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Runs good until it warms up, then


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I got a freebee donor car today from a guy at work. An 88 caprice cop car, carbed 350 (hopefully a 4 bolt) 700r4. He said it runs good and you can stomp and it pulls hard, but after it warms up it dies, it will start again, but it spits and sputters and don't want to go.

So here's the deal. The car is 40 miles away and I have to move it soon. I don't have a truck or trailer. I can come with one, but in that 40 miles is mt. pass that is no trailer traffic now and going around is 110 miles, so I really would like to drive it home.

I'm well versed at gas, spark and air. I'm hoping someone is familiar with this problem. I'm going to go play with it this weekend and I'd like some ideas on somethings I might check. The cars out in the weather and it's winter. All .02 welcome.

 

Randy

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If we assume the fuel pressure is good initially, but is it staying up at full pressure till after the engine dies?

And are you checking the pressure at the fuel rail?

I am wondering if it is running on the initial three seconds of fuel pump, then the relay dropping out.

Something else to consider is that it could be a spark problem, but checking to see if spark is present AFTER it quits running may be tricky. But if it does it time after time, I would connect a spare spark plug to one of the wires, and ground it, and see if spark continues after it dies...just a couple hits. But that will help you decide weather to concentrate on fuel or spark.

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I had a brainstorm, and thought about a buddy of mine who had a similar problem. His fuel pressue was good, and so was his ignition module. However the problem was his coil or the wire that ran to his coil I don't remember. But that solved the problem. So I would give that coil, wires, and cap a VERY close look and be prepared to replace them. Make sure you post back here whated fixed the problem.

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It has a mechanical fuel pump. I'm wondering if it is just packing the fuel filter and it's not the heat, but I don't know why it would cool down and run. I don't think it's losing spark totally because it wants to run. I'll check

 

I have a cap. I'll take it with me.

 

thanks

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Any chance that the choke is messing up, opening early?

 

On my 350, it gets really temperamental just as it's starting to come off the choke, due to the choke opening up a bit before the engine is ready for it to.

When it's doing this, it doesn't want to rev up, and will sometimes stumble and sputter.

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I'm hoping to go check it out today, weather permitting, the mt. pass thing. My plan is to get it started, give it a visual check while it warms up.(gas line, wires) When it dies, check choke, pour gas in carb. If it revs, check filters, gas line routing. If it kills it, check dist. put on different cap, check wires, connections. If its not running, call it names, say WTF. sit down, smoke cig. scratch head.

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Just an idea...since no trailers are allowed through the pass, you want the car and don't have anything in it financially, why not call a flatbed wrecker truck and have it delivered to you? Then you can work on it at your leisure and not have to worry about it.

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Just an idea, it has happened to me. Check the valve adjustment. If it is to tight it will run fine cold until the engine warms up then the heat will expand the valve clearence and if it is already to tight it will make it worse. I would loosen them up about 3/4 of a turn assuming they are hydraulic stock lifters. Give it a try......

 

 

John

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I didn't think of that. The trailer is at work and my buddy's truck has a thirsty 502. so by the time I get the trailer back, It's worth calling a wrecker. If I don't get it running, that's what I'll probably do.

 

Thanks Randy

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