Moparts
I need to pick your brains
Posted By: Kindafast
I need to pick your brains - 04/06/10 11:53 PM
Hey everyone I am having a wierd problem and I hope you can help. I got my new shortblock in about the same time I bought a new 950Hp carb, so it's been a little while getting everything working right. The engine runs fine and the carb seems to run great until it's run for a while. I can drive this thing around for about five miles and it runs fine , but when it runs a little longer than that it acts like it's flooding out to the point of cutting off. I can shut the fuel pump off and it will run fine until it starts to run out of gas. I have changed the fuel pressure, adjusted the float levels and everything I can think of but nothing helps. If I didn't give a acurate enough symptons just ask. Thanks for your help. Joe
Posted By: MR_P_BODY
Re: I need to pick your brains - 04/06/10 11:57 PM
Maybe its just getting to hot... try a wood spacer
under the carb to see if that helps
Posted By: VernMotor
Re: I need to pick your brains - 04/07/10 12:25 AM
Makes me think you got a coil breaking down..not enuff spark..so you think it is rich..
Posted By: Kindafast
Re: I need to pick your brains - 04/07/10 12:36 AM
Thanks Mr P. I thought that also but the carb don't get that warm. It has a Super Sucker spacer on it also.
Posted By: Kindafast
Re: I need to pick your brains - 04/07/10 12:39 AM
My son said the same thing about the coil. But why would it run fine as soon as I turned the fuel pump off.
Posted By: Anonymous
Re: I need to pick your brains - 04/07/10 12:55 AM
whats your fuel pressure set at?
sounds to me you got a stuck needle and seat.
Posted By: DconD100
Re: I need to pick your brains - 04/07/10 01:04 AM
Quote:
My son said the same thing about the coil. But why would it run fine as soon as I turned the fuel pump off.
Shutting the fuel pump off would send more voltage to the coil, which could potentially make it operate better? Not saying that is your problem, just a thought...I recently had a coil go bad, and it worked fine for about 5 minutes at which time it would get extremely hot. (turned out to be the wrong coil for my ignition box)
Posted By: MR_P_BODY
Re: I need to pick your brains - 04/07/10 01:05 AM
Quote:
Thanks Mr P. I thought that also but the carb don't get that warm. It has a Super Sucker spacer on it also.
Ok so its not getting too hot.... it could be coil
BUT since you arent shutting the car off just turning
the pump off till it starts to stumble(at least thats
what I'm guessing your doing) then turning the pump
back on.... if this is the case I wouldnt think coil
(it didnt have time to cool)... could be a needle
expanding and not sealing... that would be a cheap
check, try a viton needle... but it would sound like
a fuel issue.... but electronics will act weird once
heated and go back to normal once cooled, but your
not giving it cool time
Posted By: Kindafast
Re: I need to pick your brains - 04/07/10 01:22 AM
Thanks for all the replys. Mr P You are right I don't shut the car off I just shut the fuel pump off and it runs fine until it starts running out of gas. Then I turn the fuel pump on and it fills up the bowls and starts running like poop again. I am open to all possibilities at this point keep them comming.
Posted By: Kindafast
Re: I need to pick your brains - 04/07/10 01:23 AM
Quote:
whats your fuel pressure set at?
sounds to me you got a stuck needle and seat.
I have backed the fuel pressure down as low as 4.5 lbs and it really don't change.
Posted By: 602heavy
Re: I need to pick your brains - 04/07/10 01:25 AM
Needle & seats.
is the fuel pressure gauge reading ok?
Posted By: Kindafast
Re: I need to pick your brains - 04/07/10 01:36 AM
Quote:
Needle & seats. is the fuel pressure gauge reading ok?
I bought a new gauge today just to make sure.
Needle and seats are kind of what I am thinking too.
Posted By: RC91
Re: I need to pick your brains - 04/07/10 01:56 AM
Check your secondary needle & seat. If it's leaking just a little, fuel could be dripping down the secondaries causing the crappy running. Shutting the pump off causes it to level out and quit dripping.
Posted By: Dart1031
Re: I need to pick your brains - 04/07/10 02:24 AM
What about a leaking/blown power valve? When it's cold it needs the extra fuel. When it's warm it's running rich and stumbling.
Posted By: 602heavy
Re: I need to pick your brains - 04/07/10 02:31 AM
Bad pump umbrellas can cause fuel to exit over boosters/vents when you stomp on it , could also be fuel pullover from squirters if check valves are missing/not seated , are bowl vents clear? , have sec jets had extentions fitted along with correct floats? , stuck floats? ................just some things to check.
Posted By: MR_P_BODY
Re: I need to pick your brains - 04/07/10 02:46 AM
Have you looked down the carb when the problem is
happening, you might get some insight to the problem
Posted By: Kindafast
Re: I need to pick your brains - 04/07/10 11:42 AM
Quote:
Have you looked down the carb when the problem is
happening, you might get some insight to the problem
No I don't get a chance to do that. I did notice the front and rear butterfly areas had a lot of fuel in them when it did cut off.
Thanks for all the advice and I am going to try and figure it out later today. I will keep you posted.
Posted By: maximum entropy
Re: I need to pick your brains - 04/07/10 02:56 PM
what kind of gas are you running? pump gas nowadays will boil at a very low temperature. i had pump gas (ethanol free) boiling at what felt like about 120 degrees! the carb was barely warm, and the gas was boiling violently! car ran like poopy.
Posted By: Kindafast
Re: I need to pick your brains - 04/07/10 08:57 PM
Ok I messed with it all day. I did get the carb to duplicate the problem in the garage. I found if I get the engine nice and hot and drop it in gear and stand on the brake to about 2200 rps it will start to shoot fuel from the front vent tube. I can rev it up and it stops and if I let it go back to a idle it will stop. This is driving me crazy. Any more ideas ?
Posted By: maximum entropy
Re: I need to pick your brains - 04/07/10 08:59 PM
do you have clear sight plugs? if so, see if the fuel is boiling.
Posted By: Kindafast
Re: I need to pick your brains - 04/07/10 09:03 PM
No I don't have the clear ones so I can't check that. I do see a lot of vapors comming out of the vent tubes prior to the gush.
Posted By: 602heavy
Re: I need to pick your brains - 04/07/10 09:05 PM
Seems you're pulling air through the fuel line , check for any leaks on the suction side of pump , the air is causing the fuel to spill from vent.
Posted By: MR_P_BODY
Re: I need to pick your brains - 04/07/10 09:22 PM
Quote:
No I don't have the clear ones so I can't check that. I do see a lot of vapors comming out of the vent tubes prior to the gush.
Have you changed the needle and seat yet... I would
do that first... its cheap... when the fuel gets hot
and has any agitation it will put out a pile of vapor
and fuel coming in through the needle and seat is
plenty of agitation..... if you have a air leak
(sucking in air, your fuel pressure will show it also),
you can check for one but I doubt you will find one
Posted By: Kindafast
Re: I need to pick your brains - 04/07/10 09:36 PM
I am getting a new needle and seat tomorrow and a new float just in case. I sure hope that will fix it. The fuel gauge don't jump around much so I don't think it would have air in it.
Posted By: RemCharger
Re: I need to pick your brains - 04/07/10 11:30 PM
No question needle &seats. get 2.
Posted By: The Shocker
Re: I need to pick your brains - 04/08/10 12:15 AM
It sounds like the needle and seat to me as well .Proly only one end or the other ,but i would change them both...
Posted By: Kindafast
Re: I need to pick your brains - 04/08/10 12:29 AM
Thanks guy's I will give it a try tomorrow when they show up. I will let you know.
Posted By: Kindafast
Re: I need to pick your brains - 04/08/10 08:40 PM
Well I got all my new parts today. I put them in and went for a little ride. I still don't know wether it worked or not cause I broke a darn roller rocker. I am not dealing with the old Cat rockers anymore and will just save the money for a good set. So for now the carb is the least of my worries. Thanks again for all the replys. Joe