73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Fuel Systems and Drivability => Topic started by: kj4ltc on July 22, 2019, 10:47:33 pm
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Ok guys, I’m about to lose it...when I depress the gas (engine cold) the choke does not close, it still has full spring tension holding it open. I don’t know what I’m missing or overlooking. I also can’t figure out how the high idle is activated. If anyone has diagrams or anything that could help...I’d really appreciate it!
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Before I tried to start the truck today I manually adjusted the choke closed, made sure the vac line for the rear pull off was connected and capped all unused vac ports on the carb. Truck idled nicely for 15-20 mins before stalling. After it stalled I waited a little bit before going back out to crank it back up. Got it to start, and began immediately stalling out. This is my first carb vehicle and I don’t know where to go next. I need this truck up and running reliably.
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Quadrajet E4ME (http://www.73-87chevytrucks.com/techinfo/7387CKMans//Service/ST_330_83_1983_Chevrolet_Light_Duty_Truck_10_to_30_Service_Manual.pdf#page=784) (feedback) or M4ME (http://www.73-87chevytrucks.com/techinfo/7387CKMans//Service/ST_330_83_1983_Chevrolet_Light_Duty_Truck_10_to_30_Service_Manual.pdf#page=888) (conventional)? Post a pic of the carburetor. Descriptions, drawings, and adjustments of both styles are in the service manual.
To get you started, perform some basic checks to help narrow the cause of the symptoms. Don't make any assumptions. How many miles on the vehicle/engine? Verify a consistent ignition spark. Is the spark blue or reddish? Check the condition of the distributor cap and rotor. Verify the ignition timing. Measure fuel pump draw, pressure, and volume. Use some aerosol carburetor cleaner and spray for vacuum leaks around the carburetor and intake manifold. Check/replace the fuel filter behind the carburetor fuel inlet nut. Are the two idle mixture screws accessible for adjustment or are they still capped? Will the engine continue to run if you mist carburetor spray into the airhorn or hover the carburetor with a shop rag (wear gloves while doing this to protect your hand from backfire). Performing and reporting on these checks may provide a little more information to help us help you.
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Where do you live (for weather reasons, specifically temperature)?
And how did you "manually" adjust the choke closed?
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Live in Kentucky, weather is mid 80’s. I manually adjusted the choke by loosening the 3 screws on the side of the electric choke housing and rotating it until the choke was nearly closed. Engine ran excellent for 15 mins or so....choke never moved, engine stalled out and after starting back would not idle without me tapping the gas pedal to keep it running. Got mad at the Q-jet and bought an Edelbrock
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Too bad, a QJet in good working condition is a fine thing!
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If it never moved the choke coil is bad or no power to it. That’s why it was adjusted wide open because it didn’t work.
Choke pull of plays a part in this also. Pulls the high idle lever down while the choke coil is heating up and opening among playing a part in the secondary operation.
Has to be working to further T/S.
Power Goes thru an oil psi switch and possibly a relay if you have a choke light on the instrument cluster.
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did you replace the carb?
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Live in Kentucky, weather is mid 80’s. I manually adjusted the choke by loosening the 3 screws on the side of the electric choke housing and rotating it until the choke was nearly closed. Engine ran excellent for 15 mins or so....choke never moved, engine stalled out and after starting back would not idle without me tapping the gas pedal to keep it running. Got mad at the Q-jet and bought an Edelbrock
Analysis: 15 minutes brought engine up to operating temperature. Engine stalls out because it's running too rich. Bad bad Q-Jet!!!
Is it possible that some guys don't know what a choke is for? I'll bet he's saving money on gas with better mileage!
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I know exactly what a choke is for, what I don’t know is the best way to set choke and adjust carb. Next thing you know you got keyboard warriors that would rather criticize then offer any help. Either way the q-jet is off, Edelbrock is on and running flawlessly
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Didn't mean to off-end, partner.
Seems like you just gave up before anyone could assist, but given your frustration level, I don't blame you.
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I know exactly what a choke is for, what I don’t know is the best way to set choke and adjust carb. Next thing you know you got keyboard warriors that would rather criticize then offer any help. Either way the q-jet is off, Edelbrock is on and running flawlessly
ok
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You can send me that carb if it’s not remanufactured
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Beat me to it Blazer!
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I know exactly what a choke is for, what I don’t know is the best way to set choke and adjust carb. Next thing you know you got keyboard warriors that would rather criticize then offer any help. Either way the q-jet is off, Edelbrock is on and running flawlessly
kj4ltc - Good news, the reason Blazer74 and JohnnyPopper want your carb is because IF it is original to your truck, it is one of the most ideal rebuild & upgrade viable Qjets made. Forget all the nonsense about early 70's GTO carbs - early 80's truck Quadrajets are the best (for certain values of "best").
If you could read off the number from the vertical plate just behind the throttle shaft, likely 17085??? that would be ENORMOUSLY useful. Absent that, a quick photo showing the passenger side of the carb with the air cleaner off would help us solve your problem as well. Both would be best.
Assuming you have the E4ME referenced by BD earlier, that means an electric choke version and there are two fairly inexpensive solutions to your problem, all related to the choke. Based on one of your replies, I'm assuming that is what you have.
#1 - there may be no power to the choke to activate it, and of course then it doesn't work as intended. Remove the clunky power cable attached to the choke, start the engine and confirm using a multimeter that a full 12 volts is present at the choke. Low or no voltage means the electric choke won't work as intended.
#2 - If 12 volts are present in the cable, then the choke coil needs to be replaced, properly adjusted, and you'll have one of the better combined performance/economy carbs ever engineered. Yeah, I'm a Qjet fanboy - no excuses. I could go on, and on, and on about how superior they are to any substitute you might be considering or your buddy's are suggesting. Yes, they require slightly more knowledge and experience to realize their full potential, but I'm of the opinion it is all worth it.
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Too late Miner, it's probably being schmooshed into the landfill as we sit here.
He went to the E-Word dark side. :-[
Let's get back to dreaming of a perfectly jetted early model Qjet...
That being said, if it's still on your bench, start an auction! May the best man win!
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I can’t guarantee or confirm that the carb is original to the truck. There is no series number imprint or tag on this carb, I have sent several pics to quadrajetpower.com and they said it does appear to be a 17083224. I would say the choke system had issues other than just the 12v power source as the electric choke on the Edelbrock works fine. With the engine cold, my understanding is that a tap or press of the gas pedal should close the choke, after starting the pull off would slightly open and 12v to the coil would gradually open as it warms up.
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Thanks for the update, sorry it went to somewhat of a dead end.
You're spot on about the choke functionality, when they work it's a wonderful thing.
Common issue is when someone takes the element off behind the 3 screws, and doesn't re-align the spring with the actuating arm.
It just sits there getting hot and moving nothing.
Found this on your number: http://www.carburetion.com/CarbNumber.asp?Number=17083224
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The spring was engaged on the arm, but regardless of temp the choke was not functioning. I couldn’t get it to idle correctly. I may get the q-jet rebuilt in the future or may do a LS swap. My first plan was to keep the q-jet on it, but I needed the truck up and running pretty quick, so the Edelbrock performer got the nod.
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Going to keep it? You ship I’ll pay the ride.
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I'd bench test the 12v coil and see if it moves. Bet you a doughnut it's dead.
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I know exactly what a choke is for, what I don’t know is the best way to set choke and adjust carb. Next thing you know you got keyboard warriors that would rather criticize then offer any help. Either way the q-jet is off, Edelbrock is on and running flawlessly
kj4ltc - Good news, the reason Blazer74 and JohnnyPopper want your carb is because IF it is original to your truck, it is one of the most ideal rebuild & upgrade viable Qjets made. Forget all the nonsense about early 70's GTO carbs - early 80's truck Quadrajets are the best (for certain values of "best").
If you could read off the number from the vertical plate just behind the throttle shaft, likely 17085??? that would be ENORMOUSLY useful. Absent that, a quick photo showing the passenger side of the carb with the air cleaner off would help us solve your problem as well. Both would be best.
Assuming you have the E4ME referenced by BD earlier, that means an electric choke version and there are two fairly inexpensive solutions to your problem, all related to the choke. Based on one of your replies, I'm assuming that is what you have.
#1 - there may be no power to the choke to activate it, and of course then it doesn't work as intended. Remove the clunky power cable attached to the choke, start the engine and confirm using a multimeter that a full 12 volts is present at the choke. Low or no voltage means the electric choke won't work as intended.
#2 - If 12 volts are present in the cable, then the choke coil needs to be replaced, properly adjusted, and you'll have one of the better combined performance/economy carbs ever engineered. Yeah, I'm a Qjet fanboy - no excuses. I could go on, and on, and on about how superior they are to any substitute you might be considering or your buddy's are suggesting. Yes, they require slightly more knowledge and experience to realize their full potential, but I'm of the opinion it is all worth it.
Could you get into more detail as to why? Not disagreeing as my Jeg's #15805 (same part# for Jegs and Summit) reman is an 84 truck core.
BTW, here is my original, non-remanufactured 83
(https://i.imgur.com/UOgRhcT.jpg)
And NOBODYS GETTING IT ;D
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You can send me that carb if it’s not remanufactured
Beat me to it Blazer!
Just curious, how much would you pay for an original 83 core?
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How bout an unexpired can of pinto beans? What's in that glass on the far side?
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I’d be willing to bet that mine is an original 83 also, as it looks identical to yours. I’d trade someone a 6L80 for it lol
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How bout an unexpired can of pinto beans? What's in that glass on the far side?
Canned food doesn't expire, partner.
You'll have to excuse the dirty glass and table; i was very busy. Also, i don't drink that much monster, but i was working night shift at the time.
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This just popped up on my 'Tube feed, too late though......
Can Youtube monitor what you are viewing online? This is eerie.
https://www.youtube.com/watch?v=_BTEdWt2V3s
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kj4ltc - Good news, the reason Blazer74 and JohnnyPopper want your carb is because IF it is original to your truck, it is one of the most ideal rebuild & upgrade viable Qjets made. Forget all the nonsense about early 70's GTO carbs - early 80's truck Quadrajets are the best (for certain values of "best").
If you could read off the number from the vertical plate just behind the throttle shaft, likely 17085??? that would be ENORMOUSLY useful. Absent that, a quick photo showing the passenger side of the carb with the air cleaner off would help us solve your problem as well. Both would be best.
Could you get into more detail as to why? Not disagreeing as my Jeg's #15805 (same part# for Jegs and Summit) reman is an 84 truck core.
Stewart - I'm an accolyte and student of the Cliff Ruggles school of Qjet worship, and he hammers home on his forum that the early 80's truck carbs (pre-computer) are the ideal base for rebuilding and optimal tuning to modern engine configurations. I'm afraid I can't quote chapter and verse on exactly why, but I've had such great luck with my carb after buying his book and following his recommendations that I just take it all as gospel now. What REALLY made me a convert was when I was able to set up a buddy's truck better than both he and his dad ever remembered it running. All because the primary hangers were bent and not even engaging the primary jets properly.
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That's not an expiration date on your can of beans? ;)
That youtube crap is freaky, and Yes boys and girls, 'they' are watching and listening...