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Discussion Starter · #1 ·
hi im new to the forum and iv been having a few small but very anoying problems with my mk4 tdi 150, this is the one thats bugging me the most though, she seems to run rubish when i first start her i always leave her to run for about a minute or two before i take off and wait till she heats up a bit more before winding her round the rev band a bit more. im a mechanic to trade but im damed as to where to look first on this, after i first jump in the car after the 1-2 minutes of idling i try drive a bit and feels like just as the boost starts to kick in she lags like its getting no fuel or no boost?

i bought an AFM (air flow meter) for it and it ran even worse with the new one on (was a brand new cheep one from ebay £35) but i think i should try an origonal one from VW, costs like £120 though!!! this was one fault i found online the other was the VNT in the turbo being sticky/stuck, i would have thought if it was this the car would through up a code which it hasnt and do it all the time rather than just when cold???? when she gets up to full temp she seems to run fine boosts well throughout the rev band and still i get my usual 380-400 miles to a tank of fuel?

i am most confused, can anyone shed a bit of light on the matter please

thanks

mark
 

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Hum, most strange that no faults would come up, how many miles has your car done? If it's a real high miler perhaps the wiring to the MAF has failed, even then I think it would throw up a fault.

What temperature is it where you are? Although diesel tend to have additives in during the winter to stop it from going thick and waxing, my car didn't feel like it was running at it's best at minus 3 or lower.

Lastly, I'd recommend against waiting to drive your car upon starting because they really do not generate much heat and it only takes a few turns of the engine to circulate the oil to everywhere. I tend to get moving a few seconds after I have started the car, partial throttle only and only up to 2400 rpm until the temp gauge has been pointing straight up for a few minutes. Then after that, I change gear between 2400 and 3000 rpm.

Mixed driving on £50 of fuel tends to get me around 450 miles, I think £50 is about one line away from a full tank.
 

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Discussion Starter · #5 ·
its 99800 miles on a 2003 so not mad miles im in scotland aberdeen so minuse 9 is the coldest iv had and it was perfect last winter?

as for my starting procedure its just a thing i do i start the car then go over to my gate open it back to car drive through gate and close it then on my way on shutdown i wait a little bit

as for fuel even if i drive like an undertaker of like iv stole the car i always get about 380-400miles to a £60/tanks usualy clicks off at £58-59 and i manage to get the last pound of two in lol

thanks

mark
 

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Your MPG will be worse in the winter, I find I get nigh on 400 miles to a tank on mine too, it's average I would say.

What code reader are you using, some of them are not as detailed as VAG-COM/VCDS so try and get it hooked up to one of them.

Have you looked at the temperature sender, might be worth checking/replacing that. Also check the EGR sometimes these stick and will not throw up a code, so might be worth while taking it off and giving it a good clean, do the manifold at the same time.

I see you have an aftermarket cone airfilter on, these do very little for diesel's if anything at all, and do cause MAF issues, so it might be worth putting the original airbox and filter back on.
 

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Discussion Starter · #7 ·
im just using an RAC code reader from a mate it tells all the codes for vw's and i had none its very good came up with loads of codes for my mates seat lol and came up with a code for my brake light switch when it went, ye iv herd of the coolant sender fault ill look into the problems it causes

the air filter dose make and audible differance and looks the part but ye ill maby change back to the OEM or maby a new after market filter lol

thanks

mark
 

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Discussion Starter · #9 ·
no never done in the 3 years iv had it anyway.

if that was the problem why would it only do it when the car is cold coz it seems fine when hot?

id like to say im very happy for all the help im getting other forums iv been on are rubbish thanks guys

thanks

mark
 

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TEAM 88 MOTORSPORT
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no never done in the 3 years iv had it anyway.

if that was the problem why would it only do it when the car is cold coz it seems fine when hot?

id like to say im very happy for all the help im getting other forums iv been on are rubbish thanks guys

thanks

mark
Not sure why but when mine was choked up it felt like the engine was holding back when it was cold. It would be worth giving the EGR and inlet a good clean out...hopefully it will sort your problem out and its free to do. You will be surprised how quick the car is too[:O] also check your vacuum pipes for leaks or splits. The pipes go to the turbo, antishudder valve and EGR
 

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Discussion Starter · #11 ·
Ye think im going to take my car in tonight at work and give it a good look over p.s what is an antishudder valve?
So things to check....
1, VNT + its actuator for stuck or stickyness
2, EGR + inlet for chocking
3, Vacum + turbo pipes for cuts/splits
4, antishudder? Pass lolol

Will be a busy night tonight ha ha cant wait to find the problem bringing the car down big time will let you guys know how i get on but any other info will be handy too

Thanks
Mark
 

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Discussion Starter · #13 ·
Ah yes sorry know what u mean ye it works spot on no problems there wide open when running then switch the key off and it closes till the engine stops (about a second) then after an other second it opens again to stationary position so its fine lol if all else is fine figers crossed ill try a vw own AFM and if that dosnt work who knows lol

Thanks

Mark
 

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Discussion Starter · #14 ·
ok well i checked a few things today at work the VNT moves well with my hand and when engine running and reved up, EGR works perfect but was pritty chocked up with crap so took it off and cleaned it up still working as good as it was?????

my only option now is the OEM vw air flow meter just hope to hell its the problem if not its £100 down the drain if they dont do returns

thanks

mark
 

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Discussion Starter · #17 ·
ok so i bought the air flow meter and stuck it on my car still runs the same so its not that and the part is none refundable once fitted so good bye £100 but atleast it rules that out lol im going down to see my buddys at vw that i used to work with see if they cant shed a bit of cover over this slowly withering candel of mine and maby get a bit of light back into it!!!!! lol the one thing my mate from vw said over the phone was it could be the cam shaft? now i did think of this at the very start aswell as the AFM but the AFM seemed the most commen of the two and the car didnt run all that bad to think it was a damaged or worn cam/lobes? any hoo, if the cam wears then when it is cold there will be say for easy sake a 0.8mm gap between the cam lobe and the rocker which dosnt alow the valves to open that bit more to alow more air in or exhaust out hence the feeling of fuel smoaring its getting more fuel than air maby? but as the engine heats up all the metal componants expand and take up that gap a bit down to say for easyness again 0.3mm of a gap alowing more air in to better the air fuel mix giving better running? BUT the problem is with a worn cam is i bet its not cheep!!!

anybody have a clue as to how much a cam is for my 150 and if i will need rockers aswell or any other parts for that matter?

thanks

mark
 

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Hi,

I'm on my second Cam shaft at 100K, Yes a worn cam will give grotty MPG and overfueling but it is normally coupled with limp mode as the car will overboost due to the valves not opening correctly. I stuck my second cam in when I had poor mpg and smokey starts caused by failing injector patterns. The cam had slight signs of wear after about 30k and as I had the injectors out I though I might as well get it done as a Hybrid is in the post for this year!

As stated above I suggest you get the car on a vag-com, and check the injector performance, I know people say "they have never seen a pd injector fail" but from 17 years of driving diesels I've change / refurbed injectors on all but my current passat which has only 55k on it. If you have had 98K on a set your patterns could be failing causing no end of fueling issues.

With regards to the cam kit, you can get them for less than £500 but if you pull off the cam cover it is quite obvious if the lobes are shot!

HTH

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Discussion Starter · #19 ·
Ye thats what im hoping for tonight when i go to see my mate at vw get the vag-com on see whats what hope its not a cam mouchos pennys!!!! Not good if it fixes it im not worried about cost as i love my golf had a mk4 gttdi130 a bmw and range rover ago and both had been flewless till now gutted!!

Thanks

Mark
 

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Diesel Geek
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Good luck, I love my golf too but due to changes in circumstances at home it has become my weekend toy. Hence plans for this year......

With regards to cost, if it is injectors refurbing is not that cheap either as very few people will touch the PD ones. I used united diesels, they are very good and Keith who runs the place knows his stuff.

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