Why would this stop the oil needle from bouncing?
09-20-2009, 06:06 PM
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Why would this stop the oil needle from bouncing?
So once engine warms up the needle settles from 5 down to 2. Then if the water temp gets to the middle of the gauge and I come to a stop the oil pressure needle will start the bounce I've read about. Swings from 1.5 to 2.5 very rapidly.
I happened to turn on the AC while looking at the gauge ad as soon as I pressed it the needle stopped and settled back on 2. Shut off the AC and it starts bouncing again.
A few days later I notice (with the car *out* of gear) that if I press in the clutch it stops the shake and settles back to 2. Take my foot off the clutch (still not in gear) and the shake comes back.
Feeding any power at all to the engine stops the bounce also, but the two things above have me wondering.
The AC raises the rpm a hair (maybe 100 rpm) so I figured it's like tapping the gas. But stepping down on the clutch? Is it just the reduction in drag from the weight of the clutch and driveline?
Wouldn't just turning up the idle 100 rpm, like the AC seems to do when it's switched on, stop the oil pressure bounce problem? Anyone ever done this?
Have to check if maybe my idle is too low? It is tune up time so I have t clean the air filter and change the plugs, cap, and rotor.
--------------------------
Alex
1989 944 2.7 NA
I happened to turn on the AC while looking at the gauge ad as soon as I pressed it the needle stopped and settled back on 2. Shut off the AC and it starts bouncing again.
A few days later I notice (with the car *out* of gear) that if I press in the clutch it stops the shake and settles back to 2. Take my foot off the clutch (still not in gear) and the shake comes back.
Feeding any power at all to the engine stops the bounce also, but the two things above have me wondering.
The AC raises the rpm a hair (maybe 100 rpm) so I figured it's like tapping the gas. But stepping down on the clutch? Is it just the reduction in drag from the weight of the clutch and driveline?
Wouldn't just turning up the idle 100 rpm, like the AC seems to do when it's switched on, stop the oil pressure bounce problem? Anyone ever done this?
Have to check if maybe my idle is too low? It is tune up time so I have t clean the air filter and change the plugs, cap, and rotor.
--------------------------
Alex
1989 944 2.7 NA
09-20-2009, 06:31 PM
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A small idle speed change wouldn't affect oil pressure like that.
I think you have a grounding or connection issue that is put into play with normal driveline vibration (when the clutch pedal is out) . Tap the dash or the gauges and you'll see the needles flicker, same thing.
Would recommend cleaning the instrumentation connections, grounds, and oil pressure sender connections (don't get those backwards or it'll read 5 bar all the time).
I think you have a grounding or connection issue that is put into play with normal driveline vibration (when the clutch pedal is out) . Tap the dash or the gauges and you'll see the needles flicker, same thing.
Would recommend cleaning the instrumentation connections, grounds, and oil pressure sender connections (don't get those backwards or it'll read 5 bar all the time).
09-20-2009, 09:17 PM
#4
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The idle is controlled by the ICV/ISV. If the AC is ON, the idle is corrected automaticly. If your idle drops you may want to check and clean the ICV. You may also have cracked hoses near the ICV at the bends.
If your oil pressure sender connections are clean and you have checked the grounds and back of dash connections, follow the wires from the oil pressure sender up to the top of the engine. You may have cracked wires shorting out.
GL
John_AZ
If your oil pressure sender connections are clean and you have checked the grounds and back of dash connections, follow the wires from the oil pressure sender up to the top of the engine. You may have cracked wires shorting out.
GL
John_AZ
