Golf GT TDI 150bhp - bad performance after head gasket replacement

SilveR316

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Jun 28, 2006
Location
Toronto, Ontario
TDI
2000 VW Golf 1.9L TDI
barry_james1 said:
First thing I said to them... They reckon would bend valves if it was?????
I don't think it would happen if it was off only 1 tooth from what I hear. Not sure on that though. It would be hard to start and run pretty rough though.


Did they forget to plug in the MAF? :p

Bust out a vagcom and check actual vs requested MAF or just unplug it and see if there is any performance difference. If there is no difference, its probably a failed MAF. They tend to fail for no good reason....
 
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SilveR316

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Joined
Jun 28, 2006
Location
Toronto, Ontario
TDI
2000 VW Golf 1.9L TDI
barry_james1 said:
They disconnected to MAF and ran like a dog, so guess that eliminates that?
Not sure what ran like a dog means? Dogs can run pretty fast. :p

I take it that performance was worse with MAF disconnected?
 

SilveR316

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Jun 28, 2006
Location
Toronto, Ontario
TDI
2000 VW Golf 1.9L TDI
barry_james1 said:
Yes indeed, i'll cut the 'slang' in future!
Do you have a boost gauge installed? It would be easy to check if your turbo is functioning properly then. A vacuum line leak can contribute to slower turbo spool up and in return less "punch".

I really don't see how a loss of performance can have anything to do with replacing the head gasket, other than it having affected other components that were tinkered with during the swap. Maybe someone else can chime in the subject.
 

pyankura

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Jun 29, 2007
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Pittsburgh
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2005 golf a4 body style
When I had my muffler cut off and a straight piece welded in there. We disconnected the battery for about three hours because we welded it while it was connected to the car and we did not want to fry anything. So after we were done I connected the battery and drove home. I noticed that my car seemed like a slug. I thought is it possible that I lost my mapping? I called the tuner and he said that my ecu reset and it has to go through alot of rediness stuff and it would be OK. So after about 50 miles it was perfectly fine. So this could be your issue if you have not driven it very far.
 

mojogoes

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May 1, 2003
Location
england
TDI
mk3 tdi golf
barry_james1 said:
No boost gauge installed, its stock apart from remap.
Welcome.....
Then it ain't standard any more Barry is it!! lol............yes i would try looking for any slits/holes in the small vacuum line plus check your IAT/MAP sensor which is located in the inter cooler pipe work after the inter cooler as they do go down on occasion...............and if you know someone with vag-com have them check out your timing it could be of a tad.
 

im570rm

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Romania
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Audi a6 avant 2.5 tdi quattro
it would be easier to make some vag com logs and post them here.Maybe the turbocharger is broken or somethin',55hp is pretty hardcore,i didn't know you can get that much with only a remap.Or maybe a fault vacuum hose .
 

DervDub

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Nov 14, 2008
Location
Cambridge, UK
TDI
03 Golf Match ATD
Why was the head gasket replaced?

If you have ruled out the obvious with a vag com scan, checked all vacuum hoses are good and everything else looks good then I would turn your attention to the particulate filter in the downpipe, I've known catalytic converters to go into meltdown and block up due to oil & coolant being forced through them under pressure causing the structure of the CAT to break down and block the exhaust flow severely.

The ways to check for this are to listen to the exhaust exit and get someone to rev the car up, does it sound right?? Another is to take the car for a 70/80 mph blast, pull over and open the bonnet, if you get hit a heat wave then you've found the culprit.

I had this on a Vauxhall Vectra a couple of years ag, had me stumped for 3 days, it was only when the problem got really bad - IE 45mph flat out that I noticed the exhaust note was very quiet and the under bonnet temps very high (normal guage reading).

I dropped the downpipe off and went for a drive, a very loud drive at that but it confirmed that the cat had melted down.
 

tdi rs

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mk2 16v tdi
How did they measure compression ratio? theres nothing i know of that will increase the compression enough to cause poor performance by changing the head gasket.Id bet on injectors. either not set properly or if its done over 100k miles then injectors u/s.
 

DervDub

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Nov 14, 2008
Location
Cambridge, UK
TDI
03 Golf Match ATD
I think people may be confusing compression ratio with actual compression...

The only way I can think that would increase compression too high would be by using a head gasket that is too thin, the heads themselves are flat surfaced with no combustion chambers, so skimming the head won't increase compression.

I can't see why injectors failing would make it that far down on power, or increase the compression either. They might be incorrectly set up though, but how far down on power this would make it is anyones guess.

To setup injectors on a PD I'm pretty sure they have to be measured from the end of the head and sit squarely.

As the car is at a VW dealership I'm pretty sure they know what they're doing, you never know you might get lucky and have a new short motor fitted
 

mojogoes

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Location
england
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mk3 tdi golf
DervDub said:
I think people may be confusing compression ratio with actual compression...

The only way I can think that would increase compression too high would be by using a head gasket that is too thin, the heads themselves are flat surfaced with no combustion chambers, so skimming the head won't increase compression.

I can't see why injectors failing would make it that far down on power, or increase the compression either. They might be incorrectly set up though, but how far down on power this would make it is anyones guess.

To setup injectors on a PD I'm pretty sure they have to be measured from the end of the head and sit squarely.

As the car is at a VW dealership I'm pretty sure they know what they're doing, you never know you might get lucky and have a new short motor fitted

Derv you can get higher compression readings from incorrect injection from injectors plus yes what you discribe of the fitment of the injectors on a PD is correct but what about setting them up for correct injection timing and in relation with the cam etc..............and as for the stealership knowing what there doing well i'm sure a couple of foke on this forum would tell you something quite different:rolleyes: .
 

DervDub

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Nov 14, 2008
Location
Cambridge, UK
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03 Golf Match ATD
Generally compression checks are done static, not with the engine running, the OP didn't specify so I assumed a static comp. test. My bad

I forgot about the cam clearance on the pump side of the injectors, thats a case of closing the clearance up and then backing them off 225 degree's (Think it's 225, maybe wrong) I'm sure even the worst dealer will know this lol. The injectors in a PD are fired electronically by the ECU, the cam clearance is to set up the pressure at which they inject, similar to rail pressure on a common rail setup.

I generally hate dealerships, having worked for a couple as a technician back in the 80's/90's I know the stunts they can get up to. However, my VW dealership of choice know their stuff, not that I use them directly, just for parts at staff discount :)
 

mojogoes

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mk3 tdi golf
Yeah lol some are better than others......i had a bmw dealership wanting to charge me a £1000 after they suposidly diognosticly checked the tollerances on my injectors on the X5 after i took it to them with an idle shuddering......they swore blind it was just the one injector that was bad so i ask what if i'm back here again because its more than one injector but they were adement.......i then took the injectors out after doing the 6 bottles on the return lines test which didn't show anything up (all the bottles filled the same amounts of fuel!) and sent them to be checked out and setup.

And low and behold there were the 2 bad injectors and dribble on another 2 which cost me around a £180 to sort.........BMW = £108 per hour labour = to $175.
 
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sam_51

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May 26, 2008
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henley/ OXON
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115pd swap FOR 150pd
As Most The People On Hear Seem To Be From The Uk I Will Steel This Thread Quik. Were Is The Best Tdi Pd Garage In Britain Preferably Near Reading/oxford. IVE GOT COUNTLESS PROBLEMS AFTER I SWAPED MY 115PD TO A 150PD
 
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NosmoKing

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ky usa
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2009 Jetta
I like the sound of your British thinking. My compliments.
 
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NosmoKing

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DervDub said:
As the car is at a VW dealership I'm pretty sure they know what they're doing, you never know you might get lucky and have a new short motor fitted
You might think that, however, here in the States Diesel Auto competence is at a premium at the dealers' according to the common wisdom.
 
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