the Mistery deepens, expert needed

8

86sebring

New Member

May 15, 2005

22

0

0

Sep 1, 2005

#1

• Sep 1, 2005

• #1

I need help with my carburated 302. This is starting to drive me nuts. It started when out of the blue it would not idle anymore, just shut off. It would either idle at 2000RPM or not at all. I checked the timing which was good at 10° at 1000RPM and about 38° at 3000. So I rebuilt the edelbrock carb, checked everything and put it back together, but the condition was still the same, no idle and very good top end power. I installed a holley carb-- same situation.
I played with the vacuum advance in the distributor and suddenly it idled fine, I thought it was fixed, but after driving for a while the condition returned, no idle, slight stuttering in low RPM's, but good top end power.
Last night I switched to a Mallory electronic distributor. It idled fine right off the bat, but after driving for a while when it got warm, the condition returned.
So it is not the carb, it is not the distributor, I checked for leaks around the intake and carb, the timing is set correctly, what gives??? What other components influence the idle
I don't know what else to check

 

69Rcode_Mach1

Active Member

Apr 20, 2004

1,473

1

37

Salt Lake City, Utah

Sep 1, 2005

#2

• Sep 1, 2005

• #2

HAHAHAHA this sounds like the same **** that I am going through. I am eager to hear the answer. Hey atleast you can get your timing straight I can't even get that. First time engine builders woes.

 

2nd Mustang

Founding Member

Feb 24, 2002

2,488

0

46

Southern California

Sep 1, 2005

#3

• Sep 1, 2005

• #3

Do you know how much vacuum you were pulling at idle when it was running well? How about fuel filter? Believe it or not, but a poster had a similar problem a long while ago, it turned out to be his clogged air filter.

 

B

bnickel

Founding Member

Aug 21, 2002

5,640

3

77

lubbock, texas

Sep 2, 2005

#4

• Sep 2, 2005

• #4

sounds like you have a vacuum leak. try spraying carb cleaner all around the carb and intake to see if it changes the idle at all. could also be a bad timing chain but you would normally see that with the timing light since the the timing would be jumping around all over the place. i'd bet good money on a vacuum leak

 

rbohm

Founding Member

Apr 12, 2002

6,698

550

204

tucson,az

Sep 2, 2005

#5

• Sep 2, 2005

• #5

a few other possibilities;

1: a dying fuel pump

2: a clogged fuel line(it has happened to me)

3: vapor lock

 

2nd Mustang

Founding Member

Feb 24, 2002

2,488

0

46

Southern California

Sep 2, 2005

#6

• Sep 2, 2005

• #6

Did you check for vacuum leaks around the area where the intake manifold connects to the heads? This sometimes is overlooked as a lot of people assume it's tight. I know I did that.

 

Hissing Cobra

Founding Member

Jan 4, 2002

798

0

17

Massachusetts

Sep 2, 2005

#7

• Sep 2, 2005

• #7

bnickel said:

sounds like you have a vacuum leak. try spraying carb cleaner all around the carb and intake to see if it changes the idle at all. could also be a bad timing chain but you would normally see that with the timing light since the the timing would be jumping around all over the place. i'd bet good money on a vacuum leak

Click to expand...

This is very good to do. I had a vacuum leak on my '93 Ford Escort that I had to find myself. First I took it to the Ford dealer and they tried to tell me that the catalytic converter was clogged $300.00+ to replace it.) Then when I took it there for them to fix it, they called me back and said that it was fine and that the MAP sensor was bad ($100.00+ to fix it.) Fortunately for me, they didn't have one in stock so I went and picked up the car (paying them $20.00 for "diagnosing" my problem.)

Well, the bastards lied! When I went home, I popped the hood and could hear a "hissing" sound. With my wife pressing on the gas and me spraying carb cleaner, I found out my intake gasket was gone. Everytime I sprayed around the intake, the idle would smooth out. Five dollars later (new gasket) and an hour's worth of my time, and I was back on the road without a problem. Because of this, I will never go back to that Ford dealer again.

I also recommend looking for vacuum leaks. Good luck!

 

6

66_stang

Member

Jul 4, 2004

154

0

17

Woodlands TX

Sep 2, 2005

#8

• Sep 2, 2005

• #8

same exact thing happened to me, turned out the gasket on the carb had come loose. There was a huge loud hissing noise though in my engine bay, not sure if u have that or not. Im willing to bet its a vacuum issue,.

 

8

86sebring

New Member

May 15, 2005

22

0

0

Sep 22, 2005

#9

• Sep 22, 2005

• #9

I got it, finally thanks for all the help
I replaced both vaccumhoses and the PCV valve, and "voila" idles like a champ
Hopefully this info will help somone else with the same problem.
It has been a very frustrating time, I was ready to lock the garage and loose the key, but now that this thing runs, I will again enjoy it
thanks again

 

C

chrua

New Member

Sep 7, 2005

19

0

0

Sep 22, 2005

#10

• Sep 22, 2005

• #10

I had the same problem. Cleaned out the fuel line and had gottennew intake manifold a few months earlier and had not plugged up a hole in the back of it.

 

hungrymonkey

White by Birth, Trash By Choice

Founding Member

Nov 29, 1999

3,077

12

108

Oregon.

Sep 23, 2005

#11

• Sep 23, 2005

• #11

I had the clogged air filter about 4 years ago.

It would idle fine, but would die with any amount of throttle.

Then I would pull the air cleaner and try to figure out what was going on, then it would run fine.

It took about an hour to realize that it was the air filter killing the truck, and not from me sitting behind the steering wheel.