Dumb question regarding compression test on Audi a4 1.8t

"G" a écrit dans le message de news: snipped-for-privacy@news.teranews.com...

...

A compression test is easy to do, provided you have the tool to do it (a pressure gauge with writer, to be inserted in the place of the spark plug). A compression problem could lead to those symptoms, but I would be very disappointed if an engine with such a low mileage could experience this problem.

GT - thanx for the response. i too would really hate to find out that this is the problem. the thing is the warranty for the car is over in 3 months so i need to get this damn thing fixed. im down to either a blown turbo that the warranty ppl dont wanna admit or as a friend of mine was stating, a problem with o-rings. im not willing to get a new MAF right now since from what ive read, it never really makes a big difference.

I also wanted to know if anyone actually owns a 1.8T and did the compression test, because the dealer i bought the car from told me that if the compression test is done wrong itll mess up things - which i dont really understand - but then again - i wouldnt put it past Audi.

Sure. Often that's accompanied by blue smoke (ie rings or bore damage), but if you've siamesed the head gasket or fried the exhaust valves you might not see any exhaust plume but you'd be losing power.

Go to a pro who has a leak-down test rig, rather than try to diagnose a potential problem with a simple screw-in compression gauge. The former can tell you a lot more about what might be wrong.

If the lump is healthy, you should have someone go through the ECU looking for potential problems. A VAG tool or VAG-COM, etc, can tell you a lot about the health of all the plumbing bits (eg: MAF sensor adaptation at +21% when it should be within +/-4% of nominal).

And don't dismiss an imploded cat without at least a cursory inspection...

/daytripper '00 s4 6spd

in reference to my initial post - thanx for the great advice guys.

i was thinking of getting a second opinion on my turbo in my car. i am located in toronto, canada. does anyone know of a good mechanic who specialises in turbos? the one i go to is very nice but i feel the newer cars he might not be the best at. also i need a second opinion since my warranty company is trying to get out of writing a check for 1500$ to replace my current turbo k03.

thanx again - oh its a b5 a4 1.8t

Hey Mr. DJ..... Post your question to the w-t_audifans group on Yahoo - that's the West Toronto Audifans group, there's quite a few folks there with their own fave mechanics they can direct you to. Compression tests are not hard to do, but make sure you start with a fully charged battery and a warm car and ground the removed plug to avoid ignition damage. The test will tell you if there's a pressure leak in the cylinder - whether through the valves, around the rings or a blown head gasket. A leakdown test is a good thing to do in conjunction with the comp. test - it helps to narrow down the problem (if there is one). HOWEVER - the compression test will not tell you how much the turbo is compressing the air into the engine - the turbo does very little, if anything (maybe even somewhat of a hinderance), as the engine is being turned over. Have you had the codes pulled from the ECU? what do they say is wrong? Do you have a K&N filter in there? If so, chances are your MAF sensor is burned. Was the car equipped with the oft-malfunctioning coil packs? - That might be covered by a recall. Why do you think the turbo is blown? Is it noisy? Does it have lots of play in the bearings? Is there metal filings in the cat from the turbine vanes grinding against the housing? Is the turbo siezed, or the shaft busted? Cheers! Steve Sears