depollution system faulty :roll:

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Re: depollution system faulty :roll:

Post by RichardW »

Temporary Fault.
Fuel pressure regulation to high

That's the one causing limp. Need to have a look behind the fault and see what the fuel pressure was, and what the regulator was doing. Possible there is some crud on the regulator that is preventing it regulating the pressure properly.
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Re: depollution system faulty :roll:

Post by Diabolical »

RichardW wrote:Temporary Fault.
Fuel pressure regulation to high

That's the one causing limp. Need to have a look behind the fault and see what the fuel pressure was, and what the regulator was doing. Possible there is some crud on the regulator that is preventing it regulating the pressure properly.
Cool I shall look into it.
Maybe of work for a day this week see what I can sort out, may have to go to a garage.

David
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Re: depollution system faulty :roll:

Post by citroenxm »

Ah right there we are, a simmilar but completely different area of issue.

DO NOT worry about the Heater Plug Curcuit.. Thats heater plugs, but they dont really need to work. Id be carefull removing them as they could break off in the head like the 1.6 HDi heater plugs do.

If the car is starting well eough leave them for now.

Fuel pressure too high, thats interesting, useually its too low. But yes, thats what will be giving you the issue.
Sharing a pug 207 1.6 hdi Sw 16v.
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Re: depollution system faulty :roll:

Post by Diabolical »

Lighty wrote:After you have done a global test, you would normally check for faults in the engine ECU, ie, Read Fault, Erase faults etc, lower down is the actuator tests and parameters, click on Parameters, and it will allow you to select Standard , and a couple of other options. Select Standard, where it will let you chose Fuel, Air etc . A good one to view is Particle filter, as it will allow you to look at Exhaust Differential pressure, this should be zero at idle, and maybe a max of 50 mb at about 3000 rpm, if it is much more, this could well prove that your dpf is blocked. The Lexia will also tell you the soot level in the dpf etc.
Many Many thanks , done as you advised been through all Parameter checks and as you said NO problems with Particle filter, soot level 35% that I assume is good.

Have saved Fuel Pressure High info from Screen Grab to print out.

David
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1987 Citroen CX Prestige. De Corps Brun Maya - cuir blond tabac, très chic
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Re: depollution system faulty :roll:

Post by Diabolical »

Took car to a garage I know today and showed them Temporary Fault; Fuel Pressure to High screen print.

Image

Dave garage owner noticed straight away Diesel Temperature -50 c so he thinks

Permanent Fault.
Diesel temperature signal OC or SC positive (+)


The Sensor is faulty and forcing fuel through to warm it.
Going in on Wed so they can have a look.

Any opinions on this?

David
06 C5 2.0L HDi Exclusive Estate 20020k and rising. :-)
1987 Citroen CX Prestige. De Corps Brun Maya - cuir blond tabac, très chic
08 Jaguar X-Type 3.0V6 Sovereign Estate - Green (HGZ) - Leather Ivory seats.

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Re: depollution system faulty :roll:

Post by RichardW »

Looks like that sensor is causing problems, but if that was causing the limp it would be on permanently. However, if you look at the full fault it says Fuel Regulation Fuel Pressure Too High - then look at the diesel pressure (1676 bar) and the pressure setting (1570 bar) and I think that is what it is getting upset about. Could be the fuel pressure regulator on the end of the pump not opening / flowing as much as it should.
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Re: depollution system faulty :roll:

Post by Mandrake »

The "freeze frame" data recorded in a fault code can sometimes have some weird/bogus entries like negative temperatures - I would check the diesel temperature reading on the live data view and see if it still says -50 degrees while the engine is running. If it does fair doo's - the sensor should be fixed because while it may not be the main problem who knows what fall back strategies the ECU will be following with that sensor data missing. Measuring the temperature is probably to alert the ECU to the risk of boiling in the fuel rail so it may take steps to avoid that if it can't determine the temperature.

I wouldn't be surprised if the main problem is not fixed by fixing the temperature sensor though.
Simon

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Re: depollution system faulty :roll:

Post by mikeC5 »

Couldn't be something as simple as the fuel filter being bunged? After all the pump has to work quite hard when thrashing around at > 5K rpm?
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Re: depollution system faulty :roll:

Post by Diabolical »

mikeC5 wrote:Couldn't be something as simple as the fuel filter being bunged? After all the pump has to work quite hard when thrashing around at > 5K rpm?
Mike,

Changed filter no difference, however friend works for garage going to said: we could spend hours (lots of cost) trying to sort it out, didn't go there.

However he has tried car himself and feels it's Turbo Over boost? back to what others feel.

Again any ideas? again.

Cheers David
06 C5 2.0L HDi Exclusive Estate 20020k and rising. :-)
1987 Citroen CX Prestige. De Corps Brun Maya - cuir blond tabac, très chic
08 Jaguar X-Type 3.0V6 Sovereign Estate - Green (HGZ) - Leather Ivory seats.

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Re: depollution system faulty :roll:

Post by citroenxm »

Turbo overboost can only be caused by the wastegate staying SHUT, and not opening..

have you tried some KNOW WORKING vaccuum electro valves??

The are hidden in the vicsinity of the servo under the plastic cover.
Sharing a pug 207 1.6 hdi Sw 16v.
M reg Xm 2.1 td auto exclusive S2 269k and rising
L reg XM V6 12v SEi auto .. Light project

A very sad...
1994 XM 2.1 d auto
RichardW
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Re: depollution system faulty :roll:

Post by RichardW »

It's not a turbo over boost - the fault clearly shows the fuel pressure is too high. The regulator is blocked or not working.
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Re: depollution system faulty :roll:

Post by Diabolical »

I called a friend retired Citroen mechanic who used to sort my Cits out long time ago if he had a solution?
Paul said: I had C5 exact same model as yours with same fault, he said he drilled out to slightly wider bore 2 vacuum pipe plastic lugs. (pictured) these are on a joined by a larger bore pipe from the Servo. That stopped problem! as he reckoned as car got older vacuum s became weaker.
Image

So I very carefully did this, improvement but not a fix, go to higher RPM hot or cold 4200 on cold, from 3300 so I can live with this but still looking for total fix.

So Fuel temp sensor is £35.? so may go for this or try new vacuum pump?


December Citronian came through door today and C5 Columnist David Evans has same problem with his C5 X7 2.0 l HDi he suspects EGR Valve.
Seems could be no end of reasons to cause dreaded (depollution system faulty) display.

David
06 C5 2.0L HDi Exclusive Estate 20020k and rising. :-)
1987 Citroen CX Prestige. De Corps Brun Maya - cuir blond tabac, très chic
08 Jaguar X-Type 3.0V6 Sovereign Estate - Green (HGZ) - Leather Ivory seats.

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Re: depollution system faulty :roll:

Post by Diabolical »

Seems increasing the bore slightly by drilling out the plastic connectors (not lugs :oops: ) in arrowed red seems to have worked :) first go after doing increased rev range before going Iimp :-D now doesn't happen at all, cured fixed whatever but I havn't done anything else since then.

Looking in Haynes seems possibly vacuum pump seals need doing ? but wait till it re-occurs before going any further.
06 C5 2.0L HDi Exclusive Estate 20020k and rising. :-)
1987 Citroen CX Prestige. De Corps Brun Maya - cuir blond tabac, très chic
08 Jaguar X-Type 3.0V6 Sovereign Estate - Green (HGZ) - Leather Ivory seats.

citroencx.co.uk
citroenxm
Posts: 8061
Joined: 30 Dec 2004, 23:10
Location: Somewhere in North Wales, Anglesey
My Cars: M reg Xm S2 2.1td Auto Exclusive. 269k and rising
L reg XM S1 V6 12v Manual SEi
L 94 XM 2.1 TD auto total resto

2008 Peugeot 207 Sw 1.6 16v hdi. 217k and rising
2010 Peugeot 207 SW 1.6 8v HDi 161k and rising
x 70

Re: depollution system faulty :roll:

Post by citroenxm »

Ahhh. you have reminded me, I have a topic to post up about the Vaccuum pump on HDi engines!

I have discovered something ... the pumps work with engine oil. They fill up, and theres three plastic "Scrapers" that expand outward under force when spinning on the end of the cam inside the housing. The scraping effect of the oil which then drains away causes a vaccuum. its hard to explain, but I opened one up this week, should of taken some pictures..
Sharing a pug 207 1.6 hdi Sw 16v.
M reg Xm 2.1 td auto exclusive S2 269k and rising
L reg XM V6 12v SEi auto .. Light project

A very sad...
1994 XM 2.1 d auto
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Diabolical
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Re: depollution system faulty FIXED!

Post by Diabolical »

Today changed Fuel Temp Sensor took me nearly 3 years to buy one eBay in the end. could not for the life of me see it in engine bay but could see both pipes it connects to had replace just by feel.
Problem sorted! wow car goes a lot quicker than I thought now i don't have to hold back.
06 C5 2.0L HDi Exclusive Estate 20020k and rising. :-)
1987 Citroen CX Prestige. De Corps Brun Maya - cuir blond tabac, très chic
08 Jaguar X-Type 3.0V6 Sovereign Estate - Green (HGZ) - Leather Ivory seats.

citroencx.co.uk
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