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7/20/15 1:58pm - Original Message: 'Rebuilt Qjet Issues?'
Jasond56
Former Member
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Kenosha, WI - USA

Vette(s):
1973 Corvette Stingray Coupe VIN 1Z37J3S418986 350 L-48 Automatic T-Tops St. Louis Assembly, 18,986th car built in 1973, Paint = 976 Mille Miglia Red, Interior = 425 Dark Red Vinyl (Ox Blood)

Joined: 5/7/2014
Posts: 154
Hello All - Here's something - newly rebuilt Qjet, dialed in the mixture screws to what I think is correct because she idles better than ever. However, when I turn off car, she shudders like she wants to stay running. Go to restart and she won't unless I hold open butterfly. Ideas?

Thank you!

____________________________________
"You know, we always called each other goodfellas. Like you'd say to somebody: You're gonna like this guy, he's all right. He's a goodfella. He's one of us. You understand?"




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7/20/15 3:00pm - Reply: 'Re: Rebuilt Qjet Issues?'
wetvet
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Lake Oswego, OR - USA

Vette(s):
1972 Steel Cities Gray T Top. Original Owner, Original Paint and Interior. The running gear has been rebuilt after 240,000 miles.

Joined: 10/17/2003
Posts: 540
sounds like the spring on your plunger is sticking.

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7/20/15 3:52pm - Reply: 'Re: Rebuilt Qjet Issues?'
kstyer Lifetime Member
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CUYAHOGA FALLS, OH - USA

Vette(s):
1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!

Joined: 12/2/2003
Posts: 6410
Check the idle speed.  When it's too fast it will shudder and sometimes diesel when shutting off.   The choke plate should be fully open when the car is warm.  If it is shutting that would cause a very fast idle and tend to flood the car.  You may need to adjust the choke coil.  New, the coil will have a dot on the outer diameter of the plastic housing.  That lines up with the notch on the choke housing.  setting just slightly rich, one or two notches, usually works best and prevents mid range hesitation.

____________________________________
On the "Tail of the Dragon"
(some day, no strike that, October 2008 it turned red, still in progress!)

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7/25/15 1:35pm - Reply: 'Re: Rebuilt Qjet Issues?'
Jasond56
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Kenosha, WI - USA

Vette(s):
1973 Corvette Stingray Coupe VIN 1Z37J3S418986 350 L-48 Automatic T-Tops St. Louis Assembly, 18,986th car built in 1973, Paint = 976 Mille Miglia Red, Interior = 425 Dark Red Vinyl (Ox Blood)

Joined: 5/7/2014
Posts: 154
Thanks for the feedback!

You know, my choke valve is always open when car is cold.  Isn't it supposed to be CLOSED when cold and open as the car warms up?

I'd also like to confirm that when I attempt to adjust choke coil, turning counter clock wise = run lean and turning clock wise = run rich.




____________________________________
"You know, we always called each other goodfellas. Like you'd say to somebody: You're gonna like this guy, he's all right. He's a goodfella. He's one of us. You understand?"




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7/26/15 11:38am - Reply: 'Re: Rebuilt Qjet Issues?'
Vman73
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Gig Harbor, WA - USA

Vette(s):
1973 L82 4 Speed Coupe - Very original, well documented driver/survivor. 2016 Bend Regional NCRS Top Flight.

Joined: 10/2/2014
Posts: 362
Jasond56 said: Thanks for the feedback!

You know, my choke valve is always open when car is cold.  Isn't it supposed to be CLOSED when cold and open as the car warms up?

I'd also like to confirm that when I attempt to adjust choke coil, turning counter clock wise = run lean and turning clock wise = run rich.





Jason, you are correct on #1 - cold = closed. #2 is the opposite on the automatic (electric) choke coil - clockwise is lean, counter clockwise is rich. Good luck !!

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7/26/15 9:02pm - Reply: 'Re: Rebuilt Qjet Issues?'
73shark
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Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.

Joined: 7/9/2003
Posts: 394
If you have an A/C equipped car, there should be an idle stop solenoid which is used to set the idle speed.  When the key is turned off, the solenoid allows the throttle to close completely preventing dieseling.

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1973 L-82 4 spd

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7/27/15 12:20pm - Reply: 'Re: Rebuilt Qjet Issues?'
Adams' Apple Lifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19454
Jason...is this the original carb for the car, or a replacement? Original carb would NOT have the black plastic choke cover on it, afaik. The choke is controlled by a coil mounted in the intake manifold that heats up and opens the carb.
If your carb has a plastic choke cover, you need to determine if it is electric, or heat activated. Electric choke would have a small blade tye terminal on the side of it. Heat coil would have a fitting towards the bottom for a tube that would run thru a loop either in the exhaust manifold, or the EGR crossover port in the intake. Let's determine what ya have first, then see if we can get it all adjusted properly. Thumbs Up
And yes, you should have an idle stop solenoid, A/C or not.


|UPDATED|7/27/2015 10:20:38 AM (AZT)|/UPDATED|


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Joel Adams
C3VR Lifetime Member #56    
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
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7/27/15 6:40pm - Reply: 'Re: Rebuilt Qjet Issues?'
Jasond56
Former Member
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Kenosha, WI - USA

Vette(s):
1973 Corvette Stingray Coupe VIN 1Z37J3S418986 350 L-48 Automatic T-Tops St. Louis Assembly, 18,986th car built in 1973, Paint = 976 Mille Miglia Red, Interior = 425 Dark Red Vinyl (Ox Blood)

Joined: 5/7/2014
Posts: 154
I have an original QuadraJet, recently rebuilt, so it does not have the black housing.  It has the heated coil for choke.  Haven't experienced this "dieseling" before...that shake/shudder/wanting to stay on when turning off after a long drive.

From videos I've seen online, people bend the linkage going into the (I believe) coil lever...bend it just right to keep the choke closed when cold. 

____________________________________
"You know, we always called each other goodfellas. Like you'd say to somebody: You're gonna like this guy, he's all right. He's a goodfella. He's one of us. You understand?"




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7/27/15 6:45pm - Reply: 'Re: Rebuilt Qjet Issues?'
73shark
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Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.

Joined: 7/9/2003
Posts: 394
Adams' Apple said:
And yes, you should have an idle stop solenoid, A/C or not.





Yep, I got confused with my old 68 GTO (which I no longer own but wished I did) that had one because it had A/C. It was designed to keep the engine from dying when you turned on the air conditioner. I now remember that my '73 had an idle stop solenoid on it without A/C.  When I added A/C, I rewired the idle stop solenoid so that it was activated only when the compressor was on. Did this for the same reason that they had done it on the GTO.
 


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1973 L-82 4 spd

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7/27/15 9:25pm - Reply: 'Re: Rebuilt Qjet Issues?'
Jasond56
Former Member
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Kenosha, WI - USA

Vette(s):
1973 Corvette Stingray Coupe VIN 1Z37J3S418986 350 L-48 Automatic T-Tops St. Louis Assembly, 18,986th car built in 1973, Paint = 976 Mille Miglia Red, Interior = 425 Dark Red Vinyl (Ox Blood)

Joined: 5/7/2014
Posts: 154
Thank you, 73Shark.  I would like to have the GTO, too! Cool

Are you saying that something with the idle stop solenoid might be off, that it's something I should look into?  Anything in particular I should be looking for?

Thank you!




____________________________________
"You know, we always called each other goodfellas. Like you'd say to somebody: You're gonna like this guy, he's all right. He's a goodfella. He's one of us. You understand?"




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7/27/15 9:53pm - Reply: 'Re: Rebuilt Qjet Issues?'
73shark
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Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.

Joined: 7/9/2003
Posts: 394
The purpose of the idle stop solenoid was to allow one to set the idle and then when the ignition was turned off, the solenoid retracted allowing the throttle plates to close completely which would prevent dieseling or run-on.

Basically there should be 12 volts applied to the solenoid as soon as you turn the ignition switch on and start the engine. The solenoid when extended, controls the idle speed. It is adjusted by turning the hex end of the solenoid that contacts the throttle arm.

____________________________________

1973 L-82 4 spd

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7/28/15 12:30pm - Reply: 'Re: Rebuilt Qjet Issues?'
Adams' Apple Lifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19454
Jasond56 said: I have an original QuadraJet, recently rebuilt, so it does not have the black housing.  It has the heated coil for choke.  Haven't experienced this "dieseling" before...that shake/shudder/wanting to stay on when turning off after a long drive.

From videos I've seen online, people bend the linkage going into the (I believe) coil lever...bend it just right to keep the choke closed when cold. 


Jason, is the choke linkage connected to the carb properly? Can you get a pic of that side of the carb/choke for us to see? Don't really recommend trying to bend the linkage on the intake mounted coil...very easy to screw something up, even for folks that have done it before, and you have to remember...these parts are a few years old, and set in their ways.....they hate change! There are special tools to do it, but couple sets of GOOD pliers can be used. A little on the linkage makes a BIG difference at the choke blade, so ya gotta go slow.




|UPDATED|7/28/2015 10:30:02 AM (AZT)|/UPDATED|


____________________________________
Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
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7/30/15 2:26pm - Reply: 'Re: Rebuilt Qjet Issues?'
Jasond56
Former Member
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Kenosha, WI - USA

Vette(s):
1973 Corvette Stingray Coupe VIN 1Z37J3S418986 350 L-48 Automatic T-Tops St. Louis Assembly, 18,986th car built in 1973, Paint = 976 Mille Miglia Red, Interior = 425 Dark Red Vinyl (Ox Blood)

Joined: 5/7/2014
Posts: 154
Adam's - Thank you for the reply and the advice!  I was leery about bending anything...

Here is a pick of the carb/choke as requested.  I have also included a pic of how the carb looks when cold.  Wide open with zero play, meaning I cannot push it closed.







____________________________________
"You know, we always called each other goodfellas. Like you'd say to somebody: You're gonna like this guy, he's all right. He's a goodfella. He's one of us. You understand?"




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7/30/15 3:36pm - Reply: 'Re: Rebuilt Qjet Issues?'
kstyer Lifetime Member
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CUYAHOGA FALLS, OH - USA

Vette(s):
1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!

Joined: 12/2/2003
Posts: 6410
Open the throttle a little bit, and you will probably be able to push it closed.  The fast idle cam will prevent movement with a closed throttle.  Leave the engine off and give it a try.  See what it does.

____________________________________
On the "Tail of the Dragon"
(some day, no strike that, October 2008 it turned red, still in progress!)

(click either image to see a bigger version)
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7/31/15 5:23pm - Reply: 'Re: Rebuilt Qjet Issues?'
Jasond56
Former Member
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Kenosha, WI - USA

Vette(s):
1973 Corvette Stingray Coupe VIN 1Z37J3S418986 350 L-48 Automatic T-Tops St. Louis Assembly, 18,986th car built in 1973, Paint = 976 Mille Miglia Red, Interior = 425 Dark Red Vinyl (Ox Blood)

Joined: 5/7/2014
Posts: 154
Thank you, I will try doing that.  If I can open and close the choke when I push the throttle, is that a good thing?  would a little WD-40 in the coil area improve things?

Here's something interesting I completely forgot to mention: the night I came home and she dieseled pretty badly, I noticed a steady drip coming from under the car, front middle area almost looking like a bit on the passenger side.  Not entirely sure about passenger side because fluid will take the path of least resistance.  Anyway, the fluid was clear and felt almost like mineral oil...a little greasy/oily feeling.  Didn't have a smell at all.  Washed right off my hands with no residue.  AC was not running (don't think I have ever even tried turning it on) so it was not condensation.  Came out the next day before heading off to work, and A LOT of this fluid had fallen.  Could this mystery leak be causing some of my dieseling issues?

Thanks in advance!

Jason


____________________________________
"You know, we always called each other goodfellas. Like you'd say to somebody: You're gonna like this guy, he's all right. He's a goodfella. He's one of us. You understand?"




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7/31/15 9:11pm - Reply: 'Re: Rebuilt Qjet Issues?'
73shark
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Overland Park, KS - USA

Vette(s):
1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.

Joined: 7/9/2003
Posts: 394
First I would not add any lubricant to the various linkages as they are designed to operate dry and it would attract dirt and become sticky.

When the engine is cold and the choke is wide open, cracking the throttle a little should allow the choke to snap completely closed if adjusted properly.  All of the carb adjustments are detailed in the factory service manual.


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1973 L-82 4 spd

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7/31/15 9:43pm - Reply: 'Re: Rebuilt Qjet Issues?'
Adams' Apple Lifetime Member
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Duncanville, TX - USA

Vette(s):
#1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/ Am-Fm/map light National/Regional/Chapter NCRS "Top Flight" #2-1985 Bright Red/Carmine Cp.L-98/auto Member: NCRS, NCRS Texas, Corvette Legends of Texas

Joined: 11/8/2003
Posts: 19454
Jason....if you move the choke blade all the way closed, does the linkage on the side actually move? I'm thinking the dang link from the choke blade to the outside linkage of the carb MAY not be installed right. It's easy to miss getting that durn thing attached properly sometimes, and whoever built the carb MAY have missed the slotted hole on the linkage. Just looking at the pics you posted of the carb, the choke blade SHOULD be closed with the coil linkage where it is in the pics....

In this pic below, the choke rod is highlighted in green. It goes down into a cavity on the side of the carb, and a slotted plate/link then attaches to the external linkage. It's kinda tricky to get the link attached, so it's possible it is not actually attached. Worth looking into.



____________________________________
Joel Adams
C3VR Lifetime Member #56    
My Link


(click for Texas-sized view!)
             NCRS

"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
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8/2/15 1:54pm - Reply: 'Re: Rebuilt Qjet Issues?'
Jasond56
Former Member
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Kenosha, WI - USA

Vette(s):
1973 Corvette Stingray Coupe VIN 1Z37J3S418986 350 L-48 Automatic T-Tops St. Louis Assembly, 18,986th car built in 1973, Paint = 976 Mille Miglia Red, Interior = 425 Dark Red Vinyl (Ox Blood)

Joined: 5/7/2014
Posts: 154
Thanks for the replies guys - Adam's - that's the thing, the choke blade will not close all the way. However, when I do move it the amount it will move, all the linkage moves on the side of the carb as well. Choke rod does seem to be attached. I moved the fast idle cam as well and linkage moved, too. I did finger the throttle a bit As 73Shark suggested, and the blade snapped shut (did while cold). Now the blade seems to move freely, and Adan's suggestion to check all linkage while blade CLOSED checks out...everything moves!

|UPDATED|8/2/2015 11:54:58 AM (AZT)|/UPDATED|


____________________________________
"You know, we always called each other goodfellas. Like you'd say to somebody: You're gonna like this guy, he's all right. He's a goodfella. He's one of us. You understand?"




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