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severe stumble/hesitation when i push the pedal ??????
https://www.slantsix.org/forum/viewtopic.php?t=30832		 Page 1 of 1
Author:  flight704 [ Sun Aug 31, 2008 10:37 am ]
Post subject:  severe stumble/hesitation when i push the pedal ??????
well the title just about says it all. 73 dart sport 225 /6. when you first push the pedal it stumbles and stalls alot but once i get passed the stumble it runs fine.

i checked the timing / set it at 2deg before tdc / also checked to see that vaccum advance was working on the distributor. all 6 cylinders are firing/pulled each wire independantly while it was running. / glass fuel filter is always full just before the carb inlet hose. it has a holley 1920 1 barrel on it

any other ideas/suggestions welcome and thanks for your time. duke :)
Author:  SlantSixDan [ Sun Aug 31, 2008 10:59 am ]
Post subject: 
Have you already bypassed the OSAC valve? Open the hood and look at the firewall on the passenger side. There's a widget mounted there with a vacuum hose running to the carburetor and one running to the distributor. Instead, run the vacuum hose directly from the carburetor to the distributor. This will enable vacuum advance now (instead of ten seconds after you step on the pedal) and will greatly improve acceleration, without any negative side effects.

Beyond that, there's a list of usual things to diagnose and repair. Take off the air cleaner lid and look down the carburetor (engine off) while you operate the throttle. If you don't get a solid shot of fuel each time you open the throttle, there's a problem with the accelerator pump. Make sure the engine is in proper tune; tune-up parts and technique suggestions are in this thread. Try a base timing setting of 5° or so for a start. Make sure the valves are adjusted correctly; here's the valve adjustment procedure. Make sure the EGR system is either hooked up and working all the way correctly or is disabled fully.

And there's some attention to be paid to the carburetor; see threads
Here
and
Here and here.
Author:  Aggressive Ted [ Sun Aug 31, 2008 10:59 am ]
Post subject: 
A couple of things you might check. The accelerator pump on your carb may not be working per spec. Take the air cleaner off, and with the engine off, looking down the throat of the carb and see if you can see it squirting gas when you work the throttle. If not, you may need to rebuild the carb or re-adjust the accelerator pump linkage for a healthier shot.

I run the linkage on mine the third hole out for a healthier pump shot. Make sure there is no slop in the linkage.

The other item is the initial timing is pretty low. You might want to run a little more. Try 10 degrees once you have the pump lever adjusted. I actually run much higher, but I my engine is not stock.

Be sure the vacuum line from the distributor goes directly to the carb.
Author:  DusterIdiot [ Sun Aug 31, 2008 1:52 pm ]
Post subject:  Vacc. Leak...
Pretty much as everything's covered, but before doing that get some carb cleaner in a spray can and look for a vacc. leak, before expending the labor on the other tasks... it can get bad if you 'bandaid' the situation by making the carb run rich and have air leaking into the intake manifold from somewhere.

-D.idiot
Author:  flight704 [ Sun Aug 31, 2008 2:27 pm ]
Post subject: 
i changed the accelerator pump rod to the third hole on the linkage and advanced the timing to 10 deg btdc. it helped alot. it still has a small hesitation but its very mild by comparison to what it was. also when cruising at 35 mph or so and accelerating then the stumble is completely gone.

i am going to rebuild the carb or purchase a new one in the future but i do appreciate the links and reference threads you guys posted. thanks again duke :)
Author:  dusterguy225 [ Sun Aug 31, 2008 6:00 pm ]
Post subject: 
I had some similar probs with mine. I just said screw it, and put a super six on. I hope it works! :D
Author:  flight704 [ Wed Sep 03, 2008 9:53 am ]
Post subject: 
update
i read on one of those links that alot of people were upgrading thier jets between 58 to 62 size. i couldnt decide where to go with it so i chose the middle one.
so last night i upgraded the main jet from a 54 to a 60 and now and all of my problems have disappeared :lol: car runs great i will have to see how this affects the fuel mileage

thanks again for the guidance. from all those that responded

duke :)
Author:  DusterIdiot [ Wed Sep 03, 2008 6:21 pm ]
Post subject:  Yep...
Quote:
so last night i upgraded the main jet from a 54 to a 60

58 would've been a better start, 60 may be too rich or can mask a vacc. leak... 54/55 is too lean...

-D.Idiot
Author:  Aggressive Ted [ Thu Sep 04, 2008 11:49 am ]
Post subject: 
I agree with DI, a #57 is just where things start to get better. I can still feel an occasional bog on light acceleration at 10" of vacuum. Under aggressive acceleration, it isn't there. With a #58 it's all good including the mileage.
Author:  flight704 [ Mon Sep 15, 2008 6:47 am ]
Post subject: 
update

i filled it up and drove it up to norwalk and back about an 80 mile round trip on your average Ohio 55mph 2 lane highway. I filled it up again upon return and divided it out. im getting 23.8 mpg the way it is sitting now.


would it do even better with a 58 jet in it? ill probably buy a set and try it just out of curiosity anyways. the jets were only 4 bucks or so. i am kind of curious where a 35 y/o slant tops out on fuel economy.??? ive read threads about 25 mpg range on here more than once.

just for reference my 96 3/4 ton 4x4 ram with a 360 / 44re auto tranny gets a rock solid 9.7 mpg overloaded or coasting down hill with a tail wind so i am tickled pink about 23mpg. :lol:
Author:  Aggressive Ted [ Tue Sep 16, 2008 2:22 pm ]
Post subject: 
A #58 may get better mileage but you may need to adjust the vacuum pod to 1 to 2 turns in. Not sure about your engine build.
(3) turns is a nice safe spot to avoid pinging.
Basically with more fuel (#58 jet) you can use a little more part throttle advance to increase the mileage. Watch the vacuum gauge and stay above 15" if you can at cruise. :)
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