Idle question
Thread Starter
Racer
Joined: Aug 2001
Posts: 473
Likes: 0
From: Raleigh NC
Idle question
I have a relatively new Edelbrock Qjet replacement 750 cfm on my BB. I have been having a lot of work done it lately, but one thing that I cannot figure out (or my mechanic for that matter) is what is going on with the idle.
Most of the time it idles fine in the 700-800 RPM range. It can be fully warmed up and will idle fine at this RPM. Go for a drive and come to a stop light or otherwise stop, and it often will not drop below 1000 RPM. One thing we found was that the choke coil was worn out and was not holding the choke fully open once it warmed up. This seemed to help some, but the problem is still there. There is no linkage bind or anything like that that I can find.
It is not really a big deal, but I have a larger than stock cam that sounds really nice at 700 or so. The slightly higher idle just does not sound as good. I would like for it to settle back on down.
If you sit there and let it idle long enough, it will eventually settle back down to around 700-800.
What can I do to fix this?
Most of the time it idles fine in the 700-800 RPM range. It can be fully warmed up and will idle fine at this RPM. Go for a drive and come to a stop light or otherwise stop, and it often will not drop below 1000 RPM. One thing we found was that the choke coil was worn out and was not holding the choke fully open once it warmed up. This seemed to help some, but the problem is still there. There is no linkage bind or anything like that that I can find.
It is not really a big deal, but I have a larger than stock cam that sounds really nice at 700 or so. The slightly higher idle just does not sound as good. I would like for it to settle back on down.
If you sit there and let it idle long enough, it will eventually settle back down to around 700-800.
What can I do to fix this?
Racer
Joined: Jan 2000
Posts: 491
Likes: 0
From: florida
Re: Idle question (hudman)
Make sure your throttle return spring is bringing your primaries back to idle. I also had my mechanical advance weights in my distributor not returning to their initial setting because it was gummed up and dirty inside which would affect your idle. lou
Le Mans Master
Joined: Sep 2000
Posts: 5,635
Likes: 4
From: Orlando Floriduh
Re: Idle question (hudman)
My 69 with the original carb did that except it would ONLY do it after I drove at higher speeds or got on it . I would finally settle back. About drove me crazy trying to find what was going on.. It was very predictable and as long as I just drove around town it would always idle at 700..... It was the secondary throttle plates. I found that when it was idlling fast, I could push on the secondary shaft on the drivers side and the idle would be fine.. I played around with if for days..... The secondary closing spring on the linkage (on the secondary shaft) seemed a little weak so I replaced it. Now it is much better. It idles the same all of the time as long as the A/C is on. Once in a while with the A/C off it will idle at around 900-1000 after I get on it. About 90% of the time it idles at 700 though . :confused:
[Modified by silvervetteman, 6:25 AM 8/31/2002]
[Modified by silvervetteman, 6:25 AM 8/31/2002]
Thread Starter
Racer
Joined: Aug 2001
Posts: 473
Likes: 0
From: Raleigh NC
Re: Idle question (silvervetteman)
Good suggestions-
A few new things to chase. Thanks.
Silvervetteman-Sounds like mine is doing the same. When I mentioned it did it after a short drive, this does correlate with what yours does because a short drive usually always results in me getting on it a few times. I will check the spring and see if that needs some attention.
A few new things to chase. Thanks.
Silvervetteman-Sounds like mine is doing the same. When I mentioned it did it after a short drive, this does correlate with what yours does because a short drive usually always results in me getting on it a few times. I will check the spring and see if that needs some attention.
