Post by **Clogzz** » 13 Jul 2007, 14:08

Map sensor story here:

http://www.aussiefrogs.com/forum/showthread.php?t=33660

The idle stalling when stopping at traffic lights or bottom of hills is caused by air getting sucked into the vacuum.
Squirt all vacuum hoses with WD40 while idling, and where the idle increases when squirted, is the place where the air gets in.
The injection has a sort or air box or whatever

at the front, just behind the top of the radiator, with a rubber blanking plug on the battery side.
It could be loose and letting the air in.

joegood · Post by **joegood** » 17 Jul 2007, 03:34

thank clogz for your valuable input..
but i wonder , what is MAP sensor purpose?

Clogzz · Post by **Clogzz** » 17 Jul 2007, 13:37

The MAP sensor is the manifold absolute pressure sensor.
It senses pressure variations in the manifold to tell the injection ECU how much airflow there is, so as to vary the fuel flow accordingly.
Or something like that.

Post by **CitroJim** » 17 Jul 2007, 21:18

Clogzz wrote:The MAP sensor is the manifold absolute pressure sensor.
It senses pressure variations in the manifold to tell the injection ECU how much airflow there is, so as to vary the fuel flow accordingly.
Or something like that.

That is pretty much spot-on Clogzz

A MAP sensor, in conjunction with knowing the air temperature, how far the throttle is open and the speed of the engine, allows the ECU to make a fair estimate of the mass air-flow into the engine. It is the alternative method to using the Mass Airflow Meter (AFM) of either the "flapper" (vane-type) or hot-wire.

It takes a bit more processing power in the ECU to work out airflow than the AFM approach but is less affected by upstream air leaks and inlet tract reversion pulses at low speeds than the AFM approach. It is also dead easy to use with turbocharging (as it can measure pressure as well as vacuum) and automatically compensates for engine wear over time.

Information derived from mass air flow is used, amongst other sensor inputs, to determine how long the injectors spray for and thus regulate the air/fuel ratio (mixture). The MAP signal also controls, to an extent, timing, being the analogue of the vacuum advance capsule on distributors.

So, on a MAP based system, as well as checking the MAP sensor it is also necessary to check the air temperature sensor and the throttle position sensor.

Although a MAP-based system is less susceptible to air leaks upstream of the throttle body, manifold air leaks or any air leaks downstream of the throttle body seriously upset a MAP sensor and it is a fair bet this will be your problem. The pipe to the MAP sensor itself, which is usually well away from the inlet manifold, either indside the ECU or up on the bulkhead, is a prime suspect and a well-known problem. It persishes.

joegood · Post by **joegood** » 24 Jul 2007, 16:07

thank but seem i got another problem, where the location of map sensor ..is it near radiator or can somebody show me the picture of map sensor. and another one question is... how to clean map sensor? it it just wipe it with petrol or any chemical liquid availble at hardware shop?

Clogzz · Post by **Clogzz** » 25 Jul 2007, 14:01

Picture, location and cleaning ideas in this topic:

http://www.aussiefrogs.com/forum/showpo ... ostcount=2

http://www.aussiefrogs.com/forum/showpo ... ostcount=3

http://www.aussiefrogs.com/forum/showthread.php?t=33660

JohnCKL · Post by **JohnCKL** » 25 Jul 2007, 15:39

Hi Joe, are you in KL and which workshop do you go to? I might suggest a competent mechanic to check out your problems.