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Author Topic:   can't get car to!!!
Dirt Maniac

Total posts: 119
posted March 06, 2005 03:56 PM  
I can't get my Chevy 350 engine to stay running. I have to prime the carb a bunch just to get the engine going. Then, after 15 seconds, the car starts to backfire and dies. Any suggestions on where to start? I swapped out carbs, checked plug gaps, and I have new spark plugs and wires. I just bought this engine (long block) rebuilt from a local auto parts store. When I had the intake pulled, I loosened a bunch of carbon deposits under the heat shield, but I never actually got in there and took the piece of metal off to see if I got it totally clean. Could that be the problem? When the car is running, I can see some fire coming out the exhaust manifolds and sometimes when it dies, fire comes out the top of the carb.

[This message has been edited by rogracer2 (edited March 06, 2005).]

Dirt Forum Champ
Total posts: 5390
posted March 06, 2005 04:09 PM  
Check the location of the distributor_I think maybe you are way out of time.

Dirt Maniac

Total posts: 111
posted March 06, 2005 05:07 PM  
I agree, distributor would be the 1st place to look...

[This message has been edited by MetricMonte (edited March 07, 2005).]

Dirt Maniac

Total posts: 127
posted March 06, 2005 07:22 PM  
ECHO ECHo ECho Echo ecoh eco
just got a laugh at this 1
isnt that what 17j told the guy ?

racing is way too cool gave up golf for it

Dirt Maniac

Total posts: 169
posted March 06, 2005 07:40 PM  
Is fuel getting up to the carb? Seen that before myself.

Dirt Full Roller

Total posts: 34
posted March 07, 2005 04:58 AM  
ya I had that problem this year, check and make sure part of your line didn't have any water in the fuel and froze over the winter, if your in the north east at least. You will find that it will be the last piece of line check, that's just the way it happens for me.

Dirt Full Roller

Total posts: 70
posted March 07, 2005 01:50 PM  
I agree that the timing could be way off but I have never seen anything 180 off that ran at all.

Dirt Maniac

Total posts: 167
posted March 07, 2005 02:37 PM  
bad way to break in a motor for sure. the primeing with lot's of gas and the endless cranking has prob thrashed motor already. Find a friend with some good knowledge to help you out. the first start up is very important for cam break in.

Dirt Maniac

Total posts: 167
posted March 07, 2005 02:40 PM  
hope fully for your sake timming chain was installed incorectly at factory and you can warranty the motor.

Dirt Maniac

Total posts: 119
posted March 07, 2005 07:41 PM  
I replaced the gas - that seemed to help at least start the car more frequently now. It still backfires quite a bit after about 15 seconds of running. I checked the timing - it was set correctly. Checked the fuel pump, that is good. I did a compression test - the valves all check out good. What about the distributor cap? When I pulled it off I noticed burn marks on the piece of metal on the top of the rotor as well as each spark plug tower electrode (under the cap). Could this be causing the backfiring?

[This message has been edited by rogracer2 (edited March 07, 2005).]

Dirt Full Roller

Total posts: 40
posted March 07, 2005 08:29 PM  
I don't think the "burn marks" are the problem. You've got spark, fuel, and compression. And assuming everything is in time, I would start looking for a vacuum leak - a big one. Additionally, the new style sbc heads and the old style sbc heads have the intakes machined at different angles. So if you have new style heads and an old style intake (or vice versa), you have a leak. I don't think it would be a timing problem because it runs right for 15 seconds - a timing problem wouldn't run right at all.
You bought this long block rebuilt and it had carbon build up in it? Scary.

[This message has been edited by dm3 (edited March 07, 2005).]

Dirt Maniac

Total posts: 119
posted March 07, 2005 10:43 PM  
The carbon deposit was on the old intake - not the new long block. I just cleaned it off and bolted it to the long block. All the bolts and everything lined up good.

Butch Stage
Dirt Roller

Total posts: 11
posted March 07, 2005 10:45 PM  
did you get a new coil cap an rotor
if so check to mack sure that all your wire's from old cap are in place in new one
i've done this before the frist time i did this it took 3 other to help me out
hope this help's

Dirt Forum Champ
Total posts: 968
posted March 08, 2005 05:21 AM  
17j and I were posting the same thing at the same time--now that's a scary thought! LOL!
If you are SURE sbout the timing (and firing order) look for that big vacuum leak someone spore of earlier.

Dirt Maniac

Total posts: 128
posted March 08, 2005 06:44 AM  
If you have checked timing, carb, and valves are adjusted correctly, then there is only one other thing that can cause this. As mentioned already, its most likley cap, rotor, or both or crossed wires. I have seen valves set to tight cause this also. If you have hydrolic lifters, maybe after start up, lifters pump up and valves don't seat tight and cause the backfire.

sc1 racing
Dirt Freak

Total posts: 419
posted March 08, 2005 02:58 PM  
sounds like the module in the distributer to me. either that or a sticking valve.

Dirt Maniac

Total posts: 119
posted March 08, 2005 07:15 PM  

The engine runs good now - here's what I think happened:
1. The gas was bad.
2. Bad gas messed up the spark plugs.

I replaced the spark plugs, and it sounds great now!

Thanks again to everyone who gave me some advice - it was appreciated.

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