Engine Won't Stay On (Help)
Thread Starter
Melting Slicks
Joined: Sep 2004
Posts: 2,412
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Engine Won't Stay On (Help)
Hi guys, I just dropped in a 383 and everything was working fine on Monday. The engine fired right up after a few trys and I let the cam break in between 2K and 2.5K RPM for about 20 minutes. I even drove it around the block, but the timing was obviously off. The car wouldn't idle by itself and the carb backfired.
Anyways since that day I haven't been able to get the engine to run for more than about 10 seconds. I don't know what happened. I pull the throttle and fuel is squirting in there so I'm lost. Today I pulled off the dist cap with the line on the damper at 0 and checked the rotor positioning. I moved it about 1/4 of an inch but it didn't help. On my last attempt the carb backfired and caught fire. What the hell is wrong?
(Also FYI the carb is the stock 750cfm Q-Jet with the emissions hoses plugged off. Also the thermostatic coil choke doesn't hook up to the new manifold)
Anyways since that day I haven't been able to get the engine to run for more than about 10 seconds. I don't know what happened. I pull the throttle and fuel is squirting in there so I'm lost. Today I pulled off the dist cap with the line on the damper at 0 and checked the rotor positioning. I moved it about 1/4 of an inch but it didn't help. On my last attempt the carb backfired and caught fire. What the hell is wrong?
(Also FYI the carb is the stock 750cfm Q-Jet with the emissions hoses plugged off. Also the thermostatic coil choke doesn't hook up to the new manifold)
Race Director
Joined: Sep 2004
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
almost sounds like its not getting enough fuel....disconnect the fuel line at the carb and crank the engine and see how much fuel your are pumping out.
Burning Brakes
Joined: Oct 2004
Posts: 1,132
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Originally Posted by big_G
Maybe no gas in the tank? Don't laugh..It happens more than it should. 
Race Director
Joined: Sep 2004
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
yes twin turbo posts here....it may not be the tank that is failing .....i would be looking at the fuel pump......i have theory that says that when the old fuel pump is removed and the arm fully releases it tears the membrane for the pump.....you install it and it does not work properly....it gives you some flow just enough to screw with you as it craps out.....happened to me and alot of other guys, you would be surprised.
Thread Starter
Melting Slicks
Joined: Sep 2004
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It is a brand new fuel pump, but that's a very interesting theory.
I had to remove the base of the pump and rotate it so that the outlet would clear the frame rail. Do you think I could have messed something up? There was a gasket that is incorporated into the pump that didn't fit as nicely after I rotated it. And the car did run for twenty minutes on Monday just as it is now so...
I had to remove the base of the pump and rotate it so that the outlet would clear the frame rail. Do you think I could have messed something up? There was a gasket that is incorporated into the pump that didn't fit as nicely after I rotated it. And the car did run for twenty minutes on Monday just as it is now so...
Burning Brakes
Joined: Dec 2003
Posts: 1,149
Likes: 153
Originally Posted by torqvette
It is a brand new fuel pump, but that's a very interesting theory.
I had to remove the base of the pump and rotate it so that the outlet would clear the frame rail. Do you think I could have messed something up? There was a gasket that is incorporated into the pump that didn't fit as nicely after I rotated it. And the car did run for twenty minutes on Monday just as it is now so...
I had to remove the base of the pump and rotate it so that the outlet would clear the frame rail. Do you think I could have messed something up? There was a gasket that is incorporated into the pump that didn't fit as nicely after I rotated it. And the car did run for twenty minutes on Monday just as it is now so...
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Race Director
Joined: Sep 2004
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by torqvette
I had to remove the base of the pump and rotate it so that the outlet would clear the frame rail. Do you think I could have messed something up? There was a gasket that is incorporated into the pump that didn't fit as nicely after I rotated it. And the car did run for twenty minutes on Monday just as it is now so...
Drifting
Joined: Mar 2001
Posts: 1,600
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From: Valencia (near LA) CA
I made the mistake of not driving the Vette all week, well she was mad at me this moring and need some special time, just me and her before work.
She started up ok, I let her get all warmed up, and then I took my foot off the gas pedal and she wanted to stall. I thought maybe she needed to be driven a bit then she'll settle down. At the bottom of the driveway she stalled and refused to start. I persisted to the point at which I ran the battery out.
So at 8am I'm dresses for work and need to hook up the batterey charger and get her running well enough to at least get her out of the street.
The problem was a sticking needle valve in the carb. I just twisted it a bit to loosen anything and free what ever was causing it to stick.
After that she ran great and I took her to work with me.
~Jay
She started up ok, I let her get all warmed up, and then I took my foot off the gas pedal and she wanted to stall. I thought maybe she needed to be driven a bit then she'll settle down. At the bottom of the driveway she stalled and refused to start. I persisted to the point at which I ran the battery out.
So at 8am I'm dresses for work and need to hook up the batterey charger and get her running well enough to at least get her out of the street.
The problem was a sticking needle valve in the carb. I just twisted it a bit to loosen anything and free what ever was causing it to stick.
After that she ran great and I took her to work with me.
~Jay
Thread Starter
Melting Slicks
Joined: Sep 2004
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Talked to a friend who suggested I do the following: Rotate the dist counterclockwise about 1/4 of an inch, close the choke, and let out the idle mixture screws a bit.
It fired right up, damn is that a lopey cam! It won't idle below about 800 or 900 rpms and right there the timing is set at 7.5BTDC.
It obviously needs a professional tune but right now it is definitely driveable.
It fired right up, damn is that a lopey cam! It won't idle below about 800 or 900 rpms and right there the timing is set at 7.5BTDC.
It obviously needs a professional tune but right now it is definitely driveable.
Race Director
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by torqvette
....It fired right up, damn is that a lopey cam! ...
...
Thread Starter
Melting Slicks
Joined: Sep 2004
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Well I know I don't have the timing right, this is the first engine that I've assembled (from a shortblock) and installed myself. So I'm not really experienced. And the fastest engine I've been in control of before this was the old stock L48.
But the cam is a .520 .540 236 242 actual duration at .05 retro fit roller. What do you think, is that lopey?
Anyways I'll post a video tonight.
But the cam is a .520 .540 236 242 actual duration at .05 retro fit roller. What do you think, is that lopey?
Anyways I'll post a video tonight.
Race Director
Joined: Sep 2004
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by torqvette
Well I know I don't have the timing right, this is the first engine that I've assembled (from a shortblock) and installed myself. So I'm not really experienced. And the fastest engine I've been in control of before this was the old stock L48.
But the cam is a .520 .540 236 242 actual duration at .05 retro fit roller. What do you think, is that lopey?
Anyways I'll post a video tonight.
But the cam is a .520 .540 236 242 actual duration at .05 retro fit roller. What do you think, is that lopey?
Anyways I'll post a video tonight.
any body who has been fortunate enough to go to a Lars tuning for beer session has seen Lars take cars that were "Lopey" and that we all thought sounded good and make them run better an eliminate alot of the lope by concentrating on making the distributor run correctly by shimming the shaft and using new springs etc....and then he moves to the carb and the cars just purr....
Melting Slicks
Joined: Jan 2004
Posts: 2,672
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From: New Cumberland PA
Originally Posted by torqvette
But the cam is a .520 .540 236 242 actual duration at .05 retro fit roller. What do you think, is that lopey?
Anyways I'll post a video tonight.
Anyways I'll post a video tonight.
Burning Brakes
Joined: Sep 2004
Posts: 1,167
Likes: 2
From: Ft.Worth Texas
Originally Posted by bobs77vet
......making the distributor run correctly by shimming the shaft and ....
Race Director
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by David Ey
Are you saying shimming the end play at the gear? How much clearance should there be?
Race Director
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by bobs77vet
i don't know the clearnances.........Lars used a box of shims and added them until the excess slop was removed but so that it still could have some movement...
Burning Brakes
Joined: Sep 2004
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From: Ft.Worth Texas
Ok, I forgot you can also shim the dist. to intake surface which is another question altogather. I was asking about the shim between the gear and dist. housing.
Didn't mean to steal the post guys. sorry.
Didn't mean to steal the post guys. sorry.
Last edited by David Ey; Oct 15, 2005 at 11:19 PM.