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73-87 Chevy _ GMC Trucks => Fuel Systems and Drivability => Topic started by: 88rxna on October 14, 2019, 09:23:37 pm
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The other day my 84 c10 with a jegs 350 almost died as i was climbing a grade. I had to feather the gas to make it the rest of the way.
Now its having trouble staying running. Sometimes it'll idle fine, other times it may stall. Sometimes it'll fire right back up, other times i need to use starting fluid and itll idle fine after it starts. Heres a list of things of tried:
Changed fuel pump and filter
Checked vacuum advance with a vacuum pump, fully opened at 12psi and held open for 5 minutes
Checked cap and cleaned contacts
Checked wires for distributor
Checked plug wires at night for arcing
Im really not sure what else to look for as im prettt new to carbs? Any other ideas?
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Here's a few pictures of the carb(https://uploads.tapatalk-cdn.com/20191015/60dd7403fd480f369c8385dffa709ece.jpg)(https://uploads.tapatalk-cdn.com/20191015/48197f9db41d8966b085011111bd0ce4.jpg)
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The first problem is uremco..... Do you still have the original carb?
i would want to check the float level first.
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Did you check you fuel level?
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I filled up with 93 the day before.
Unfortunately i do not have another carb to try.
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Heres a plug...
But i did find that the rotor wires to the cap wouldnt clip onto the cap correctly (clip is loose). I zip tied it on for now and itll drive decent but and sometimes i can even give more than 1/4 throttle..
But itll still stall out and wint start unless i give it starting fluid.(https://uploads.tapatalk-cdn.com/20191015/51cfaf43e4f01610f363d1e26cafc8dd.jpg)
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Looks pretty lean.
You said 'filter'. Did you check the one at the carb intake or just the inline?
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I changed out the fuel filter on the carb it does not have an inline fuel filter.
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Measure fuel pump draw (>20" Hg), pressure (5-7 PSI) and delivery (1+ qt within 30 seconds of cranking). Transfer the fuel into a clear container. Is the fuel sample cloudy or does it separate into layers after sitting for a minute? Check the spark from a plug wire disconnected from an easily accessible spark plug. Will the spark jump a 3/4" air gap? Is the spark blue?
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Does the vehicle have single or dual fuel tanks? Check the condition of the rubber fuel hoses all the way back to the tank(s). Make sure none are stiff, cracked, or pinched.
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In your pic with the "Rochester Quadrajet" in it, Is that fuel on the gasket? could it be leaking or causing a vacuum leak?
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Is there a mounting bolt missing in the first pic? What is that hole for?
Is the timing set properly? Perhaps the distributor slipped.
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Saying you had to feather to get her up the hill sounds like you had enough fuel entering the bowl, so you could keep momentum by deploying accelerator pump as extra, richer source of fuel. Was that a run-on sentence? ::)
I think you have gunk in the carb and or clogged jets/metering rods, etc.
Get her running and spray carb cleaner into the bowl vent, the center tube just ahead of the primaries (little barrels). It's about 3/8" diameter.
You will probably start to flood if you don't gas it, so gas it while spraying into the vent. Your float bowl will regulate the level for the most part.
Doing this will clean the internal passages where gas flows.
If that does not do it, pull the top off the carb (not that intimidating) and look for gunk in the bowl and the inlet where the needle seats. Could be a chunk of rust or other debris.
Next, looking down the barrel of the primaries, you will see little opening ahead of the venturies, (round tubes suspended in the middle of the barrel) Get the red tube of the cleaner to blow those out. You will know it if they're clogged.
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Thank you all for the suggestions..i really appreciate them.
I ended up having a rebuild kit sent to me and will tackle it this weekend. The carb is pretty bad on the outside so i can only imagine what the inside will be like.
Before i tear into it i will try your suggestions johnnypopper.
When i last messed with it, it would start right up and idle for about 5 or 10 minutes then run out of fuel and stall. If i would let it set for 5 minutes it would fire right back up and repeat the same thing.
When id first start it i could rev it pretty good without a hiccup, afyer a few minutes, not so much...then it would just die.
I opened the gas cap ( when it would start ti stall) hoping it was a vacuum issue but it did not make a difference.
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You might also want to find a copy of the Cliff Ruggles Quadrajet book. Its organization can be a little confusing if you are new to Quadrajets, since it has descriptions for all years and models, but it has all the information you need to make a basic rebuild go more smoothly. I know Amazon sells it, and it might even be in a local library.
Bruce
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Per instructions from bd, i removed the fuel line from the carb and cranked the truck. I got about 4 good squirts before it fizzled out and stopped... id let it set, try again and it would do the same thing. Its a single tank truck with a newer tank.
I recently had the bed of so i wonder if i crushed a line enough to starve it? Guess ill be crawling under the truck in the AM.
again, i really appreciate the help!
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I also removed the cap during that test to see if i had a vapor lock and it made no difference
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Sigh...(https://uploads.tapatalk-cdn.com/20191020/347bec163f350521e9f878929466f0e6.jpg)
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Something sounds weird-
Try repeating what you last wrote and AFTER it dies, look down the carb and pump the accelerator to see if there is gas spraying down or not.
If it's spraying, and it's still dying, it might be ignition.
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I get lots of fuel to the carb now after replacing the kinked lines..but im waiting on parts for the carb now. The float was cracked and the needle connected to the float had no clip whatsoever.. not sure how it was functioning?
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Wow, good catch! I think you will be please with a better running truck when you get the carb rebuilt.
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Thanks! Shes running thanks to all of you! Got the parts in today and fired right up!
I had a vacuum guage shipped today too to tune the carb so i guess we will see if i can get it dialed in.
Ive found a few videos on YouTube so lets hope i get it right..lol
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