No idle after duraspark conversion.

[chickhauler]

OK I just finished my duraspark and the truck starts fine if you tap the gas. It tries to idle really high for a couple seconds then it will slow down and die. If you tap the gas again it will rev up and try to idle high again for a couple seconds and then die. Any suggestions? I didn't block off my EGR yet because I don't have a metal plate laying around. I used all new parts for a 79 mustang II except the carb was re manufactured but right from the parts store. Any help is greatly appreciated. One other question, I cannot seem to find the wire that goes to the electric choke. Can anyone tell me how I can power the electric choke so it will work? Should it have power when the key is on or what? Again thanks for any help with these problems.

 

[dangerranger83]

I just use a manual choke and call it all good. But some people use the white/black wire that comes off the alternator for the electric choke, it supplies 8 volts. As far as idle, you may have to adjust the mixture screws on the carb to get it to idle for you.

 

[chickhauler]

I have messed with the mixture screws a little but it doesnt seem to really change anything. Will try more of that today. Thanks for the choke help will do that.

 

[kimcrwbr1]

Turn the idle air screws out three turns from the lightly seated position. Is the carb for a mustang also the 2150 non feedback carb. You may need a new spacer to plug the vacuum leak on the bottom of the carb. Get the spacer felpro # 60529 for a 302 $18 and slowly tighten the carb down real snug not too tight. put the vacuum advance on manifold vacuum turn the idle air out three turns and adjust the timing at 10 degrees once you can get it to idle with the vacuum disconnected and plugged. Dont even mess with tyhe choke until you get the engine timed and the carb dialed in.

 

[kimcrwbr1]

If the egr aint leaking dont mess with it either for now just make sure all the vacuum leaks are plugged first once you get it to idle. You only need the advance the brake booster and the vapor cannister that is plugged into the egr spacer on the carb spacer behind the carb down low center make sure that nipple is plugged. and I just wired the two solenoids to hot key on and put a restrictor from the vacuum tree to the cannister to pull a slow steady vacuum from the cannister so you dont vent the tank in the engine compartment. I hate the smell of fuel I always think I have a leak somwhere.

 

[kimcrwbr1]

Turn the choke thermostat to hold the choke all the way open for now you cant set the high idle until you get the carb dialed in.

 

[chickhauler]

I am at my wits end with this thing. I have tried everything I know. It will try to idle now but man does it run very rough down low. If it idles at all it is at an extremely fast idle. It revs very freely without any hesitation at all. The mixture screws seem to do nothing.

 

[kimcrwbr1]

If you dont answer questions we cant help what carb and are you using the stock spacer under the carb.

 

[chickhauler]

If you dont answer questions we cant help what carb and are you using the stock spacer under the carb.

Using the stock spacer and a stock remaned 2150 from a 75 mustang 2.8. Sorry for not getting back to anyone. I just got back from a cross country trip due to a death in the family. I really appreciate all the help you folks are giving me. I had to make a gasket between the stock spacer and the intake. I am using the new thick gasket that came with the carb between the spacer and the carb. I might need thicker gasket material between the spacer and the intake. I am not sure on that though.

 

[kimcrwbr1]

If your using the stock spacer from the feedback carb the leak is under the carb between the carb and the spacer get the spacer felpro # 60529 for around $20 and the engine should settle down. The spacer has gaskets on it but you will need to get a carb gasket or make one for the bottom of the carb unless the carb you have has been surfaced. From personal experience the spacer and gasket will solve the problem. I took a piece of 180 grit sandpaper and glued it to a flat piece of plywood and surfaced the bottom of my carb just work it around slow and flat until you see scratches on the entire surface. The ears allways get bent expecially if you reefed on it tightening it down. Clean the egr spacer good put the new spacer on and the carb gasket surface the carb if necessary then tighten it down slow and even good and snug not real tight. Get it up to temp a couple times and keep snugging it after it cools down until it stops turning it is real easy to break the ears off if it is not flat. Just keep your idle air screws out three turns until the engine is up to temp time at 10 degrees with no vacuum (plugged) to the advance plug the advance to the vacuum tree should be around 20 degrees at an idle then dial in the carb. set the idle air for the highest rpm or vacuum pressure.

 

[chickhauler]

If your using the stock spacer from the feedback carb the leak is under the carb between the carb and the spacer get the spacer felpro # 60529 for around $20 and the engine should settle down. The spacer has gaskets on it but you will need to get a carb gasket or make one for the bottom of the carb unless the carb you have has been surfaced. From personal experience the spacer and gasket will solve the problem. I took a piece of 180 grit sandpaper and glued it to a flat piece of plywood and surfaced the bottom of my carb just work it around slow and flat until you see scratches on the entire surface. The ears allways get bent expecially if you reefed on it tightening it down. Clean the egr spacer good put the new spacer on and the carb gasket surface the carb if necessary then tighten it down slow and even good and snug not real tight. Get it up to temp a couple times and keep snugging it after it cools down until it stops turning it is real easy to break the ears off if it is not flat. Just keep your idle air screws out three turns until the engine is up to temp time at 10 degrees with no vacuum (plugged) to the advance plug the advance to the vacuum tree should be around 20 degrees at an idle then dial in the carb. set the idle air for the highest rpm or vacuum pressure.

Thank you so much. I will try that.

 

[kimcrwbr1]

Thank you so much. I will try that.

Cool once you get the carb dialed in then you can adjust the choke just make sure the choke is all the way open when you dial the idle in then you can adjust the choke after it cools down all the way.

 

[chickhauler]

If your using the stock spacer from the feedback carb the leak is under the carb between the carb and the spacer get the spacer felpro # 60529 for around $20 and the engine should settle down. The spacer has gaskets on it but you will need to get a carb gasket or make one for the bottom of the carb unless the carb you have has been surfaced. From personal experience the spacer and gasket will solve the problem. I took a piece of 180 grit sandpaper and glued it to a flat piece of plywood and surfaced the bottom of my carb just work it around slow and flat until you see scratches on the entire surface. The ears allways get bent expecially if you reefed on it tightening it down. Clean the egr spacer good put the new spacer on and the carb gasket surface the carb if necessary then tighten it down slow and even good and snug not real tight. Get it up to temp a couple times and keep snugging it after it cools down until it stops turning it is real easy to break the ears off if it is not flat. Just keep your idle air screws out three turns until the engine is up to temp time at 10 degrees with no vacuum (plugged) to the advance plug the advance to the vacuum tree should be around 20 degrees at an idle then dial in the carb. set the idle air for the highest rpm or vacuum pressure.

OK tried all the above with not really much luck. It still idles rough I mean real rough. When ya tap the throttle it revs freely and then takes a min to idle back down. I cant really get it to truly idle, what I am calling idle is a fast idle. If you adjust the idle screw down it just dies. Ok here is the interesting part. I took it out for a spin today and it runs like a banshee when you take off. It has never felt like it has ever had this much power. It will spin the tires with ease and even bark them changing to second.

 

[kimcrwbr1]

Did you check the egr and make sure it is not leaking internally, are the brakes working properly, do you have a new PCV valve. It sounds like a vacuum leak somewhere. Use a length of vacuum tubing and put one end up to your ear and search around the base of the carb and the nipple on the back of the egr spacer is easy to miss down below the brake hose from the vacuum tree. You will hear a hissing when you get close to a leak it is also good for isolating exhaust leaks also. Glad it is running better find the vacuum leak and you should be set. Make sure to check the timing and adjust the idle air after you find the leak. If your using a 2100 or 2150 carb is the hole plugged for the choke thermostat htere is a fitting or threaded poet on the section that goes down at a 45 degree angle that is a direct vacuum leak also plug the hole or cap the fitting. Some pics would help.

 

[RICO9]

when i got my reman. carb i too had a high idle. it turned out the throttle spring that came with the new carb was too soft so i used a stiffer one.