wont idle..

superbean · May 2nd, 2009, 10:12 PM

I know the motor in my car has a radical cam in it and won't idle smooth, but for the life of me I can't get it to stay running at idle for more than ten seconds..

Timing is very close to being set correctly.. maybe +2- deg
Fuel pressure is set at 7.5 psi..
If I hold my foot on the gas lightly it will sit there and idle fine..

not really sure what to look into first. anyone have any ideas?
I'm not too familiar with carbs, mostly done fuel injection, but I think maybe I need to adjust my float level..

ViperblueGT · May 2nd, 2009, 10:15 PM

try adjusting the idle set screws to bump the idle up a little bit other than that you probably just need a good tune

superbean · May 2nd, 2009, 10:19 PM

alright. I don't have a good tach in the car, so I have no idea what it's trying to idle at. I know long duration camshafts should idle around 1200/1300 .. it might just be at about 1000 rpm and doesn't like the surging idle/low vacuum.

ViperblueGT · May 2nd, 2009, 10:26 PM

a cam with a huge amount of duration is always gonna have a pretty rough idle but it shouldnt' die so yeah just try those things

1slo5.0 · May 2nd, 2009, 10:59 PM

What kind of carburetor? Get familiar with it. Buy a book on it and learn. Carbs are as complicated or more complicated than EFI. There are many things that can cause these issues but if you are not familiar with carburetors then it is all going to be greek to you.

89LX347 · May 3rd, 2009, 01:26 AM

check your idle screws on the side and make sure they are all the same length out. screw them in all the way and put them all at about 1 and a half turns out. try that for starters, but like darrell said, there are SO many things that could be your problem.

1slo5.0 · May 3rd, 2009, 10:11 AM

Originally Posted by 89LX347

check your idle screws on the side and make sure they are all the same length out. screw them in all the way and put them all at about 1 and a half turns out. try that for starters, but like darrell said, there are SO many things that could be your problem.

The correct way to set the idle mixture is with a vacuum gauge and set them for the highest vacuum. They won't necessarily be turned out the same amount on each side. I'll guarantee this isn't his problem though. I'm willing to bet the throttle blade is open too far exposing too much of the transfer slots.....for starters anyway. He is about to find out why I say EFI is easier than carburetors.

JBIGBOOTSY · May 3rd, 2009, 12:49 PM

Originally Posted by Darrell

The correct way to set the idle mixture is with a vacuum gauge and set them for the highest vacuum. They won't necessarily be turned out the same amount on each side. I'll guarantee this isn't his problem though. I'm willing to bet the throttle blade is open too far exposing too much of the transfer slots.....for starters anyway. He is about to find out why I say EFI is easier than carburetors.

Hogwash darrell, he just gotem sum gremlins init.

Iwannagofast · May 3rd, 2009, 12:59 PM

Originally Posted by JBIGBOOTSY

Hogwash darrell, he just gotem sum gremlins init.

i know how to get rid of gremlins....shave one side and burn the other....o wait maybe i thinking of something else

JBIGBOOTSY · May 3rd, 2009, 01:00 PM

Flea shampoo, then scrub it in with a chainsaw.

superbean · May 3rd, 2009, 01:42 PM

alright, thanks for the help guys.

It would sit and idle fine for minutes on end before, but the only thing ive changed was my alternator .. (changed the fuel regualtor back to 7.5) because of the added volume of the fuel.

Perhaps my throttle return spring is too stiff and pulling the throttle blade beyond base idle if that makes sense. Ill adjust the idle screws out to the most vacuum.

superbean · May 3rd, 2009, 05:57 PM

so i think i figure out what's up with the idle problems. It's a fuel pressure problem..

I turned my key on (fuel pump primes) and i hear a bunch of noise coming from my fuel pressure regulator and the needle is bouncing like crazy and doesn't sound good. I've had nothing but problems from this regulator. First the nipple on the back side wouldn't seal because of lousy machining, so i had to ghetto jb weld it, not the diaphragm isn't holding pressure..

Can anyone link to me a fuel pressure regulator that will hold up to a large efi pump but drop pressure down to 8psi or so?

Mine currently is a mallory. I think they should just stick to ignitions.

86er · May 3rd, 2009, 06:13 PM

aeromotive will have a good one, but if its not an intake pump, think about a non efi pump

superbean · May 3rd, 2009, 06:27 PM

well it needs to be a return style regualtor, single inlet single outlet

superbean · May 3rd, 2009, 07:15 PM

after reading on the topic more, people who run the stock efi pumps are having trouble with steady fuel pressure.

What else have everyone done that has gone from fuel injection to carb? I don't care about spending a hundred bucks or w/e as long as it fixes this problem once and for all!

1slo5.0 · May 4th, 2009, 01:32 AM

Originally Posted by superbean

after reading on the topic more, people who run the stock efi pumps are having trouble with steady fuel pressure.

What else have everyone done that has gone from fuel injection to carb? I don't care about spending a hundred bucks or w/e as long as it fixes this problem once and for all!

That is because you are using the wrong parts for the job. Mixing and matching shit just to save money always results in problems like this. Put a low pressure high volume carb pump and regulator on the car and be done with it.

May 2nd, 2009, 10:12 PM	#1
superbean Hardcore Enthusiast 1998 Cobra 13.24@105.66 Join Date: Aug 2008 Location: North Carolina Posts: 1,778 iTrader: 0 reviews	wont idle.. I know the motor in my car has a radical cam in it and won't idle smooth, but for the life of me I can't get it to stay running at idle for more than ten seconds.. Timing is very close to being set correctly.. maybe +2- deg Fuel pressure is set at 7.5 psi.. If I hold my foot on the gas lightly it will sit there and idle fine.. not really sure what to look into first. anyone have any ideas? I'm not too familiar with carbs, mostly done fuel injection, but I think maybe I need to adjust my float level.. __________________ weeee foooord!

May 2nd, 2009, 10:15 PM	#2
ViperblueGT Newbie 1988 mustang GT 13.06@106.09 Join Date: Apr 2009 Location: Lee's Summit Posts: 30 iTrader: 0 reviews	try adjusting the idle set screws to bump the idle up a little bit other than that you probably just need a good tune __________________ 88 mustang 5.0 e7 heads edelbrock intake mezeire electric water pump... electric fan... f cam 4.10 gears t-5 tranny best pass 13.06 @ 106.09

May 2nd, 2009, 10:19 PM	#3
superbean Hardcore Enthusiast 1998 Cobra 13.24@105.66 Join Date: Aug 2008 Location: North Carolina Posts: 1,778 iTrader: 0 reviews	alright. I don't have a good tach in the car, so I have no idea what it's trying to idle at. I know long duration camshafts should idle around 1200/1300 .. it might just be at about 1000 rpm and doesn't like the surging idle/low vacuum. __________________ weeee foooord!

May 2nd, 2009, 10:26 PM	#4
ViperblueGT Newbie 1988 mustang GT 13.06@106.09 Join Date: Apr 2009 Location: Lee's Summit Posts: 30 iTrader: 0 reviews	a cam with a huge amount of duration is always gonna have a pretty rough idle but it shouldnt' die so yeah just try those things __________________ 88 mustang 5.0 e7 heads edelbrock intake mezeire electric water pump... electric fan... f cam 4.10 gears t-5 tranny best pass 13.06 @ 106.09

May 2nd, 2009, 10:59 PM	#5
1slo5.0 I Post Entirely Way Too Much 1990 Mustang LX 9.36@143 mph Join Date: Jan 2006 Location: North Fond du Lac, Wisconsin Posts: 11,375 iTrader: 1 reviews	What kind of carburetor? Get familiar with it. Buy a book on it and learn. Carbs are as complicated or more complicated than EFI. There are many things that can cause these issues but if you are not familiar with carburetors then it is all going to be greek to you. __________________ My daily driver has 16 cylinders and 4400hp @ 1000 rpm.... ***1988 Mustang GT - Stock....almost

May 3rd, 2009, 01:26 AM	#6
89LX347 Hardcore Enthusiast Join Date: Apr 2007 Posts: 1,304 iTrader: 0 reviews	check your idle screws on the side and make sure they are all the same length out. screw them in all the way and put them all at about 1 and a half turns out. try that for starters, but like darrell said, there are SO many things that could be your problem. __________________ I believe in art when it is not seen. I believe in music when it is not audible. I believe in God when He is silent.

May 3rd, 2009, 01:00 PM	#10
JBIGBOOTSY MM Fanatic 1990 LX hatch Join Date: Aug 2006 Location: Hobart Indiana Posts: 4,402 iTrader: 0 reviews	Flea shampoo, then scrub it in with a chainsaw. __________________ Bolt-on Abraham Lincoln Log motor. With extra wiring.

May 3rd, 2009, 01:42 PM	#11
superbean Hardcore Enthusiast 1998 Cobra 13.24@105.66 Join Date: Aug 2008 Location: North Carolina Posts: 1,778 iTrader: 0 reviews	alright, thanks for the help guys. It would sit and idle fine for minutes on end before, but the only thing ive changed was my alternator .. (changed the fuel regualtor back to 7.5) because of the added volume of the fuel. Perhaps my throttle return spring is too stiff and pulling the throttle blade beyond base idle if that makes sense. Ill adjust the idle screws out to the most vacuum. __________________ weeee foooord!

May 3rd, 2009, 05:57 PM	#12
superbean Hardcore Enthusiast 1998 Cobra 13.24@105.66 Join Date: Aug 2008 Location: North Carolina Posts: 1,778 iTrader: 0 reviews	so i think i figure out what's up with the idle problems. It's a fuel pressure problem.. I turned my key on (fuel pump primes) and i hear a bunch of noise coming from my fuel pressure regulator and the needle is bouncing like crazy and doesn't sound good. I've had nothing but problems from this regulator. First the nipple on the back side wouldn't seal because of lousy machining, so i had to ghetto jb weld it, not the diaphragm isn't holding pressure.. Can anyone link to me a fuel pressure regulator that will hold up to a large efi pump but drop pressure down to 8psi or so? Mine currently is a mallory. I think they should just stick to ignitions. __________________ weeee foooord!

May 3rd, 2009, 06:13 PM	#13
86er I Post Entirely Way Too Much Join Date: Nov 2006 Location: Memphis, TN Posts: 7,748 iTrader: 0 reviews	aeromotive will have a good one, but if its not an intake pump, think about a non efi pump __________________ Just a truck 5.4 3v: 264hp 317ft lbs rock stock The "search" button, its not just for porn piecing together the next project faster than your first sexual experience

May 3rd, 2009, 06:27 PM	#14
superbean Hardcore Enthusiast 1998 Cobra 13.24@105.66 Join Date: Aug 2008 Location: North Carolina Posts: 1,778 iTrader: 0 reviews	well it needs to be a return style regualtor, single inlet single outlet __________________ weeee foooord!

May 3rd, 2009, 07:15 PM	#15
superbean Hardcore Enthusiast 1998 Cobra 13.24@105.66 Join Date: Aug 2008 Location: North Carolina Posts: 1,778 iTrader: 0 reviews	after reading on the topic more, people who run the stock efi pumps are having trouble with steady fuel pressure. What else have everyone done that has gone from fuel injection to carb? I don't care about spending a hundred bucks or w/e as long as it fixes this problem once and for all! __________________ weeee foooord!

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