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Re: Diagnosing a misfire
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Re: Diagnosing a misfire
My edelbrock 1405 ran rich the fuel pump pressure was toohigh I installed regulator. It ran so rich the idle mixture screws had noeffect i could close them and engine still ran. After installing reg. I was able to tune carb changing metering rods.You have a carb that is running rich clean floatbowls install fresh fuel filter and then trytuning carb.Big carbs and big exhaust is meant for full throttle high rpm work
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Re: Diagnosing a misfire
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Re: Diagnosing a misfire
We need more info 1did the carb ever run well? if it did then clean and rebuild adjust floats. 2 ha ve you changed anything else? on the carb or fuel delivery system? pump? regulator?? good luck might want to change oil if it has gas in it
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Re: Diagnosing a misfire
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Re: Diagnosing a misfire
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Maybe this will afford me a chance to finally use my cool starter button that I got for setting lash but then found out it's better to hand crank the engine lol I got a Bosch compression checker, hoping that's a decent brand tool. The rotohammers I've used were always great so I figured the Bosch one would be a good tool. I think after work today I'll get a good vacuum gauge too, I keep hearing that guys tune Holleys with one so I better add that to my tool collection. It's funny now that I think about it, my first thread a looong time ago when I was trying to identify what can I had, my tool set consisted of basic box wrenches and a socket set in one of those 100 peice tool kits lol now I have all kinds of pullers and timing lights, every depth and diameter gauge there is, and all kinds of other crap. I never thought I'd end up with all that stuff and know how to use it. |
Re: Diagnosing a misfire
you have quite a ride brought a smile to my face. yeah my 750 was faster top end too not like yours though. looking forward to hearing the solution
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Re: Diagnosing a misfire
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Re: Diagnosing a misfire
I can just hear GrumpyOldMan now, "how do you like those HIGH PERFORMANCE parts now huh??" lol its comin, just wait
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Re: Diagnosing a misfire
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Re: Diagnosing a misfire
been trying to post not working operator error im sure... fuel coming out of vacuum port needs to be addressed maybe more than one thing is wrong but dont adjust valve train to oblivion carb is running rich not because of size
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Re: Diagnosing a misfire
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You've saved me money on haircuts because I keep pulling it out reading your engine build threads .... almost weekly .....:lol: I've edited my signature below for your benifit ! |
Re: Diagnosing a misfire
I guess i have to keep my post short I have a vacuum guage mounted inside cab. also a vacuum pump is handy for testing under the hood
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Re: Diagnosing a misfire
I am impressed with the amount of work that you have done and hope i dont offend anyone but fuel from vacuum port needs attention maybe a holley expert would help you out. Its not the size of carb
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Re: Diagnosing a misfire
just sittin here waiting for parts the vacuum pump has a gauge on it the vacuumgauge in cab helps me tunemy carb and save gas. torque wrenches are a must. I noticed you invest in tools so just thought id suggest . ive got a cool multimeter has digital tach even a temp probe
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Re: Diagnosing a misfire
I reviewed thread and I would GUESS that when you installed valve train parts you got some debris in carb...as plugs became fouled it ran richer if you change plugs it will run better until they foul too
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Re: Diagnosing a misfire
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You're right on about the carb, I put a set of spark plugs in it 2 weeks ago and they looked just like the ones I pulled yesterday after only a few short trips to the store. These guys have seen me go from not being able to use a timing light to rebuilding a top end on my small block, and there's kind of an ongoing joke about how much unnecessary (and sometimes detrimental lol) wrenching I do on my truck haha I actually REPLACED HEAD GASKETS once about 4 months ago because I thought I blew one, and when I got it all back together it turned out to be one of my spark plug wires wasn't clipped in all the way on the distributor cap lol it's been fun. |
Re: Diagnosing a misfire
you could pop of gauge from under dash plug line then use gauge under hood. I use gauge under dash to select step up springs in edelbrock. I use manual to select rods and jets.BTW the more gas in manifold the bigger the backfire
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Re: Diagnosing a misfire
they wouldnt pick on you if they didnt like you. thats what i was told about 50 years ago
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Re: Diagnosing a misfire
Just thought i wouldmention this fuel in oil can ruin an engine even a small amount may not show up on dipstick. and your plugs? wow pardon me but sure you are not burning oil? Oil creates bluish smokeand fuel moreblack.
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Re: Diagnosing a misfire
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Re: Diagnosing a misfire
Anyone ever try using this calculator to figure out which size carb your vehicle needs? Last time I checked, it said my stock 350 cid needs about 340cfm
http://www.carburetion.com/calc.asp |
Re: Diagnosing a misfire
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A Chevy 350 -just- maxes out a 2GV, becasue adding a 4MV is worth 5hp (250hp vs 255hp). So I figure whatever a 2GV flows, that's what a normal 350 can use. |
Re: Diagnosing a misfire
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Re: Diagnosing a misfire
yes displacement and rpm . It sounds like your truck runs pretty well with 750. with my gearing and sm465 I only got to enjoy it getting on on ramp never did find out when it stop pulling too chicken with those drum brakes
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