Can't get 289 to idle

Hi,

I have a 66k hipo fastback with an automatic.

It was not running very well, and will not idle. I can keep the car running at about 1500 rpm, but I cannot get it to idle and run consistantly below 1500rpm. I knew the carb was getting old, so I took off the autolite and put on a brand new Edelbrock 600cfm with a manual choke. I also replaced the fuel pump. I have a glass fuel filter attached in between the pump and the line coming in from the side of the firewall. I noticed that the fuel level in the filter only fills in the very lower level of the filter. This is why I changed the pump as well. Shouldn't that filter be full of gas, or is this normal? It revs well and does not seem to starve for gas.

But it just will not idle at a respectable rpm. When I get to a light, I have to pop it in neutral or it will die, and it is embarrasing that it idles so high.

I don't hear (or see areas of) any vacuum leaks, unless it could be leaking out of the intake somewhere. I have the stock single point distributor with the points removed and replaced with pertronix.

I do have an aftermarket yellow top coil. I read somewhere here in the forum that this could be a problem. I adjusted the lifters properly and timing seems fine. It starts easy. If anyone could give me some ideas, I would really appreciate it.

Thanks in advance!

Hi There,

Thanks for all of the tips. I will use the carb cleaner to check for vacuum leaks. It seems like vaccum leak to me, but I was not able to hear, or see any problem areas when I checked the other day. I didn't know about the carb cleaner trick at that time, so I'll give that a try. I have all of the vacuum ports plugged on the front and back of the carb.

The car did idle rough with the old carb, but not as bad as it does now. It also smelled like it was running very rich. I tried to lean it out, and there was no difference at all when I adjusted the right side adjuster screw. I turned it clockwise as far as I could go, and there was no change in the engine rpms at all. The new Edelbrock does the very same thing. I thought that the Edelbrock was defective too, so I took it back and they were nice enough to replace it for me. The second Edelbrock worked exactly like the first.

When the car is running, I can see very little gas going into the glass filter, but the car seems to be getting enough fuel to run well at high rpms without cutting out at all. Still, it would seem that the filter should be at least half full. The main problem I have is just not getting a good solid idle speed.

I'll work on it today and let you know if I was able to find the problem.

Thanks for your help.

Update,

I did the carb cleaner spray test and it showed that I did have a vaccum leak at the base of the carb. I'll get two new gaskets and hopefully this will take care of the problem. I did not use any silicone the last time I installed the carb. It is ok to put a light coating of silicone on these gaskets to help seal it up?

Thanks...

Yes, the intake and adapter plate are OEM ford.

I'm guessing maybe the adapter plate is a little warped and this is why I am not getting a good seal.

I'll let you know how it turns out.

Thank you....

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I would not use a gasket sealer. BTW, is the intake manifold a stock Ford item?

good luck, and keep us posted.

Z. Ray

Edited by - zrayrichter on 08/28/2010 14:23:58

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Well, I put on two new carb base gaskets and it made a big difference. The idle is much better, but it still won't run very long when I am stopped at a light in drive. It just dies out. But if you put it in nuetral, it idles back to a somewhat normal rpm, but still a little higher than normal. So, I did the old carb spray trick again, and the engine did rev up just slightly each time I sprayed the base of the adapter where it meets the manifold.

It's only in the front of the adapter. The sides and rear seem to be fine. Is it possible that my adapter is warped?

Here are some shots of the car and engine.

Thanks again for all the tech support!

http://picasaweb.google.com/11318870394591…388513346919634

It appears that the leak is between the adapter and the manifold itself, right in the front. I think I am going to replace the adapter. I see that California Mustang has them, and hopefully it is a good repop of the original. Would there be any problem with doubling up on the gaskets, both top and bottom of the adapter?

Thanks....

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not familiar with edelbrok, but is it possible the carb doesn't match well with the adaptor? If the autolite is handy, I'd try putting it back on to see the difference, if any.

Z.

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Hi,

Thanks for the advice. My studs were threaded long enough so I did not have a problem with the shoulders, but I did yank off the adapter again and it was definitely warped. I layed it on a flat surface and it rocked back and forth. I found a good used adapter and it works fine. The vacuum leak is solved. Thank you everyone for your help.

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I chased a similar problem and ultimately found the threaded portion of the stud was not long enough to allow proper tightening of the carb to the manifold. I would think I had everything cinched up tight and everything looked good, but it was only cinched up tight to the stud. It is easy to check, just remove the front nuts and look to see if you can see the shoulder of the stud.

Jay

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