vibration?
09-06-01, 04:37 PM
#1
vibration?
my car's been running a little bit rough lately.
it idles rough and starts vibrating pretty badly above 4500rpm.
had the compression tested and it came out good. anyone have any ideas as to what would cause a rough idle/vibration at speed?
also, when decelerating, it seems like the timing may be off a bit...it seems to kind of miss on it's way down from 3000 to idle.
the idle is pretty annoying 'cause it shakes at the perfect frequency to get everything under my hood and in my car to rattle around.
i have an '83 GSL, with a rebuilt engine (50k miles on it currently). i take care of it, it always has enough oil, i take it up to redline occasionally to cough out some of that carbon crap, and i let it heat up to normal temp before i turn it off everytime i turn it on.
it appears my shutter valve is bad - would this cause vibration liek this?
it idles rough and starts vibrating pretty badly above 4500rpm.
had the compression tested and it came out good. anyone have any ideas as to what would cause a rough idle/vibration at speed?
also, when decelerating, it seems like the timing may be off a bit...it seems to kind of miss on it's way down from 3000 to idle.
the idle is pretty annoying 'cause it shakes at the perfect frequency to get everything under my hood and in my car to rattle around.
i have an '83 GSL, with a rebuilt engine (50k miles on it currently). i take care of it, it always has enough oil, i take it up to redline occasionally to cough out some of that carbon crap, and i let it heat up to normal temp before i turn it off everytime i turn it on.
it appears my shutter valve is bad - would this cause vibration liek this?
09-06-01, 10:52 PM
#2
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When my shutter valve was bad, the idle was bouncing from 600 RPM to 900 RPM and it would surge pretty bad while decelerating.
Do you have these problems?
Do you have these problems?
09-06-01, 10:57 PM
#3
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I forgot about your vibration prob....
Does it happen in every gear at a certain RPM, or is it at a certain speed? If it's at a certain speed, check your tires, they may be out of balance. If it's at a certain RPM, then it might be something internal(motor) or in your clutch.
Does it happen in every gear at a certain RPM, or is it at a certain speed? If it's at a certain speed, check your tires, they may be out of balance. If it's at a certain RPM, then it might be something internal(motor) or in your clutch.
09-07-01, 02:52 AM
#4
it does surge on deceleration. i think i'll replace the shutter valve.
but the vibration does come from certain rpms. bleh. maybe my timing's a bit off. anyone know how much shops usually charge to check the timing?
i've heard of cars running pretty rough if the distributer was one tooth off...i'll check that out too.
but the vibration does come from certain rpms. bleh. maybe my timing's a bit off. anyone know how much shops usually charge to check the timing?
i've heard of cars running pretty rough if the distributer was one tooth off...i'll check that out too.
09-07-01, 10:39 AM
#5
EliteHardcoreCannuckSquad
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If your distributor was off by one tooth or so, your engine could still be somewhat smooth. The most noticable symptom would be a kind of squeaky alternating rattle coming from the engine at higher rpm (misfiring, detonation). I'd be checking your plugs and wires first (remember Silverrocket?).
As far as the chutter valve is concerned, just unplug the small vacuum line (on the right) and cap both the line and the valve. While your car is idling, open the valve (by pulling the diaphragm rod out). I think its "out" open, in "closed" (when its closed the car will choke and stall). Just leave it open as far as it will go and forget about it.
As far as the chutter valve is concerned, just unplug the small vacuum line (on the right) and cap both the line and the valve. While your car is idling, open the valve (by pulling the diaphragm rod out). I think its "out" open, in "closed" (when its closed the car will choke and stall). Just leave it open as far as it will go and forget about it.
Last edited by RXcetera; 09-07-01 at 10:42 AM.
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09-07-01, 01:46 PM
#9
Just switch your pager to beep mode.
How are your plug wires? I was getting a bad vibration due to leaky plug wires. They were attracting dust in places like static electricity. I swapped them out with some other old ones I had laying around and the vibrations became less noticable (but they're still there, and it's running better now).
How are your plug wires? I was getting a bad vibration due to leaky plug wires. They were attracting dust in places like static electricity. I swapped them out with some other old ones I had laying around and the vibrations became less noticable (but they're still there, and it's running better now).
09-07-01, 02:11 PM
#11
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I like to upgrade anything I have to replace, so I'd love to go with 8.5 mm wires. Mazdatrix has 'em, RB has 'em. Unfortunately, the price usually inhibits me on making some upgrades, like $65 for plug wires(if my memory serves me correcly).
09-07-01, 02:14 PM
#12
Super Newbie
Originally posted by jimmyv13
What is the actual function of the shutter valve? Should I cap mine off?
What is the actual function of the shutter valve? Should I cap mine off?
**** that. Rip it out and JB weld the hole up
09-10-01, 11:47 PM
#13
Passenger
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cpt
This may be way off, but my '79 RX vibrated bad, especially upon deceleration and at some specific rpm's (apx. 1500??). Turns out the U-joint(s) in drive shaft were worn. Of course they showed most wear and vibration at the rpm's you normally cruise at. An easy fix.
Hozer.
This may be way off, but my '79 RX vibrated bad, especially upon deceleration and at some specific rpm's (apx. 1500??). Turns out the U-joint(s) in drive shaft were worn. Of course they showed most wear and vibration at the rpm's you normally cruise at. An easy fix.
Hozer.
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