# Compression test for 2.0t FSI - few questions



## skateboy918 (Apr 26, 2008)

I am planning on doing a compression check this weekend on my 07 GLI.

My only question is which fuse should I pull? The one for the fuel injectors? or fuel pump?

Also if you could direct me to the location (under hood or side of dash) I can figure it out from there.

I will be using the Craftsman compression test kit if that matters at all.

But if someone has done this before, maybe you can just give me a quick list of what to do just so I dont end up doing anything stupid, just in case :laugh:


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## GolfRS (Feb 4, 2006)

I used the same kit.It's not that dificult especially if you already have an intake and don't have the OEM filter on.

You have to undo the coil connection and remove the coilpacks.
Then you should remove the spark plugs.
Then you should pull the injector harness clip right below the throttle body.
Then you should screw your tester in each cylinder sequentially, and crank the engine (some say 5 some say 10 times)
You should also unplug your manifold PCV connection to simulate an open throttle.
That's about it.

As for "normal" values, you should look for consistency across the cylinders (not lower than 10%).
Mine did 200 psi on almost all four.

Have fun... :laugh:


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## jhines_06gli (Feb 3, 2006)

Don't wanna hack the thread, but I'm just curios on this. About to do my test again(every 20K) with some other routine documenting I do.

But people who view this and have done a compression check on their FSI, post the findings......
-Year:
-Mileage:
-Compression readings 1-4
-Extent of mods
See what these engines are holding up to.......I'll do my test later today along with hopefully getting the car running good.
-J. Hines


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## GolfRS (Feb 4, 2006)

jhines_06gli said:


> Don't wanna hack the thread, but I'm just curios on this. About to do my test again(every 20K) with some other routine documenting I do.
> 
> But people who view this and have done a compression check on their FSI, post the findings......
> -Year:
> ...


ΜΥ2006 
200-196-200-200 PSI
Full stage 3 TFSI (K04)


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## jhines_06gli (Feb 3, 2006)

2006 GLI
120K miles
190-200-190-190

STG II+ with about every bolt-on out there

Also looked in cylinders with a bore-scope...looks awesome still. No carbon on pistons and all cross-hatching still there and good
-J. Hines


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## Krieger (May 5, 2009)

no carbon on your pistons???

****, when i changed out my plugs, i looked down there and it looked like someone spilled some ****ing asphalt all over my pistons, mixed with some chocolate cake.

interesting.


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## skateboy918 (Apr 26, 2008)

> Then you should pull the injector harness clip right below the throttle body.


Any chance anyone has a picture of this clip? I cant seem to find it

It might be b/c i'm missing it alltogether or b/c I have the S3 K04 kit and it is covered up?


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## jhines_06gli (Feb 3, 2006)

it's held in a plastic clip that is pushed onto the coolant transfer pipe under intake manifold. Look straight down from where the large vacuum port is on the intake manifold, where the PCV->intake hose goes, right down there. Small D-shaped connector that has 10 or so .5mm wires in it. I'll try to snap a picture tomorrow for you.

And to the clean piston thing.....not sure why. I installed the EuroJet PCV fix when it was first released, then went to the BSH STG. I catchcan, then went "race" VTA when it was released. I have been using SeaFoam every 10K miles through the IAT sensor since 50K and ALWAYS run 93oct. from the same station(Pilot). But not exactly sure why it's so clean, but I'm happy. My goal was to make it to 150-175K miles and then go in and do new rings, rods and pistons to prep for BT build, but may not have to just that soon at this rate
-J. Hines


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## theblue (Aug 16, 2001)

good thread.. I'll be using this info when I test.


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## T0neyDanza (Apr 25, 2007)

Krieger said:


> no carbon on your pistons???
> 
> ****, when i changed out my plugs, i looked down there and it looked like someone spilled some ****ing asphalt all over my pistons, mixed with some chocolate cake.
> 
> interesting.


 He said that he has pretty much every bolt on which should include water meth which would eliminate a lot of carbon build up. Also the use of a PCV reroute or catch can would help a lot


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## skateboy918 (Apr 26, 2008)

2 more questions:

do I disconnect all 4 spark plugs all at the same time or only the spark plug in the cylinder I am doing then put it back then remove the next spark plug and test that cylinder?

and is this the connector for the injectors?:








[/QUOTE]


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## GolfRS (Feb 4, 2006)

You remove all the plugs for the test and test each cylinder individually with the other
plugs off....

You also have to unplug the PCV/manifold connection to simulate a wide open throttle.

And yes THAT is the connector....


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## ROH ECHT (Dec 9, 2010)

PCV to which mani? Exhaust?...since none go to the intake manifold. Or intake?...since none go to the exhaust manifold.


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## R32ManiaK (Aug 21, 2003)

I did a compression test last week
2008 fsi GTI
134k miles

157 154 150 155

not quite the 200psi you guys are getting 
does this mean its soon time for a rebuild?


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## bzflag (Apr 27, 2003)

R32ManiaK said:


> I did a compression test last week
> 2008 fsi GTI
> 134k miles
> 
> ...


You're numbers are fairly consistent, so I'd be inclined to say it's an issue with your testing methods or gauge.

What was your reasoning behind performing a compression test?


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## R32ManiaK (Aug 21, 2003)

bzflag said:


> You're numbers are fairly consistent, so I'd be inclined to say it's an issue with your testing methods or gauge.
> 
> What was your reasoning behind performing a compression test?


I suspect my turbo is blown but was advised to do a compression test.
car smokes heavily through catch can, burning oil at an alarming rate and is not holding boost.
It spikes to 18/19lbs then falls off quickly to 8/9lbs... when it was healthy the car use to spike to 23lbs then hold 19lbs.


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## ROH ECHT (Dec 9, 2010)

Mine tested 1 to 4 @ 191, 195, 192, 192


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## R32ManiaK (Aug 21, 2003)

ROH ECHT said:


> Mine tested 1 to 4 @ 191, 195, 192, 192


this doesnt make me feel confident about my results


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## ROH ECHT (Dec 9, 2010)

I believe 102psi is minimum limit...and 145psi is the low parameter for "Good". So you likely need to address it between 102 and 145psi.


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## bzflag (Apr 27, 2003)

R32ManiaK said:


> I suspect my turbo is blown but was advised to do a compression test.
> car smokes heavily through catch can, burning oil at an alarming rate and is not holding boost.
> It spikes to 18/19lbs then falls off quickly to 8/9lbs... when it was healthy the car use to spike to 23lbs then hold 19lbs.


Have you done a pressure test? How is your catch can setup? Did you eliminate the PCV?

Are you able to do a leak down test? That would tell you whether your rings are the culprit or not.


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## R32ManiaK (Aug 21, 2003)

bzflag said:


> Have you done a pressure test? How is your catch can setup? Did you eliminate the PCV?
> 
> Are you able to do a leak down test? That would tell you whether your rings are the culprit or not.


Yes my compression test resullts 4-1 are 157 154 150 155

vta catch can smokes like no tomorrow


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## bzflag (Apr 27, 2003)

R32ManiaK said:


> Yes my compression test resullts 4-1 are 157 154 150 155
> 
> vta catch can smokes like no tomorrow


No, not a compression test. Have you pressure tested your intake to check for any leaks and checked if your PCV(if still installed) is doing it's job?

Your valve cover could have also failed internally along the pcv or egr passages.


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## R32ManiaK (Aug 21, 2003)

no i have not done a pressure test, an pcv replaced with catch can


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## ZuluB602 (Aug 31, 2010)

Where is the the PCV/manifold connection located to simulate a wide open throttle.?:screwy: 

I've like to test too.


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## winger1050 (Mar 15, 2015)

mine are between 150-152 across the board (i thought that was good am i wrong?)


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## ROH ECHT (Dec 9, 2010)

145psi is the floor for the good range...so it is your call 
http://forums.vwvortex.com/showthre...-questions&p=86613121&viewfull=1#post86613121


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## ZuluB602 (Aug 31, 2010)

Is it the green arrow or red arrow that has to be disconnected?


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## ZuluB602 (Aug 31, 2010)

So I did not disconnect anything, just pulled the fuse 27 out (fuel pump),


06 GLI FSI
145K miles
stock (just BSH air intake)

172,161,160,172

I think it went pretty good for a car with almost 150K miles.


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## Cizx123 (Sep 14, 2015)

So I’ve having a huge smoking issue and oil burning issue in my 07 GTI plus metal flakes in the oil hoping it’s just the turbo going to do a compression test ha anyone going there solution to this issue?


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## ROH ECHT (Dec 9, 2010)

Depends on how far you are willing to go with a rebuild. Because yes, it could be just the turbo. Mine had good compression but was losing 1L per 600 miles. I decided to remove the head for rebuilding, with new valve guides and seals, and the combustion chambers of cylinders 3 and 4 were soaked in oil. So the pistons were all removed for new rings and one ring was stuck in the #4 piston. So that piston needed replacing. Went ahead and replaced the rod bearings as well. That rebuild was just 35k miles ago and now mine is smoking a tiny bit when stopped and when it starts to roll from a stop. I hope this time it is just the turbo that has 96k miles on it. 

I suggest removing the spark plugs and do the compression test. If any are of the plugs are oily, then you have internal wear. If the compression is good and the plugs appear clean, it may just be the turbo. But if you replace the turbo first, be prepared to go further. This is all assuming the crankcase ventilation is functioning properly. Because if ventilation is obstructed, it may be pushing oil past seals and rings rather than venting.


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## Butcher (Jan 31, 2001)

You could have good compression but bad oil rings. Not much you can do to test them but remove the pistons. If the rings are seized to the piston, that will cause the rign not to do their job. Even when the rings on sitting on the bench, unless they are broken, you usually cannot see with your eyes what is wrong with them. 

Oil consumption can be a real chore to locate the cause.


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