MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: Mackenzie79 on September 17, 2019, 06:30:05 pm

Title: Mk5 golf gti tfsi hesitation
Post by: Mackenzie79 on September 17, 2019, 06:30:05 pm
Hi, please help.. I have a mk5 2.0 tfsi The car has no fault codes, and has had various parts changed; PVC, spark plugs, temp sensor and fuel filter changed, still no joy.
If the car has been left for a few hours it hesitates when pulling off like it's getting no fuel. This is very brief and after runs perfectly. I have been told that this is 'choke mode' and this is supposed to happen?! I'm lost as never heard of this or had this issue before. Should these cars hold back when cold?.
Title: Re: Mk5 golf gti tfsi hesitation
Post by: titchy on September 17, 2019, 08:31:55 pm
there is fuel enrichment which is a form of choke have you checked the air filter enrichment is controlled by ecu via temp sensor is the temp getting to normal 90c when hot could be stat
Title: Re: Mk5 golf gti tfsi hesitation
Post by: Mackenzie79 on September 17, 2019, 08:49:32 pm
I've had it on live data at my local garage. I replaced the coolant temp sensor. It wasn't a vw part though and it came up that the sensor was faulty. He said everything else seemed normal and changed the sensor for a geniune one. Still no joy. The temp dial appears to work it reaches 90and stays there. Once I reach the end of my road all is good no issues. Its just when I start from cold and fisrt pull off for a second or two there is nothing, hard to explain just feels like it has no power. If I keep my foot down it just crawls along briefly then slightly judders into life. I guess I can live with it, it's just really bugging me. How do I check the air filter enrichment?
Title: Re: Mk5 golf gti tfsi hesitation
Post by: muff1991 on September 17, 2019, 10:22:59 pm
Try disconnecting the MAF sensor then drive away, see what happens?


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Title: Re: Mk5 golf gti tfsi hesitation
Post by: Mackenzie79 on September 17, 2019, 10:33:25 pm
I have cleaned the Maf sensor although could still be an issue. What should happen? If the MAF was faulty would it cause this problem just on startup from cold and then be OK?
Title: Re: Mk5 golf gti tfsi hesitation
Post by: muff1991 on September 17, 2019, 10:45:33 pm
Hi mate, I too have been suffering with cold start issues.. except my issue only happens when cold outside not just cold engine. If the weather is 8-10 degrees upwards.. cars fine!!! I have various threads about this forum but not a simple answer it seems. Either that or overlooking the easy stuff lol. I have searched and replaced almost all the common stuff and I still can’t figure it out. If the air temperature is below freezing (0 degrees) the car will start on the button and then cut out after 10 seconds or so.. the engine just slowly dies/stalls. But let’s say it’s 5 degrees outside, my car starts and runs, I pull away and the throttle is ridiculously laggy. Until around 2.5k and then the power kicks back in. So weird and the laggy throttle (hesitation) is defo sounding similar to your issue. Keep an eye on colder temps as they come to see if it gets worse. And if you find a fix please let me know. The only one thing I did and thought I nailed it... was one cold morning I started the car and it cut out (-1 I think it was) so I disconnected the intake air temperature sensor just above the throttle body and hey presto.. the car ran perfect, no cutting out, no laggy throttle and most of all.. no power cuts at 4K. Only when colder I get power cuts at 4000rpm, the engine just cuts all power! This disappears too with the IAT sensor disconnected. So what I would recommend to you, if your problem could be the same or similar to mine, disconnect MAF sensor and see what happens, If it’s worse then that’s a good thing! If better then your MAF is goosed! But if all is ok with that... then connect it back up and then Disconnect the IAT sensor. Then let me know what happens after a drive. Cheers. Muff.


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Title: Re: Mk5 golf gti tfsi hesitation
Post by: Mackenzie79 on September 17, 2019, 11:13:34 pm
Thanks I will try disconnecting the maf and see what happens. If your issues disappear when you disconnect the iat sensor surely it can't stay disconnected I mean it must serve a purpose? Would replacing this sensor solve your prob? I've not had mine long so not experienced a winter yet. So far not had any idling/cutting out issues. Starts straight away and runs perfectly besides the initial issues I'm having. If it does get worse in the cold I will try as you've suggested though, fingers crossed it don't though. If I find a fix I'll let you know.. Thanks
Title: Re: Mk5 golf gti tfsi hesitation
Post by: muff1991 on September 18, 2019, 11:47:11 am
I've only given you a percentage of the story as its very long lol
But yes, its a fairly vital sensor for the management and I don't leave it disconnected forever.. I have replaced it yes but it didn't cure it. I've checked wiring to and from ECU to Sensor Plug and all good, I'm fairly stumped tbh.
If your hesitation is happening every cold start then try disconnecting the IAT then, it might get worse as the cold weather arrives, if it does then you'll have a head start. By disconnecting mine, It instantly fixes all those problems above. Once the day warms up a bit the car will run fine with the sensor connected again. it is literally only Cold Air Temperature related. I can only put it down to the Software (maybe a rubbish or corrupted remap) or another sensor. mechanically the car is fine. its 100% electrical I just don't know what - YET!
I'm not saying you have the same issue as me, but certainly sounds similar. I have found old posts from people in the past but no answers :(
Title: Re: Mk5 golf gti tfsi hesitation
Post by: Mackenzie79 on September 18, 2019, 07:05:10 pm
I had a look at the iat sensor just, took it off and sprayed it with MAF cleaner. Noticed when I took it out, it had a bit of oil on the plastic. I assume this isn't normal? Figured cleaning it couldn't hurt. Disconnected the battery and took the sensor out with the plug attached. If it does get worse when colder I've got no hope of getting those vw plugs off lol nightmare don't wanna break it and it don't wanna budge
Title: Re: Mk5 golf gti tfsi hesitation
Post by: muff1991 on September 19, 2019, 11:14:46 am
yes, you will always get a bit of "blow by" oil in your intake.. and then hitting the sensor. My sensor was oily too.

not teaching you how to suck eggs, but the key to these VAG electrical connectors is to push the plug towards the sensor (so imagine compressing the sensor pins into the connector pins) then pull on the plastic tab, then slide the connector off. real easy but even some of them can still be a pain, especially if you have crud on a connector.
Title: Re: Mk5 golf gti tfsi hesitation
Post by: Mackenzie79 on September 19, 2019, 07:13:25 pm
Thanks will give it another go.. Was looking through the paperwork I got with the car earlier and noticed its had a turbo act valve in the past. Is this another name for a DV valve? . Keep reading maybe this could be an issue but maybe not if it's the same thing. Also found paperwork for 'vehicle on board diagnostics' and on the last page is states that one malfunction was detected and lists, fuel pressure regulation valve below lower control limit intermittent. Could this be causing my problems? The paperwork has no date on it and obviously don't know if this issue has been addressed. Is this something that can be easily replaced?
Title: Re: Mk5 golf gti tfsi hesitation
Post by: Mark_DF05 on September 20, 2019, 04:11:20 pm
I'd check the map sensor too, mine was damaged when I had the thermostat changed and gave similar symptoms. I've read of them not being properly connected or wires snapped a few times so worth a look.
Title: Re: Mk5 golf gti tfsi hesitation
Post by: muff1991 on September 20, 2019, 04:29:06 pm
funny you should mention the MAP sensor as that is next to clean/replace on my list. If that doesn't do it, I'll be flashing a stock file onto it.
cold weathers coming and this morning it was 8 degrees, I was getting power cuts around 4000rpm. bring on the cold weather!

@Mackenzie79 (https://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=42713) the valve they're referring to is more than likely the Diverter Valve yes, never a bad thing putting a new one of those on, could be part of the issue. As for the diagnostics, It might be worth having a scan done with VCDS to see if anything comes up.
Title: Re: Mk5 golf gti tfsi hesitation
Post by: Mackenzie79 on September 26, 2019, 06:27:39 pm
Hi again.. Had a scan done with Vagcom at the lion garage today and diagnosed two faults. Turbo over boost fault and number 2 misfire injector is at fault. They said the "built in dv valve on the turbo" was sticking when cold and was causing the fault and quoted over £2000 to fit a new turbo and injector. Is their a built in dv valve that can't be replaced I'm confused. I thought this was a sepearte thing?! My local garage disagrees saying that I could just clean the turbo and the misfire could be historic. The car runs perfectly after the initial stumble and there are no warning lights on the dash. Any advice would be appreciated thanks
Title: Re: Mk5 golf gti tfsi hesitation
Post by: pudding on September 27, 2019, 05:06:40 pm
They probably mean the wastegate is jammed and not opening, hence the over-boost faults.  DVs normally cause under-boost faults. The DV is replacable, but the wastegate is indeed part of the turbo. You might be able to replace the actuator assembly and see if that helps, but if the penny valve in the turbo is shot, you will indeed need a new turbo.  Approx £1000 inc VAT from the aftermarket, or £1000+VAT from VW.

Clear the fault codes and see if either come back.  Persistent misfire is usually always a bad injector. £100 for the part and a few hours labour, so you might as well replace all 4.

These engines aren't the most responsive during warm up anyway, some kind of warm up routine restricting power a bit, but yours sounds like the ECU is slamming the anvil down on the power.......which it would do if it's over boosting, for engine protection.



Title: Re: Mk5 golf gti tfsi hesitation
Post by: Mackenzie79 on September 27, 2019, 05:55:55 pm
I've only had it a few months and had to issue from day one and it hasn't got worse. It only happens under load from cold start and it's very brief. It runs perfectly after with no stutters or misfires. I'm gonna get it motd Monday and if all is well get the oil changed, change the dv and clean the turbo. Hopefully this will help. My local mechanic doesn't see it as a huge issue and says I should just live with it as it drives perfectly besides this initial fault. Unless it's a bearing cleaning the turbo will hopefully help.
I've read a few comments about the warm up routine, some have said the issues I'm having are normal?! It's does as you say slam down the power sometimes but only very briefly. It feels like the exhaust is blocked and then is ok. The car is 55plate and don't think its worth changing the turbo. Personally think the issue would still be there especially if they do suffer bad starts anyway.
Title: Re: Mk5 golf gti tfsi hesitation
Post by: pudding on September 27, 2019, 06:27:51 pm
You can't really clean a turbo unless it's dismantled.  All you can do is squirt some carb cleaner into the compressor housing to remove PCV gunk, but that doesn't achieve anything anyway as the turbo is designed to run like that.  They are pretty much sealed units and designed to replaced as a job lot.

The cold start flatness just feels like it's down about 50hp, but still perfectly smooth and drivable. As soon as the closed loop fuel control kicks in (40 deg water temp) it's got full power.  That is what's normal.  The momentary loss of power that you describe isn't though!  Does it feel like a fuel cut, or throttle closure?  The ECU can close the throttle independently of pedal position if it's not happy with something.

How many miles on it?  If the turbo is still going strong well past 110-120K miles, it's obviously been looked after and will carry on going strong if maintained well.  Abused/neglected cars are usually lucky to see 90-100K from a turbo.
Title: Re: Mk5 golf gti tfsi hesitation
Post by: Mackenzie79 on September 27, 2019, 07:03:42 pm
The car has 118000 miles and has full service history. It came with lots of receipts and was advertised as having a  full engine rebuild and stage 1 remap. When it's been hooked up no one has mentioned the remap so I'm not entirely sure it is. How would you know as it wasn't mentioned when on vagcom? Visually is immaculate inside and out.
It feels like a fuel cut but as said very brief and then has full power long before it's reached temp. It happens first thing in the morn and when I leave work in the evening so when it has been left for a while. If I idle until the needle drops and pull away slowly it doesn't happen. If I put my foot down a little it crawls along like it's getting no fuel for 3-4seconds and jumps into life and drives with no issues.
I've seen on YouTube you can buy cans on turbo cleaner that is sprayed into the intake that is supposed to remove gum, carbon ppl have even used Mr muscle oven cleaner (I don't intend on doing that) but with the issue I'm having I don't see using the turbo cleaner will hurt. It may not work but ifs there is a slim chance it could clean possible carbon away its worth a shot. My local mechanic said he would clean it next week after mot but not sure how.
Title: Re: Mk5 golf gti tfsi hesitation
Post by: muff1991 on September 30, 2019, 11:47:56 am
The Mr muscle trick, is usually used for cleaning a diesel Variable Vein Turbo (someone correct me if i'm wrong). Some form of cleaner sprayed into the intake may help clear some of the oil residue inside the cold side of the turbo (compressor) but it'll more than likely gather again soon after but i guess it wouldn't hurt to try.

My hesitation, cold start issues etc etc is for sure closing the throttle plate. having no throttle is causing my hesitation! i have seen it on VCDS: Throttle pedal = maxed out! and Throttle plate = 30% (for example) remember i was banging on about the Intake Air Temperature sensor.. well if i disconnect this, i get full throttle function at both ends! its worse for me the colder it is, anything under minus the car starts, idles for like 10 seconds and then just stalls, if i try throttling it doesn't even work at all loool I've got to figure what the hell is retarding the system and closing the throttle plate!

You can look at the flash status on VCDS to see how many "flashes" the ECU has had by going into Engine, Advanced ID and scrolling down to flash attempts. mine has had 4 so maybe 1 or 2 for VW updates or whatever, and 1 or 2 for mapping i guess! - I learnt this from good old @Pudding (https://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=10733)  ;-P

You cant buy the actuator from OEM without buying a turbo = big money! But you can buy a new aftermarket actuator from the likes of Forge Motorsport, you'd need to have the Penny Valve checked on the turbo to makes sure it seals ok and nothings broken. i can't see the Actuator sticking when cold tbh but the most weirdest of things can happen! A worn or perished diaphragm inside the Actuator could cause the Actuator not to release the penny valve correctly and cause an Over boost though.

honestly though, please try disconnecting the IAT sensor before you start and drive off as normal.. see if theres any hesitation at all. Just in case you're slowly approaching my territory. Not that i have a solution for you haha.
Title: Re: Mk5 golf gti tfsi hesitation
Post by: Mackenzie79 on September 30, 2019, 07:04:36 pm
I asked my mechanic exactly what he intended to do and he said there was a foam cleaner that is left on for a couple of hours much like the Mr muscle trick but he says it's proper turbo cleaner. I wouldn't know,  but he's got a good rep and think it's definitely worth a shot.

Mot failed, rear spring snapped near the base and on its way the other side. Getting them replaced Thurs so will look into the oil change and turbo clean after. The guy at the lion garage with vagcom definitely said it was sticking at the dv value built into the turbo. I know this is a separate part after reading all the stuff on here.

When he put it on vagcom he called to tell me the faults but said it would cost more to see why the faults were happening and told me as above. Got the feeling he just wanted me to get a new turbo. I asked for a print out and he just gave me a basic reciept with very little info.

As you mentioned I can't see it sticking just when it's cold and for so briefly and then being fine. I will try disconnecting the iat and see what happens. You say it gets worse in the cold? Is this also solved by disconnecting the iat? Is this something you have to do every morning?
Title: Re: Mk5 golf gti tfsi hesitation
Post by: Mackenzie79 on September 30, 2019, 07:19:02 pm
Also I mentioned to the guy at vagcom that these faults didn't show at my local garage. My local garage managed to read live data and diagnosed a temp sensor a few weeks ago so his diagnostics must me reasonable but he just said vagcom was better and prob wouldn't have shown up on my mechanics diagnostics. Does that sound legit?
Title: Re: Mk5 golf gti tfsi hesitation
Post by: muff1991 on September 30, 2019, 07:25:18 pm
Also I mentioned to the guy at vagcom that these faults didn't show at my local garage. My local garage managed to read live data and diagnosed a temp sensor a few weeks ago so his diagnostics must me reasonable but he just said vagcom was better and prob wouldn't have shown up on my mechanics diagnostics. Does that sound legit?
Yes mate, vcds (vagcom) is much better than most generic OBD code readers. How old is the DV? What temp sensor was replaced, as possible the Coolant temp sensor could cause issues. I only drive the car once a week, but if the temps outside are above 10 I get no problem at all with the IAT connected. If the temps are 4 degrees outside I get really laggy throttle and if the temps are below 0 I get stalls etc. Totally undrivable. Then if I disconnect the IAT at those temps the car drives fine like you’ve just flicked a switch. I know by disconnecting it makes the ECU run on a “basic” setting.
If yours is doing it every morning then possibly this might help it might not. Have you tried things like the PCV test etc? You might have a vacuum leak and on warm up the cars having to try and compensate.


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Title: Re: Mk5 golf gti tfsi hesitation
Post by: Mackenzie79 on September 30, 2019, 07:47:27 pm
It was the coolant temp sensor he said it was faulty and reading really high. I assume the dv is as old as the car as its not in any of the receipts although it had a turbo actuator valve in 2014, wasn't sure if this was another name for it?
I had the PCV valve changed a few weeks ago, what's the PCV test? I've changed the plugs, fuel filter and cleaned the iat sensor, maf and map sensors. The idle doesn't flicker and has never stalled yet. Vagcom mentioned a misfire, my mechanics said this could be historic as it doesn't misfire unless they are suggesting my issue is caused by a misfire and a sticky turbo valve? Does my issue sound like a misfire?
Title: Re: Mk5 golf gti tfsi hesitation
Post by: muff1991 on September 30, 2019, 10:35:45 pm
The DV (diverter valve) is separate to the turbo actuator. The DV is a good thing to change for the price, if this hasn’t been done then definitely get it changed over for a revision G.

The misfire could cause it I guess but your mechanic has probably cleared the fault as it could be an old code and wants to see if it comes back, if it comes back then it will indicate you do have a misfire for sure. If you do, it will probably be down to an injector. Or plugs and/or coils, but usually turns out to be an injector. If not then don’t worry about it.

The PCV test is easy, have the engine running on idle and pull the dip stick out if the engine begins to run lumpy and wanting to cut out then you know it’s fine. If it doesn’t change then you have a weak/faulty PCV.


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Title: Re: Mk5 golf gti tfsi hesitation
Post by: muff1991 on October 01, 2019, 10:14:26 am
apologies, i just remembered :smiley: you have a new PCV so ignore the test and suggestion.
Title: Re: Mk5 golf gti tfsi hesitation
Post by: bobby_fodge on October 03, 2019, 10:51:04 am
I had slightly different symptoms to you. I would get what felt like fuel cuts randomly when accelerating. This had been going on for about a month. The cuts would only last a second, the revs would drop and then the power would return. The two VCDS codes I got were around fuel pressure. In the last 6 months I'd replaced the in tank pump, the in tank pump harness and the fuel filter, after reading the VCDS ouput even though I didn't have any symptoms.

A couple of weeks back I changed the HPFP and still had the issues. I ended up buying a genuine VW in tank fuel pump and that has solved the problem.

 
Title: Re: Mk5 golf gti tfsi hesitation
Post by: muff1991 on October 04, 2019, 09:23:33 am
I had slightly different symptoms to you. I would get what felt like fuel cuts randomly when accelerating. This had been going on for about a month. The cuts would only last a second, the revs would drop and then the power would return. The two VCDS codes I got were around fuel pressure. In the last 6 months I'd replaced the in tank pump, the in tank pump harness and the fuel filter, after reading the VCDS ouput even though I didn't have any symptoms.

A couple of weeks back I changed the HPFP and still had the issues. I ended up buying a genuine VW in tank fuel pump and that has solved the problem.
Hi @bobby_fodge (https://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=26224) , funny you should say this. as about a year ago.. i was driving home in the scorching heat and when idling in traffic i heard a whining noise from the rear seat, thought straight away my in tank pump is on the blink, as soon as id rev the whine stopped but return to idle and it was whining. on my next journey the noise had gone, I've never heard it since so never thought any more on it, but its been at the back of my mind for a while as a possible culprit but hard to say its that when the hesitation goes away with the IAT disconnected. What was you looking at on VCDS to indicate a bad fuel pump? i have looked at low fuel pressure, i get around 3.9bar in cold weather and this morning (12 degrees) i was getting 4.8bar everything else seemed to look ok too going by Ross Tech's "fuel pressure testing".

Also @Mackenzie79 (https://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=42713)  did i see you post a reply about DPF cleaner etc? if you did.. its now gone! Or it was on another thread and not this one  :signLOL:
Title: Re: Mk5 golf gti tfsi hesitation
Post by: bobby_fodge on October 04, 2019, 10:19:41 am
These are the codes i saw in VCDS

012555 - Low Pressure Fuel regulation
               P310B - 008 - Fuel Pressure Outside Specification
             Freeze Frame:
                    Fault Status: 01101000
                    Fault Priority: 0
                    Fault Frequency: 110
                    Reset counter: 255
                    Mileage: 138671 km
                    Time Indication: 0
                    Date: 2000.00.00
                    Time: 09:17:18

             Freeze Frame:
                    RPM: 1343 /min
                    Load: 14.5 %
                    Speed: 35.0 km/h
                    Temperature: 36.0°C
                    Temperature: 15.0°C
                    Absolute Pres.: 1010.0 mbar
                    Voltage: 14.605 V

004195 - Fuel Pressure Regulation
               P1063 - 002 - Control Range Not Reached - Intermittent
             Freeze Frame:
                    Fault Status: 00100010
                    Fault Priority: 0
                    Fault Frequency: 14
                    Reset counter: 255
                    Mileage: 139640 km
                    Time Indication: 0
                    Date: 2000.00.00
                    Time: 16:37:00

             Freeze Frame:
                    RPM: 1241 /min
                    Load: 69.4 %
                    Speed: 33.0 km/h
                    Temperature: 91.0°C
                    Temperature: 26.0°C
                    Absolute Pres.: 1010.0 mbar
                    Voltage: 14.478 V

Readiness: 0000 0000

The VCDS website expands on them about checking fuel pressure etc, tests which I didn't carry out as I am looking to get mine mapped soon so decided to replace the HPFP with uprated internals as an attempt at a possible fix. I'd need this for stage 2 anyway. As the new HPFP didn't solve my issue and I'd had two new fuel filters in the last 6 months it had to be the in tank pump. I took it to awesome GTI who measured the fuel pressure between the tank and the engine bay with the car on the dyno which confirmed the in tank pump wasn't pushing out the fuel at a high enough pressure.

In tank pump is 200 and somthing quid but super easy to fit, take out the bench seat. 
Title: Re: Mk5 golf gti tfsi hesitation
Post by: muff1991 on October 04, 2019, 10:49:54 am
thanks Bobby, my only issue is i have no codes popping up at all on VCDS :-(
Title: Re: Mk5 golf gti tfsi hesitation
Post by: pudding on October 04, 2019, 11:03:33 am
I've put 2 OEM LPFPs in over 5 years.  They're not the best!  They changed the design because people were getting fuel cuts on long journeys due to the pump overheating.  The fix was to basically remove the lid from the pump housing  :grin:
Title: Re: Mk5 golf gti tfsi hesitation
Post by: bobby_fodge on October 04, 2019, 11:13:28 am
I've put 2 OEM LPFPs in over 5 years.  They're not the best!  They changed the design because people were getting fuel cuts on long journeys due to the pump overheating.  The fix was to basically remove the lid from the pump housing  :grin:

That's interesting Pudding, I first starting getting the cuts at the end of the long drive to the in-laws. I then got them at the end of the 25 mile drive to work until I was getting them after a few miles.
Title: Re: Mk5 golf gti tfsi hesitation
Post by: muff1991 on October 04, 2019, 11:17:57 am
i only get cuts when the outside temps are low  :thinking: and even then i dont think its the pump  :smiley:
Title: Re: Mk5 golf gti tfsi hesitation
Post by: pudding on October 04, 2019, 11:18:34 am
I've put 2 OEM LPFPs in over 5 years.  They're not the best!  They changed the design because people were getting fuel cuts on long journeys due to the pump overheating.  The fix was to basically remove the lid from the pump housing  :grin:

That's interesting Pudding, I first starting getting the cuts at the end of the long drive to the in-laws. I then got them at the end of the 25 mile drive to work until I was getting them after a few miles.

The first time I got fuel cuts was when blasting over roundabouts with aggressive camber changes when the tank was 1/4 or lower.  Stuck a new LPFP in and noticed the change of design.  That was 5 years ago and fixed the problem, and has been fine until recently and had to stick another one in.  Not sure if the second one has solved anything but looking at the state of the pump that came out, it was worth doing anyway.  Filthy and clogged with black crap.
Title: Re: Mk5 golf gti tfsi hesitation
Post by: pudding on October 04, 2019, 11:22:06 am
i only get cuts when the outside temps are low  :thinking: and even then i dont think its the pump  :smiley:

Are you still getting those weird problems?  Mine's been OK so far with the recent temp drops, but let's see when it's zero degrees  :grin:
Title: Re: Mk5 golf gti tfsi hesitation
Post by: muff1991 on October 04, 2019, 11:45:46 am
i only get cuts when the outside temps are low  :thinking: and even then i dont think its the pump  :smiley:

Are you still getting those weird problems?  Mine's been OK so far with the recent temp drops, but let's see when it's zero degrees  :grin:
yes mate, had 4000rpm cut last Friday so i know its lingering. Waiting for the colder weather to arrive more permanent for it start doing its spasticated professions again :) Once it does its first cold start stall and im getting bad hesitation again, i'll be looking into things more with VCDS. I didn't have VCDS till the winter was nearly over earlier this year. (still wont find it though, haha)
0 degrees or lower would be better as the colder it is the worse it is, so hopefully i'll spot something obvious.
Title: Re: Mk5 golf gti tfsi hesitation
Post by: pudding on October 04, 2019, 03:41:09 pm
How annoying! It does sound like some some more yawn inducing spreadsheets are required  :grin:  Happy to look them over for you again and as and when  :happy2:


Title: Re: Mk5 golf gti tfsi hesitation
Post by: Mackenzie79 on October 04, 2019, 05:41:44 pm
I have receipts with the car that say its had the in tank fuel pump done. My prob is only at start up from cold. It got worse the other day, lasted longer than usual so took it for a blast that evening to burn off some carbon. The next morning the startup issue wasn't there and although since it has it hasn't been so bad.
I do alot of short journeys and usually stop start stuck in traffic plus its a tfsi known for bad carbon build up so getting it carbon cleaned tomo so fingers crossed. If not may get my mechanic to try the Mr muscle trick.
@muff1991 (https://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=9978) nah I took it down as it seems ridiculous lol. My mechanic assured me that putting dpf clean and regenerator in a quarter tank and idling it for 30mins and then taking it for a blast would clean the turbo. He said the guy he gets it from is a turbo specialist and it's tried and tested. Apparently it's the same stuff that's for cleaning turbos just bottled in a bottle stating diesels only. Didn't wanna take the risk plus already got treatment in my fuel atm.
Title: Re: Mk5 golf gti tfsi hesitation
Post by: pudding on October 04, 2019, 07:50:39 pm
I suspect it could be the injectors.  I think you said you had some misfire fault codes.  Lots of short journeys doesn't exercise the injectors, spark plugs get fouled and the engine just doesn't really get up to temperature.  If things improve after an 'Italian tune up', it's certainly a clue.  When the injectors start to go, it's usually the lower rev range that suffers.
Title: Re: Mk5 golf gti tfsi hesitation
Post by: Mackenzie79 on October 04, 2019, 08:42:36 pm
Yes misfire on cylinder 2 injector they said. I guess if this is not historic as my mechanic thinks then itilain tune, injector/carbon cleaning, will not help? The Vagcom guy said replacing the injector alone wouldn't solve it as needed new turbo too.
If it was misfiring would it run smooth through every gear with no hesitation or misfire besides the initial bogging?
It's just passed its mot too so emissions all good
Title: Re: Mk5 golf gti tfsi hesitation
Post by: muff1991 on October 04, 2019, 08:57:03 pm
How annoying! It does sound like some some more yawn inducing spreadsheets are required  :grin:  Happy to look them over for you again and as and when  :happy2:
Thanks pudding, I sure will be leaning on you again mate! We’ll get to the bottom of it this year!


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Title: Re: Mk5 golf gti tfsi hesitation
Post by: muff1991 on October 04, 2019, 09:01:16 pm
Yes misfire on cylinder 2 injector they said. I guess if this is not historic as my mechanic thinks then itilain tune, injector/carbon cleaning, will not help? The Vagcom guy said replacing the injector alone wouldn't solve it as needed new turbo too.
If it was misfiring would it run smooth through every gear with no hesitation or misfire besides the initial bogging?
It's just passed its mot too so emissions all good
I thought I wasn’t going totally blind lol I see it but didn’t have time to reply, but in a nut shell it might be the same stuff, I wouldn’t bother risking it though. Don’t ever hear of anyone having to clean one of these turbos.i plugged mine in today and noticed on idle I was getting 1 to 2 misfires on cylinder 3 and 4 they’d disappear then one by one flag back up on the counter. I guess an injector clean/replacement and carbon clean might be something I’ll need to do too. We’ll get to the bottom of it mate.


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Title: Re: Mk5 golf gti tfsi hesitation
Post by: pudding on October 05, 2019, 11:44:24 am
Yes misfire on cylinder 2 injector they said. I guess if this is not historic as my mechanic thinks then itilain tune, injector/carbon cleaning, will not help? The Vagcom guy said replacing the injector alone wouldn't solve it as needed new turbo too.
If it was misfiring would it run smooth through every gear with no hesitation or misfire besides the initial bogging?
It's just passed its mot too so emissions all good

Injectors are mechanical devices and can therefore misbehave intermittently. The pintles get gummed up and lazy.  It could just be a particular temperature and duty cycle they're not happy at.  These engines never misfire if all is well.  Misfires severe enough to flag a fault (it has to miss several times for that happen) it's certainly a clue.  I had an intermittent misfire on mine on cyl 3 at approx 90K miles which was a bad injector.  I just put another set of 4 in and it's never missed since, not once.

I'm not suggesting it's them 100% because you can't be certain over the internet, but at your mileage and the symptoms, they can't be outruled.

Unless the turbo has bad shaft wear (wobbly turbine wheel) I really wouldn't go there with that.  Focus on the cheaper, more fundamental issues first is my advice.  The turbo should be the last thing on the list as it's very expensive and they either work or they don't, kind of like a light switch.

I would give it several hard runs over a week and see what that achieves and go from there.  These engines really don't like short journeys.  Well, they can do them, but they prefer to get a lot of air through them and heat to blow the cobwebs away.

Coilpacks and plugs recent/good?

When my injector went, it didn't feel rough, just very flat and unwilling to rev.  The only clue was an occasional lumpy idle when hot.

Title: Re: Mk5 golf gti tfsi hesitation
Post by: Mackenzie79 on October 05, 2019, 02:19:50 pm
If it was misfiring would I not feel, hear it? Is the initial feeling of hesitation considered a misfire or because its apparently got a sticky turbo? I know that cheaper readers are not as good as vagcom but to be honest myself and my mechanic don't trust what they've said. The garage had a lot of bad reviews.
My mechanic says it is not misfiring but doesn't understand why the initial hesitation is there. I had it carbon cleaned today and the guy said it wasn't misfiring and his reader showed no misfire/faults. Getting new filter, and oil flushed and changed Monday. Won't know if carbon clean has helped with cold start I guess till I cold start again but definitely felt more responsive when taking it out after the treatment.
Yeh had my plugs changed recently along with fuel filter, temp sensor, PCV and had a few of the sensors out for cleaning. I use shell high octane fuel and have intector treatment in at the min. He looked at coils and said they looked ok.
When I first bought it I was told it was remapped.. I messaged the guy I bought it off and he told me it had always done this and it was because it was remapped and the injectors were sorting themselves out, putting more fuel in. Could a bad map be the issue possibly? Thanks for the responses much appreciated