Couple of carb issues. What should I do.
05-24-2003, 02:41 AM
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Couple of carb issues. What should I do.
I have a cc quadrajet on my 350. If I set the idle when the car is warm then shut it off and wait a few minutes or couple hours(either or) then start it back up it idles a couple hundred rpms below what I set it at. After a few seconds to a minute(depending on how long it was since it was ran) it will pick up to where I set it. This is kind of frustrating because I would like to have my idle set at 750, but if I set it that low it tries to idle around 500 when I start the car. Right now I have it set at about 1000 and it idles at 800 when I first start it. It is plenty drivable this way, but the idle doesnt sound that nice up higher and cant be good for mileage. I have already eliminated the kicker silenoid as the probem because it does it with it unplugged. Also, the throttle linkage is shut all the way when it is idling higher so it is not a sticking throttle. Any ideas? Could it be a vacuum leak? I have checked all the vacuum lines I knew of and replaced a couple. I should be putting new heads and intake on it in a month or so, so if i have a leak on the intake manifold I should be able to fix it.
Also, I took a section of heater hose and listened to my valvetrain through it(up near valve covers and I seem to have a slight tick around my #1 cylinder. I think that maybe the valve lash could be not quite right on that cylinder but it is nothing you can hear without using the hose.
I am also getting about 11 mpg in town. I know that i am not going to get good mileage, but it doesnt seem like I have hardly ever seen anyone get this bad with a quadrajet. I will be testing highway mileage sunday.
One other problem is that if I get on the gas decent but not wot sometimes I will get a gurglish noise out the exhaust. It is almost a bog but not real bad.
One last thing. I had the car hooked up to a snapon scanner. It didnt indicate wot when I had the throttle all the way down. Could this be throwing off my timing at wot?
Ben
Also, I took a section of heater hose and listened to my valvetrain through it(up near valve covers and I seem to have a slight tick around my #1 cylinder. I think that maybe the valve lash could be not quite right on that cylinder but it is nothing you can hear without using the hose.
I am also getting about 11 mpg in town. I know that i am not going to get good mileage, but it doesnt seem like I have hardly ever seen anyone get this bad with a quadrajet. I will be testing highway mileage sunday.
One other problem is that if I get on the gas decent but not wot sometimes I will get a gurglish noise out the exhaust. It is almost a bog but not real bad.
One last thing. I had the car hooked up to a snapon scanner. It didnt indicate wot when I had the throttle all the way down. Could this be throwing off my timing at wot?
Ben
05-27-2003, 10:13 AM
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Car: 82 camaro SC
Engine: 350
Transmission: 700r4
Re: Couple of carb issues. What should I do.
I have a cc quadrajet on my 350. If I set the idle when the car is warm then shut it off and wait a few minutes or couple hours(either or) then start it back up it idles a couple hundred rpms below what I set it at. After a few seconds to a minute(depending on how long it was since it was ran) it will pick up to where I set it.
Doesn't sound unusual. Have you tried revving it up a few times?
This is kind of frustrating because I would like to have my idle set at 750, but if I set it that low it tries to idle around 500 when I start the car. Right now I have it set at about 1000 and it idles at 800 when I first start it. It is plenty drivable this way, but the idle doesnt sound that nice up higher and cant be good for mileage. I have already eliminated the kicker silenoid as the probem because it does it with it unplugged. Also, the throttle linkage is shut all the way when it is idling higher so it is not a sticking throttle. Any ideas? Could it be a vacuum leak? I have checked all the vacuum lines I knew of and replaced a couple.
Could be a vacuum leak, if it only leaked for a short while or something. If you want the idle that stable, try fuel injection--the computer compensates the idle(like you are with the screw) to maintain a given rpm.
Also, I took a section of heater hose and listened to my valvetrain through it(up near valve covers and I seem to have a slight tick around my #1 cylinder. I think that maybe the valve lash could be not quite right on that cylinder but it is nothing you can hear without using the hose.
Probably nothing to worry about. Get it adjusted if it bothers you.
I am also getting about 11 mpg in town. I know that i am not going to get good mileage, but it doesnt seem like I have hardly ever seen anyone get this bad with a quadrajet. I will be testing highway mileage sunday.
Town mileage doesn't mean much, post your highway mileage over a few tank fulls.
One other problem is that if I get on the gas decent but not wot sometimes I will get a gurglish noise out the exhaust. It is almost a bog but not real bad.
Have a sound clip?
One last thing. I had the car hooked up to a snapon scanner. It didnt indicate wot when I had the throttle all the way down. Could this be throwing off my timing at wot?
Adjust the TPS, or replace it.
Ben [/B][/QUOTE]
Doesn't sound unusual. Have you tried revving it up a few times?
This is kind of frustrating because I would like to have my idle set at 750, but if I set it that low it tries to idle around 500 when I start the car. Right now I have it set at about 1000 and it idles at 800 when I first start it. It is plenty drivable this way, but the idle doesnt sound that nice up higher and cant be good for mileage. I have already eliminated the kicker silenoid as the probem because it does it with it unplugged. Also, the throttle linkage is shut all the way when it is idling higher so it is not a sticking throttle. Any ideas? Could it be a vacuum leak? I have checked all the vacuum lines I knew of and replaced a couple.
Could be a vacuum leak, if it only leaked for a short while or something. If you want the idle that stable, try fuel injection--the computer compensates the idle(like you are with the screw) to maintain a given rpm.
Also, I took a section of heater hose and listened to my valvetrain through it(up near valve covers and I seem to have a slight tick around my #1 cylinder. I think that maybe the valve lash could be not quite right on that cylinder but it is nothing you can hear without using the hose.
Probably nothing to worry about. Get it adjusted if it bothers you.
I am also getting about 11 mpg in town. I know that i am not going to get good mileage, but it doesnt seem like I have hardly ever seen anyone get this bad with a quadrajet. I will be testing highway mileage sunday.
Town mileage doesn't mean much, post your highway mileage over a few tank fulls.
One other problem is that if I get on the gas decent but not wot sometimes I will get a gurglish noise out the exhaust. It is almost a bog but not real bad.
Have a sound clip?
One last thing. I had the car hooked up to a snapon scanner. It didnt indicate wot when I had the throttle all the way down. Could this be throwing off my timing at wot?
Adjust the TPS, or replace it.
Ben [/B][/QUOTE]
05-27-2003, 01:51 PM
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Well, I have been driving it and it doesnt seem to start up at as low of an idle or stay down there as long. You say it seem normal, but if I were to set it down about 600 where the stock idle would have been it would only idle around 300-400 when I start it. I dont think that is normal. There may be some variation, but I wouldnt think 2-300 rpm. I tried to set my idle at 750(which is where I would like it) but when I start it it tries to run at 400-500 and that doesnt work with this cam. Also, when I have the idle set down where I want it, it is not a question of whether I have tried to rev it, because if I dont it will die. I have to hold the rpms up for a minute or so until it decides to come up to an idle that the motor can run.
As far as any leaks or my rocker, I am getting new heads intake and rockers soon(already ordered them) so I will make sure to get everything set right and sealed.
As far as gas mileage, I plan on checking it on the highway, but over a few tank fulls may not be a possibility, because I dont really drive on the highway much, and especially not exclusively.
As far as the noise, I dont have a sound clip. I could try to get one, but I dont know if it will come out good enough. It is kind of a low rumbley noise.
With the tps, it seemed to be in range voltage wise, but it just didnt indicate wot. I have another that is practically new that I put in another carb but never used that I could put in it and probably will when I swap the heads to see if that helps.
About the fuel injection. I will get there eventually. I have a LT1 sitting in the garage waiting for me to decide what I want to do to it.
Ben
As far as any leaks or my rocker, I am getting new heads intake and rockers soon(already ordered them) so I will make sure to get everything set right and sealed.
As far as gas mileage, I plan on checking it on the highway, but over a few tank fulls may not be a possibility, because I dont really drive on the highway much, and especially not exclusively.
As far as the noise, I dont have a sound clip. I could try to get one, but I dont know if it will come out good enough. It is kind of a low rumbley noise.
With the tps, it seemed to be in range voltage wise, but it just didnt indicate wot. I have another that is practically new that I put in another carb but never used that I could put in it and probably will when I swap the heads to see if that helps.
About the fuel injection. I will get there eventually. I have a LT1 sitting in the garage waiting for me to decide what I want to do to it.
Ben
05-27-2003, 03:29 PM
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Car: 82 camaro SC
Engine: 350
Transmission: 700r4
"if I dont it will die." Ah, it's not really that it idles slow so much as it won't idle at all(it dies). Warm start idle problems are usually(for me anyway), the carb overflows after you shut it off. From heat in the carb and/or too high of a float level and/or needle and seat problems. Check the exhaust for black smoke or gas smell when it happens. You say you are running a 'good' cam, the computer may not like it. Also, a 'good' cam can really hurt mileage--they can be inefficient at lower rpms.
05-27-2003, 04:18 PM
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Actually, that gives me an idea. It is a xe268. It runs fine in closed loop, but the problems are when I first start it. Anyway, you said it can be from to much heat causing the fuel to over flow. Well, I didnt know what they were for at the time, and I have the heat crossovers in the intake manifold completely open with no restrictor plates or bock offs. If that could be part of my problem I should have it fixed in a couple weeks because the new intake gaskets I ordered with my new intake and heads have those ports blocked off.
Ben
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