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bucking problem...almost completely gone..but still there :(


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Ok if you have been following along with my other posts you kno that my 83 GL has been having a bucking problem when i take my foot off the gas and put it back on. Well here are the things that i ended up fixing to get to the point i am at now. BTW my car has a weber carb.

 

-bigger idle jet (55)

-reset the floats to 35mm from the top...they were way off

-retuned the carb after both of these were done

-checked the vacuum advance unit on the distributor and found out i was not getting ANY vacuum advance...so i threw in a spare distributor (thanks moosens) that i had hanging around

 

The car runs a million and one times better than it did before. For the most part the bucking is gone but sometimes it will still do it. Im not sure if it isnt just the nature of the carb at this point. It seems to want to buck more if im making a slow turn while still in gear, and i get back on the gas. If its in a straight line it doesnt seem to do it but then again it might be doing it and its just less noticable. So what do you all think? Should i just live with it the way it is? Or should i continue to fine tune it and work with it? I think another suggestion before was to change the plugs. I may do that just to see if it makes a difference.

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Mine seems to do this two if I let off the gas with the car in gear and then reapply the gas. I have a weber also, but i had always figured it was because the car did have enough power to turn over the big tires... it just seemed like a sort of stall almost because it would go away if id tap the clutch.

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Could you give a better explanation of exactly what you mean by "bucking"?

 

I think what you are saying sounds like there is a little slop in your gearbox/drivetrain, which can make things a little nasty when you start going rapidly between accelerating and decelerating with the engine.....

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Its a hessitation. But since the clutch is still engaged when the engine hesistates the entire car bucks back and forth a bit. As i said it did it bad when the carb and distributor were messed up and now it barely does it at all. the motor has barely 70,000 miles on it and the tranny has roughly 80,000 on it now and is very tight shifting so im not sure what you mean by slop.

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By slop, he's refering to an excessive amount of backlash in things like tranny gears, drive axles, and what nots...

 

As for the hessitation, mine does something simular. One particular corner I take on my way to work is usually the only time it does it. If I have to downshift into 2nd due to traffic, it doesn't do it when I hit the gas and take corner. If I take corner while still in 3rd, it'll complain about it, usually just a quick cough if you will. Then again, it may not do it. Thinking it's more to do with actual engine RPM's than anything else. Mine's Webered also.

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it was probably covered in one of the other threads, but you do have plenty of fuel supply to the carb, right? there isnt a possibility of fuel starvation going on?

 

what about the accelerator pump, didn't i mention that before or was that a different thread? I am no carb man so i only have vague ideas; maybe they'll help?

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i noticed today that my cable stop for the throttle cable was loose and that the throttle cable was just a hair loose so i tightened both of those things and now the car doesnt seem to have that same hesitation. might be something to check while your at it:)

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Yea my throttle cable was a bit too loose awhile ago so i tightened it. Thanks for the suggestion. Im running out of ideas. If i free rev the car it revs nice and smooth up until 3000 RPMs. Then i can feel an ever so slight..almost unnoticable stumble and then it continues to rev relatively smooth after that. Im almost thinking i might need to step my primary jet. Either that or wait until i get the new axle put in and see if that fixes it seeing as how i only seem to notice the problem when im going around corners these days.

 

Another thing that it does that is almost more annoying than its stumble is if im in gear and i take my foot off the gas really quick..say if im in second, the car jerks back and forth a few times. Ive never been in another manual car that did this. Is this due to a sloppy axle or my carb?

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Another thing that it does that is almost more annoying than its stumble is if im in gear and i take my foot off the gas really quick..say if im in second, the car jerks back and forth a few times. Ive never been in another manual car that did this. Is this due to a sloppy axle or my carb?

 

 

many cars do this - especially once the gearbox & drivetrain have worn a little. Nothing to worry about, just don't take your foot off the pedal so fast...

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