Technical EGR valve not functioning?

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Technical EGR valve not functioning?

Could it be that the EGR-valve did not make good contact with the earth?
Possibly the 12v has to be measured between a contact and the earth. One contact for 12v (actuating the valve), the other contact for measurement.

From my experience the EGR-valve is open when the car is driven, it only closes while accelerating or heavy load.

I think your EGR-valve is OK.
I clean my EGR-valve every year.
 
Thanks for your input Crombel. It could be that there wasn't a good earth contact.

As I said, I'll keep an eye on things and check any error codes as soon as the 'Check engine' light comes on ... if it does at all.

Next thing is to make sure I get the car to do a full DPF regeneration. I'll take it for a run tomorrow after work with FiatECUScan connected and see if I can spot the regen happening.
 
OK, now I'm confused.

I took the car for a normal driving run and after about 20 miles the 'Check engine' light came on again. I pulled over and checked with FiatECUScan - P0401 was logged again. So I cleared the error and then drove at 3000+ revs for another 20 minutes while monitoring Particle Filter Temperature, Particle Filter Obstruction, and Regeneration Progress. All that happened was that Particle Filter Obstruction crept up and Regeneration Progress stayed at 0.00%.

So I pulled over, kept the engine running, and saved the graph and quickly checked Fault Codes, not expecting ot see any. Surprisingly P0401 was logged again but without the 'Check engine' warning light coming on. Strange. So I cleared that fault code again and drove back the way I'd come for another 20 minutes in an attempt to force a regeneration. Still no joy but P0401 logged again without the 'Check engine' light coming on.

So I cleared it again and then headed for home driving normally but also monitoring EGR Valve Opening together with Particle Filter Temperature and Particle Filter Obstruction. The images on the left below show that for the first 7 minutes or so the EGR Valve Opening value swung between 4.00% and 95.95%. But then after that it stuck at 4.00% even though driving conditions were similar to the first 7 minutes - see the the image on the right. This coincided with quite a drop in the Particle Filter Temp but I don't know if that is relevant.

FiatECUScan Graph 4_1.jpg FiatECUScan Graph 4_2.jpg

When I got home I checked the fault codes again and P0401 was once again logged without the 'Check engine' light coming on. What I don't know is whether the P0401 was logged at the same time as the EGR Valve Opening value sticking at 4.00%.

Anyone recognise the symptoms I've described? Is the EGR valve fully opening and closing so often normal?

I think I'm going to have to take it in to the Fiat dealer to get it sorted. It may be the EGR valve but if it's not I've spent £130 I didn't need to. We have several long journeys coming up at the end of April and I need to be 100% certain (ok, not 100% but as much as you ever can be with a Fiat) that the car will be reliable.
 
It is quite a long time ago that I last made a graph but as far as I remember it was open most of the time.

On my Croma (8 valves) the EGR is also open or closed, not much in between.
I don't think it is OK that the EGR-valve is closed in the second graph.

What I also clean, together with the EGR-valve, is the pressure sensor next to it.

Waiting for the regeneration to happen is quite frustrating. One time when the obstruction was in the high eighties it took more then 70 km before it took place.
 
Thanks for taking the time to reply Crombel.

So my next obvious question is .... what does the pressure sensor look like and where on earth is it on a 1.9 16v Croma? If it's easy to get to and remove then I'm happy to have a go at cleaning it. But I'll still book it in with the Fiat dealer because I bet they can't fit it in for a week or so.
 
Look at my post here https://www.fiatforum.com/croma/201645-egr-valve-2.html?p=2470179 about EGR and how the ECU works out actual EGR flow (which is calculated and not directly measured)

As for your graphs of EGR I think the simple answer is this. FiatECUScan is looking/recording the EGR as demanded by the ECU. The ECU pulse width modulates the EGR valve to get the desired overall EGR.

Your second graph when the EGR signal goes flat is when the ECU finally realises that the EGR valve is not working and so it shuts off the EGR valve/signal.
 
Thanks s130. I'm failry sure it's the EGR valve but as this is my first attempt at diagnosing the 'Check engine' light I've booked the car in with a local independent who will do a full diagnosis for £30 + VAT. If it is the valve then I'll buy the latest part number, get the revised gasket from Fiat (already on order) and fit the valve myself.

I'll report back what the diagnosis reports.
 
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hi, fit new egr valve, so plunger works & at same time block off egr with a blanking plate- end of egr problems

While this will work on older diesel engines (Stilo etc.) on the Croma the ECU will turn the MIL lamp on quite quickly. Running with the MIL on will mask other errors the ECU might want to report and this is not such a good idea.
 
or you can switch egr off by going into the ecu.

There is of course the S130 clean air EGR mod but this requires a little pipe building/plumbing. Saves having to have the ECU mapped and potential insurance issues if you don't declare it.

I've not done the mod on my car but I see no reason why it wouldn't work.
 
Got the mil light on, found fault code P0401 (EGR sensor got weak signal). Dismounted the valve and cleaned it with stuf left by the house painter. After parts (solenoid and valve) moved freely I connected 12 Volt to the coil straight from the battery, kept it only for 2 seconds (was affraid to burn it) but no movement at all. Fitted stuf on the engine again and deleted the error code. All went fine, no check engine licht any more, but don't understand why the solenoid didn't move when tension was applied.
 
I think you will find that the solenoid did move, well tried to but was already extended.

The solenoid throw is very small. If I remember correctly with no mechanical back pressure it is extended and when power is applied it tries to extend but has nowhere to go.

Did you test the solenoid on its own or with the mechanical valve head attached?
 
Did you test the solenoid on its own or with the mechanical valve head attached?
I tested the solenoid on his own and as you write it must have been extended all ready.
Next time I will put tension on while solenoid and valve are connected together.
 
I believe the croma engine is the same as the Stilo so maybe my vid might help. This is my EGR after I cleaned it. Working 100% now.

[ame="http://s296.photobucket.com/albums/mm189/Shadeyman67/?action=view&current=04072011075.mp4"]04072011075.mp4 video by Shadeyman67 - Photobucket@@AMEPARAM@@http://vid296.photobucket.com/player.swf?file=http://vid296.photobucket.com/albums/mm189/Shadeyman67/04072011075.mp4@@AMEPARAM@@vid296@@AMEPARAM@@296@@AMEPARAM@@mm189/Shadeyman67/04072011075@@AMEPARAM@@mp4[/ame]
 
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There is of course the S130 clean air EGR mod but this requires a little pipe building/plumbing. Saves having to have the ECU mapped and potential insurance issues if you don't declare it.

I've not done the mod on my car but I see no reason why it wouldn't work.

NOTE! The clean air mod is NOT suitable for a Turbo Diesel so please don't try it. (n)
 
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