Have to press down the throttle a bit - Xantia starting problem

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Kiiva
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Have to press down the throttle a bit - Xantia starting problem

Post by Kiiva »

My xantia has always started up, cold or hot. Until now.

I just cant figure this out: ignition on, eveything looks in order, starts up easy and dies again.
If i push down the throttle for about 10 seconds after i turned on the key, then its acting normally.

There is gas, no black smoke or anything weird. Im reading up but it feels like its impossible to know.

I was thinking that maybe the key stopped working and it wont receive signals. But if that was the case, the throttle wouldnt help i guess?

I have the radio and the radio code was included when i bought it. And the key i have is a keyfob original from Citroen, but without LED. just the 2 buttons.

So i wanted to ask, is there anything i can do with the radio settings or the key to see if it works? If its not the anti tefht then i dont know what to do.

Its a xantia break 1.8 1999
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xf1ref
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Re: Have to press down the throttle a bit - Xantia starting problem

Post by xf1ref »

Hi, maybe is the idle control valve or IAC. I had the same problem in the past at xantia 1.8 16v.
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CitroJim
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Re: Have to press down the throttle a bit - Xantia starting problem

Post by CitroJim »

Coolant Temperature Sensor is a possibility too...

Plus any air leaks on the inlet side...
Jim

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Mandrake
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Re: Have to press down the throttle a bit - Xantia starting problem

Post by Mandrake »

A faulty MAP sensor can also cause inability to start without pressing the throttle. After the car has run a few seconds the ECU will register a fault with the MAP sensor and revert to using the TPS only, at that point the engine will be able to run without the throttle being depressed. Depending on the engine/ECU it might not even light the fault light on the dashboard. (It doesn't on my Xantia V6 if the MAP sensor is left disconnected!)

Do you have access to a Lexia to run a diagnostic on the engine ECU ? It would help avoid a lot of guesswork and trial and error as there are many things that could cause the symptoms you see. But it is almost certainly a sensor fault of some kind if it can idle without pressing the throttle after say 10 seconds of running.
Simon

1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White

2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
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Kiiva
Posts: 35
Joined: 06 May 2017, 20:39
Location: Israel
My Cars: C5 Break 2003
Xantia V6 2000
x 2

Re: Have to press down the throttle a bit - Xantia starting problem

Post by Kiiva »

I have thought about those things too. Aaargh... its driving me crazy since it sounds like almost anything. Idle control, immobilizer, leaks, coolant sensor... Is there something that i could try to check even without Lexia?

If i find the coolant sensor maybe i can unscrew it and put it back or something easy? Yes, i suck at fixing cars..
Kiiva
Posts: 35
Joined: 06 May 2017, 20:39
Location: Israel
My Cars: C5 Break 2003
Xantia V6 2000
x 2

Re: Have to press down the throttle a bit - Xantia starting problem

Post by Kiiva »

Mandrake wrote:A faulty MAP sensor can also cause inability to start without pressing the throttle. After the car has run a few seconds the ECU will register a fault with the MAP sensor and revert to using the TPS only, at that point the engine will be able to run without the throttle being depressed. Depending on the engine/ECU it might not even light the fault light on the dashboard. (It doesn't on my Xantia V6 if the MAP sensor is left disconnected!)

Do you have access to a Lexia to run a diagnostic on the engine ECU ? It would help avoid a lot of guesswork and trial and error as there are many things that could cause the symptoms you see. But it is almost certainly a sensor fault of some kind if it can idle without pressing the throttle after say 10 seconds of running.


Yes, thats so weird. It runs fine, except for those 10 seconds of reving so it "learns" to stay alive. Then all fine.
Well the engine temp needle is sometimes messing up, going all the way up. But then i can turn off the car and wait 1 minute and start (with throttle) and the needle is acting like it should again.

Can i do something with the MAP sensor to see if it works? I have no Lexia, and no friends with Lexia or Citroens.
I so much want to believe i can fix this easy on the parking, but i guess there is no quick fixes like that.
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Re: Have to press down the throttle a bit - Xantia starting problem

Post by CitroJim »

The coolant temperature sensor can be checked by reading its resistance at roughly 20 degrees and then comparing it with a known good one. That'll be the green sensor.

I'm not sure what the resistance should be at that temperature but I'm sure someone will soon supply the information..

A faulty coolant sensor can make the ECU 'think' the engine is hot when it is actually cold and then the mixture is not properly enriched for a cold start...
Jim

Runner, cyclist, time triallist, duathlete, Citroen AX fan and the CCC Citroenian 'From A to Z' Columnist...
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