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Is there a way to post videos on here? I'd like to post a video of my car running so that those here can see what is going on and have a better way of helping.
The problem I have is the car idles fine and even revs fine as long as I don't give it quick gas. If I gradually increase the rpms it is smooth but if I hammer the gas, it stumbles and sputters.
The timing is set mechanically at the middle of the timing tab (I don't have numbers that represent each peak and valley); the cam has 4 degrees advance built in.
The carburetor is an Edelbrock Thunder Series AVS 650 currently set at all factory settings. I would like to post a video to show what is happening so you all may be better able to help.
Posting youtube videos is easy. Just copy the link and paste it into the dialog box that pops up when you click the "link" icon (
) when you're composing the message.
If you have an actual video file, I don't know if it's possible. But it's easy to upload a video to youtube, and I've always done it that way and then shared the link.
Posting youtube videos is easy. Just copy the link and paste it into the dialog box that pops up when you click the "link" icon (
) when you're composing the message.
If you have an actual video file, I don't know if it's possible. But it's easy to upload a video to youtube, and I've always done it that way and then shared the link.
The timing is set to the middle peaked tab. The Idle is somewhere around 6-700 . The fuel pressure is about 7.5 psi. Vacuum is showing 7 at the intake manifold port on the carburetor (though I may be reading it wrong; I am using the harbor freight fuel pressure and vacuum gauge multi-tool for reading the vacuum).
Acts like the accelerator pump is not working. Have you pulled the air cleaner and checked to see if you are getting two heavy streams of gas when you quickly open the throttle? If no stream of gas your accelerator pump will need to be replaced or rebuilt,,,, Just my thoughts ..Tedd
Vacuum is showing 7 at the intake manifold port on the carburetor
I'm no expert, but I just got done playing with the 403 in my '78 Toronado. It draws about 15 in Hg at idle with a steady needle. Yours is showing 7 assuming "7" is in the same units. Everything I've read says that a properly-running engine should draw a steady 15-22 in Hg at idle. A low reading like yours indicates a vacuum leak in the intake manifold or carburetor. To be honest, I don't like the sound of your engine at idle. It's too "glub-glub-glub" instead of a more smooth idle I'd expect.
This assumes your reading of 7 really is 7 in Hg. If it's 7 psi, that is about 15 in Hg, and your vacuum reading is ok. But it still sounds a little too glub-glubby, at least to me.
Last edited by jaunty75; Oct 17, 2017 at 12:37 PM.
I see you have an HEI, did you remove the resistance wire? With an HEI you can't set your timing to stock specs. You need to be up around 16-18*btdc. From the looks of your timing tab I think your only running 7.5-10. I don't think your tach is accurate cause it sound like its idling around 500 rpm. With the low idle and timing, your vacuum will also be low and the engine will stall on short bursts.
If you do not have an adjustable timing light, turn the engine so the line on the harmonic balance is at the 10 line (the one all the way on the left) then mark a line to the right of it with chalk on the balance at the far right line on the tab (0), another mark in the middle of the tab (5) and and lastly a mark between the 2 (7.5). Rotate the engine a bit so you can extend the lines fully across. Now you have 3 chalk marks, the one farthest to right on the balance is now 20* the one to the left of it is 17.5* and the last one closest to the original line is 15*. Now start your engine and adjust your timing the middle line is lined up with the 10 mark on the timing tab. That will put your timing at 17.5* btdc.
Successes! I can't thank you all enough for your taking the time all these years and helping me through the ups and downs of all of this; especially the downs and terrible process I had to go through with BW. You guys are great!
Sounds great. Now all you need to do is put a pcv in one of the valve covers connected to the big port in front of your carb.
Hey Eric,
I installed the PCV valve (in the driver's side for sake of room) and the air breather on the passenger side. As soon as I did that, the engine began running rough and the smell of gas from the exhaust increased. Is the PCV causing the engine to be on the rich side? Also, the bog returned. Throttle response went from quick and free to slow and sluggish.
Do I need to revisit the timing to see if it needs adjustment? Vacuum is hovering right between 13-14 inches of mercury. Maybe there is not enough vacuum to make the PCV work properly?
Where did you connect the vacuum line for the PCV valve?
I connected it to the PCV port on the front of the carburetor.
Here's a quick video (for display of issue and comparison to previous video to see the difference - sorry for the lack of enthusiasm, I'm not feeling well right now ):
):
