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Thread: hesitation problem
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Tom93R1
Redlining
Posts: 458
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posted July 29, 2002 09:09 PM |
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hesitation problem
What causes a hesitation? If I am cruising along at about 1500 rpm and floor it I get a real bad hesitation then it just takes off running perfectly. Is that timing? Is it air/fuel mixture? I am sure that I am running rich but that doesn't seem like something that could cause a hesitation like this. Vaccuum leak maybe? What is the best product to spray in the engine bay when looking for a leak?
I had this problem before I put DLIDFIS in so I know it isn't a problem with my handywork last weekend. I also disconected the vaccuum advance, what do you guys with no vaccuum advance set the timing to? I can't recall off the top of my head where mine is currently, maybe will be able to brave the heat and check tomorrow.
thanks
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'74 lawn-green
4-port 13b
Weber 48DCO
Racing Beat Header
Magnaflow
resonator/amplifier
really loud!
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Jeff20B
Moderator
Posts: 661
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posted July 29, 2002 10:47 PM |
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In my article I mention setting timing to 20º total advance at 4000RPM. The L/T split should be at 10º for '74 and 15º for '77. I'd still set it to 10º though.
You may have a bad accelerator pump. Mine was acting up until I added some gas treatment to the tank.
You could try spaying certain areas with WD40. It's flamable so be careful.
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Klaus43
Rotorhead
Posts: 1259
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posted July 30, 2002 01:43 PM |
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...I dunno...I wait until about 2500RPM to floor mine; of course I know little about 2nd gen motors... Don't spray anything to detect a vacuum leak! Visual and audio inspection,(look and listen), always worked for me... When in doubt, replace the hose or pull it 'n plug it... you can always put it back if you must!
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Tom93R1
Redlining
Posts: 458
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posted July 30, 2002 02:29 PM |
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What is the accelerator pump? I have a Weber side draft carb but I don't know much about carbs, Is the accelerator pump something all carbs have?
After driving the REPU today I am starting to feel like my problem is a vaccuum leak. It has a fluctuating idle and no matter what I do with timing or idle mixture adjust I can't smooth it out. I think I have only 1 vaccuum line and that is for my brake booster. If I have a leak it is either a gasket or improperly torqued intake manifold or something along those lines. It is actually cloudy outside so I will be able to work on that tonight.
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Tom93R1
Redlining
Posts: 458
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posted July 30, 2002 09:40 PM |
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Looks like my problem was most likely a vaccuum leak. I discovered I was missing a bol that holds the upper and lower intake manifolds together. Put a new one in there and the idle seems to have smoothed out and hesitation seems to be alot less. Now it is more like the stumble I would expect any car to do when you floor it from almost no throttle.
On a possible related topic, how much should the needle on a vaccuum gauge bounce? I get a reading where the needle bounces between -16 and -17. Is that a reasonable bounce or is it indicative of more trouble? When I rev it to 2k the needle stabilizes at around -16.
____________
'74 lawn-green
4-port 13b
Weber 48DCO
Racing Beat Header
Magnaflow
resonator/amplifier
really loud!
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