Engine help needed
Thread Starter
Advanced
Joined: Jan 2002
Posts: 96
Likes: 0
From: san mateo ca
Engine help needed
First off i have a 69 corvette with a 400 sbc in it. Today i was driving around 35 mph when I heard to small backfires. I immediately downshifted and braked, then the car engine shut off, power went out ... i was able to get the car to the side of the road. i waited like 5 minutes and tried re-starting. The car would almost start but would never fire up. i tried this 3-4 more times and each time it got weaker and weaker in starting up. Curently it acts like the battery is out when starting up (battery is fine though). I completely understand that it's hard to diagnose over the internet but any input is appreciated. thanks Adam
Racer
Joined: Aug 2004
Posts: 354
Likes: 6
From: Winston Salem NC
Sounds like it may have jumped timing. Timing chain could have broke or the gears sheared off the end of the distributor. Check to see if your distributor is loose. You can also remove the cap and see if the rotor is turning.
Thread Starter
Advanced
Joined: Jan 2002
Posts: 96
Likes: 0
From: san mateo ca
power going out
Basically once the engine backfired, I let off the gas immediately to start to pull over, the engine turned off by itself and i coasted to a stop. thanks for the opinions
any one have any other ideas i could look for? (i'm not currently with the car)
Basically once the engine backfired, I let off the gas immediately to start to pull over, the engine turned off by itself and i coasted to a stop. thanks for the opinions
any one have any other ideas i could look for? (i'm not currently with the car)
Tech Contributor
Joined: May 2005
Posts: 15,576
Likes: 118
From: Conroe Texas
Sure sounds like bad points, condensor, or distributor rotor. If you can get to the car, verify the timing chain is still intact by removing the distributor cap and bumping the starter over - the rotor should move. If it does, that eliminates the possibility of a broken timing chain.
With the cap off, you can also check for a bad rotor or cap.
With the cap off, you can also check for a bad rotor or cap.
Drifting
Joined: Sep 2004
Posts: 1,959
Likes: 1
From: North Bend Ohio
Now we have had several of these "car was running fine then a couple backfires and now it's dead" threads lately. I'm thinking there is something else going on here. I don't think there is anything wrong with the engine. I think there is something wrong elsewhere in the car and the engine is the first place it is showing up. I think the alternator may not be charging the battery enough and when it gets low enough the ignition system cuts out. Or maybe there's a bad connection or bad ground somewhere on the engine or charging system.
I would say take the alternator and get it tested. Check all charging system connections between the alternator and the battery. Check all the grounds between the battery and the engine. Some of these connections haven't been touched in years.
BigBlockk
Later.....
I would say take the alternator and get it tested. Check all charging system connections between the alternator and the battery. Check all the grounds between the battery and the engine. Some of these connections haven't been touched in years.
BigBlockk
Later.....
Le Mans Master
Joined: Nov 2004
Posts: 6,128
Likes: 21
From: North Alabama
dumb question but...are you still getting gas in the carb? Sure you have gas in the tank? I had this happen with a 327 Camaro years ago and got a loud backfire then it died. Tried restarting until the battery drained before realizing I had run it out of gas... 
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Drifting
Joined: Jan 2001
Posts: 1,347
Likes: 4
From: Slidell La
Don't remember if that is mechanical tac. I think it is.. if so you might have stripped the tac drive gear. This usually results in the distributor rotating fully to the end of the stop and killing the engine. If the timing is off,, check the distributor to see if it has moved. My guess is you can retime the distributor and it will run ok, but the tac will not work. THis will require a distributor rebuild. 99 Nassau Blue
Pro
Joined: Mar 2005
Posts: 635
Likes: 118
From: Lakemont, GA
Did it backfire (through the carb) or afterfire (out exhaust)? Usually I try to start simple, if you were not accelerating or decelerating it is unusual for an engine to jump valve time. A new set of points and a condenser may work wonders.
Good luck!
Good luck!
Thread Starter
Advanced
Joined: Jan 2002
Posts: 96
Likes: 0
From: san mateo ca
thanks for all the great tips so far.
I checked the distibutor and it was extremely loose. I figure the timing must be wayyy off? i have no idea what the timing was before. Even with the distributor tightened it still makes the same noise (have no idea where to set distributor) any ideas to go from here? thanks a lot
I checked the distibutor and it was extremely loose. I figure the timing must be wayyy off? i have no idea what the timing was before. Even with the distributor tightened it still makes the same noise (have no idea where to set distributor) any ideas to go from here? thanks a lot
Pro
Joined: Mar 2005
Posts: 635
Likes: 118
From: Lakemont, GA
Try turning your crank to 12-14 BTDC (use timing mark) and using an ohm meter position your distributor where the points are just opening. Use this as a starting position and use Lars' paper on engine timing to set your timing and curve.
Good luck
Good luck
