Finally It Runs . . .
08-18-2001, 11:53 PM
#21
Le Mans Master
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Re: Finally It Runs . . . (veech)
Veech,
If you have a Quadrajet then you probably have a small sintered brass filter integral to the carburator. It is located right inside the fuel inlet to the carb. It is supposed to be a secondary fuel filter designed to catch the very smallest trash that could get into the fuel. There should be another filter between the fuel pump and the carb. It is usually a can shaped object about 3 inches long by 2 inches wide. It is supposed to stop all the large chunks that might be in the gas tank.
If you don't have a inline filter then it is very possible that any dirt, rust or general crap in your tank, ended up in the sintered brass filter and plugged it up.
If you have a Quadrajet then you probably have a small sintered brass filter integral to the carburator. It is located right inside the fuel inlet to the carb. It is supposed to be a secondary fuel filter designed to catch the very smallest trash that could get into the fuel. There should be another filter between the fuel pump and the carb. It is usually a can shaped object about 3 inches long by 2 inches wide. It is supposed to stop all the large chunks that might be in the gas tank.
If you don't have a inline filter then it is very possible that any dirt, rust or general crap in your tank, ended up in the sintered brass filter and plugged it up.
08-19-2001, 04:18 PM
#22
Drifting
Thread Starter
Re: Finally It Runs . . . (Smokehouse69)
I have an Eddelbrock Carb.
The Car Fires up and Idles , but dies at the Slightest though of throttle :(
The Car Fires up and Idles , but dies at the Slightest though of throttle :(
08-19-2001, 05:41 PM
#23
Le Mans Master
Re: Finally It Runs . . . (veech)
Long post with most of the normal things covered, so here goes a different sequence.
First, pull the valve covers and make sure all the valves are opening. You said the vacum gauge was "bouncing", what values? Bounching gauge along with ran fine before and sits a lot makes me thing you have a good prossibility for a stuck valve. You can also try losening every valve 1/2 turn and see if it changes (enough to seat a valve that wasn't quite making a seal but not enough to hurt anything).
Check the ignition timing (yes again). I'd pull and plug the vacum can, then set initial timing to 16 degrees (again, enough it should run even with no centrifugal advance etc, but not enough it will hurt anything). When I first fired the new boat motors I set timing to 12 degrees and they ran great, but you couldn't put it into gear to save your soul, until I bumped timing up to 16 degrees (I have bigger cams so little vacum, but it's a similar case to yours).
Out of gear you should be able to rev the engine by opening the throttle slowly even without an accelerator pump. If you can rev it by slowly opening the throttle, but not quickly, then I'd check/replace the accelerator pump.
Out of gear if it won't rev when you open the throttle slowly it can be the power valve. It could be leaking (Holley with just one backfire will toast a power valve), or if you have really low vacum (from leaks, stuck valve or other cause) the power valve can actually be opening "normally" since it thinks you need fuel due to a low vacum reading. Look down the throat of the carb at idle (carefully in case it backfires in your face). If you can "see" fuel in the barrels the power valve is likely open or leaking.
The only other thing I can think of is that the engine will "somewhat" run with the ignition 180 degrees out (ask me how I know :D ), so I'd check that again too. Pull the number 1 plug, put your finger on the hole, and turn the motor. When the compression blows your finger out of the hole, your on compression, so continue till the dmper shows TDC on that cycle (go the shortest way from when your finger got blown out).
Good luck - Greg :D
First, pull the valve covers and make sure all the valves are opening. You said the vacum gauge was "bouncing", what values? Bounching gauge along with ran fine before and sits a lot makes me thing you have a good prossibility for a stuck valve. You can also try losening every valve 1/2 turn and see if it changes (enough to seat a valve that wasn't quite making a seal but not enough to hurt anything).
Check the ignition timing (yes again). I'd pull and plug the vacum can, then set initial timing to 16 degrees (again, enough it should run even with no centrifugal advance etc, but not enough it will hurt anything). When I first fired the new boat motors I set timing to 12 degrees and they ran great, but you couldn't put it into gear to save your soul, until I bumped timing up to 16 degrees (I have bigger cams so little vacum, but it's a similar case to yours).
Out of gear you should be able to rev the engine by opening the throttle slowly even without an accelerator pump. If you can rev it by slowly opening the throttle, but not quickly, then I'd check/replace the accelerator pump.
Out of gear if it won't rev when you open the throttle slowly it can be the power valve. It could be leaking (Holley with just one backfire will toast a power valve), or if you have really low vacum (from leaks, stuck valve or other cause) the power valve can actually be opening "normally" since it thinks you need fuel due to a low vacum reading. Look down the throat of the carb at idle (carefully in case it backfires in your face). If you can "see" fuel in the barrels the power valve is likely open or leaking.
The only other thing I can think of is that the engine will "somewhat" run with the ignition 180 degrees out (ask me how I know :D ), so I'd check that again too. Pull the number 1 plug, put your finger on the hole, and turn the motor. When the compression blows your finger out of the hole, your on compression, so continue till the dmper shows TDC on that cycle (go the shortest way from when your finger got blown out).
Good luck - Greg :D
08-19-2001, 10:45 PM
#24
Drifting
Thread Starter
Re: Finally It Runs . . . (veech)
Wheres the Power Valve on a eddelbrock Carb?
Also, how can i tell if its not good? (Car has backfired b4)
Also, how can i tell if its not good? (Car has backfired b4)
08-20-2001, 09:09 AM
#25
Drifting
Re: Finally It Runs . . . (veech)
(using my own id this time)
I don't know where the power valve is on the Edelbrock (I've run mostly Holley's), other than it will be inside and accessed either by removing the top cover or the baseplate. When I've had a bad p-valve, I've been able to see raw fuel trickling into the vanturies when the car is running, so I'd take a look for that first.
On the Holley p-valve after you remove it you can suck on it, and if it's good the plunger will move in and stay (or they make a vacum tester for this job too), or you can push the plunger in, put your thumb on the top, and it will stay in. If bad the plunger either won't pull in under suction (vacum), or will slowly come back out with your thumb covering the top hole. Some sort of "similar" test should be possible with the Edelbrock, but will depend on what the actual geometry is. I'm sure there are other guys on the forum who use the Edelbrock carbs, so might try a "do you have an Edelbrock carb" type post and see if they can give you better info.
-Greg
I don't know where the power valve is on the Edelbrock (I've run mostly Holley's), other than it will be inside and accessed either by removing the top cover or the baseplate. When I've had a bad p-valve, I've been able to see raw fuel trickling into the vanturies when the car is running, so I'd take a look for that first.
On the Holley p-valve after you remove it you can suck on it, and if it's good the plunger will move in and stay (or they make a vacum tester for this job too), or you can push the plunger in, put your thumb on the top, and it will stay in. If bad the plunger either won't pull in under suction (vacum), or will slowly come back out with your thumb covering the top hole. Some sort of "similar" test should be possible with the Edelbrock, but will depend on what the actual geometry is. I'm sure there are other guys on the forum who use the Edelbrock carbs, so might try a "do you have an Edelbrock carb" type post and see if they can give you better info.
-Greg