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post #1 of (permalink) Old 02-22-2003, 07:45 AM
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Engine compression, bad rings, etc.

How do I suspect if my engine is having a bad compression, leaking rings, head gasket, etc?
I can't say I'm noticing any lack of power - the engine works the same way it did 6 months (3k miles) ago. It does not consume much oil - in 5 months (some 2.5k miles) oil came down to a bit over a half. Sparks are in a very good shape - not greasy, not black, not burned, just normal wear. I just noticed today, after driving in the city for some 30 minutes, that my oil pressure gauge showed something a bit under 3. It is usualy at the upper end, like around 4 - 4.5, but I can't really say I ever checked it when idling - just riding. As I pt it in idle today, on a warm engine, it went down to under 3. If I pushed the gas pedal, it went back up. Letting go the gas and it went back down. In the morning, when it's cold, I crank the engine up and it goes from 0 to some 4. Then I begin riding and (again) I can't say I checked it, so that's why I got worried when I saw it going low today, idling.

Are those readings normal? Does the oil pressure always go that way? Or is something wrong with compression?

Also, when I'm in the city, and all that stop-and-go stuff when it's crowdy, it sometime happens that, if I start moving (1st gear) but don't put it in 2nd cos the cue stops, but rather step on the clutch and let go of the gas and brake, it goes wery low on RPM, almost dies. It comes back to normal almost that moment, but for a second it seems to be stalling. Then another couple of times that effect doesn't show up. And other times it comes up again. Also happens (not always) if I give it a bit of gas when idling. Then the rpm goes up some, and when I release the gas pedal, it (sometimes) goes stalling. But it gets itself out & adds a couple of rpms (all by itself) and continues to work normally.

Is that normal?

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post #2 of (permalink) Old 02-22-2003, 08:05 AM
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Re: Engine compression, bad rings, etc.

1. Pefrom a compression check by:
a. Pulling all plugs.
b. Rotate the engine about 3 revolutions, dry.
c. Note compression.
d. Repeat b - c with a little oil squirted in the cylinder.
2. All readigs should be wihin 15% of each other, lower than 120psi, I'd be worried..
3. All readings should be within about 20% of New Compression, about 150psi.
4. High oil pressure at cold, and higher RPM's - normal.
5. The RPM drop between gear shifts is a concern.
6. The Fuel Injection should be keeping a good monitor on the RPM's.
7. I'd be looking a the air injection motor and the MAP sensor.
8. How many miles(KM) on the Cat Converter?
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post #3 of (permalink) Old 02-22-2003, 09:35 AM
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Re: Engine compression, bad rings, etc.

d. Repeat b - c with a little oil squirted in the cylinder.

little oil - spoon full will be enough
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post #4 of (permalink) Old 02-22-2003, 05:51 PM
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Re: Engine compression, bad rings, etc.

</font><blockquote><font class="small">In reply to:</font><hr />
The RPM drop between gear shifts is a concern.

[/ QUOTE ]
I wouldn't say it like that. But then again, I could (and probably am) wrong. It's like you are standing on a light, idling. Shift into 1st, and go. But before you get to go let the clutch completely go (still in 1st gear), you have to slow down and stop. So you press the clutch back down all the way, letting go of the gas pedal and you brake. Obviously, the rpm go down. But sometimes they go a bit too much low, so the engine seems to stall, but it gets back normal. All by itself, no my interferance with gas pedal or anything. Not that at every shift of gears my rpm run low - no, it behaves perfectly normal. Just at those points, when I start but have to stop right back. Plus, it happens only sometimes. Was that what you ment?

</font><blockquote><font class="small">In reply to:</font><hr />
I'd be looking a the air injection motor and the MAP sensor.

[/ QUOTE ]
How do I check them?

</font><blockquote><font class="small">In reply to:</font><hr />
How many miles(KM) on the Cat Converter?

[/ QUOTE ]
Still the original one: 60-62k miles on the odometer. Now that you mention it, I did have some bad emission test [img]images/graemlins/bs.gif[/img] last month, but I don't think the engine was at the operating temp. So darn cold [img]images/graemlins/cussing.gif[/img] I couldn't warm it up enough.

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