GolfGTIforum.co.uk
Model specific boards => Golf mk4 => Topic started by: Sammy14913 on 29 June 2016, 20:32
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Hi all I've been looking on a few owner club site but still can't solve my problem... I know you have probably herd this time and time again but it's worth a try basically I got another mk4 gti t but only to find out it's a arz with a agu head not a problem apparently... Basically since the day I got it it's been boggy/misfiring up to 3k revs in every gear I've changed maf sensor, spark plugs ,coil packs , n75 valve to a new s3 n75 the diverter valve to the tt one witch is apparently stronger the rear lambda new fuel filter oil and oil filter , got it plugged into vagcom and there is no fault codes on now and no lights on the dash but yet the problem is still ther and its over fuleing by the smell of it as well
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get some pics of the engine bay, inlet manifold and the area around the injectors. The injectors are different between the AGU and ARZ so hopefully nothing has been bodged. It won't be a good idea running a large port head with a small port inlet though...
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I think everything is arz apart from the head how do I post pics on hear and I'll do it now for you to have a look at
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Would the pcv cause these problems
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If the PCV is leaking it will run poorly yes
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This cars beginning to become a headache .. As the revs dropped it popped a few times so think might be blowing from exhaust manifold like a failed gasket
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Do you think a map will sort it out
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I'm starting to think the whole engine is agu would that cause the problem a agu engine running off a arz ecu
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Shouldnt do if all the sensors and such are plugged in. The engines are the same its just sensor differences at the most.
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The agu head has bigger ports so fort the air/fuel mixture would be different plus it's running rich as well...I'm Gona give up on this car soon I'm starting to loose my cool with it I can't see how there's no fault codes and its misfire: bogging at 1.5/3k revs
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Might not maie a difference as the ecu corrects fueling. Ive not come across a car running bad because of bigger valves.
I have however got a customers agu in that is bogging down misfiring below 3k. I unplugged and cleaned the throttlee position sensor and plugged it back in and seems to have resolved it. Ill know for sure when I take it out In the morning
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Already cleaned the throttle body and reset it and it's the same all I get off everybody is remap the car and it will solve it might get new coil harnes as apparently they get funny over time due to engine heat... But everything has been done I got no codes no boost/vac leaks compression has been checked and its 165 all across. I read on here somewhere that the spark plugs have to be gapped to .028 as this can make a 1.8t misfire due to density of the air... other then that there isn't anything else apart from it running rich
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Just realised what you meant mine is electrical throttle where is the sensor located and how do I clean it I'll give that a try
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Its under the throttle body, I cleaned the connection on this one, was a bit of dirt in the contacts.
Spark plug gap should be 0.6mm
I got some plugs the other day that were 2mm gap and had to be changed.
I dont know if a map would solve it. It could make the problem worse because of the extra load on the engine.
Have you checked the lambda?
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Yer bank 1 position 2 was out we changed it reset and hasn't come back on again where as before it was being cleared and coming straight back on when you started the ignition the only code on there is secondary air sensor open circuit but that's been removed and blanked and have been told that wouldn't cause the problem.
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Thanks for your help people.. Come to the conclusion I'm Gona get rid of this thing as the problem can't be resolved
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Had the car on the ramp at work today and it has a leak from the flexi down pipe would this cause the misfire /flat spot up until 3k and it running rich? As the problem seems to be getting worse
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2nd lambda would read wrong. I assume 1St lambda is befire the blow.
So it would put more fuel in and possibly over fuel it to the point of spluttering
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1st is before the cat after the flexi and 2nd is after cat so the leak is before the 1st ... The mechanic at work has no idea as we have done everything possible he has a mk5 gti took it to a vw specialist and I told them what we have done there reply was have not got a clue take it to a place that deals with modded cars all because it has a agu head some specialist they are but now it isn't just a miss fire/flat spot it's starting to judder when it's in the flat spot.
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It would make it overfuel still being as a lamda is reading lean with the blow.
I cant see why it matters its modded. Engines still have the same problems.
Sort the blow mate and see if it gets the judder gone. It should help with fueling definately
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Yes I will hopefully this is the problem was thinking of getting a decat pipe but have been offered a power flow turbo back for. £100 but just thinking will a decat make it run rich again.. If fixing the blow solves the problem and over fuel .. If u get what I mean
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Decat will still have to lambda holes to read from. Just wont Obvously get rid of the sh!t for emmisions
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that doesn't bother me atm the main thing is getting this running right I've owned owned it 3 weeks and have spared no money trying to resolve this problem that seems to be Un fixable I just didn't want to resolve the problem by replacing leaking exhaus and then cause another by having no cat I'm going to give it a few more weeks then if I can't resolve it I'm just going to break the car or just sell it as spares or repair :(
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Gaped the plugs to 0.28 and no difference tbh seems to be running a bit worse imo or could it be a faulty fuel injector or would a bent valve cause this problem and is there a way to find out?
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Bent valve youd hear him chuffing in the inlet or exhaust, thats how youde know. Injector dodgy youde also know by puttin it on vag com and checking the resistance on the injectors
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Went and baught some bosh super 4s earl is Gona fit them tomorrow and the exhaust is blowing worse hopefully it's that that's causing me the problems through loss of back pressure
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Can some one confirm this... A friend of a friend had the same problem and apparently the head has vvt and my ecu isn't set up for that hence the bogging / misfire up to 3k or the other way around and apparently I can get it mapped out he had same prob got vvt mapped out and car ran sweet
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Hmm, from what I heard vvt on Vags is for emissions at higher revs so under 3k shouldn't make a difference.
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just out of curiosity what air filter are you running?
have you tried running the car without the MAF connected to see if it runs any better?
Mines an ARZ
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Yer brand new bosh maf when unplugged runs bad and tbh mat I'm not sure if it has arz bottom end or wether whole engine is agu but wording is arz I don't know if there is a way to tell what bottom end you have
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Fitted the power flow turbo back today sounds nice turbo spools quicker but it's louder and so is the misfire would a knackered turbo core cause this? Been offered a k03s minimal play in the core/impeller £50 is it worth getting as a back up in case it is the turbo causing these problems ?
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Finally found out my issue... It was a mapping isue basically the car was heavily moded and put back to standard but ecu was set up to run previous mods they flash wiped the ecu or something like that now it runs like new.
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Glad you sorted it mate, would have never thought it would be put back to dtandard but the map left on
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Only found this out due to a friend of mine asking around and about 5-6 different people said the same thing they recon you wouldn't change the head unless your already running around 300bhp and wanting more power and to run that power you obv have to have a map get it checked so that's what I did obviously 2 owners befor got another 1.8t and transferd all the stuff over but head was to big of a job so left it on with the mapped ecu is what they all are saying I appreciate all who had a input in this thread and helped me get to the bottom of this problem
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Glad you sorted it