73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: nfinholt on May 27, 2016, 05:32:39 pm
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Hello,
First time poster, hope I do alright. My 1985 Chevy c10 died on my one morning when warming her up. It seemed like I ran out of gas but after a few trips to the gas station with a gas can, it's still not starting. I'm able to get some firing off of starter fluid so I assume that points to a fuel issue. I ran microphones into both the left and right tank to see if I can hear the sending units prime the lines and heard nothing. I can hear the switch kick in when I switch from one tank to the other. I'm also having difficulty finding the relay. I think it's on the ac unit. Does this seem right? I also plan to take the line off the pump on the engine and see if I can spew gas into a jar. Does anyone know if this truck actually has fuel sending units and not just a fuelpump? Where should I go next to diagnose this problem. It doesn't seem like a filter does it? I would guess that to be a more gradual problem. Thanks so much for your help!
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you wont hear a prim cause you should only have a mechanical fuel pump on the engine with that year. you might be able to hear the fuel tank control valve and you switch from tank to tank. be take the main fuel line off at the carb and run it into a jar of sort and try and start the engine and watch to see how much fuel (if any) goes into the jar. while youre at it if you have the original quad jet carb you might want to change it out since you have the fuel line off. it should be right where the fuel line screws into the carb it will look like a brass cone
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http://forum.73-87chevytrucks.com/smforum/index.php?topic=5220.0
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Hello,
First time post - thank you for your help and info. My 85 c10 suddenly died one morning during warmup. I can spray started fluid in the carb and she runs for a moment. Do you know if this truck had both fuel sending units and a fuel pump? I put a small microphone into each gas tank and turned the key and heard nothing in either. I could hear a click when hitting the switch to select the right or left tank. Also I'm unsure if I've correctly identified the relay - could it be mounted on part of the AC unit on the passenger side? The relay I found haa five pins in a T shape. Tomorrow I hope to pull the hose off the pump on the engine and see if I can get it to spew gas in a jar. Please offer any other suggestions of what I should do to futhet test the system and get her on the stree again. Thank you very much!
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First, welcome to the site. A 1985 should only have a mechanical pump on the engine if it stock as it came originally.
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Pull the line off the carburetor and see if fuel comes out when you crank the motor....if none comes out then make sure the fuel filter isn't clogged...then make sure none of the rubber lines are cracked before the fuel pump....and then make sure the fuel pump is working...i would do all this before condemning the fuel tanks.
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Thanks for the welcome - nice having such a cool community now that I'm a proud owner of a c10...
Interesting, no fuel sending unitis? Indeed it's almost entirely stock. So does this mean no relay?
Thanks for the tip, i'll try this soon and post the results.
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Hi Vile, are you suggesting I provide more info? 85 c10, 305 engine with quadrajet carb, mostly stock, anything else that would be helpful to know?
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Each tank had a sending unit to monitor the fuel amount in the tank but that is it. When you switch tanks the switch is supposed to flop both the lines per tank to and from the engine mounted mechanical fuel pump. No relays are present.
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Irish, you're referring to replacing the filter, correct?
Thanks
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Great call on the test - running the line into a clear container. I'm getting a good volume of squirts. I also put on accelerator and see so evidence of the carb squirting into the carb. The filter doesn't look bad and I washed it around in some gas, nothing came out though I'll still replace it. What's next, pull the carb and check the float? Do a carb rebuild kit?
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Hi Vile, are you suggesting I provide more info? 85 c10, 305 engine with quadrajet carb, mostly stock, anything else that would be helpful to know?
Yes, your post makes it sound like you EFI. You won't hear anything in the tanks as your truck has a mechanical fuel pump. If you have dual tanks, the tank switching valve is on the passenger side frame rail. If it runs with starting fluid then it sounds like your tank switching valve may be the issue. You can try bypassing it from one tank directly to the fuel pump and see if that solves the problem. If it does then, get a new valve.
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EFI is electronic fuel injection right? I do have a quadrajet carb and don't see any systems like a rail or injectors that make me think it's fuel-injected, just a good-ol' corroborated engine. And I am getting gas to spew out of the main fuel line into a container which makes me think and I am getting some flow (though I will be testing the pressure soon), and that the engine should at least run or try to fire. Up until the fuel filter things are visual functioning which leads me to believe that it's the carb, and I would also think that the fuel filter is not the issue because it seems clean and I imagine it to be a gradual problem instead of the vehicle just dying like it did. Am I off?
I plan to run the pressure test, replace the filter, and do a carb rebuild kit. Seem like a good plan?
Thanks,
Nils
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Pressure is irrelevant for your issue. If you are getting the volume then ignore my previous post. If you are getting fuel to the carburetor but it will not run unless you spray starting fluid or carburetor cleaner in it then it's time for a rebuild or replace for the carburetor.
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**No need for two threads on the same topic/issue. -Merged**
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Ok here is a trick you can do.....tap lightly with a hammer on the carburetor where the line goes in as someone cranks it over....it is very possible that you got some trash in the carburetor.