-= Quick write-up for the archives: Checking compression (1.8T) =-

Andy_FL · 01-23-2005, 07:25 PM

How to check compression on my 1.8T? There's plenty of info in various posts in the archives--thought I'd just sum it up into one. Nothing new here, just a concise post for the archives..

You'll obviously need a compression test kit, which can be found at Sears or your local SnapOn truck. The one pictured below was from Harbor Freight (my local Sears had none in stock), and I would not recommend it. So, consider the picture for reference only.

On a warm engine....

1) Pull all coilpacks and plugs

2) Pull 15A fuel pump fuse (#28)

3) Ideally, you'd want to hook up your battery to an external charger so that it doesn't drain--which might affect your readings. It's not crucial IMO (I didn't use one and my readings seem fine). But if your readings seem to drop off a cliff like this: 180, 175, 170, 160....you might blame the battery and not your cylinders. Just depends on the condition of your battery I suppose.

4) Screw in the hose carefully, then connect to the gauge.

5) Start cranking. [For nDBW, hold the gas pedal to the floor while turning over for each cylinder. For DBW, you could pull the intake hose and prop the throttle plate open] I turned the engine over exactly 6 times per cylinder, as the reading had leveled off at that point. (The most important thing here is to treat all cylinders exactly the same. If you don't, then you may get inaccurate readings.) Repeat for all cylinders. That's it!

So what's a normal reading? Well, Bentley claims anywhere from 144-190psi is within spec. The more important, general rule of thumb is that all cylinders should be within 10% of each other.
On my '97, with 122K, the readings were: 168, 165, 175, and 172.

Oh, why don't I recommend the HF compression tester? It was just plain inaccurate. My initial readings with the HF gauge were: 147, 149, 137, 145. I went back with a SnapOn gauge and got consistently higher numbers.

Good luck.

Andy

Search keywords: compression checker gauge tester test compression readings cylinders.

RNO.Audi · 01-23-2005, 07:29 PM

Andy_FL · 01-23-2005, 07:32 PM

SpeedyDTP247 CQ+UrS4 · 01-23-2005, 07:38 PM

EGainer · 01-23-2005, 07:39 PM

EGainer · 01-23-2005, 07:40 PM

im takin care of it

~~ModifiedA4~~ · 01-23-2005, 07:44 PM

umm those screws sitting on the valve cover make me nervous :P

Silver Streakin' · 01-23-2005, 07:56 PM

bestbuy489 · 01-23-2005, 08:01 PM

Firstly write engine (and oil to be really precise) temp down, and write down what readings you get because that will be the only true test on YOUR car. Also Snap-On sells a leak down adapter for little less than price of comp-tester so if you do have loss you can see where it is coming from.

Digit@lex · 01-23-2005, 08:07 PM

01-23-2005, 07:25 PM	#1
Andy_FL AudiWorld Super User Account #: 12690 Join Date: Nov 2000 Posts: 9,790	-= Quick write-up for the archives: Checking compression (1.8T) =- How to check compression on my 1.8T? There's plenty of info in various posts in the archives--thought I'd just sum it up into one. Nothing new here, just a concise post for the archives.. You'll obviously need a compression test kit, which can be found at Sears or your local SnapOn truck. The one pictured below was from Harbor Freight (my local Sears had none in stock), and I would not recommend it. So, consider the picture for reference only. On a warm engine.... 1) Pull all coilpacks and plugs 2) Pull 15A fuel pump fuse (#28) 3) Ideally, you'd want to hook up your battery to an external charger so that it doesn't drain--which might affect your readings. It's not crucial IMO (I didn't use one and my readings seem fine). But if your readings seem to drop off a cliff like this: 180, 175, 170, 160....you might blame the battery and not your cylinders. Just depends on the condition of your battery I suppose. 4) Screw in the hose carefully, then connect to the gauge. 5) Start cranking. [For nDBW, hold the gas pedal to the floor while turning over for each cylinder. For DBW, you could pull the intake hose and prop the throttle plate open] I turned the engine over exactly 6 times per cylinder, as the reading had leveled off at that point. (The most important thing here is to treat all cylinders exactly the same. If you don't, then you may get inaccurate readings.) Repeat for all cylinders. That's it! So what's a normal reading? Well, Bentley claims anywhere from 144-190psi is within spec. The more important, general rule of thumb is that all cylinders should be within 10% of each other. On my '97, with 122K, the readings were: 168, 165, 175, and 172. Oh, why don't I recommend the HF compression tester? It was just plain inaccurate. My initial readings with the HF gauge were: 147, 149, 137, 145. I went back with a SnapOn gauge and got consistently higher numbers. Good luck. Andy Search keywords: compression checker gauge tester test compression readings cylinders. __________________ Last edited by Kris Hansen; 04-29-2009 at 10:42 AM. Reason: added to wiki

01-23-2005, 07:32 PM	#3
Andy_FL AudiWorld Super User Account #: 12690 Join Date: Nov 2000 Posts: 9,790	Good call, done. Did I leave any out? __________________

01-23-2005, 07:38 PM	#4
SpeedyDTP247 CQ+UrS4 Member Account #: 69531 Join Date: Feb 2004 Posts: 4,742	nice write-up...anyone have a nice write-up for the 30v 2.8 with nDBW? __________________ rice belongs in a bowl not on cars!! My CQ project thread and My S4 project thread Gone but not forgotten Supercharged and Intercooled A4 MI's Audi Enthusiast Forum Who I cheer for in sports (in no particular order) with some stats. Tiger Woods 14 Major Championship as a professional, 65 PGA Tour wins, 7 consecutive PGA Tour wins and 9 PGA Tour wins in one year. 1st ever winner of the FedEx Cup. People have to stop putting Phil Mickelson's name in the same sentance with Tiger Woods. Rory Sabbatini needs to keep his BIG MOUTH SHUT!! Red Wings 11 Stanley Cup championships and 17 consecutive playoff appearences. 8 consecutive 100+ point season. Pistions 3 NBA championships and 6 consecutive Eastern Conference Finals. Tigers 4 World Series titles and 10 AL pennants. U of M Football 11 National Championships, 42 Big Ten championships, 33 consecutive Bowl Game, 170 consecutive crowds of 100,000+, spectators in record attendance of 112,118. U of M Hockey 9 NCAA, 5 Big Ten, 8 CCHA tournament championships. U of M Basketball 3 National Invitional Tournament, 11 Big Ten, and 1 Big Ten tournament championships. Packers 9 NFL, 3 Super Bowl, 8 conference, and 13 division championships. Soon to be Hall of Famer Brett Favre, Thank you for the Great Memories Brett!!! Also cheer on Ruvell Martin (my high school alumni classmate) #82.

01-23-2005, 07:39 PM	#5
EGainer AudiWorld Super User Account #: 59163 Join Date: Jul 2003 Location: NC Posts: 19,566	nice nice nice, bookmarking __________________

01-23-2005, 07:40 PM	#6
EGainer AudiWorld Super User Account #: 59163 Join Date: Jul 2003 Location: NC Posts: 19,566	hmm ya know what, someone turn this into a tech article... im takin care of it __________________

01-23-2005, 07:29 PM	#2
RNO.Audi Senior Member Account #: 42725 Join Date: Sep 2002 Posts: 6,219	Nice write-up, add some search keywords to the bottom so it'll be easy to search for. __________________ AIM: SantorinTim I heart Audis... K04 Santorin Blue APR Stg. 3 Brilliant Black But sedans were too impractical for me... Now driving a 4runner, Sport (I want an Avant!)

01-23-2005, 07:44 PM	#7
~~ModifiedA4~~ Banned Account #: 143 Join Date: Mar 2000 Posts: 34,564	nice. umm those screws sitting on the valve cover make me nervous :P

01-23-2005, 07:56 PM	#8
Silver Streakin' Member Account #: 10901 Join Date: Oct 2000 Location: PA Posts: 42,089	and what would you do differently for a DBW? __________________ -Jeff 2001.5 A4 1.8TQMSCC with APR SIII, EVO FMIC, Stoptech-less, STaSIS Tracksports 600F/750R ACNA MidOhio video Montreal race school and PDA Pocono video

01-23-2005, 08:01 PM	#9
bestbuy489 New Member Account #: 86583 Join Date: Jan 2005 Posts: 9	Don't forget... Firstly write engine (and oil to be really precise) temp down, and write down what readings you get because that will be the only true test on YOUR car. Also Snap-On sells a leak down adapter for little less than price of comp-tester so if you do have loss you can see where it is coming from.

01-23-2005, 08:07 PM	#10
Digit@lex Elder Member Account #: 1308 Join Date: Mar 2000 Posts: 26,685	Great write-up Andy! __________________

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