Last post on Feb 29, 2012 at 4:08 PM
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Brakes, Electrical, Engine, Coupe, Convertible, Hatchback, Truck, Sedan, Wagon, SUV, Van
This topic will hopefully allow the more knowledgable of our community members share what they know with those seeking a good explanation for "how things work" in a car; or, this is a good place for equally knowledgable people to discuss the finer points of a technology.
#362 of 401 old school chevy issues
Jun 27, 2008 (8:22 pm)
got a 67 chevy, 283, hedders, edelbrock manifold & edelbrock 1405 600 cfm performer carburetor.
Problems while exercising my car I turned into a lot and it died. Got it started but it would not run unless the RPM's were kept up a little. So I figured time for new mechanical fuel pump. Installed new Holley 110GPM. Started up good idle, drove down the road nice and thought I'd get my foot into it a little. As I let up on gas to turn around it died as before. Start up & had to RPM up somewhat. Now same ole keep RPM up or dies and some popping. In playing with it today a good shot of fire came out of carb. The distributor is not stock ie points etc It has the look of a Summit HEI power type. I'm guessing carb float adjustment or rebuild or maybe timing. Thanks for any help. Rick
#363 of 401 Re: old school chevy issues [rws800]
Jun 28, 2008 (7:28 am)
Well if you have fire out of the carb, then either you have a camshaft timing problem (your whole valve timing is off), a valve problem (one intake valve leaking), or your ignition timing is way off.
Valves should be shut, when the cylinder mixture is compressed, and then ignited by the spark plug. If the intake valve is still open when ignition occurs, then the fire backs up thru the intake manifold and out the carb.
#364 of 401 Re: old school chevy issues [rws800]
Jun 28, 2008 (4:19 pm)
How did you, or did you adjust the float?
Sounds like the float level is way too high.
When you turn or decellerate, the fuel sloshes out of the float bowl.
Or, the needle and seat are leaking by.
It will cause similar symptoms to being advanced.
Any fuel leaks in the carb?
Have you checked for vacuum leaks?
#365 of 401 Re: old school chevy issues [kiawah]
Jun 28, 2008 (5:33 pm)
Thank you for the response.
I had thought of timing issues but wasn't sure if I was on track.
I also need to gear up and purchase timing light etc. I haven't fooled with the older cars for a long, long time and those days were the 60's & 70.s. So I am rusty .
I'll keep you informed as to the fix.
#366 of 401 Re: old school chevy issues [0patience]
Jun 28, 2008 (5:48 pm)
Thanks for the response.
No I did no work on the carb as all was working great and then at idle the engine died.
Even by keeping the RPM's up and on higher end all things were good, so that's why I changed out the fuel pump. After changing out fuel pump it ran good as I went up the road, say 35 or 40, then after getting into the gas it went great but upon decellerating it again died . Same problems as before so I let it set for a while.
I think there some issues with the carb & timing.
Got it running today only at higher RPM's (1200 or 1400) Then I heard some back firing through carb.
#367 of 401 Re: old school chevy issues [rws800]
Jun 29, 2008 (7:28 am)
Do a compression test on each of the cylinders
#369 of 401 Re: old school chevy issues [kiawah]
by Mr_Shiftright HOST
Jun 29, 2008 (2:30 pm)
And check for a vacuum leak, too.
#370 of 401 Re: old school chevy issues [rws800]
Jun 30, 2008 (5:56 am)
I'm with 0patience, check the float level first. Then timing.