High Idle RPM , engine stalled and hesitate

[IrfanIbrahim]

Had this problem on my Xantia for 2 months if not mistaken , changed a recond throtle body with a full set of sensors and even swap the ecu with my friend's just to check for the cause. It won't be easy for me to hook it onto computer for fault checking as my car need 21 pins instead of 16 and its hard as hell to get that here. So my last bet would be a leak in air intake manifold. Anyone had a same problem recently? I wonder how would i check for leaks.. Some suggest carb cleaner , is there any other method to check for leaks?

[lurchy666]

petrol??? if it is check your idle valve, as on my 1.8 it had jammed then when i got it replaced i found out it had knackered my ecu,

you can get the 21 pin thing off ebay to fit to a normal lexia (well the ones i found on ebay are 30 pin but have a look see if its what u mean)

http://www.ebay.co.uk/itm/New-Car-30-PI ... 3a78dac22b" onclick="window.open(this.href);return false;


air leaks can be a pain but if your engine is quiet enough you can sometimes hear them (sounds like a sucking, best done wile revin the car slightly) silly question (as im sure u have already checked them while doing the throttle body) have you checked all the hoses and pipes are on tightly as 1 small leak on them can make the idle go up,


edit: i just saw your in malaysya so my ebay link might not be much help sorry

[Mandrake]

I can't see why you couldn't obtain a 30 pin (Mk1 Xantia) to 16 pin OBD adaptor cable on ebay like the one listed above even in Malaysia - it would be worth getting as diagnosing the fault without some sort of reading of fault codes and sensor data is likely to be expensive trial and error...

That ebay listing is the correct adaptor cable - its the same as the one I have in my Lexia kit for attaching to Mk1 Xantia's.

[IrfanIbrahim]

I will try to get my hand on 21pin connector later on.. Have'nt check for leaks yet as it is raining here and no shade to work under. Is there any possible it could be O2 sensor? Symptoms of leak and faulty O2 sensor are quiet the same.. Is changing O2 sensor an easy job?

[IrfanIbrahim]

Idle valve do you mean stepper motor? Changed it last week but nothing improved.

[Mandrake]

A faulty oxygen sensor won't cause a high idle speed, although it may cause an uneven idle and a hesitation when first accelerating. To test it try running the car with the oxygen sensor left disconnected. If faulty the car should run almost normally with it disconnected.

[lurchy666]

Yh steper motor. Is idle valve. Im just used to the old terms from old fords hence why I call it an idle valve

[IrfanIbrahim]

RPM idle around 1.2k and sometimes rise around 2k for few seconds before decline to 1.2k slowly. Its hesitate when accelerating too. I guess it could be leaks in manifold and not o2 sensor. Or it could be both. :3

[IrfanIbrahim]

That ebay listing is the correct adaptor cable - its the same as the one I have in my Lexia kit for attaching to Mk1 Xantia's.

Sorry to ask. Are they for earlier Xantias? I was told it should be 21 pin but that ebay is 30 pin. Are they the same?

[lurchy666]

I have been told earlier xantias are 30 pin not 21 but maybe someone more knowledgeable than me can answer.

[Mandrake]

The connector pictured is the correct one for all Mk1 Xantias. It's a 30 pin plug but only about 21 pins are actually populated...

[handyman]

Your faults running, given the rpm range, is more than likely a duff idler valve, or stepper motor or whatever you like to call it as it goes under several different guises.

This valve covers the initial engine rpm from 890rpm upto 2000rpm, where the throttle valve takes over. Was the replacement you fitted a new or secondhand unit? They can get covered in oily deposits which inhibit their operation, so it might be worth taking it off and cleaning using electronic switch cleaner ONLY, and then adding a sparing light oiling to the shaft. Do not pull or push the shaft as you risk destroying the electronics by so doing.

Other possible areas to check are a worn throttle valve spindle, especially if your car is fitted with a crap plastic throttle body, and the inlet manifold to head 'O' ring gaskets. If your throttle body is duff, get an earlier alloy unit from the same series engine as fitted to a number of Citroen & Peugeot cars. If you cannot find one, PM me as I have several reconditioned units for both the 1.8 & 2.0 engines. I also have the gaskets but you can get these from a local dealer.

Sometimes the primary temperature sensor (blue), located on the thermostat body, can cause this problem if it is failing, due to feedback to the ECU and it has been known for the wiring to this sensor to fail due to crappy materials.

Lastly, the high pressure valve, located on the return on the injector rail can fail and cause over fueling and therefore add extra fuel to the injectors, making the ECU increase RPM to cope with supposed differing conditions.

A session on a Lexia will pick up some of this but not all, but its best to also use a gas analyzer in your test sessions.

Has the car also seen an increase in fuel consumption?

Handyman

[IrfanIbrahim]

Not sure which make the throtle body my mechanic had replaced, but it is differ from the old one, the new one is in silver colour while the old one is in black. He tested with a number of throtle body but the problem is still there, so it could'nt be the throtle body. He even tested with a working throtle body from other xantias..

I will be sending the car to the mechanic in few days to get the intake manifold check because i was told an air leak could cause this problem too?

Other suspected issue might be the water temp sensor as i've fitted a shorter one than the original. So it would be an inexpensive try and error here.

If the problem still there, i'll check on the high pressure valve..

There is slighly increase in fuel consumption after the problem started but not really giving me headache yet.. I guess it was from the high idling that increase in fuel consumption.

What confused me is that the problem occured randomly, sometimes it was okay , sometimes not..

Thanks for advices though..

[IrfanIbrahim]

The connector pictured is the correct one for all Mk1 Xantias. It's a 30 pin plug but only about 21 pins are actually populated...

Okay, i might try to find it near local shops before going after ebay.

[IrfanIbrahim]

So, i had tested something. Start the engine and disconnected the stepper motor, go for a spin and everythings fine except the hesitation is still there, even when revving while in P. But there is no more sudden rise of RPM when shifting from D to N. Is this helps in troubleshooting? Can I drive w/o the stepper motor because the RPM seems to be acceptable than before? Other than that there is no problem except for the hesitation when accelerate..