Rough idle & lope, 92 model
Thread Starter
Team Owner
Joined: Mar 2012
Posts: 27,118
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From: Montgomery, Alabama
2017 C6 of Year Finalist
Rough idle & lope, 92 model
The car has been sitting for about 2 weeks under a cover until today. I have been working on the sill carpet and decided to go get the tank filled at the station about 2.5 miles down the road. It started fine with the idle staying a little above 800. I ran out of gas about a 1/4 mile from the gas station and was able to coast to the pump. Just before it ran out it started the "out of gas" bucking.
Filled it up and when I started it it had a lope, and a little rocking, as if someone had switched out the cam. It ran okay on the way home except for a slightly harder than normal shift (auto) and a faint exhaust lope sound.
Checked under the hood and there were small drops of clear water that resembled condensation on several flat areas. I restarted the engine after I wiped off the water and it again started fine with the lope still there. If you rev the engine it smooths out with no lope. It does still have the ticking sound on the right front side that I posted about a month or so ago.
The idle lope does sound good but it never sounded like that before.
Could use some ideas on what to check.
Filled it up and when I started it it had a lope, and a little rocking, as if someone had switched out the cam. It ran okay on the way home except for a slightly harder than normal shift (auto) and a faint exhaust lope sound.
Checked under the hood and there were small drops of clear water that resembled condensation on several flat areas. I restarted the engine after I wiped off the water and it again started fine with the lope still there. If you rev the engine it smooths out with no lope. It does still have the ticking sound on the right front side that I posted about a month or so ago.
The idle lope does sound good but it never sounded like that before.
Could use some ideas on what to check.
Thread Starter
Team Owner
Joined: Mar 2012
Posts: 27,118
Likes: 135
From: Montgomery, Alabama
2017 C6 of Year Finalist
Drove to the store, 12 miles round trip, with plenty of power but still had the rump. When I stopped it still does the rocking.
I have had a slight tick that I think is the right front injector. The tick is now lowder. Could the injector having gone bad caused the rump?
When you burb the throtle it will pop when the rpm drops back down to idle.
I have had a slight tick that I think is the right front injector. The tick is now lowder. Could the injector having gone bad caused the rump?
When you burb the throtle it will pop when the rpm drops back down to idle.
Last edited by Old Ben; Aug 12, 2012 at 03:27 PM.
Drifting
Joined: Jun 2010
Posts: 1,853
Likes: 8
From: Westerly RI
Could be an injector is dirty. You can test by pulling the electric plug from each injector one at a time with the engine running to see if the rpm or engine note changes. The pop could be unburned fuel in the cat.
Thread Starter
Team Owner
Joined: Mar 2012
Posts: 27,118
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From: Montgomery, Alabama
2017 C6 of Year Finalist
Thanks for the help. No cats. The pop is on the same side as the ticking injector. I do not know how old the injectors are so if one has gone then the others are probably not too far behind.
Heel & Toe
Joined: Aug 2012
Posts: 18
Likes: 0
From: Bell Buckle, TN
Sea Foam a benefit for this, you think? (seems to work wonders for my motorcycle--never tried it in a Corvette).
Last edited by bdmccray; Aug 12, 2012 at 11:36 PM.
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From: pittsburgh pa.
how damp was it under the hood and why was it wet? you could have condensation in the optispark which should be dried out right away! only way to do it is to drive it . take a long ride right away otherwise it will rust internally. you'll be replacing the optispark. pain in the butt!
Last edited by chrldo; Aug 12, 2012 at 11:38 PM.
Thread Starter
Team Owner
Joined: Mar 2012
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From: Montgomery, Alabama
2017 C6 of Year Finalist
Thanks all for the suggestions.
I drove it to work today. It still had a very slight lope when I started it and you could hear the injector ticking. When I got to a traffic light, after about 8 miles of mostly country road driving, the lope was gone and the ticking was barely noticeable.
Continued to work on city streets and it ran like it had prior to running out of gas. I will have too see what it does on the way home.
I drove it to work today. It still had a very slight lope when I started it and you could hear the injector ticking. When I got to a traffic light, after about 8 miles of mostly country road driving, the lope was gone and the ticking was barely noticeable.
Continued to work on city streets and it ran like it had prior to running out of gas. I will have too see what it does on the way home.
Thread Starter
Team Owner
Joined: Mar 2012
Posts: 27,118
Likes: 135
From: Montgomery, Alabama
2017 C6 of Year Finalist
With the exception of the injector tick, the behavior seems remarkably similar to what mine was doing and what prompted me to look at the wiring/distributor (I've had wiring issues cause similar loping/erratic idling on other vehicles). In my case, I did in fact find some issues (see my "Returning to stock ignition" thread) with wire and distributor condition. It doesn't hurt to look at those really close, but with the ticking, I'd have to agree with everyone else--seems like something going on with your injector.
Sea Foam a benefit for this, you think? (seems to work wonders for my motorcycle--never tried it in a Corvette).
Sea Foam a benefit for this, you think? (seems to work wonders for my motorcycle--never tried it in a Corvette).
I ran a bottle of Techron through it about three months ago to see if it would loosen a stuck gauge. Shortly after that is when the injector started ticking.
how damp was it under the hood and why was it wet? you could have condensation in the optispark which should be dried out right away! only way to do it is to drive it . take a long ride right away otherwise it will rust internally. you'll be replacing the optispark. pain in the butt!
The moisture appeared to be condensation. It was on the top of the A/C compressor and on some of the exposed metal. It had sat outside under a cover for two weeks. The cover does not seem to breath which leads to some condensation under it. The cover came with the car and is old so I guess that I will be shopping for a new cover.
