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Discussion Starter #1
Hello everyone, I have a question on a 1969 GTO, 400 block rebuilt a few years ago with a newer Edelbrock carb installed last year, car has been running great up until yesterday, we took it on a pretty good run since the rebuild and was just getting ready to pull her into the garage and the idle seemed unusually high so I tapped the gas pedal to get the idle down and it sputtered and dies, have not been able to get it to stay running since. It will crank over and I can get the car to start and run by holding the gas a little but it just will not run without some pressure on the gas pedal, if I place too much pressure on the gas pedal it sputters out and dies, if I let off the gas pedal it sputters out and dies, it acts like the choke is stuck or something like that. Any ideas would be greatly appreciated from the experienced GTO crowd here. This car has been in my family for over 40 years. 1969 GTO, 400 (from a 67), 4 Speed with 3.55 gears, mostly original and very well cared for but sat for years after the rebuild.
 

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Check to make sure a vacuum line hasn't come off. I had those symptoms when the vacuum fitting on the front of the manifold just decided to come loose.
 

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Also check the points. Make sure the dwell is where it needs to be. Check the rotor. I've had the tangs come off. Look at the choke. Is it indeed stuck closed? When the car is barely running, have a helper spray some carb cleaner down the carb. (Fire extinguisher handy!) Does the car speed up when you spray? If so, it's too lean. Look for a vacuum leak. I think your points/ignition system got a hiccup, or a vacuum line popped off, as the other guys said. Let us know what you find!
 

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Discussion Starter #5
Thank you all for the replies, my initial thought was vacuum but after checking there are no vacuum leaks so I am going to check points this weekend. Its very strange as I can start the car and keep it running with a slight bit of throttle, as soon as I let off that slight throttle it sputters out and dies. Its an edelbrock 1404 carb and has been running a little rich. Again thank you all for assisting I will post more results this weekend.
 

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Also check for fuel contamination like rust or water. Disconnect the fuel line at the carb and pump some gas into a glass jar by having a friend crank the engine. If it looks cloudy you may have water in the fuel. In cold climates we try store cars with near full tanks to prevent water condensation. Water collects below the gas and the gas will look cloudy when stirred up.
 

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Discussion Starter #7
First off, thank you all for the replies. I truly appreciate the help here. I have been at this a few days here and checked all vacuum lines and they are good, points test out good, fuel does not look contaminated at all. I have an Edelbrock 1404 and it looks to me like the choke is getting stuck open, this has an electric choke but it's not hooked up. I can force the choke closed and the car will start and idle, once I tap the gas the car dies as the choke gets stuck open, once the car is dead I tap the gas pedal again and the choke will close. I can then start the car again, it will idle and again I tap the gas to get the idle right and the choke opens again and the car dies.
I have never hooked the electric choke up on this carb, again the car was running perfectly fine, then all of a sudden it wouldn't start. Closed the choke manually by hand under the hood and it started? I am going to remove the carb and clean the crap out of it this week to see if that helps. Again, I appreciate the comments and I appreciate any advice, assistance and wisdom you might add here.
 

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You are starving for fuel. Try adjusting the choke so it stays open and drizzling a little fuel or spraying carb cleaner down the carb throat when you feed it some throttle. If it runs on the prime, and picks up, you've got fuel delivery issues or a jammed up carb. Keep your hair and eyebrows out of the line of fire when you goose it, and keep a fire extinguisher handy. The reason it starts with choke but dies when you gas it is because it's very lean.
 

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Did you just install the Edelbrock carb or has it been on for a while and these issues are new? If you installed right out of the box, there are probably some adjustment issues. I had one on a Camaro and it ran awful as received. I pulled the top off and neither float was correct (one was too high, the other too low). Another easy check is that the metering rods, or the vacuum springs that hold them up are installed correctly (I had to change the springs as well since the factory ones allowed the rods to drop too early). You can access those right from the top without removing the carb, just don't drop anything in.

If your going to pull it to clean it, take the top off and see if anything is blocking the jets. These carbs are pretty simple compared to the Qjets or the Hollys.

Also, re-check the vacuums. Make sure there isn't one that has split or disconnected at the other end away from the carburetor.

Good luck!
 

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Discussion Starter #10
Ok, everyone thanks again. I am back at it this weekend. I believe we have ruled out fuel as the car will start and will run fine. We have eliminated the vacuum as an issue. The issue is when the car is running the choke linkage is sticking. High Idle screw get stuck on the high idle cam and kills the engine.
Once the car dies, I can tap the accelerator and it will return to normal position but only when car off, when running it will not return to normal position.
 

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Discussion Starter #11
back at it

Ok, everyone thanks again. I am back at it this weekend. I believe we have ruled out fuel as the car will start and will run fine. We have eliminated the vacuum as an issue. The issue is when the car is running the choke linkage is sticking. High Idle screw get stuck on the high idle cam and kills the engine.
Once the car dies, I can tap the accelerator and it will return to normal position but only when car off, when running it will not return to normal position.
 

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Ok, everyone thanks again. I am back at it this weekend. I believe we have ruled out fuel as the car will start and will run fine. We have eliminated the vacuum as an issue. The issue is when the car is running the choke linkage is sticking. High Idle screw get stuck on the high idle cam and kills the engine.
Once the car dies, I can tap the accelerator and it will return to normal position but only when car off, when running it will not return to normal position.

Electric choke or hot air? If electric, it may not be working. I have never had an electric choke, so at a loss on 'em, but suspect you can check for 12-volt power.

Depending on what operates the choke, it might need an adjustment on the choke bi-metal spring inside the housing. If you see a small metal tube rising up from the manifold into the choke housing the bi-metal spring is internal. Some have the bi-metal spring/linkage arm outside the choke located on the manifold, usually under a cover/hood. Either could be broke and causing your choke not to operate correctly.

If it is the internal bi-metal type choke housing, I have found it where someone has been in there and did not locate the bi-metal spring correctly for proper operation or it was way out of adjustment. If it has this type of choke, you will see 3 small screws holding the plastic cover. Loosen the 3 screws to where you can turn the plastic cover. This is how you adjust the tension on the bi-metal spring inside and set the choke opening - turn it one way or the other, not sure which. Yours may be too loose and not having enough tension to open the choke. I would think in this heat that your choke should be open and your high idle cam should not be engaging when starting your engine -just my opinion on that one. I often would turn the cover in the direction that put more tension on the choke to keep it wide open on the GM cars I had that had them. In winter, I would re-adjust them.

I take it you are not having any binding or sticking with the choke linkages? I assume your high idle cam drops down if you manually open your choke? If everything seems to be free and working, then I would next look into the choke housing/bi-metal spring to be a possible source of your problem. :thumbsup:
 

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Discussion Starter #13
Choke Linkage issue?

The electric choke is not hooked up, however we did hook it up with no change and we also bypassed it as well. When the car is running and I tap the accelerator to get the idle down, the choke butterfly will stick open and kill the engine, it loos like the idle cam is getting stuck on the high idle screw and will not release however once the engine has died, I can tap the accelerator again and get that choke to close like it should. This sure seems more and more like a vacuum issue to me, the carb bolts and manifold bolts were loose but after tightening these still have the same issue. I am baffled here and I know it must be something simple as the car was running great for months and all of sudden after a long ride, I tapped the accelerator to get the idle down and it choked out, hasnt been right since.:nonod:
 

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The electric choke is not hooked up, however we did hook it up with no change and we also bypassed it as well. When the car is running and I tap the accelerator to get the idle down, the choke butterfly will stick open and kill the engine, it loos like the idle cam is getting stuck on the high idle screw and will not release however once the engine has died, I can tap the accelerator again and get that choke to close like it should. This sure seems more and more like a vacuum issue to me, the carb bolts and manifold bolts were loose but after tightening these still have the same issue. I am baffled here and I know it must be something simple as the car was running great for months and all of sudden after a long ride, I tapped the accelerator to get the idle down and it choked out, hasnt been right since.:nonod:

Well, not sure. If I understand you correctly, the engine dies if the choke butterfly is open or closed - regardless of the high idle cam sticking.

It sounds like the accelerator pump may be bad. As you hit the throttle to open the carb, the accelerator pump shoots in a squirt of gas. If the gas does not squirt in, the carb opens up and takes in more air without the gas richening up the mixture and it will die. If you were driving it, you would get a stumble or possibly a backfire through the carb if you opened up the throttle real fast.

BUT, it could be a vacuum problem as well. Get a vacuum gauge and see what is going on in the engine.:thumbsup:
 
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