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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 75_chevy on February 25, 2014, 05:48:43 pm
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350 crate not running very good. brand new carb edel 1406. carb has not had new jets and I've heard that usually comes factory - not tuned - more info on that?
it seemed to be running great with the carb so I don't think that's it. I have cheap spark plug wires from summit two already melted and have been replaced. also I bought a blue distributor cap (just the cap) and I put it on. my motor is seeming to have a very choppy idle. when I start it at 5 in the morning it almost doesn't want to run at all. revs very low when cold. when shifted to revers it revved at 300-250rpm. not normal. when it is warm it still does it as well very choppy idle. runs good when actually driving. I just realized te dist cap was not fully on. one of the push in anchors won't anchor and I broke it. could this be the cause of poor idle? I'm going to replace it either way but what else could be going on. I really want to know my truck but I can only learn so much each day. thanks y'all (http://img.tapatalk.com/d/14/02/26/a6aqebyt.jpg)
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Do not use cheap ignition components.
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have you adjusted the idle screw on the carb?
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learned the hard way vile I plan on replacing all the wires with good quality replacements. speaking of which, any noticeable benefit from larger millimeter plug wire?
mike: yes a few times. gonna watch the vid on it and gonna do it again just to be sure it's where it should be
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oops I thought you meant something else sorry yes I've adjusted the idle screw
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I may add the idle when running normal in park is around 1k rpm, vs when I start it in the morning it will struggle at 600 rpm then when put in gear drops to like I said around 300rpm
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#1 fix the cap if you haven't already.
#2 I'm trying to follow, but I think your truck idles poorly while cold but ok while warm, although choppy.
Do you know anything about the cam that is in it?
Thirdly, Is the choke adjusted correctly? Is the fast idle screw adjusted?
It sounds like to me, and I'm not the sharpest tool in the shed, but it is almost like the fast idle is set too low and when it gets off fast idle the normal idle is fine and takes over.
What is you timing set at?
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When you swapped the carb where you careful not to get the vacuum line to the distributor mixed up? You could have the vac advance hooked up wrong.
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1k in park is pretty high if you're talking about after its warmed up. If it drops that much after you put it in drive you may have a vacuum leak. Fix the obvious ignition prob's first. Check for vacuum leaks, check proper choke operation and high idle setting. If there's nothing else wrong you should just set the high idle higher.
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thanks for all the input y'all. as far as cam specs it's in this pic ill post, unless the po replaced it but I doubt they did. (http://img.tapatalk.com/d/14/02/26/rumesyna.jpg)
also attached a pic of #1 spark plug cuz I'm doing a compression test does it look weird? looks to orange to me(http://img.tapatalk.com/d/14/02/26/9eqyga4y.jpg)
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plug looks good. i dont care what wires you have if you let them touch the exhaust they will melt. but you dont need a bigger wire or the most expensive wire. i use the wires from the parts stores
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Make sure that the choke is working, and that the high-idle cam is working.
Make sure you have the distributor vacuum advance lead connected to manifold (driver's side) not ported (passenger side) vacuum port.
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When I turn the key the choke opens up so I believe that means it's working, should I still check to see if it's getting 12v ? I also leaned out the choke and now I stripped one of those t20 screws so I can't move it back..
high idle cam? that's the screw under the regular idle screw right? is clockwise faster idle or slower?
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On a cold engine, the choke plate should stay shut for several minutes after the ignition is turned on, then gradually open.
Before starting, depress the pedal all the way to the floor once to reset the idle cams. When you start a cold engine, it should be on the high-idle cam. After the engine has warmed up and the choke opens, it will be stuck on the high idle cam until you give it a shot of gas, then the cam will rotate out from under the screw and you should fall to the normal idle screw. Clockwise on both idle screws is more throttle/faster idle.
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ok cool thank you! and have you used a multimeter? I'm trying to see if I'm getting 12v but it's not reading anything. I have the dial turned to dcv 20 and it's reading 0's
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Put it across something known, like a 9 volt battery, and play around until you get the right reading. Then use it to measure the choke voltage.
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The red lead on the connector to choke, the black meter lead to something steel on the engine or battery negative. You will only have 12 volts with the key on or if you're going through the factory oil pressure switch then only when the engine is running.