the symptoms of low compression?

[redcoupe86]

All my spark plugs look good and the same. No one sticks out over anther. They all have good color. So all cylinder are burning good

Yet my engine has this rocking back and forth like its not balanced. Its at idle and you can feel the vibration through the car.

My question is could you have a cylincer or two with low enough compression as to get combustion and good spark plug coloration but cause the engine to vibrate as I described above?

[ken_xman]

change your plugs, wires, cap and rotor.
.... inspect the motor mounts too.
How many miles?
Oil burn rate?

[BK911]

I had an engine with low compression in two cylinders. It ran rough at low RPM's and much better at high RPM's. Get a compression check that way you know for sure. A compression check will tell you if it's low, a leakdown test will tell you why it's low. Do a search, lots of info here. 3.2's are infamous for exhaust valve guide wear.

Good luck!
BK

[redcoupe86]

yeah, a compressin check is on the way after I put the vacuum gauge on it. However, I've never done compressin checks on a fuel injected engine. I imagine you pull the coil wire, take out all the plugs and open the throttle, but what do you do about the fuel - Im not sure I want the car dumping unburnt fuel into the system without it combusting.

BTW, I just replaced plugs and wires.

[Rot 911]

Originally posted by redcoupe86
yeah, a compressin check is on the way after I put the vacuum gauge on it. However, I've never done compressin checks on a fuel injected engine. I imagine you pull the coil wire, take out all the plugs and open the throttle, but what do you do about the fuel - Im not sure I want the car dumping unburnt fuel into the system without it combusting.

On your car you would just disconnect the DME relay located under the driver's seat. That takes care of spark and fuel.

[ken_xman]

Originally posted by redcoupe86


BTW, I just replaced plugs and wires.

Did you change cap/ rotor?
Did it have the symptom before?

[redcoupe86]

no, I did not change the cap and rotor. But I looked at the underside of the cap and everything looked "ok".

[Gunter]

Check the firing order and make sure the wires are going to the right cylinder and are connected to the plug.

[redcoupe86]

Originally posted by Gunter
Check the firing order and make sure the wires are going to the right cylinder and are connected to the plug.

I double checked all the connections. All were OK.