Hey guys some help here, I have a problem when I turn the car to warm up and I let go of the throttle car turns off. The when I get it into drive the car stalls. I’m assuming a vacuum leak or bad carburetor( bad fuel mixture) ? but how can I find what is given the issue. It is 68 4 barrel edelbrock carb.
Start with a vacuum gauge like this one to rule out a vacuum leak:
If you still have the original vacuum headlight system hooked up, you probably have a vacuum leak. The headlight door actuators leak vacuum when they fail.
The headlight work fine, how would I test with vacuum gauge where would i connect it to?? Thanks
There’s a vacuum fitting on the rear of the intake manifold behind the carburetor, or use the driver’s side vacuum port on the Edelbrock carb. Either one will give you manifold vacuum. A properly running motor with no leaks should see about 18-20" of vacuum at idle, lower than that you probably have a leak. The vacuum gauge I linked comes with good instructions that explain all this in more detail.
Also, My headlight doors technically work but leak vacuum profusely (and make the engine run poorly) if I have the system hooked up. I’ve disconnected mine until I can rebuild/replace with electric motor conversion.
Great I will pick up a vacuum gauge and check it out
If your headlights stay closed for more than 1 or 2 hours after you shut off the engine, you do not have a bad vacuum leak there. The factory spec was a minimum of 18 hours closed, and a tight system will stay closed much longer than that. But a bad vacuum leak will cause them to open pretty quickly.
67/68 will stay in whatever position they are left in, 69/70 are designed to open with no vacuum.
Points or electronic ignition?
Let’s start with the basics… a '68 but what motor. What’s been done to it that you know about.
Has the motor ever run properly or are you just starting to work on it with no history… in other words, do we know that the base settings of timing, idle and idle mixture have been done and done properly?
Right now all that’s happening is throwing darts at a dart board.
Let’s get systematic.
I forgot that part Sorry, 302 rebuilt and it was running at one point, I messed with the Idle mixtures the last time I tried to start it up, I might have be off. When I turn it on I have give it gas to keep from stalling out.
Does the carb have a choke? And does it do it before it is warmed up or always?
You probably should go back to baseline settings such as:
Remove and plug all vacuum lines.
Seat and turn out the idle adjustment screws to whatever the baseline setting for an Edelbrock carb is.
Start the car and increase the idle adjustment until the motor will run without you having to hold the throttle open.
From there you can do the normal idle adjustment with a vacuum gauge.
IF you get it idling to your satisfaction that way, then start adding the vacuum settings and you’ll see if one of them is causing a problem and
can go from there.
If you can’t get it to idle, then you have a carb problem… assuming of course that your valve and ignition timing are all correct.
I got a vacuum gauge but can’t run the car just yet my garage springs broke and cant open garage. Stonesg I will try your suggestions , where would I connect my vacuum gauge on the Edelbrock carb?
I’m sorry I don’t have any experience with an Edelbrock carb.
Do a google with the model number if you don’t have the paperwork for it and find out if there’s a manifold vacuum port on the carb.
If not there, you should be able to tap manifold vacuum from your manifold itself. Tap it where all the other vac stuff hooks up. You may have to go buy some plugs to close off all but your vac gauge. The parts places have kits of them.
I still advice removing all vac devices till you get your idle settled as that will eliminate them as a cause and be pretty obvious to be a problem when you start hooking them back up.
Drivers side port on the Edelbrock is manifold vacuum, passenger side is timed vacuum.
I recently had the same problem on a 67 XR7 which I just fixed about 3 weeks ago. On the rear of the intake manifold was a vacuum port where a vacuum line came out to a T. One side went to the headlights and the other to the AC Vacuum tank. The lines to both systems were badly deteriorated. Some of the hosed just crumbled if I tried to move them. I removed the headlight vacuum tubing altogether and replaced the headlight system with the WCCC probe motor electrical replacement. Since my AC is not currently working, I removed the hose from the manifold. I picked up a pack of 1/4" vacuum caps and some small hose clamps from O’reilly for a couple of bucks. After sealing up the vacuum port with this cap, the stalling you describe went away. Also, prior to this fix the inside of my car was smelling like exhaust but now no longer does. There was one line from the headlight system going through the firewall. After removing that, the smell went away. And now my headlights work great too.
Just try sealing the vacuum port with a vacuum cap. If that fixes it, go back and find the leak.
Can you post some good pictures of your carb and vacuum lines?
So i connected my vacuum tester and it was in the red zone of lateing timing, so I changed the timing now it in the green zone but it fluxuates in the green zone.I think part is my carb I made the adjustments on the air/fuel mixture and nothing happens until i rev the engine? It should respond right away right?? I all ready bought a kit to replace parts on the carb but i think it the carb. Since the last time I had the car running to now nothing has changed, so im pointing to carb, so will a bad carb make my car stall??
What kind of choke mechanism does the carby have?
Also have you checked to make sure enough fuel is making it into the fuel bowl?
I had the same problem with mine idling fine in park or neutral and dying when I put it in gear. It turned out the idle mixture needed some adjustment. Since that is what you messed with last, I am guessing that is your problem.