Running rough...

[born2saw]

Running rough

Drove my car today for the first time since late November. At that time it was running a little rough, but I did not want to mess with it as I put it into storage. Today, I hooked up the battery and fired her up (my car will be a part of our clubs 50th anniversary display at world of wheels next weekend & I wanted to make sure she would start). She started up easy on the first try & idled great! As it was a beautiful sunny day, but cold (7 degrees!!) I took her for a 30 minute drive to lube everything up and make sure I had a full charge on the battery.

She ran great accelerating, either full or partial, pulled real strong (for a L48). The secondaries were a little hesitant but were definately opening which improved as she warmed up fully. But, when I tried to cruise at a steady speed, she bucked and ran rough. Still idled smooth at about 900 rpm. She ran a little smoother at high speed (70-80 mph) but still was rough at steady speed. Pulled strong to 100 mph where I backed off (can't afford a ticket right now).

The car is stock with about 45,000 miles. I have some minor exhaust problems--I can feel it banging & am planning to replace the exhaust system early this spring. I do not think I have an exhaust flow problem, but I think the cat is original (I may eliminate it and go with true duals-will a 74 system bolt right on?).

I know the good folks at CAC will have a good idea where to look first. Is this carburation? timing? something more serious?

I plan on taking her to my mechanic first thing this spring for a complete tune-up, but is there something I should be concerned about or have my mechanic check very carefully?

Thanks in advance--CAC rules.

 

[C3forME]

I don't know the answer to your question, however I was considering removing the cats from my 77 and going true duals also. I was just wondering is this something that is legal to do on cars that were equipped with cats from the factory, and will they be allowed to pass state inspection without them even if they come in with low emssions numbers?

BTW, Sharp looking roadster you got there.

 

[Stallion]

When you guys say that your Vettes run "rough", what exactly does this mean? Isn't this a timing issue? And, how exaclty do you know it's running rough? Does it sound different than it should, or feel different?

Thanks!

TR

 

[silver 80]

C3forME, I don't think you will pass if they do a visual, if they only sniff and it's with in the parameters no problem.
tom

 

[c4ever]

I would go with the basics. Coil,rotor,wires,plugs,cap.

carlo

 

[dmrodco]

Check for water / condensation buildup in the gas. carbs are real sensitive to this and I know I tend to forget that sort of thing cause all my other stuff is injected. good luck

 

[DDLS3]

born2saw,

Hopefully when you put your car away you added some fuel preserve or sta-bil to the gas tank to keep the old gas from gumming up your carb. If you didn't then you may want to add some carb cleaner to the tank. I'm thinking the cold air has leaned out the carb quite a bit to the point that it may be running a little off. See if your problem goes away after the weather warms up. If you expect to be driving more than occasionally in the cold then maybe you should think about re-tuning the carb for the cold air. Just my .02 worth.

 

[born2saw]

C3forME,

I believe it is a federal law that cats cannot be removed. That said, there are no inspections in Indiana and I may decide to be "responsible" & put dual cats on it.

BTW-thanks for the compliment, I think she looks even better in person.

Stallion,

Running rough can mean a variety of things, but in my case it feels like it is not firing on all 8 cylinders (maybe), the engine kind of cuts out--but very briefly and when you try to maintain a steady speed, it feels like it is "bucking" instead of maintaining a smooth, steady, speed. It is very easy to know when it is running rough. The tricky part is figuring out why. That's why I posted this. I have owned 'modern' cars for so long, I have forgotten all those things I used to know when I worked in a service station (not a gas station-ask your dad about them) in the late 60's and early 70's. I do not even own a timing light anymore! (though I think I better buy one). One way is to replace things until you fix it (coil, wires, rotor, plugs, cap -- part of a routine tune-up Thanks for reminding me c4ever, like I said, its been years since I had a car that required tose things).

dmrodco & DDL-81,

I ran her down to less than 1/4 tank, then filler her all the way & added Sta-Bil before storing her. I did not intend to drive her until spring, but, I did not know about the car show then. Do fuel additives help get rid of moisture? Any recommended carb cleaners?

I guess I'll be doing a major tune-up this spring when I get ready to drive her regularly (probably should have planned on it anyway :duh ;stupid

Thanks for the suggestions!!

 

[Stallion]

I see what you mean by running rough. Sounds like it might be tough to find the reason for. Good luck with the find and fix!

 

[C3forME]

I find that Chevron Techron fuel system cleaner does a very thorough job of cleaning things up. I believe that they recommend that you wait until you have less than 1/4 of a tank of gas, add the contents of the can and fill up your car. It works very well and you can actually feel the difference. Doing it every 3,000 miles when you do an oil change should keep your fuel system spotless, at least that's what I find anyway.

 

[DDLS3]

I've always used Gumout. It works best if you start with fresh gasoline and run the whole tank through. I do not believe that Sta-bil addresses the moisture issue. At some point mabe a can of dry gas would be appropriate.

 

[born2saw]

Thanks all!!

 

[cruzer99]

Change your fuel filters................

 

[Eddie 70]

Is it surging at cruise speed? This may be a sign of too much vaccum advance timing. Check out www.corvettefaq.com for vaccum advance.

 

[Rich80]

When I first got mine I did the cap, rotors, plugs and wires. Cheapest stuff first. After I did that she immediately started missing. Here after pulling each plug I had a bad plug. Replaced that and she runs fine....

 

[Stallion]

Nice Vette, Rich. Very nice.

Good luck with the problem, born2saw.

TR

 

[born2saw]

cruzer82 - If the fuel filters were nearing the end of their life or clogged, she would not accelerate strong, but as I do not know when they were last changed, I'll probably get new ones.

Eddie 70 - not surging as much as cutting out at cruise speeds. The link is not working right now, but I will check it out later.

Rich80 - all those things are on my spring clean up list (man is it getting long!!) I agree with Stallion, nice Vette.

Stallion - Hows the car hunt going? Did you and your dad go to that auction yet?? I saw some nice sounding Vettes advertised locally in your price range but don't really know what they are like. Good luck finding your Vette.