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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: Ben_Greenberg on August 16, 2014, 09:46:52 pm
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Hey everybody,
I wish my first post on this forum wasn't under these circumstances, but my wife and I bought a new to us 78 c15 with the 350ci 5.7 and we did all the usual tune-up items, new fluids, air filter, PCv, plugs and wires, and checked all the hoses.
We also took it to our favorite classic car mechanic to get the timing dialed in and the carb tuned up. At that time we were also having trouble with idle droop when in gear and getting the truck started in general. Turned out we had a fuel leak in the line from the tank to the pump.
We got the truck back and it started right up. Got it home and let it sit overnight. Now it won't start up again. It will crank and crank but will not fire up
Any thoughts?
I haven't replaced the distributor cap/rotor or the fuel pump which is the last few ideas I have left. Any help is greatly appreciated! Thanks everybody! Looking forward to years of future trucking after getting this little hiccup resolved.
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When it's a cold start are you pumping the gas twice before your turning the key?
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I am pumping the gas a few times before turning the key for a cold start and still nothing.
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i'm thinking don't pump it so much---only once may be all you need. What carburetor is it?
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Its 4bbl i believe.
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Right, but which 4bbl? Can you provide a pic?
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As soon as im home ill be sure to take one.
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(http://tapatalk.imageshack.com/v2/14/08/17/9744dcb52db605c484011491191e1230.jpg)
(http://tapatalk.imageshack.com/v2/14/08/17/2608c5313acd51d6af67140da17a68dc.jpg)
There are a few pictures of the carb. I was able to get the truck fired up, but it took letting it crank and pumping the gas pedal at least 4-5 times.
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Sounds like you have fuel delivery problems. when you open the throttle is it spraying fuel?
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When the truck is running? I haven't checked. I was wondering if the fuel pump is on its way out. It looks old if not original. Gasket is definitely old.
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After is has been sitting?
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After it has been sitting and I pull the throttle back nothing appears to be spraying. Having said this, after pulling the throttle back a few times to check for fuel spray my wife started the truck up first try with one good pump before turning the key. Not entirely sure what that means, but this thing is incredibly inconsistent.
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Captkaos,
Should I see fuel spray when I pull back the throttle on the carb when the truck is off? Im afraid I dont know much about carbs, any help is appreciated!
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Yes
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Shoot, so should I be ready to replace the fuel pump and filter? And pushrod for good measure? Or could the culprit be elsewhere?
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If you are pumping the throttle you won't see any fuel spray. After you've discharged what's in there you won't get any more fuel until you replenish it. Nevertheless back up:
When it won't start, give it a shot of starting fluid. If it fires up you know the problem is fuel related. If not check for spark.
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Spark should be good unless the distributor is shot. The plugs and wires are brand new. I will try some starting fluid.
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Alrighty! So I tried the starting fluid and it fired right up. Didn't stay started ie. Wouldnt idle, but after doing it again and pumping the gas the truck fired right up. Am I looking at fuel pump issues?
As always, any and all help is appreciated. You guys are awesome!
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Its time to try the fuel pump. After todays little project of replacing that and belts we will see how the truck runs. Fingers crossed!
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The other thing i don't like to see is that there is a rubber line running from fuel pump to carb. Probably not real safe.
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Alright! So far so good! After installing the new pump, pushing the throttle down a few times to prime it all up and the truck fired right up! I will keep things updated. Thanks everybody!
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Well... the problems continue. Hesistant start, once started if I shift into reverse or drive too soon after starting stalls out and dies. Any thoughts? At this point I have replaced the fuel pump, plugs and wires, fuel filter, belts (not really associated) and had my regular mechanic time it by ear as the marker is gone and the harmonic balancer... doesnt appear to have any marks on it.
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Choke.
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I will take a look this evening. Thanks Stewart!
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Yep sounds like it needs more choke
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Yep sounds like it needs more choke
does that mean that the choke needs to be closed tighter when first starting? Or do I need it to be more open when starting?
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closed,open throttle 1 time when cold and choke should set closed with some spring tension on it.then adjust daspot\choke opener to maintain idle till it warms up
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So, the plot thickens. Now the engine wont crank and there is a quick ticking noise when I turn the key. Starter? Any ideas?
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Make sure the battery is fully charged, check your connections at the battery and ensure the ground cable is securely fastened to the engine block.
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I will definitely do that! The battery should be good, but connections are worth checking.
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Well I was wrong. The battery is now dead after letting the truck sit for a day after hearing the ticking sound. The only thing I can think of that would have drained it is the dome light. I just replaced the bulb and I couldn't figure out how to operate it, so I figured I have a bigger electrical issue somewhere else, but that is the only new thing in the truck that takes power... Any thoughts? The battery is charging now.
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dome works off of door jamb switches and headlight switch.Make sure h\l switch knob is not turned all the way to the right
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the starting problem to me seams to be maybe the carb is still dripping gas after the engine is off and siphoning all the fuel out of the bowl. then when you try to restart theres no fuel in the bowls. or the fuel pump is allowing fuel to return back to the tank. since you just replaced the pump that kind of narrows that down.
take the breather off start the truck let it run, then turn it off and look and listen down the barrel of the carb you might be able to hear it and see fuel being dripped out. if so the well plugs are shot and need to be repaired. another test is once you get it started for a minute or so turn it off clamp the rubber supply hose to the carb. (this will prevent fuel from back flowing into the tank) let it cool the normal time when you have problems and remove the clamp and try to start.