Egr (Petrol)

[clipper]

Nearly completing a year of ownership of the C8....

 

Having had the Anti-pollution fault light on for nearly all this time, I have decided that I should at least clean the EGR valve. All of my symptoms point to the valve being stuck in the "open" position.

 

Has anyone successfully cleaned and EGR Valve on the 2.0 16v petrol motor? Can it be opened once removed or can it only be cleaned with spray products?

 

Any help appreciated!

[paul.h]

I had a 1988 petrol Saab 900 with an egr valve and that would coke up. Each service I would remove it and clean it. Files/scrapers did the job but probably there are chemicals you can buy - possibly oven cleaner would do since that removes carbon.

 

Before trying the egr valve you should use a code reader to find out what the fault is, otherwise after cleaning and if the fault still exists you will not know if you have caused another fault.

[clipper]

Thanks Paul. The car has been to various garages during the year and no codes have ever been found.

 

I don't have a computer suitable for Lexia, so my only option now is to take it to a main dealer to see if they see a code which Bosch service and other professional code readers are missing.

 

Given that removing and cleaning the valve is effectively free, I figure that it is worth a go before chucking money in the dealer's pocket!

 

However, from pictures I can find on internet, this particular EGR seems to be pretty much a sealed unit, so I'm not sure if it is even cleanable, or even if it is accessible easily.

[Simple]

Why did you exclude that the fault may actually be with the DPF? Did you regenerate it or physically clean it? has your car passed the 180k KM? Is it continuous or does it disappear sometimes (after long drives)? You could try taking it apart and jet washing it, I did mine in the Car Wash (it cost 2 euros).

 

My car is diesel, and I was bothered by this problem for a long while and I discovered it was vacuum leak that was causing the problem. It was not in any of the pipes, it was in the body of the intake flap actuator which is made of heat resistant plastic. Due to friction against one of the pipes that was resting on it, its casing thinned causing a tiny little hole, hence a mixture imbalance. 

 

I discovered it by accident, I was standing in front of the opened bonnet when I asked my son to turn the car off. I heard a hissing noise that lasted few seconds, so I placed a plastic pipe against my ear and the other side hovering over the various parts until I located it.  

 

Because it is an air suction, I used a (rubbery) sealant the could take temperatures up to 300 C. The problem with hard Epoxy is that a crack could develop between the plastic and the epoxy (heat/cold). It has been working fine since repaired.

 

With respect to Lexia, if you have the Device (VCI), then nearly any laptop 6 year old or less will do, try evaluating VirtualBox as an option to installing the software. I have written an article about this on this site, here it is:.

 

http://www.citroen-owners-club.co.uk/citroen/topic/23435-diagbox-7xx-from-preparation-to-operation/?hl=diagbox

Edited August 2, 2017 by Simple

[clipper]

Some good questions there! And some that I don't follow!!!

 

DPF = Diesel Particulate Filter no? My C8 is petrol, so I would be surprised if it had a DPF.

 

180k Kms? Yes, it is showing approx 190k.

 

I have looked for air leak symptoms (well know to me from previous experience on a BMW E30) and I am 99% sure that this is not happening on the C8. I could be wrong though.

 

The reason for suspecting the EGR is that being a mechanical valve with electronic control, there are cases of the mechanical part blocking up and no codes being thrown as the ECU doesn't detect any fault. This coupled with the fact that on first start up I get a slightly rough idle and a reluctance to pick up revs. This exact symptom is described on some technical sites as a result of an EGR valve stuck in the fully open position, hence allowing the full amount of exhaust gas from start up into the induction side, which should not happen. On start up the valve should be closed and the induction 100% "clean".

 

I appreciate your work doing the Lexia write up, but really I would have to invest in the software and a PC to run it on, and I am sorry to say that I do not really plan on keeping the C8 for that much longer and honestly I would think very hard about buying PSA again, so the investment is really not worth it.

[clipper]

Just to make things easier, yesterday it decided to throw its service belt as my wife was driving home from work at 3 p.m....

 

Full credit goes to my wife who drove the 30kms home with no PAS, and no air con (it was 38º here yesterday afternoon!!), so there went another 200€ in the garage for a new belt and tensioner pulley..... since January I have spent 1,000€ on this vehicle!

[clipper]

 

Can anyone confirm that the EGR valve is the component labelled  "Y10.13" in this image?

 

I believe that this image may be for a 2.2 Hdi engine, but was that ever used in a C8?

Edited August 3, 2017 by clipper

[paul.h]

If the engine management light is on, then there should be a fault code logged, unless it is a fault with the light. Since your car is a petrol any code reader should be able to read the codes that light up the eml. Only Citroen specific ones may need a Citroen diagnostic. Something like a faulty cam shaft sensor, lambda sensor, catalyst not working, etc could put the eml on and still let the car run.

 

Poor running on starting could be something like the throttle body and plate needing cleaning or an engine temperature measurement fault or something else that affects the air/fuel mixture. Is the air filter clean and other servicing up to date such as spark plugs ?

 

To identify the egr valve you could look at the parts diagrams if you register on service.citroen as an other professional non emergency services and as a member of the Citroen Owners Club. Once on the site use your VIN (VIS) top left to find your car. http://service.citroen.com/do/changerParametres

[clipper]

Thanks. I have got onto Citroen Service with no problem and identified the EGR valve. The diagram above is indeed incorrect!

 

My plan is to clean the throttle body at the same time as the EGR valve. All other service items are recently changed including plugs.

 

Even the garage I take it to agrees with you about the EML, they have told me that it is the first time they have ever seen an EML illuminated with no codes stored, but it has been that way for the last 4 or 5 times it has been in, so there seems little point in keeping on looking unless I take it to Citroen, which will be the next step if the EGR and admission clean fails.

[clipper]

Well, that's that theory blown.

 

The valve is pretty clean, not clogged up at all, moving parts are free and it defaults correctly to the closed position.

 

Back to square 1!!

 

At least the EML has been off since the last big service nearly a month back.

[paul.h]

Did you clean the throttle plate and body, was there any carbon build up that needed removing ? How long does the rough idle last for since if you are going to change the car and it is not that bad, then most people would not spend any money fixing the problem.

[clipper]

Yes, I had a can of throttle cleaner and used about a quarter of it cleaning the EGR. The rest I used to clean the throttle (with the motor off).

There was a 1mm rim of carbon on the edge of the plate which came off quickly. The majority of the can went on the walls of the throttle and any technical features visible in there.

I started it after a few minutes and drove it round the block. The start up was the same as ever, in warm weather you can rev the engine up in neutral after about 5 seconds of spluttery idling.

In the cold it is worse, maybe 20 or 30 seconds, and even then it will bog down on the first clutch action.

To be fair it has only had one start since spraying all those chemicals in it, maybe tomorrow it will be better....

Edited August 6, 2017 by clipper

[paul.h]

If it does not run too well when cold, then maybe the temperature sensors need checking with a code reader that does live data - inlet air temp, engine coolant temp - just in case they are giving the wrong value so the fuel/air mix is wrong. There could also be an air leak causing a lean mixture.

[Simple]

I haven't had dealings with petrol cars for some time, but what you describe might be caused by the Spark generation system,  Spark Plugs, Coils, Cables or even timing.. Each fault would have other associated symptoms with it, but I am expecting these to come out as the trial and error continues..

 

The fault (now) sounds like a combustion problem caused by a mixture or ignition fault.. Since both are computer controlled (ECU), then it could be the Computer itself (unlikely) or the sensors (possible) or the delivery mechanism (highly possible) because it has mechanical parts that are exposed to the elements and wear and tear..

[clipper]

It was the same old routine this morning according to my wife, but, the EML has been off now for a good while.

 

The engine was flushed with a cleaner at the last service and it seems to have drastically reduced the oil consumption. We think that it has possibly unstuck a gummy piston ring, but no comp test was done before, so we'll never know.

 

That could have been why the EML and polution fault was on, but I would have thought that the cat would complain like hell of burnt oil coming through it?

 

For the start up, it has to be said that it looks like temp sensors to me now. Going on a trip to Portugal and the north of Spain later this week, so it will go as it is now. MPG is reasonable and except the service belt loss the other day it hasn't actually let us down yet (even then it drove home).

 

I'll get back to it in September. Thanks for the inputs so far!

[clipper]

OK, so time for an update...

 

The C8 has made it through another winter of spluttery start-ups and revving the hell out of it so that it doesn't bog down on pulling away.

 

But in a strange way I am now quite relieved that the fault is getting worse. Relieved in the way that if it is worse it might be easier to find out what's going on.

 

Now the engine doesn't even start if the temperature is below around 12 degrees C. We have to turn it over for a while without it firing, stop cranking for a second or two, then try again. At this point it will start with its "juddery misfire" type symptoms and eventually the idle evens out and off we go with a heavy right foot to stop it from bogging down.

 

Sadly, there are still no consistent convincing codes being given (they seem to be random and range from coil pack codes, through to Lambda sensor faults, but none seem to repeat themselves after being cleared), but the EML light now does not go off from time to time as it did before.

 

However, reading up on other petrol engined citroens of a similar vintage, I see that very similar symptoms have been reported in Picasso 1.8SX models.

 

Anyone know if that engine is similar to the 16v c8 motor?

 

It is of particular interest because one of the people reporting the similar fault said that the dealer "eventually found a faulty coolant temp sensor" and that cured the problem, and that indicates that it wasn't an immediately obvious issue from the codes. It also would make perfect sense for a faulty temp sensor to be the culprit in my case.

 

I would be prepared to change the coolant sensor just to try it , but where do I find the sensor which sends the temp to the ECU? (from experience with other cars, it may not be the same one as sends the signal to the temp dial for example).

 

Any help or suggestions where to look appreciated!!

[paul.h]

The coolant temperature sensor should be in the thermostat housing at the gearbox end of the cylinder head. It could be Citroen part 1338A7 and they do not cost much. On the parts diagrams they are found under Mechanical, Engine, Air and fuel supply, INJ calculator sensor.

 

If you have a code reader that does live data it will give you the temperature the sensor is saying so you could check it without replacing it. Before starting the engine first thing it ought to be the outside temperature of about 15°C and once the engine is warmed up it should be around 90 to 96°C. The air flow meter will also have a temperature measurement and that should also be around 15°C before first starting and then go up to 30 to 40°C as the engine compartment gets hot - possibly part 19204G. You could also disconnect the coolant temp sensor and that should put the car in limp mode, put the engine management light on with a fault code, but it might start/run better in limp mode suggesting the sensor is faulty. It is not a good idea to run it for long in limp mode since the exhaust catalyst might suffer.

 

An example of a code reader (£39) that does some engine live data https://www.gendan.co.uk/product_FXNT200.html

[paul.h]

I realise you have cleaned the egr valve but it could be possible the egr valve actuator valve could be faulty. Have a look at this post from pikesrelaybus http://www.citroen-owners-club.co.uk/citroen/topic/25035-30-hdi-160psi-with-poor-idle/?do=findComment&comment=95298

[clipper]

Thanks a lot!

 

My EGR doesn't have a vacuum hose though, it is electrically operated. I guess it is a different system to the diesel motor.

 

I was initially reluctant to buy a code reader to use on this vehicle because frankly, I didn't think it would be in my possession, or even still be running after two years, but maybe it is time to invest! My local mechanic is getting a bit annoyed that I keep "dropping by" to get the codes read.

 

It does look pretty clear that the fuelling is regulated by the 1338A7 sensor given its name in the Service Box. Given its very low cost I'm tempted to just change it and see what happens, or at least have a good look at it and the state of the wiring / connections (clearly not best practice to change it on spec, and not my normal modus operandi, but it's ok to rebel once in a while right?) 

 

Thanks again! I will report back!

[paul.h]

If you get a code reader it can be used on any future cars so still worth while investing in one. Also you can help friends with their cars.

[clipper]

So, changing the temp sensor didn´t turn out to be such a good idea.

 

On the first trip out after the change, the motor overheated to the point that the "stop engine" warning came on.

 

I assumed that it wasn't related to the sensor itself, but rather to the act of changing it, thinking there may be air in the system. I couldn't find a procedure to bleed the cooling circuit, but I put the nose of the car up in the air with respect to the back, ran the engine hot with the heaters on full and bled the radiator at the bleed screw at the top. I couldn't find any more bleed screws on the thermostat housing nor elsewhere, so Iam assuming that the radiator is the only bleed point.

 

The engine still overheats though in slow traffic, and the engine fan apears to do very little, spinning only slowly if the air-con is on, and not kicking in at all if the air-con is off. I took out the fan to inspect it and it seems ok. The thermal resistors in the fan shroud are visually ok.

I checked that the fan relays are all in place and with good connections and they seem to be OK. But I don't have a multimeter with me at the moment to check them.

 

Any thoughts? I just can't see why changing the temp sensor would suddenly make the fan not kick in. I had never paid attention to the fan behaviour before as I had not had any temp problems, so I don't know if it has always been like this, or something I have done / disturbed.

 

I'm currently waiting for the engine to cool down to go and put the old temp sensor back in....

Edited July 22, 2018 by clipper

[paul.h]

To get the air out Citroen use a tool so the coolant level can be raised to give a bit of pressure in the system. I made something to do the job from a bit of pipe http://www.citroen-owners-club.co.uk/citroen/topic/24799-coolant-filling-tool-alternative-to-cylinder-4520-t-and-4222-t/

 

Possibly the temp sensor is in a pocket of air and is not seeing the temperature of the coolant. If you have a code reader with live data you would be able to see what temperature the sensor is giving. There could be something wrong with the new sensor or if a copy part, maybe it is not right.

 

This is the procedure for filling the coolant from the Citroen Service box procedures for the 2.0 16v engine:

 

1. Recommended tools

[1] filling cylinder 4520-T.

Filling cylinder adaptor for screw cap 4222-T.

 

2. Drain and refill

CAUTION : Drain the cooling circuit with the engine cold.

Remove the degassing tank cap .

Uncouple the cooling radiator bottom hose (CONRAD quick connector).

 

3. Filling and bleeding the system

Before filling, flush the cooling system with clean water.

CAUTION : Check the sealing of the cooling system.

Fit the filling cylinder [1] to the filler orifice (expansion tank).

CAUTION : Check that the bottom hose is in place on the cooling radiator.

Open the radiator bleed screw.

Slowly fill the circuit with coolant.

Close the bleed screw as the fluid starts to flow out without bubbles.

To bleed the heater matrix correctly, the filler cylinder should be filled up to the "1 litre" mark.

Start the engine.

Maintain engine speed at 1500 to 2000 rpm until the end of the second cooling cycle (starting and stopping of the cooling fan(s)), keeping the filling cylinder full to the 1 litre mark.

Run the engine at idle for a few minutes.

Stop the engine.

Remove the filling cylinder [1].

Refit the venting box plug and tighten it to the second notch (expansion tank cap).

Top up to the maxi. level (engine cold).

-------------------------------------------------------------------------

 

The engine fan may be a 3 speed one with settings slow speed 97°C, mid speed 101°C and high speed 105°C.

The thermostat should start to open at 89°C, you can check if the radiator top hose gets hot. Also look at the temperature gauge at the same time which could indicate if the sensor is ok if the gauge is showing a normal temperature as the thermostat opens..

[clipper]

Thanks for the info. I haven't seen any written procedure for coolant filling specifically for the C8, but as per your write up on the use of the "special tool", it should technically not be required in the C8 as the expansion tank certainly is higher than the bleed points. It is in fact the highest part of the cooling circuit.

 

That doesn't mean to say that I don't have an air leak of course....

 

More worrying is the statement that the fan is a three speed affair. Mine most certainly is not. In fact, it is possible to have the engine at well over 100ºC and the fan not spinning at all. It will spin slowly if I engage the air-con, so I know that the fan motor does physically work, but I have doubts about the fan control system.

 

Given that a decent fan is up around the 200€ mark, and I don't understand the fan speed control circuit, all I have been able to do is test the fan relays (all OK), and clean up the connectors in the fan area. But this made no difference, so it has gone to the workshop.... yet again...

[paul.h]

The filling procedure I posted was for the C8 2.0 petrol engine. Before I made the special tool I had struggled to get the air out of a C3 and used a vacuum pump to get the air to come out of the bleed points. On our C5 I have only used the tool and it does work well but unlike the C8, it has a bleed point on the pipes from the cabin heater matrix and a small diameter pipe from the thermostat housing which goes back to the expansion tank - this pipe can be disconnected at the tank end and used to part drain the coolant.

 

Hopefully the workshop will sort it out and it will not cost much.

[clipper]

I stand corrected on the filling procedure! But in the end I did not have an air lock. It was indeed the fan which had packed up. Cooling system checked, topped up, and fan changed for 250€. Seems fair.

 

It seems it was just an unlucky coincidence that it happened just when I changed the temp sensor. 

 

Thanks again for your continued help!!