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q-jet

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xsmokey11499x

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Hey guys. Picked up an 84 k5. 350/700r/208 setup
.
Has a qjet on it.. starts and idles fine. When you give it gas it starts to die unless you ease into it. Then it stumbles the whole time.
 
xsmokey11499x said:
Hey guys. Picked up an 84 k5. 350/700r/208 setup
.
Has a qjet on it.. starts and idles fine. When you give it gas it starts to die unless you ease into it. Then it stumbles the whole time.
Click to expand...


here's a ton of good info if you want to dyi clicky :waytogo:
 
Mark1968 said:
That's a great link. Here's another

http://www.vetteprojects.com/kstyer/quadrajet.htm
Click to expand...

Ok well I threw an edelbrock 1410 marine carb on there. It was a freebie. It idles now. Won't stall out. But now idk what the problem is . Still feels like it lacks power.. and the exhaust sounds Like it's popping or putting. This sounds is coming out of muffler [YOUTUBE]https://www.youtube.com/watch?v=_QFLOWNUUrw&feature=youtube_gdata_player[/YOUTUBE]
 
What Kind of mileage? Check timing, readjust the carb mix mixture, check for vac leaks, vac hoses and hose connections. Look at the plugs. Basic tune up. Check valves with a vac gauge on it to see if the needle bounces around. Do a compression test. Take the oil cap off and see if you have excessive pressure/smoke coming out .

Just a few thoughts.
 
also put a new fuel pump on and filter there is a little bit of smoke when I pull off to or oil cap but not excessive I would say it's about normal. it seems to rev up ans idle ok.. but that popping noise and then it runs like crap and sounds like crap when under load
 
It could have a bad camsahft lobe,that will not show up on a compression test usually also..

If you take off the air cleaner and rev it up quickly and let it get up to about 4500 rpm for a few seconds,and you hear a gargling noise or any muffled backfires coming from the carb while its accelerating (it may spit back thru the carb,so dont lean right over it)--then its a good bet you have a camshaft lobe going out..you can confirm it by taking off the valve covers and watching how far each rocker arm moves with it idling (oil will spatter everywhere so be prepared!)--if one or more rockers dont seem to be moving as far as the rest,the cam lobe for that valve is wiped out and rounded over,and the valve lifter will be ruined as well..

Hope its just something simple like bad plug wires or plugs,distributor cap,etc,and not that...unfortunately many older chevy's with flat tappet cams seem to be eating lobes more than ever lately,now that motor oils lack the zinc additive they used to have to prevent lobe wear--all the newer engines have roller lifters and dont have that problem..
 
I had the bad cam lobe experience also, Idled fine, reved fine. But under load it would pop thru the carb and lack power, light throttle it was ok.
I think mine was #6 intake lobe but it was a while back.
 
Either way it could be a worn cam or valves. Start with the basic tune up and go from there.
 
Yeah,if an intake lobe wears down,that cylinder will be weak,it cant suck in the right amount of air & fuel mixture..if an exhaust lobe wears down,the exhaust cant get out of the cylinder fast enough and builds up in it,and it'll tend to try blowing back thru the intake valve next time it opens and out the carb..most cam lobe failures I have had on chevy V8's were the exhaust lobe on #1 cylinder,but I have had a few that wore several lobes down..
 
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