motor is stumbling

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motor is stumbling

Post  johndickjr on January 16th 2012, 11:42 pm

ok, here goes , you guys are my last hope before i go insane, my 302 in my mustang has a issue ,..motor will idle perfect, takes the throttle nice once its warmed up,will hit any rpm in park-neutral...but put it in gear and it stumbles and sputters..now driving down the road and nail it it will go to 3000 rpm and start sputtering and spitting out the carb..motor is a 302..heads flow 306@600 big single plane intake.2.05 intake valve.i know it miss matched with my cam..which is a small 498 lift 220 dur@.050.. has a msd 6al box and a stock ford duraspark distributor....i have changed..the fuel pump..new plugs and wires..tried a stock ford ignition box..3 carbs..new timing set..only ingition part i have not changed is the pick up inside the dizzy..and have not ran a compression check yet

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Re: motor is stumbling

Post  LivermoreDave on January 17th 2012, 12:10 am

Two things come to mind. First I would check the ignition's initial timing and total timing. If the Duraspark distributor has not been recurved (rate and amount of advance modified) you may have a high total timing issue. Get the ignition timing correct before any tuning continues . The cold stumble is normal for a correct jetted street carburetor without the choke engaged. Now on the other hand, the erratic idle may be caused by a lean fuel mixture at idle, although you mentioned the changing of carburetors, I suppose I would look at the distributor and tailor it to your application.

Just my two cents,
Dave.

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Re: motor is stumbling

Post  johndickjr on January 17th 2012, 12:40 am

LivermoreDave wrote:Two things come to mind. First I would check the ignition's initial timing and total timing. If the Duraspark distributor has not been recurved (rate and amount of advance modified) you may have a high total timing issue. Get the ignition timing correct before any tuning continues . The cold stumble is normal for a correct jetted street carburetor without the choke engaged. Now on the other hand, the erratic idle may be caused by a lean fuel mixture at idle, although you mentioned the changing of carburetors, I suppose I would look at the distributor and tailor it to your application.

Just my two cents,
Dave.
its stock dizzy..total timing i have try every thing from 28-38 and initial timing from 10-20..etc..it idles prefect..with that said in my younger day..i have had some stuff so miss matched it should not have even started..like a tunnel ram and a 600 carbs on a stone stock 302...ran pretty dang good..hell if i know

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Re: motor is stumbling

Post  bbf-falcon on January 17th 2012, 8:54 am

Like Dave said,1st move would be the dizzy.

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Re: motor is stumbling

Post  jbozzelle on January 17th 2012, 11:56 am

Play with the dizzy first. I had a similar issue on a BBF recently. Problem was the dizzy was up into the mechanical advance at idle and once in gear and under load timing would drop and be retarded. Caused all sorts of problems....

If you can lock out the dizzy, or put some real stiff springs in it and close up the mech advance window with a large bushing and see if it gets better...

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Re: motor is stumbling

Post  johndickjr on January 17th 2012, 12:32 pm

thinking back, i had taken apart the dizzy to see what springs and advance weights it had..when i did, i did not mark the reluctor wheel with a mark to put it back on the same way.....can the wheel just be put back on or does it have to be in the exact same place..?

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Re: motor is stumbling

Post  johndickjr on January 17th 2012, 12:34 pm

only thing let that i have not done..is the distributor and could valve springs do it..its a small hydraulic roller cam..heads came off my friends car with a 600 lift hydraulic roller cam in it..and it was fine..

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Re: motor is stumbling

Post  jbozzelle on January 17th 2012, 12:35 pm

How many slots or grooves are on the reluctor. There was only one on the reman dizzy I got recently so the reluctor could only go on one way.

Something to definitely look at though.

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Re: motor is stumbling

Post  johndickjr on January 17th 2012, 6:54 pm

scratch scratch scratch scratch scratch

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Re: motor is stumbling

Post  jbozzelle on January 17th 2012, 7:15 pm

Also make sure the roll pin that aligns the reluctor didn't slip out of the groove when you reinstalled the reluctor. Maybe the reluctor isn't where it needs to be.

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Re: motor is stumbling

Post  johndickjr on January 17th 2012, 8:05 pm

jbozzelle wrote:Also make sure the roll pin that aligns the reluctor didn't slip out of the groove when you reinstalled the reluctor. Maybe the reluctor isn't where it needs to be.
it didt slip..i took it apart again ty have a look..there is a 10 slot and a 15 slot..i swapped to the 10 slot, then back to the 15..15=30 degrees..i set initial timing at 8 degrees plus the 30=38 degrees..checked it with light cant see tach but motor is pretty high rpm when all timing is in..i followed the instructions on Scotty site, just did not changed the springs, so i guess they are stock..i have the battery on charge right now..will see how it does in the morning
http://www.reincarnation-automotive.com/Duraspark_distributor_recurve_instructions_index.html

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Re: motor is stumbling

Post  johndickjr on January 17th 2012, 8:10 pm

could a intake that is way to big casue a problem..the intake i have is mismatched match bad..im in the process of getting another one..the current intake is a parker funnel web..its extremely tall..almost as tall as a tunnel ram..its a 3500+ ---8000 rpm intake..im getting a rpm intake

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Re: motor is stumbling

Post  johndickjr on January 20th 2012, 9:59 pm

well..i put a new distributor in it..helped but not right....but..i had charged my big battery all night(no alternator) and only had car running for a few minutes and killed it and tried to fire it back up..well my battery cables started smoking, and..im a tard..the ground cable was not hooked up at all..only ground was a small wire about size of a piece of hay.. so i got it fixed, but still need jetted correctly and my power valve is blown..it pulled nice, had a bad stumble when i hit about 3k got past that ,..good all the way to 6500, but not right..easy 11.90 car once its lined out

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Re: motor is stumbling

Post  jbozzelle on January 20th 2012, 10:22 pm

So you think you had low voltage all along?

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Re: motor is stumbling

Post  johndickjr on January 20th 2012, 10:23 pm

jbozzelle wrote:So you think you had low voltage all along?
...my ground cable was not hook up..just a tiny wire..and it was smoking..just something i over looked about 500 times

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Re: motor is stumbling

Post  BOSS 429 on January 20th 2012, 10:28 pm

ohm the coil, and the pickup the pickup ( or stator as some call it) should be between 400 and 800, if its a stock ford unit, if its 801 or 399 its junk


i dont rem coil spec off hand
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Re: motor is stumbling

Post  johndickjr on January 20th 2012, 10:38 pm

BOSS 429 wrote:ohm the coil, and the pickup the pickup ( or stator as some call it) should be between 400 and 800, if its a stock ford unit, if its 801 or 399 its junk


i dont rem coil spec off hand
im sure i got my stumble issue fixed, other then the jetting and power valve(see my other post)but i will check the coil to be be sure

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Re: motor is stumbling

Post  johndickjr on January 27th 2012, 12:44 am

update---pulled that high rpm intake off and got one more suited for my motor..a rpm airgap..and decided on a holley 670 avenger carb..will get this stuff on next week..i have to work this weekend..

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