Cliptin Posted August 31, 2004 Share Posted August 31, 2004 85 MPFI EA82 non-T 3AT I did a compression test this weekend and found readings of 130 for all cylinders. I know it's good that they all match but I have not been able to find what the reading should be. Link to comment Share on other sites More sharing options...
exister99 Posted August 31, 2004 Share Posted August 31, 2004 85 MPFI EA82 non-T 3ATI did a compression test this weekend and found readings of 130 for all cylinders. I know it's good that they all match but I have not been able to find what the reading should be. Those sound good, but to be sure you should consult one of the manuals. I have all 3, Haynes, Chilton and Murray Press, with the last being my favorite. I am pretty sure I found my compression numbers in that one. Like I said though, they sound about right. Link to comment Share on other sites More sharing options...
Cliptin Posted August 31, 2004 Author Share Posted August 31, 2004 Could you look it up for me? I only have the Haynes and the info is not in there. Link to comment Share on other sites More sharing options...
thealleyboy Posted August 31, 2004 Share Posted August 31, 2004 Clip: You should think of compression readings as they relate to each other, and to the engine as a whole - not as an absolute measurement. I believe the "correct" range is between 90psi and 175 for the EA82. But a good running motor with hi miles may be 70-80. On the other hand, a motor with excessive carbon buildup can have healthy compression readings, and still be on it's last leg. If your motor is under 200k, and you are getting 130's all the way around, I would be feeling pretty confident about it. You can safely shift your attention to other systems of the car that may need attention. good luck, John Link to comment Share on other sites More sharing options...
exister99 Posted August 31, 2004 Share Posted August 31, 2004 Could you look it up for me? I only have the Haynes and the info is not in there. What I referred to as the Murray Press book actually is the John Muir Publications book. They are the same folks that published the classis "How to Keep your Volkswagen Alive", and now publish the excellent and entertaining "How to Keep your Subaru Alive." Anyway, it says the range for your model is like 132-161. If they are all reading the same though I would agree with alleyboy that the numbers look good. You could be losing a couple of PSI through your testing equipment. Are you using the screw in tester or the push in rubber tipped one? The last time I did a compression test on my 84 GL was due to terribly slow acceleration. After much poking around the cause turned out to be a clogged catalytic converter. What are your symptoms? Link to comment Share on other sites More sharing options...
Cliptin Posted September 1, 2004 Author Share Posted September 1, 2004 Thanks guys. This info is most excellent. This car (for that matter a Subaru) is new to me. Maybe 1.5 months now. It has 190K on the dial 130 in each cylinder so I did a little Irish Spring leprechaunkick when I read the post from thealleyboy. In general, you have to have good compression or you won't get good force from the combustion explosion. Symptoms: (Caveat - my other car is an 01 Jetta VR6 manual so I'm trying to be fair to the Subie but it's hard to know where to place expectations when the car is so new to me.) The Subie does not seem to have the power I would expect in first gear and third. The shift into second will give you whiplash though. There was an eighth inch of metal shavings on the plug when I changed the ATF. It sems to be drinking gas. I got 187 miles out of the last tank of gas. In the morning it wants to die on the first start with a sputtery idle and then runs fine on the second start. After coasting down hill (under engine breaking or a neutral coast) the engine goes all sputtery and I lose 90% of my power for 5-10 seconds and then all is well. FWIW, I just replaced the exhaust (cat back) and seem to have got some power back I didn't have before but the symptoms above still exist. TIA for any leads. Link to comment Share on other sites More sharing options...
DerFahrer Posted September 1, 2004 Share Posted September 1, 2004 130psi isn't what you want to see on a brand-new engine, but one with 190k miles? That's just fine. Really, you're looking more for even numbers across all the cylinders more than you're looking for high numbers. If you had two cylinders down a bit, there's a possibility of a leaking head gasket. If you have one cylinder down, could be a burnt exhaust valve. If all 4 cylinders are down significantly, your rings are probably shot. But 130psi is good. Keep up the maintenance and that engine should last you another 100k Link to comment Share on other sites More sharing options...
exister99 Posted September 1, 2004 Share Posted September 1, 2004 FWIW, I just replaced the exhaust (cat back) and seem to have got some power back I didn't have before but the symptoms above still exist. TIA for any leads. What do you mean by "cat back"? Did you replace the catalytic converter? The honeycomb structure in those things inevitably falls apart and clogs the thing up. Your symptoms sound like mine before I replaced the cat. BTW, the cheapest I found the cats was on the Internet for about $215 with shipping. This was for a "bolt in", which actually required a bit of cutting and filing to fit. Have you checked your timing? The distributor is probably on its way out too. Take the cap off and shake the rotor. I was surprised by how easy it was to rebuild my distributor. Napa carries the bushings. I saw you have the MPFI so you might look into the state of the fuel injection system. My '84 is carbureted so I don't have any personal experience there. Finally do you have hydraulic valve lifters? If not you should probably adjust the valve clearance. It sounds like your engine is mechanically sound, so I would look for a problem with the breathing, spark or fuel. Good luck! Link to comment Share on other sites More sharing options...
thealleyboy Posted September 1, 2004 Share Posted September 1, 2004 Clip: Your motor will not have adjustable valves, so you can scratch that from your to-do list. Your gas mileage is pretty crappy - especially with MPFI. Since you didn't mention tune-up, I would go there next. Unless you have reason to believe otherwise, I would do a "major" maintenance schedule (all the 120K items). This would cover many of the possible causes for your poor mileage (ignition, fuel, PCV etc). As far as power, your Sube will not give you the kind of performance you are used to in your Jetta. That is definitely not a good comparison. You are talking about an 80's era economy/utility car vs a modern pocket rocket. Apples and oranges. However, what you give up in power, you'll get back in other ways. The things that made it a great car in the 80's still make it a great car today. Just keep on driving your Sube and you'll soon understand... good luck, John Link to comment Share on other sites More sharing options...
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