86 camaro z28 305, quadrajet starts and runs for seconds the dies
06-02-2017, 03:30 PM
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86 camaro z28 305, quadrajet starts and runs for seconds the dies
it will start and run for a few seconds then shutdown, seems like an electrical problem but haven't been able to trace it down. it is an electronic controlled quadrajet and it seemed like a noise (snap/click) came from the carburetor when it shutdown. I might only get one or two shots at starting it up then it seems like something gets too hot and will not allow the engine to start until I shut it down and wait a bit
06-02-2017, 05:56 PM
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Re: 86 camaro z28 305, quadrajet starts and runs for seconds the dies
No-start is about the eeeeeeeziest kind of a problem to figure out.
To troubleshoot a no-start:
Start at the beginning, which is, an engine requires "The Big 3" magic ingredients in order to start: compression, air/fuel in somewhat reasonable proportions, spark at the right time.
Odds are VERY good, that in any given such situation, EXACTLY ONE of The Big 3 is missing. All you have to do is, determine which one; then fix it, while leaving the other 2 alone. Which of course includes, DON'T mess with the "timing" EVER.
Compression doesn't just "go away" on its own, with the exception of the timing set. I say "set" and not "chain" because the part that fails is almost never the chain, it's the CAM SPROCKET. When it fails, the cam stops turning with the crank, and the dist stops as well since it's driven by the cam. You can take off the distributor cap and have your assistant whirl the engine over while you watch the dist and see if it's turning smoothly.
If that's OK, you're down to only 2 of The Big 3.
1 of those 2 is VERY EEEEEEEEEZY to substitute for; namely, fuel. Spray starting fluid or pour some gasoline into it. If it starts RIGHT UP and runs for a second or 2 then dies, and will keep right on doing that as long as you keep spraying or pouring, then you have a fuel delivery problem. Obviously, be REAL CAREFUL doing this, it'd be a shame for a backfire out of the carb to set a gas can on fire or to create some other Darwin Award kind of situation.
If it still doesn't run, you have an ignition problem.
Which one is it? Go find out and come back and tell us.
A little history wouldn't hurt either. Car ran fine, and did this all the sudden while cruising down the highway? Been getting worse and worse for a few months and now it's like this? New motor build? Car been sitting around for acoupla years and you're trying to revive it? Thought you'd change out the spark plugs and now it's like this? What have you already done to it? etc. etc. etc.
To troubleshoot a no-start:
Start at the beginning, which is, an engine requires "The Big 3" magic ingredients in order to start: compression, air/fuel in somewhat reasonable proportions, spark at the right time.
Odds are VERY good, that in any given such situation, EXACTLY ONE of The Big 3 is missing. All you have to do is, determine which one; then fix it, while leaving the other 2 alone. Which of course includes, DON'T mess with the "timing" EVER.
Compression doesn't just "go away" on its own, with the exception of the timing set. I say "set" and not "chain" because the part that fails is almost never the chain, it's the CAM SPROCKET. When it fails, the cam stops turning with the crank, and the dist stops as well since it's driven by the cam. You can take off the distributor cap and have your assistant whirl the engine over while you watch the dist and see if it's turning smoothly.
If that's OK, you're down to only 2 of The Big 3.
1 of those 2 is VERY EEEEEEEEEZY to substitute for; namely, fuel. Spray starting fluid or pour some gasoline into it. If it starts RIGHT UP and runs for a second or 2 then dies, and will keep right on doing that as long as you keep spraying or pouring, then you have a fuel delivery problem. Obviously, be REAL CAREFUL doing this, it'd be a shame for a backfire out of the carb to set a gas can on fire or to create some other Darwin Award kind of situation.
If it still doesn't run, you have an ignition problem.
Which one is it? Go find out and come back and tell us.
A little history wouldn't hurt either. Car ran fine, and did this all the sudden while cruising down the highway? Been getting worse and worse for a few months and now it's like this? New motor build? Car been sitting around for acoupla years and you're trying to revive it? Thought you'd change out the spark plugs and now it's like this? What have you already done to it? etc. etc. etc.
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