Diagnosing a problem I can't desribe....
Thread Starter
Racer
Joined: Feb 2002
Posts: 322
Likes: 0
From: Alexandria VA
Diagnosing a problem I can't desribe....
Is it possible that one side of the engine is better timing wise than the other? When I am running my car it seems like the drivers side is running more smoothly than the passenger side. Maybe a bad plug? I have no idea where to even start on this one. Am i even asking the right question?
Drifting
Joined: Sep 2001
Posts: 1,427
Likes: 1
From: Boxford Mass
Re: Diagnosing a problem I can't desribe.... (pingdashf)
Short of listening for noise, I don't know how you tell which side is running better. Even at idle, 800 rotations per minute... man thats hard to pinpoint.
Maybe a valve, spark plug, or your idle screws set differently? :confused:
Maybe a valve, spark plug, or your idle screws set differently? :confused:
Drifting
Joined: Apr 2003
Posts: 1,323
Likes: 2
From: Castle Hills Texas
Re: Diagnosing a problem I can't desribe.... (pingdashf)
Is there something in particular that makes you believe you could tell one side of the motor from the other in regards to how smoothly your engine is running? What symptoms does your Vette have? Give us more information to help the forum help you. Is the car running rough, surging, blowing smoke? I have never heard of an engine having better or worse timing on one side. Give us more of a blow by blow of what is happening and I bet someone on this forum can tell you your issues. I bet there is not a single Vette related problem that has not been discussed at some point on this forum.
Pro
Joined: Sep 2002
Posts: 599
Likes: 0
From: High Point, NC
Re: Diagnosing a problem I can't desribe.... (pingdashf)
The timing chain drives both side equally. You must have a spark plug or plug wire problem or maybe a bad cam lobe
[Modified by wayne_69_427, 8:49 PM 3/1/2004]
[Modified by wayne_69_427, 8:49 PM 3/1/2004]
Le Mans Master
Joined: Aug 2001
Posts: 7,804
Likes: 4
From: Standing still with all my might Texas
Cruise-In X Veteran
St. Jude Donor '09-'11
Re: Diagnosing a problem I can't desribe.... (pingdashf)
If you really suspec that it is one cylinder causing the rought running you can try to isolate the problem by unplugging one plug wire at a time and see if you can pinpoint a bad cylinder.(shut the engine off when plugging and unplugging the wires to prevent shock and keep the open wire away from grounds to prevent a spark that could ignite gas fumes)
If one cylinder is not firing correctly you will notice very little (if any) change in how poorly it runs when it's plug wire is disconnected, it will run worse when you disconnect a plug wire from a "good" cylinder.
If you can pinpoint a bad cylinder then you are halfway throug the diagnosis, the next thing will be to find out why that cylinder is not firing properly. The next logical step would probably be a compression test.
If all cylinders appear to be firing evenly it is probably time to do a complete tune up.
If one cylinder is not firing correctly you will notice very little (if any) change in how poorly it runs when it's plug wire is disconnected, it will run worse when you disconnect a plug wire from a "good" cylinder.
If you can pinpoint a bad cylinder then you are halfway throug the diagnosis, the next thing will be to find out why that cylinder is not firing properly. The next logical step would probably be a compression test.
If all cylinders appear to be firing evenly it is probably time to do a complete tune up.
Thread Starter
Racer
Joined: Feb 2002
Posts: 322
Likes: 0
From: Alexandria VA
Re: Diagnosing a problem I can't desribe.... (CVT4ME)
I have true dual mufflers on the car. The passenger side muffler "pops" more than the drivers side. The drivers side idles very smoothly, while the passenger side seems more bumpy.
Race Director
Joined: Nov 1999
Posts: 10,643
Likes: 8
From: Foxfield CO 1970 Convertible
Re: Diagnosing a problem I can't desribe.... (pingdashf)
Could be valves, plugs, cam lobes, wires, etc. I'd pull the plugs on that side and examine them to see if one of them appears to be different in appearance than the remaining ones. If so, there is probably a problem with that cylinder.
Good luck... :)
Good luck... :)
Drifting
Joined: Apr 2003
Posts: 1,323
Likes: 2
From: Castle Hills Texas
Re: Diagnosing a problem I can't desribe.... (pingdashf)
Interesting. Do you have any kind of "H" or "X" pipe on your dual setup? The reason I ask is that I have read that you can get a kind of popping, like you are talking about, if you don't have this type of setup. In fact, I just had my 2-1-2 setup converted to true duals on my '80 and I do not have an "H" or "X" pipe and there is a slight pop at idle on the passenger side of the exhaust. It almost sounds like a slight exhaust leak or something along those lines but I know it is not. I wonder if the fact that the EGR is on that side of the motor could have anything to do with it? Do you still have the EGR valve on your car?
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Safety Car
Joined: Jan 2000
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Re: Diagnosing a problem I can't desribe.... (pingdashf)
I have true dual mufflers on the car. The passenger side muffler "pops" more than the drivers side. The drivers side idles very smoothly, while the passenger side seems more bumpy.
Drifting
Joined: Mar 2003
Posts: 1,608
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From: Canberra AUSTRALIA
St. Jude Donor '05-'06
Re: Diagnosing a problem I can't desribe.... (pingdashf)
Do you have the exhaust riser on the passenger side?
This looks like a spacer on the passenger side and causes heat to pass through the manifod to warm up the engine on cold days. When the engine heats up the thermal spring causes the butterfly valve in the rise to fully open and lets the exhaust flow better.
If the thermal spring is worn or broken the only thing that will keep it open is exhaust pressure from the engine. Thus the flap inside will flutter depending on the exhasut pressure and could give a variety of lean/rich conditions. You can replace it with a new one or a straight thru spacer (Paragon $20). Use some wire to tie it in the open position and see if the engine runs different.
If this isn't the problem. Pull each plug and check the condition. If one is gunked up compared to other then do a comparison of compression and spark to other cylinders.
Good Luck.
:steering:
This looks like a spacer on the passenger side and causes heat to pass through the manifod to warm up the engine on cold days. When the engine heats up the thermal spring causes the butterfly valve in the rise to fully open and lets the exhaust flow better.
If the thermal spring is worn or broken the only thing that will keep it open is exhaust pressure from the engine. Thus the flap inside will flutter depending on the exhasut pressure and could give a variety of lean/rich conditions. You can replace it with a new one or a straight thru spacer (Paragon $20). Use some wire to tie it in the open position and see if the engine runs different.
If this isn't the problem. Pull each plug and check the condition. If one is gunked up compared to other then do a comparison of compression and spark to other cylinders.
Good Luck.
:steering:
Drifting
Joined: Apr 2003
Posts: 1,323
Likes: 2
From: Castle Hills Texas
Re: Diagnosing a problem I can't desribe.... (stingry)
That sounds very plausible to me. I still have mine and while I know it works, I don't know what it does once it is in the open position. It very well could be fluttering about causing the slight popping I am hearing. I know mine opens and closes by the condesation that is steamed out in the mornings. Condensation steam comes out of the drivers side only and nothing out the passenger side until about 3-5 minutes goes by, then the steam starts on that side as well. I have been tempted to lose the heat riser in the past and it is still on my list of things to lose at some point possibly.
Thread Starter
Racer
Joined: Feb 2002
Posts: 322
Likes: 0
From: Alexandria VA
Re: Diagnosing a problem I can't desribe.... (CVT4ME)
Do you have any kind of "H" or "X" pipe on your dual setup?
Do you still have the EGR valve on your car?
what about your vacuum ? ....is it continuous or does the amount of vacuum pull vary ?!?
Do you have the exhaust riser on the passenger side?
Do you still have the EGR valve on your car?
what about your vacuum ? ....is it continuous or does the amount of vacuum pull vary ?!?
Do you have the exhaust riser on the passenger side?