Engine Backfire Diagnosis Led to Wiped cam Lobes

[DoubleDingo]

This is the link to where I got the manuals. http://carburetor-manual.com/ It took about an hour for them to become available for download.

 

[Skweegle89]

85swb "Fancy"

It is a must to have more than one running vehicle for times like that when you are struggling to get one back on the road. But it can get expensive to keep them all maintained and fueled too.

Luckily it's a newer truck, and my wife has a new car, so at least I can get around. Sometimes I wish it was my only ride so I would be more motivated to fix it. Thanks for the link, I will get on ordering that so I know a bit about it. I also found a sticky on the qjet on this site that has a lot of good stuff on it. Luckily the carb was built for me, I just have to fine tune it once I get the truck running.


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[Skweegle89]

85swb "Fancy"

Got the plugs in, she fired right up. Went to set the idle mix screws and get no rpm change no matter how far I turn them in either direction. What's the deal?


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[Quadrajet Power]

Got the plugs in, she fired right up. Went to set the idle mix screws and get no rpm change no matter how far I turn them in either direction. What's the deal?


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That would indicate there is still a vacuum leak somewhere. But make sure engine is warm and choke is all the way off, and engine is idling at regular rpm, not fast choke idle.

 

[Skweegle89]

85swb "Fancy"

It was warm, choke was off. I filing fine. Guess I will get back to looking for a leak.


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[350runner]

Try backing off the throttle screw to bring the carb running off the idle circuit

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[Skweegle89]

85swb "Fancy"

Well when I first started it the idle would surge a bit. Idle real low and then idle back up, so I increased idle speed a bit and it quit. I will back it off and adjust them again.


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[Skweegle89]

85swb "Fancy"

I can't find a vac leak anywhere. Been squirting and looking for an hour. Backing off the throttle screw didn't help me any with adjusting idle mixture. I have a bit of lifter rattle going on. Still won't hardly start when it's warm and then it fast idles, even when choke is open and engine is warm.


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[Skweegle89]

85swb "Fancy"

Don't seem to have vacuum at any of my manifold ports on the carb. Can unplug them with no change to idle. Gas dripped out of the bottom left one when I unplugged it. About to say *** it and just take it to a mechanic.


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[350runner]

Sounds like you still have a vacuum leak of some sort. Are you ask getting that thick gasket?

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[Skweegle89]

85swb "Fancy"

No I'm going to pick it up when I go back to town. But iv sprayed all the way around it with carb cleaner and WD-40 and can't ever get an RPM jump. Once I get it on the road it runs great. Kill it and start it again and it won't keep an idle unless you feather the throttle. Then fast idle kicks in 30 seconds later or so, even when the truck is warm. My old choke didn't work, so not sure if this is normal or not. Guess I will swap gaskets when I can get back to town and see if anything changes.


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[350runner]

Ok. Start up the engine and let it idle. Cover the primary choke you hand covered in a towel. If it chokes the engine is possible you have no leaks. If the rpm goes up or stays the same then you still have leaks

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Edit.

 

[Skweegle89]

85swb "Fancy"

I did as you said, and it killed it.


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[350runner]

Ok. I'm thinking this has to do with the secondary side bein open a hair causing this high idle. How many ports are on the front and back of the carb?

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[Skweegle89]

85swb "Fancy"

I will check when I get home and get back with you.


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