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Idle mixture screws on Qjet

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Old 12-05-2000 | 02:04 AM
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Idle mixture screws on Qjet

The Two Screws on the TB of a mech jet, One is for Idle Misture, what is the other for ?

The one Below the ACC pump is giving Me greif Because I accidnetally Mal adjusted it and Now My car runs like ****. With the screw loose, the car Won rev past like 1500 Rpm, but with it All the way Tight, It will Only stumble a bit and then rev fine, I cant seem to get it back to Running properly however.

This is only in gear it behaves normally while In Neutral, however the idle is quite rough.

I also seem to have gas coming out the acc pump shaft, not a visible leak, just moisture around that area.

any ideas ? I wasnt paying attention when i was going to adjust the mixture and I accidentally turned the wrong screw and now is all messed up




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60 Ranchero - Project ( Money Hole )
85 Z28 LG4 - Daily Driver
**Mods**
MSD Superconductors
14" Open Element
KYB all around
Old 12-05-2000 | 02:27 AM
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I fiddled with it a little, and Now it feels like there is a "dead spot" in the trottle travel, where below it is Fine, and above it is fine, but at about 1/4 trottle, the Car Bogs and Sputters, I got it driveable So i can go to work now, But any Ideas would be Much appriciated.

The car ran Fine untill today I removed the Smog pump Hoses and associated ****, and then accidentally messed with that screw. Also, I had to readjust the Idle mixture screw but that worked out Fine it seems, Just another thing I changed that Might have an effect.



------------------
60 Ranchero - Project ( Money Hole )
85 Z28 LG4 - Daily Driver
**Mods**
MSD Superconductors
14" Open Element
KYB all around
Old 12-05-2000 | 07:16 PM
  #3  
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From: Brooklyn, NY, USA
Car: Trans Am
Engine: 350
Transmission: 700R4
If you are talking about the two scews on the front of the TB, then they are both idle mixture screws. Each controls fuel mix to their respective primary bores. I'm guessing from your signature that you have an 85, so the screws should be backed out 3 3/8 turns from the fully seated position.
However, it is almost impossible to accidentally mess with them because they are under factory plugs. If you mean the screw on the driver side, that is the curb idle speed screw, not idle mixture. The screw on the passenger side is fast idle speed.

[This message has been edited by Nightcruzer (edited December 05, 2000).]
Old 12-05-2000 | 10:40 PM
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This is a MEch Qjet off a 78 Vette, Not the Stock 85 One.


And I know what the Idle Speed screw is

If the screw in the TB on the driver side is idle mixture as well as the one on the passenger side, why does the Driver side one Not effect Idle RPM at all where as the Passenger side one does Just like it should ?



------------------
60 Ranchero - Project ( Money Hole )
85 Z28 LG4 - Daily Driver
**Mods**
MSD Superconductors
14" Open Element
KYB all around
Old 12-06-2000 | 07:42 AM
  #5  
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From: Reno, NV
Car: yep
Engine: uhuh
Transmission: sure does
If one side works and the other doesn't you have an internal passage plugged in the carb, or there is a vac. leak on that sides intake runners.

Have you tried unplugging the EGR to see if the dead spot goes away??

You might need to throw a kit into it. This most likely will also cure your "dead spot". The accelerator pump is probably bad.



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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3
Old 12-06-2000 | 01:18 PM
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Going to try the EGR deal right now, and if that dosent solve it, Im gonna Swap the carb out for yet another and see if that does...

Eliminating variables One at a time



------------------
60 Ranchero - Project ( Money Hole )
85 Z28 LG4 - Daily Driver
**Mods**
MSD Superconductors
14" Open Element
KYB all around
Old 12-06-2000 | 02:28 PM
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Okay, Egr Didnt make a Differance, So Carb is off and car is cooling down a bit.

I pulled the #2 plug and it is Brown, Rusted looking. What does that mean ? I cant find My damn Referanc sheet

Its about the shade of Rusted iron. Does that mean Too Rich? That would Make sense.




------------------
60 Ranchero - Project ( Money Hole )
85 Z28 LG4 - Daily Driver
**Mods**
MSD Superconductors
14" Open Element
KYB all around
Old 12-06-2000 | 03:29 PM
  #8  
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Okay, Last Update on this Problem!


Switched in the Carb Off My Old Firebird, and It runs great! :0

Thanks Guys.



------------------
60 Ranchero - Project ( Money Hole )
85 Z28 LG4 - Daily Driver
**Mods**
MSD Superconductors
14" Open Element
KYB all around
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