[Bogdan1986]

Some new developments.

I just came back from visiting a friend that lives 50km away. When I left, I had the check engine light on, P0404 trouble code. Outside temperature : 25C. All the way there, the engine didn't rev over 2900 rpm, no matter how hard I tried.
When I left his house, outside temperature was 19C. Check engine light on. I stopped to answer nature's call after about 20km. When I started the engine again, check engine light was off, outside temperature: 18C. All the rest of the way home, accelaration was responsive and I could rev over 2900 rpm, while outside temperature went down a couple degrees more.

Otherwise, cleaning the egr cooler proved to have a positive effect, fuel consumption went down to normal values.

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[adrek]

Here you go, driving speed was stable, RPM also, EGR actuator was behaving like this:


I replaced EGR, made new harness and it did not help, later friend told me about ECU issues..

[Bogdan1986]

Thanks for sharing that with us, @adrek !

I think I have what I need to make a graph of the EGR, what other parameters do you need, besides engine RPM and Speed?
Over how many seconds should it be done? Should the speed be constant throughout the graph?


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[adrek]

if the problem occurs it could be 20-30 seconds recording, but now you can easily say from your data if it will be the same as mine then 99% ECU is faulty. All you really need to monitor is EGR, engine speed was there for me only for warranty documentation (because it was warranty repair for this car).

[tw2005]

Here you go, driving speed was stable, RPM also, EGR actuator was behaving like this:


I replaced EGR, made new harness and it did not help, later friend told me about ECU issues..

So has the ECU been replaced and confirmed was the fault? I'm wondering at the graph, that could be duty cycle of 41% which could mean the EGR was open. manual mentions at about 43% it's open, 5 % closed. I notice the graph shows 5% - 50% as the min - max recorded, Just some thoughts really

[adrek]

yes, engine ECU was replaced and problem was solved. ECU was not properly steering EGR valve, P0404 was set and engine power was limited to max 3000rpm.

[Bogdan1986]

I changed the glow plugs and went for a short drive. Nothing changed.
These graphs are from that drive. As you might notice, the first one is taken when coolant temperature was under 70C, the second when it was at ~90C. To me, it looks nothing like the bad ECU graph.
What do you think, @adrek, bad EGR valve, after all?

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[Bogdan1986]

I changed the glow plugs and went for a short drive. Nothing changed.
These graphs are from that drive. As you might notice, the first one is take when coolant temperature was under 70C, the second when it was at ~90C. To me, it looks nothing like the bad ECU graph.
What do you think, @adrek, bad EGR valve, after all?

Just in case tapatalk didn't upload the pics.

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[Skovsgaard]

Now I have made some new test runs (approx. duration is 2 min +/- ) and here are the results:

EGR investigation - Album on Imgur

#1

Running with A/C ON.

Immediate response when accelerating.

The engine is calm and stable.

#2

Running with A/C OFF.

Delayed and bad response when accelerating.

The engine is chocking and unstable.

A thought: “If the engine is “dirty” inside and produces “dirty” exhaust gas – I guess that would somehow chock the engine when the EGR is opening 100% and recirculating the “dirty” exhaust gas”.

I have used Bell-Add for the last two weeks according to the workshop recommendations. Additionally I have been considering a more effective engine cleaning.

The correlation between A/C ON(#1) and OFF(#2) is still a mystery...

#3

This graph is showing the same situation as Bogdan1986s latest comment describes (rpm limited to 2900 rpm). As the graphs shows the EGR is closed at all times, which means an immediate response when accelerating and a calm and stable engine.

Why the limitation in rpm aroused is unknown to me…

Shutting of the engine and starting it again clears the limitation.

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@adrek: What do you think?

----------------
For some reason i couldn´t see your latest posts adrek and Bogdan1986. But I can see now that you have both submitted graphs.

@adrek: In the case with bad ECU, where there other symptoms beside the incorrect driving of the EGR?

[tw2005]

snapshot from my 2008 D4FB i30 manual

[adrek]

GDS screen looks good for me. Screens from ELM327, I don't know, these OBD plugs are too slow in my opinion to read data and show graph, look at peaks in GDS or my mobile GDS - data is way more detailed. Anyway these graphs seem to be good. My input was just suggestion to check EGR graph, because it costs nothing and potentially could save you some money in the end

[Bogdan1986]

There is a trend that I noticed, and that is the fact that EGR error is way out of acceptable range only at operating temperature. I ordered a new EGR valve, I ran out of stuff to check and rule out.
The ELM plugs are cheap, I would love to use GDS, but I can't find an affordable one...
I don't trust dealerships, otherwise I would pay to have them diagnose the problem. However, I only hear stories where they throw parts at the car and the problems come back. It's certainly something that will happen in my case, with an intermitent fault.
Anyway, thanks for your help, guys!

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[tw2005]

GDS screen looks good for me. Screens from ELM327, I don't know, these OBD plugs are too slow in my opinion to read data and show graph, look at peaks in GDS or my mobile GDS - data is way more detailed. Anyway these graphs seem to be good. My input was just suggestion to check EGR graph, because it costs nothing and potentially could save you some money in the end

[tw2005]

There is a trend that I noticed, and that is the fact that EGR error is way out of acceptable range only at operating temperature. I ordered a new EGR valve, I ran out of stuff to check and rule out.
The ELM plugs are cheap, I would love to use GDS, but I can't find an affordable one...
I don't trust dealerships, otherwise I would pay to have them diagnose the problem. However, I only hear stories where they throw parts at the car and the problems come back. It's certainly something that will happen in my case, with an intermitent fault.
Anyway, thanks for your help, guys!

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Mine just an Ebay Chinese knockoff but the software they give is US based so I had to go hunting for Europe version, loading the software was painful and a dedicated laptop is a good idea, does not need to be a fancy one

[Bogdan1986]

Mine just an Ebay Chinese knockoff but the software they give is US based so I had to go hunting for Europe version, loading the software was painful and a dedicated laptop is a good idea, does not need to be a fancy one

Can you help me with a link or a model number?

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[Skovsgaard]

Hi Skovsgaard!
I'm sorry you're having issues with your car, but I must say, I'm glad I don't feel like I'm crazy anymore.
Unfortunately, my AC doesn't work. Another thing I noticed when the temperature went up...
I did go to a shop to have the AC system serviced, they filled it with gas and dye, and said it was empty, so they suspect a leak. I was to contact them when the AC would show signs it doesn't work again. Ofcourse, a week later it wasn't cooling so well anymore, so I made an appointment with the same shop to find and fix the leak. The date: 12.06. So, I can't test the AC - EGR correlation until they are done with it.

However, I did notice a change in engine tone whenever I would engage or disengage the AC during the week it did work... So there could be a link.

I am curious what @adrek can interpret from the graph you shared!

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Hi Bogdan1986

I´m curious to hear if you see a correlation between aircondition ON/OFF and EGR steering after you have had your aircondition fixed.

Here are some graphs showing the phenomenon (posted earlier): EGR investigation - Album on Imgur

Regards

[Bogdan1986]

Hey there, Skovsgaard.

Driving with AC on doesn't seem to make any difference. I get the same hesitation.

However, regardless of wether the AC is on or off, when I press the acceleration, instead of the egr closing, it stays on for another second or so, and when it does finally close, I get a sudden power surge. In the limp home mode, the valve stays shut for me too. I ordered a new EGR valve, I'll install it when it arrives and see what happens, hopefully I've been chasing a ghost so far.

My problem only appears after the engine is warm; if coolant is under 70 C, the acceleration is responsive and I don't have any rev limitation.
I did have one instance on the motorway, a couple of days ago, when the revs were limited to 2900 rpm. 10 minutes later, the DPF regeneration process kicked in and the rev limitation went away. On the return trip, the limitation was back on. Funny...

Did you notice anything new?

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[Bogdan1986]

Hello, people!
Can anyone tell me what is the normal intake air temperature at highway speeds? I could only find some info on other car makes and it appears that it shouldn't be more than 10 degrees over outside temperature. I can't find normal values for FD i30's.
I ask because I noticed that my IAT (as read by the Torque app) is 50-53 C at 26C outside temp. This sensor should be the one on the intercooler and it is the only one  that I didn't change in the EGR system, as I changed the MAFS a couple of months ago. It should be the one most affected by outside temperature, from what I understand about it.

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