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Sq5 diesel, feels like a misfire

3111 Views 7 Replies 5 Participants Last post by  Lostflyer, 
D
I'm having a weird one...........
Only plays around until temp hits 90 degrees.
At very low revs it lurches about, bit like a miss fire.
You can drive through it. No lights coming up yet.
Car has 78k on the clock.
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SQ-Raphster
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Suspect your inlet manifold flap in clogged with gunk. Spray inlet manifold cleaner to remove as much gunk as possible. Problem being you will need to do this on a regular basis to keep it in check, and do a good motorway drive every now and then to help the engine burn up as much as possible. Also some cleaner in your fuel might help.

I took inlet manifold apart and cleaned it out about 2 years ago (intend to do it again when I have time):

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D
SQ-Raphster said:
Suspect your inlet manifold flap in clogged with gunk. Spray inlet manifold cleaner to remove as much gunk as possible. Problem being you will need to do this on a regular basis to keep it in check, and do a good motorway drive every now and then to help the engine burn up as much as possible. Also some cleaner in your fuel might help.

I took inlet manifold apart and cleaned it out about 2 years ago (intend to do it again when I have time):

View attachment 12609
View attachment 12610
Click to expand...
It's had the fuel treatment and the motorway runs already, so said flap next.
Thank you😊
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missile
SQ-Raphster said:
Suspect your inlet manifold flap in clogged with gunk. Spray inlet manifold cleaner to remove as much gunk as possible. Problem being you will need to do this on a regular basis to keep it in check, and do a good motorway drive every now and then to help the engine burn up as much as possible. Also some cleaner in your fuel might help.

I took inlet manifold apart and cleaned it out about 2 years ago (intend to do it again when I have time):

View attachment 12609
Click to expand...
Wowser that was really dirty, what did you use to clean the parts?
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SQ-Raphster
I used a lot of elbow grease :ROFLMAO: But I would use manifold cleaner / spray etc next time (anything that breaks down grease). You will need small brush or old toothbrush etc also. Be careful getting the screws out, recommend good magnetic tools for the ones at the back that are difficult to reach, otherwise there is a risk of dropping them (never to be seen again). I also have all the part codes for replacement screws, washers and parts etc if anyone is interested?

You think thats dirty, but I have seen worse (in another SQ5)! Plus my SQ5 has been run on mostly premium diesel (Shell V-Power), so if you use regular or supermarket, I could imagine that it will be even worse. EGR valve / recirculation is such a [email protected] design for longevity of your engine, its there purely to meet emission standards! I would like to take the actual manifold off, but there are so many cables and bits in the way, I'm not sure it can be done easily :confused:

Ultimately an EGR delete (which requires a DPF delete and remap to work) is the best solution for avoiding this issue. But its not legal and you will fail your MOT test (UK only).

At least with electric vehicles these types of issues go away... but probably replaced with battery issues etc :unsure::LOL:
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SQ-Raphster
Also was going to mention, I think the what you think is a misfire until the engine warms up - is actually the manifold flap getting stuck in the gunk at parked revs. When the engine warms up or you are driving it goes away. Just my opinion though...
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J
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SQ-Raphster, can I please offer a sincere thank you for your help with this subject. We had an SQ5 that was stumping us here in Australia. Searched the net and everything we found was “injectors injectors injectors”. Like Dazzler, no fault codes, just running terribly on startup and first movements out a driveway in the morning. Warmer was better.
I assumed (prior to reading this thread) the injectors were possibly leaking overnight, or for prolonged periods of parking. Although it didn’t start up “rich”, it seemed plausible. Injectors out and tested, nothing wrong with them. New seals and stretch bolts, back in, exactly the same.
It seems so obvious once you know the answer, but never in my wildest dreams would I have imagined what we saw when following your advice.
This car is 10 years old, and the lady has literally done 60,000km in that time. All in the city of Sydney, so she’s simply done short runs, and never used it on the Highway. A bad combination of those short runs and low quality diesel we get served up here, and the result was exactly as you said.
Thank you so very very much.

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SQ-Raphster said:
I used a lot of elbow grease :ROFLMAO: But I would use manifold cleaner / spray etc next time (anything that breaks down grease). You will need small brush or old toothbrush etc also. Be careful getting the screws out, recommend good magnetic tools for the ones at the back that are difficult to reach, otherwise there is a risk of dropping them (never to be seen again). I also have all the part codes for replacement screws, washers and parts etc if anyone is interested?

You think thats dirty, but I have seen worse (in another SQ5)! Plus my SQ5 has been run on mostly premium diesel (Shell V-Power), so if you use regular or supermarket, I could imagine that it will be even worse. EGR valve / recirculation is such a [email protected] design for longevity of your engine, its there purely to meet emission standards! I would like to take the actual manifold off, but there are so many cables and bits in the way, I'm not sure it can be done easily :confused:

Ultimately an EGR delete (which requires a DPF delete and remap to work) is the best solution for avoiding this issue. But its not legal and you will fail your MOT test (UK only).

At least with electric vehicles these types of issues go away... but probably replaced with battery issues etc :unsure::LOL:
Click to expand...
Hi SQ-Raphster, I'm having the same start-up and misfire issue but I have had the intake manifolds clean at an Audi dealership, but I'm suspecting they may not have done the Intake flap you show in your photos. Are there parts required, ie seals, for replacement when doing this job?
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