MK5 Golf GTI
All Things Mk5 => Mk5 General Area => Topic started by: Graham1990 on February 21, 2018, 07:34:55 pm
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I posted a bit about a rough idle on my 2005 mk5 gti the other day. The post won’t seem to load up for me to update it now so I’ll make a new one. Anyway I’ve just been out to pick the Mrs up when I got there I sat out the front for a bit just to see how the car was idling and it was awful. Feels juddery like it’s misfiring so I turned the car off went in to the in laws for 15 mins came out started car, drove home. when I got home I sat in the car for a few mins and let it idle and it was perfect 🤔. I was thinking it may be the intake valves being covered in carbon but surely if it was the valves it would idle rough all the time? Not every now and again? I’m now thinking maybe the butterfly valve/plate in the throttle body may sometimes be getting stuck slightly open and allowing to much air through for idle. It drives perfect doesn’t stutter, hesitate at all. It only has the judder/misfire at idle. Any one got any ideas ??
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Forgot to mention I have replaced:
Spark plugs
Coilpacks
Thermostat
Coolant
Oil and filter
Oil pick up pipe
Diverter valve
Cam follower
Air filter
Coolant temp sensor
In line thermostat
N205 camshaft adjustment valve.
I know some of them probably won’t solve the issue but they needed doing anyway. 👍
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Check pcv
Try a throttle body reset
Pull injectors out and test them and clean valves at same time.
In that order
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Firstly - unplug the MAF with the engine running. If it stabilises then it points to an air leak. Secondly I would suspect the PCV valve as mentioned above which is a 5 minute job to check by simply blowing down the pipe
I've never known a TB reset solve anything on these cars, and jumping straight to injector pulling testing is a big and expensive step, plenty of other things to check first. A fault code scan (using something VAG specific - VCDS - as generic OBD2 code readers miss a lot of codes that don't trigger the EML) and a check of the Block 032 trims using VCDS would be useful too
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Thanks lads, I have scanned the ecu and it has no codes. I haven’t bothered with pcv as I thought the symptom of that was more the engine going up and down the revs a few hundred or so rpm. I will try unplug the maf and see what happens and I will also check the pcv. I’ll report back and let you know what I find 👍
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If only the idle is lumpy intermittently but all other loads and rpms are fine, it's either an air leak as already mentioned, or injector(s).
An air leak at idle would normally show a larger than normal positive percentage in the long term trims (block 32). Idle normally sits around 1.5%, if it's 5% or more, you probably have a slight leak.
If the trims are very low, I would put money on a lazy/partially clogged injector, given that you've replaced everything else. Try giving it death on some quiet roads to wake the injectors up a bit. Short journeys are the bain of these cars.
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P.S. Where did you get the N205 (06F109257C) valve from? I see they are £20 on ebay for a very obvious Chinese copy, and look to be well over £100+ for the official VW part!
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@Pudding (http://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=10733) I got the n205 from vw i think it was £98 including vat I’ll check the receipt when I get home 👍
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Yeah the n205 was £98.40 from vw. Same part number as you mentioned. Any suggestions on the easiest way to find an air leak? Cheers.
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Yeah the n205 was £98.40 from vw. Same part number as you mentioned. Any suggestions on the easiest way to find an air leak? Cheers.
Smoke test
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Yeah the n205 was £98.40 from vw. Same part number as you mentioned. Any suggestions on the easiest way to find an air leak? Cheers.
Thanks mate. I physically checked mine yesterday, and also tracked it's adjustments with VCDS. It's fine, so £100 saved :smiley:
Mine also has a lumpy idle intermittently. Seems worse when it's cold. My car is a bit like me, it prefers the warmth of summer!
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Yeah the n205 was £98.40 from vw. Same part number as you mentioned. Any suggestions on the easiest way to find an air leak? Cheers.
Thanks mate. I physically checked mine yesterday, and also tracked it's adjustments with VCDS. It's fine, so £100 saved :smiley:
Mine also has a lumpy idle intermittently. Seems worse when it's cold. My car is a bit like me, it prefers the warmth of summer!
Haha it’s always nice when you don’t have to spend money on boring parts. I hate intermittent faults, it seems they are all I ever get. I have actually noticed another symptom that may be linked. Sometimes it will struggle to start. Not the battery that is fine and turns the engine over really well. If you keep the key twisted it keeps cranking and eventually fires into life. Sometimes if you twist the key and as it starts let go it will die, then you twist the key again and it fires up fine. Does this help anymore with the diagnosing? Thanks
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You could try cleaning the MAF with some Isopropanol alcohol, or 'MAF cleaner'. If not that, it's probably injectors or an air leak. Idle is where you notice a dodgy injector the most.
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You could try cleaning the MAF with some Isopropanol alcohol, or 'MAF cleaner'. If not that, it's probably injectors or an air leak. Idle is where you notice a dodgy injector the most.
Thanks mate, all I want to do is get the thing remapped! 😩 it was booked in for the 3rd of Feb but I had to cancel because of the code coming up which was the n205 in the end. I really want to sort the dodgy idle before I book it back in for the map. I’ll be checking the maf, pcv and have a visual check for leaks tomorrow. If all seems ok I’m going to get the engine smoke tested next Saturday. See if I can see any leaks. If not I’ll be replacing the injectors and cleaning the valves while I’m at it 🤑🤑
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Firstly - unplug the MAF with the engine running. If it stabilises then it points to an air leak. Secondly I would suspect the PCV valve as mentioned above which is a 5 minute job to check by simply blowing down the pipe
I've never known a TB reset solve anything on these cars, and jumping straight to injector pulling testing is a big and expensive step, plenty of other things to check first. A fault code scan (using something VAG specific - VCDS - as generic OBD2 code readers miss a lot of codes that don't trigger the EML) and a check of the Block 032 trims using VCDS would be useful too
I had two mins spare earlier so I tried what you said with the maf. The engine was running I unplugged the maf and the car very nearly stalled and then it ran like normal. So I plugged the maf back in, started the car, tried it again and the car died immediately. Then I plugged the maf back in and the car wouldn’t start at all, tried for a while with no joy then tried again with the accelerator down a bit and it started and ran fine again. Any ideas ?? I will check the pcv tomorrow when I have a bit more time spare.
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If the engine behaved like that pulling the maf, it was using it to measure load, which suggests it's fine. If you unplug the maf and nothing happens, the ECU is not using it and basing load measurement from the throttle instead.....which is not ideal, but it works. Try pulling the battery for 30 mins which will force the ECU to recheck and relearn all of the sensor inputs.
Needs to be 30 mins minimum because if it's less than that, sometimes the driver's side door module won't work. Which will need another 30 minute battery pull! Weird I know, but these cars are quirky like that.
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Does anybody know if there is a place that could recondition my injectors? Is there such a place or would it be a case of buying new ones. (If they are the problem).
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You can send them off to someone like Mr Injector. New ones are about £100 each from VW.
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Ok, thanks mate. I’ve just found out one of my mates has vagcom. Do you know how to check if the injectors are working properly with vagcom?
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That isn't a check you can do with VAG-COM unfortunately. The only way to test them properly is on an ASNU type test rig....
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fwww.asnu.com%2Fimg%2Fpages%2Fmachines%2Fgdi%2Fmachine.01.jpg&hash=186adbda2d85158a02b31eb9fa8db6e64fd12d2d)
I would get it smoke tested and compression tested before investing in injectors. The MAF also plays a key part in idle quality, so perhaps get hold of a can of MAF cleaner, or electrical contact cleaner. Give it a blast and see if things improve.
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That isn't a check you can do with VAG-COM unfortunately. The only way to test them properly is on an ASNU type test rig....
(https://www.mk5golfgti.co.uk/forum/proxy.php?request=http%3A%2F%2Fwww.asnu.com%2Fimg%2Fpages%2Fmachines%2Fgdi%2Fmachine.01.jpg&hash=186adbda2d85158a02b31eb9fa8db6e64fd12d2d)
I would get it smoke tested and compression tested before investing in injectors. The MAF also plays a key part in idle quality, so perhaps get hold of a can of MAF cleaner, or electrical contact cleaner. Give it a blast and see if things improve.
Ok mate, It’s getting smoke tested Saturday 10th March all being well. Is there anything I can look for on vagcom that would help my cause finding the rough idle and or the random appearing p000a code? Thanks for your advice 👍👍
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Process of elimination mate. I'm in the same boat as you. Slower than usual and rough idle, performance is down and some surging on part throttle acceleration.
Everything looks fine in VCDS and I've also replaced everything you have, so it's time to investigate the mechanicals. Cylinder compression, turbo wear, fuel pump(s), boost leaks etc.
Given everything you've replaced, I'd be inclined to do the same!
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@Pudding (http://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=10733) it’s a pain in the arse 😅. I’ve also noticed sat on tick over it sits at 800 or 900 rpm which ever it feels like. Never higher or lower and it doesn’t flutter it will either sit bang on 900rpm or bang on 800rpm. Either way the headlights lights are constantly flickering. That annoys me lol. Oh well if you find out your problem let me know what sorted it. If I cure mine before that I will let you know what cured mine. Thanks mate.
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Yeah tell me about it. All the love and attention rewarded with strops!! Cars are like women!!
Mine's been like that too. The 900ish rpm is smooth, but when it drops to 800ish, it's lumpy! I blasted the MAF with some MAF cleaner after work, so I'll see if that helps in the morning.
Flickering headlights could be a clue on yours. Do the interior lights pulsate slowly with the engine running? That's a sign of a dying alternator diode pack, which is a cheap fix at an auto electricians vs £400 odd for a new alternator from VW! A dying alternator / weak battery would almost certainly cause your symptoms.
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Yeah tell me about it. All the love and attention rewarded with strops!! Cars are like women!!
Mine's been like that too. The 900ish rpm is smooth, but when it drops to 800ish, it's lumpy! I blasted the MAF with some MAF cleaner after work, so I'll see if that helps in the morning.
Flickering headlights could be a clue on yours. Do the interior lights pulsate slowly with the engine running? That's a sign of a dying alternator diode pack, which is a cheap fix at an auto electricians vs £400 odd for a new alternator from VW! A dying alternator / weak battery would almost certainly cause your symptoms.
The interior ones aren’t so bad but they do flicker as well yeah. Battery is fine it cranks the engine over really easily and will do for ages as I tried to start it for ages after I was messing with the maf. Next Saturday is the smoke test and I might see if I can get it compression tested at the same time. I never have much luck with cars 😅
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@Pudding (http://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=10733) do you know how To log misfires on vagcom ?? If so could you write a step by step how to for some one who has never used vagcom like me 😅. I would really appreciate it 👌
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Google is your friend and pocket library mate - "misfire counter tfsi vcds" brings up everything you need to know!
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I've got a strong feeling its air leak related. Which your upcoming smoke test will highlight :)
Also, you might have a number of leaks, so dont stop the smoke at the first leak. For example, if introduced at the inlet you might have some smoke egress from the MAF housing which wouldn't be significant enough to cause your issue. If you let the smoke continue round, you might find a much more significant leak at say the turbo outlet pipe or a bayonett coupling at the intercooler etc.
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I've got a strong feeling its air leak related. Which your upcoming smoke test will highlight :)
Also, you might have a number of leaks, so dont stop the smoke at the first leak. For example, if introduced at the inlet you might have some smoke egress from the MAF housing which wouldn't be significant enough to cause your issue. If you let the smoke continue round, you might find a much more significant leak at say the turbo outlet pipe or a bayonett coupling at the intercooler etc.
Ok, hopefully you are right and the smoke test reveals my problem! Thank you for the advice, it’s appreciated and very much needed 😆I will let you know how I get on 👍
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Morning all, just had the engine smoke tested and there is a leak from one of the little plastic pipes that clip onto the pcv! Fingers crossed replacing this will solve my problem. Does anyone have recommendations on getting rid of the pcv? Just buying a blanking kit and putting that on. Or should I just replace the plastic pipe and keep the pcv all how it is ?
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Keep it standard mate. It's the cheapest and best solution :happy2: PCV deletes cause more problems than they fix. VW's engineers kind of knew what they were doing when they designed this engine :smiley:
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VW's engineers kind of knew what they were doing when they designed this engine :smiley:
Making money? :laugh:
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Yeah, I imagine a primary oil separator, a partitioned cam cover and a front PCV system was proper cheap to make. Running a cheap bit of rubber pipe down to the floor and getting massive fines from Brussels is a far better way to make money :stupid:
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Haha no, you're right the OEM PCV system is obviously the way to go. I was more alluding to the rationale that just because a VW engineer designed it, it doesn't mean it was the best possible option for the engine. Let’s not be under any illusions, VW, like any other car manufacturer is in it to make money, not good engines, money. Twas just a joke :laugh:
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Lol, I notice you've snuck a smiley in there now :grin: It wasn't so easy to tell it was a joke before!
Well obviously VW don't make cars for the good of their health, but I think you'd be surprised by how little they make on each car. Regardless of costs and rationale, the EA113's PCV system is the best I've seen on a 4 cylinder turbo car to date for a road car.
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I've got a strong feeling its air leak related. Which your upcoming smoke test will highlight :)
Also, you might have a number of leaks, so dont stop the smoke at the first leak. For example, if introduced at the inlet you might have some smoke egress from the MAF housing which wouldn't be significant enough to cause your issue. If you let the smoke continue round, you might find a much more significant leak at say the turbo outlet pipe or a bayonett coupling at the intercooler etc.
I’ve replaced the pcv and the two hoses that had the vacuum leak. Still a rough idle!! 🤔🤔 all that’s left to do is repair/refurb the injectors and clean the intake valves. So that will be next on the to do list. Bloody car! 😖😖
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Injectors is fairly standard. They all need new ones, or refurbed at least, at some point! Direct injection causes more issues than it solves!