engine hesitates...

[Chas]

i dont know what it is....the engine seems to run fine most of the time.
When i go for a longer trip , it runs bad when i give it the gas....hesitates , like the timing is off or a vacuum issue....would a leaky valve cover cause a leak in the vacuum?
I have what seems to be a leak in the valve cover , but only when it gets hot.
I bought these to replace the big block style that was on it when i got it...i had this leak issue last season and thought i got it fixed with a new gasket....looks like i didnt...im going to get a new set of covers , cast aluminum...hope this will be the fix for the leak....i spoke with c4c5specialest at the cruisefest seminar , and would hope he see's this to help jog my memory as to how i was to test for a leak in the vacuum.
Does it sound like im on track ?
or do you think it could be a diffrent issue?
have new manifold gaskets and a brand new edelbrock performer carb 600 and a performer intake...i have the fuel regulated at 6 lbs.
Any thoughts?
Chas

 

[curtis]

hesitation onthrottle tip in could be incorrect accelerator pump setting. Your
edelbrock carburetor should have the tuning instructions to fix your problem. If you have vacuum leaks then your idle should really suck. good luck.

 

[GerryLP]

Chaz,

It seems that your are refering to positive crancase venting on the valve cover oil leak. My pcv valve failed on the the way back from Auburn, and the oil was leaking from the old-style (vented) oil plug.

The stumble could be fuel related or ignition related. I am unfamiliar with Edelbrock carbs, but they should function as closely as AFB carbs.

 

[Chas]

would this be normal for a carb fresh out of the box 3 weeks ago?
i have the paperwork from it , i will look , or i may have to try there website.
Thanks for your input...
this is bugging me!
Chas

hesitation onthrottle tip in could be incorrect accelerator pump setting. Your
edelbrock carburetor should have the tuning instructions to fix your problem. If you have vacuum leaks then your idle should really suck. good luck.

 

[Chas]

the valve seems to rattle when i idle...is that normal at idle?
i mean i can hear it and feel it ...
Also , my dipstick holder seems floppy...can move it to the side easy, is there a seal down there that could be toast?
Thanks Gerry....

Chaz,

It seems that your are refering to positive crancase venting on the valve cover oil leak. My pcv valve failed on the the way back from Auburn, and the oil was leaking from the old-style (vented) oil plug.

The stumble could be fuel related or ignition related. I am unfamiliar with Edelbrock carbs, but they should function as closely as AFB carbs.

 

[AKRAY4PLAY]

check your plugs, you may be running lean. is it a short hessitation or long chugging-sputtering type problem. is your exhaust run close to your fuel lines?? hot fuel will boil in the float bowl, and make it run like crap. start with the plugs, they are the biggest tattle-tail. Brian

 

[Chas]

it is a hesitation that lasts as long as i throttle up...if i just ease it up it seems to run "ok" .i can put in neutral and rev it up and it bogs and sputters , almost backfiring...i will pull the plugs....the fuel line is aeroquip stuff with a liquid filled pressure gauge...i have a set-up from Edlebrock that has a solid fuel line that runs from the carb inlet to the Edlebrock filter then to the gauge...it is at the front edgeof my block at this point, 90 degree elbow down the front of the block between the A/C bracket and block...on the A/c bracket is where it goes into the regulator...then down from there to the pump....i dont think its getting heated other than the block...its about 1 ince away from the surface...i replaced the cover block for the egr port...i had made one from aluminum to polish for show...i re-installed the one from Edlebrock and put new super black RTV between it...

Thanks for all the input guys...im gonna get it yet!
Chas

check your plugs, you may be running lean. is it a short hessitation or long chugging-sputtering type problem. is your exhaust run close to your fuel lines?? hot fuel will boil in the float bowl, and make it run like crap. start with the plugs, they are the biggest tattle-tail. Brian

 

[Chas]

could you please explain this...

hot fuel making it run bad???
i was under the hood today and noticed that my fuel filter , its Edelbrock inline , was actually touching the exhaust manifold. i took it apart and switched the fuel pressure gauge after the filter and nothing touches now.
So im thinking this may well have been the problem, i was heating the fuel. but to me it seems its gonna flame out eventually so why would making it hot , have this bad of an effect on the way it runs....im just looking for a laymans term type ...this is amazing if it was the problem...i actually have never drivin it long enough to really get hot, till i went to the Cruise fest...we arrived after a 3 hr drive and checked in , then hit the road in caravan style to the museum...all the way it would run bad if i hit the throttle anything over a creep to hit speed...once it hit speed i was ok.
Thanks for this info,
Chas

check your plugs, you may be running lean. is it a short hessitation or long chugging-sputtering type problem. is your exhaust run close to your fuel lines?? hot fuel will boil in the float bowl, and make it run like crap. start with the plugs, they are the biggest tattle-tail. Brian

 

[AKRAY4PLAY]

Chas,

hot fuel sucks!!! if you heat the fuel, it boils just like water but at a different temp. you car needs liquid gasoline to run, the carb converts it to tiny droplets that burn faster, atomization is the key word here. since fluid under pressure does not boil at the same temp as fluid in a vacuum, you can get a cause and effect. the fuel line is pressurized, the carb is a vac. when the fuel hits the carb, it turns to vapor. since your carb is jetted to use liquid fuel and not vapor, you end up with a instant lean condition. adding more air by openning the throttle only makes this condition worse, and results in poor operation.
the other thing that is more important, SAFETY! i would hate to see you loose your car to a fuel fire, or your life. good eye on getting the line off the exhaust. what did your plugs look like?? Brian

 

[Chas]

plugs were like a light brown powdery i guess is best i can explain...dont see any oil or nastyness....thanks for the reply...i honestly think that was the case...i didnt think the intake got that hot...i will get to try it tomorrow i hope .. rainin here a bunch...thanks again

Chas

Chas,

hot fuel sucks!!! if you heat the fuel, it boils just like water but at a different temp. you car needs liquid gasoline to run, the carb converts it to tiny droplets that burn faster, atomization is the key word here. since fluid under pressure does not boil at the same temp as fluid in a vacuum, you can get a cause and effect. the fuel line is pressurized, the carb is a vac. when the fuel hits the carb, it turns to vapor. since your carb is jetted to use liquid fuel and not vapor, you end up with a instant lean condition. adding more air by openning the throttle only makes this condition worse, and results in poor operation.
the other thing that is more important, SAFETY! i would hate to see you loose your car to a fuel fire, or your life. good eye on getting the line off the exhaust. what did your plugs look like?? Brian

 

[curtis]

I just read about similar hesitation sputtering etc. and his problem was the vent tube coming out the top of the carburetor was plugged by an aircleaner top that set down too low. there was a mark on lid where it hit. his remedy was to angle cut the top of the vent tube. i assume because the top of cleaner is fla t that the angle on the tube makes it impossible to seal.

 

[AKRAY4PLAY]

did you get it figured out??

 

[GerryLP]

Dawg et al,


FR-12 is legal. Here is a helpful website: http://www.epa.gov/Ozone/snap/refrigerants/lists/mvacs.html

 

[Chas]

Looks like i got it fixed...

i was installing my nice new Edelbrock valve covers and noticed that the Edelbrock fuel filter was actually touching the manifold. I redid the entire line down to the pump with Aeroquip stuff and got the carb hook up from Edelbrock, polished stainless to the front , then filter, then pressure gauge, then 90 degrees to the regulator and on to the pump.
I had a simple fix for it...i switched the gauge and filter....so now the gauge is the end before the carb...nothing touching..you can see in the photo its clear...valve covers installed , new pcv, and breather.
Had it out today for a few hours , ideling and running..."purr-fect".
Thanks for all of the feedback....
Bottom line , Boiling the fuel after getting hot , then feeding it into the carb.
and venting....now running just free and easy.Thanks AKRAY4Play

 

[SG4206]

I'm glad you fixed the fuel heating problem! I was afraid to tell you how we use to put wooden clothes-pins on fuel lines to stop vapor lock problems ; but that just dates my age.

 

[AKRAY4PLAY]

sweet!! glad to hear things are working right!! very clean install, looks good, my compliments to you. Brian