I just put a Holley "heat shield" under my edelbrock 600 EC performer. yesterday morning and this morning today I started up the engine and it idled around 1200-1500 for the first 5 minutes of driving. I know the warm-up period should idle a bit different, but it's idling 500-800 RPM higher than it normally would.

Is there a way I can adjust the electric choke to not idle so high or something during the warm up? It never did this before the heat shield/spacer. I checked the timing and it's right at +12 where I set it a while ago, and once it's warmed up it idles real nice at around 700.

I'm going to crank down on the bolts holding the carburetor down to the manifold, maybe there is a leak somewhere?

And for those of you wondering, YES the heat shield/spacer really does keep the carburetor cool, after running 20 minutes I can leave my hand anywhere on the carburetor for as long as I want, where the manifold and actual shield it self are way way to hot to touch. Works like a charm and my idle is back to normal when I crank it over after running all day.

Thanks!

 

Turn the fast idle screw out until you get the speed you want.

 

ah, I just found where the screw is on google, I'll give that a shot, thanks!

 

Make sure the shield isn't interfering with anything on the carb. Mine did on the 750 Holley I had when I first installed the shield.

 

On the Edelbrock there isn't a whole lot of linkage or anything dangling below the level of the flange that the shield could interfere with, apart from the throttle linkage itself, which would cause bigger problems.

 

I checked and made sure that the shield was not in the way of anything. I did have to pound one of the tabs down (on the shield) to clear the linkage bracket though. Other than that it went in with out any problems.

I am in Phoenix Arizona, is there really any need for the choke? If I turn the idle of the choke down to say 800 or so, would that be bad? It's so dang loud idling at 1200-1500 early in the morning, I just don't think it's that cold to require that kind of warm up, I'm out there in shorts and a hawaiian shirt 1/2 way buttoned up.

What do yall's warm-up period idle at? Mine used to be 1000 before I put the shield and spacer in. I must have accidentaly bumped something on the carb maybe? I left the carb all connected and just lifted it up off the studs with one hand and slid the shield and spacer in with my other hand. Set the carb back down, bolted everything down again. Maybe I accidentaly grabbed and bent one of the choke linkage connector rod thingies?

 

Don't play with the fast idle speed too much, but you could probably back the choke tension off quite a bit. In warm weather you probably don't need the choke on for long.

 

Ok, instead of messing with the choke settings (now that it's starting to get warm/hot in Phoenix) I'd like to just disable it. Unplugging the positive wire to the electric choke will completely disable the choke, right? I obviously would tie it back somewhere out of the way and cover up the wire with electrical tape to keep it clean.

That should do the trick, correct? I have it unplugged right now, but I won't find out untill tomorrow morning if that does the trick or not.

I just want to make sure this will not cause any other problems. The choke is the only thing in the carburetor that runs off of that electrical wire, correct?

 

No, unplugging the choke wire will keep the choke closed all the time, which is not what you want. With the enging cold, loosen the screws on the choke housing and turn it all the way in the "lean" direction, until the choke plate is fully open. You could end up turning it past the cast markings, but that's not a problem.

 

I'll do that, thanks I see the scale you are talking about. I assume that means turn it all the way to the left (counterclockwise) right?

 

Ok, I got the choke plate to be all the way open (yes I did have to go off the scale, thanks for that tip!).

But.... nothing has changed. *sigh* Still a 1500 RPM idle when it's cold. ("cold", I was out there in a tshirt and my sleeping shorts with no socks... it's not cold out there)

Any other suggestions?


I'm getting a bit tired of the high morning idle, it will idle it's way into 2nd gear, and I have to mash the breaks real hard to come to a stop for the first 5-6 minutes of driving. It never did this before I put the heat shield and heat spacer on there. But I can see such a big difference in the smoothness of the engine after it gets warm now that I have the heat shield. I'm not going to take it off.

Thanks for any more info/suggestions!

 

That says more than anything else yet related. Either the shield and/or spacer is hitting something, or you whacked something while doing the job.

 

The spacer isn't hitting anything, I putt it WOT and check everywhere and nothing hits anywhere. I must have bent something Well, at least it's only a problem when the engine is cold. Guess I should have someone who knows more about carbs take a look at it.

 

Yeah, if it's still idling high with the choke open then it's probably not a fast-idle problem.

 

any ideas where I should start looking? Again, it only happens when the car is cold, for about 5 minutes then everything goes back to normal all day long.

 

Take the shield out, leave the spacer in, see if the problem is still there. If it is, take the spacer out, repeat. If the problem is still there after removing the things you added, then something else has changed.

It doesn't make much sense that it only has a fast idle problem when cold. If the choke is never on, the idle should increase as the engine warms up, not decrease.

It may be some weirdness caused by a vacuum leak, though.

 

I didn't run the car all day (accept for the first little test this morning after I dialed the choke all the way open), and tonight I started the car up and it died with in 2 seconds. I thought that the choke was going to still kick in. So I start it up again and keep the RPMs up a bit for about 10 seconds, then it would idle on it's own.


So.... I guess the choke is not operational now Good! I don't mind helping it to idle when I start it up cold, It's much better than the 5 minutes of 1500 idle. I'm not sure why the idle raised so much when I started it this morning after dialing the choke wide open.... but it seems to do what I want it to now, absolutly nothing


I guess I'll find out for sure tomorrow morning, tonight it's colder than it has been for a few weeks.

 

Okee Dokeee! It's all good now!

It takes about 20 seconds to warm up then it idles nice and perdy

I'll post up an audio clip here in a little bit, I'm glad I don't have to sit through the 5 minutes of 1500 RPM anymore when it's not even cold out. Thanks guys!

 

http://www.danielbuck.net/idle.wav


It's a bit muffled sounding, my Camera doesn't take good audio clips, and for the first 2/3s of the clip I was sitting in the car. Once I got it to idle I walked around to the rear, and you can hear it pretty good at the end of the clip.

Later when I'm not sitting in the appartments sometime I'll take a clip of it with the cutout open, this clip was going through a cat and muffler.