Does it still have the catalitic converter? It might be plugged.

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Not much of a computer on an '80.  Have you checked to ensure you have fuel?  Sounds like a fuel starvation problem to me with the info above.

Dennis is thinkin the same thing I am...fuel issue.
Once it dies, can you look down thru the carb(air cleaner off), pump the accelerator, and see any fuel squirting down the carb? If not, then there's your problem. Could be the pump, carb filter, or the "sock" filter in the tank. Sounds more like the sock filter, tho. It picks up crap while running, until it get stopped up, then dies. Once it dies, the suction from the pump is released, and the crap falls off.
It could also be the ign. module...another common malady...you may need to check to see if the plugs are getting fire when it dies. Sometimes, when the module gets hot, it will crap out, then once it cools, it'll work until it gets hot again.
There are a few other threads on this, with some testing info for the module. You may do a "search" in the "Engine" forums, and find one that will help.

btw...the ECM(computer) on that car really doesn't do a whole lot...it only controls the idle mixture, and timing. Being the 305, it must be a Cali car, so the fuel mixture is prolly gonna be lean to start with...

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Joel Adams
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I had that problem on my 90 Lumina. Dang car would stop on this on bridge everytime. We thought there might be some electormagnetic force in the area or the bridge was haunted. This happened 4x.  Sure enough it was computer module.

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Corvettes and women are the same...You want to make love to them but they keep breaking down.

How long before you can restart?  If it is jus a short time then it most likely is fuel delivery.  That is where I would start.

[QUOTE=dwright]Does it still have the catalitic converter? It might be plugged.[/QUOTE]

usually with a clogged exhaust the car will idle fine but will lose all power when you are driving. just went thru that with my 90. one other thing that might do it is the coil. had a car when it got hot it would die. after cooling a bit it would start right up. just a thought.


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LIFETIME MEMBER #97
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I had a simular problem. MartinsVette2007-10-29 21:26:03

Ok, here's what has been done.

Fuel pump on an 80 sux.  You will need to jack it up and pull the rt front wheel off to make it easier to get to.  Hopefully you have a long bolt to stick in the front of the motor to hold the driver rod in place to keep it from coming out.

Just seeing the fuel in the carb is not enough.  It is pumping quite a bit with a load.  Also the fuel filter may appear clear but may not be.  Did you try to blow through it?  I tried mine and wondered how to fuel could pass when I tried the new one.  Doesn't taste too good and but I never claimed to be too smart. 71Shark2007-10-30 16:27:51

Damn! I posted a response to this earlier today! Mustta got lost in cyber-space!

I was kinda thinking maybe jumped timing for a while, after reading the update, but...maybe not. Tim is right in the fuel squirting out of the carb has to be a strong, steady steam...not just a spit. It's the heat thing that keeps me going back to an ign problem. If the carb was low/empty of fuel, it wouldn't fill up after sitting for a few minutes...it either has fuel when it dies, or it don't. I think you have a weak spark, from the coil. You say you changed the module, but what about the coil? This is starting to sound like a classic case of GM coil failure.
You may try to test the spark when it dies. If you have a spare plug, any plug will do, start the car and let it run until it dies. Then quickly pull the easiest plug wire to get to off, and stick the spare plug in the wire, and hold it tightly against the exhaust manifold, while someone else cranks it over. You should see a nice, blue spark jump across the gap. If it is a faint yellow color, or no spark at all, you've found the problem. (You can also buy a cheapo spark tester at most parts houses, that will do the same thing.) Unless, of course, you replaced the ign. module with another bad one, which happens more than you might think.
Also, when replacing the HEI modules, be sure to spread the gooey grease stuff over the entire bottom of the module before bolting it onto the dist. This is a heat sink grease, that helps transfer the module heat to the dist. Without this grease, the module will fail.


I'm going with a bad coil, module, or pole-piece(pick-up)


(dam spel-chek!)Adams' Apple2007-10-30 19:25:04

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Joel Adams
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Don't forget,... if you suspect a fuel issue, always check the 3" fuel hose couplers ( just to the right of the gas cap) before replacing the pump. Even a pressure test is deceiving if the pickup line is sucking air.

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Jimmy B.
Just can't wait to get on the road again.

 
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I am still with ignition  - Coil, Ign module.

Ok, so I replaced the coil. No improvement. Same o, same o. Stops dead. Ignition module already changed earlier. I did spead the "gooey grease" over the entire bottom.

Get ya a large drain pan, and stick it under the fuel pump/line area on the pass. side. When it stops running, pull the rubber hose from the frame to the fuel pump off(Take the clamp off, and break the hose loose first, before starting, so it will be easy to get off.) Once it dies, pull the hose, and see if fuel comes out from the frame side of the line. If you have a steady stream of fuel, the sock filter is ok, and you may have a bad pump. If there is no fuel, or just a trickle, then you have either a stopped up sock, or a collapsed fuel hose at the tank end.
If you have an air compressor, and you find no fuel coming from the line, remove the gas cap, and blow back thru the metal line for a fews seconds. This will blow most of the crap off of the sock. If the sock is really stopped up, it might also blow the sock off completely. Either way, hook it all back up, and see how it runs then. If it seems to have corrected the problem, then out comes the sender unit, to change the sock.
It would be nice to have a pressure gauge on it, so when it does die, you'd know for sure if it was a fuel issue or not. There's just no easy way to do that without cutting the steel line from the pump to the carb, tho...or rigging up a "T" fitting on the carb inlet fittingAdams' Apple2007-10-31 19:09:05

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Joel Adams
C3VR Lifetime Member #56    
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"

How did you make out with this problem?