Idleing Issues!!!!

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4mulaSvaliant

4mulaSvaliant

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OK, here we go with another gremlin in the system.

I have a 360 with a fairly mild cam, 650 edel. dual plane intake, electronic ignition, manual choke, headers. Ok now that I have most of the info people ask for when you post something like this Ill carry on! lol

I am unable to figure out why my valiant idles incredibly low after it has warmed up. When starting it, it acts just as you would expect. Use the choke and itll fire and then I have to slowly ease the choke after a bit. Once she gets up to about 180 or so it starts idleing low and rough. so much so that itll die about 50% of the time if left alone. Not to mention if I drive it, it will die for sure when I come to a stop in gear, that is if I dont left foot the brake.
So now here is what I have checked to start looking for the answer.
Plugs--- could not ask for it to burn any cleaner!
Elect. Ign. ---- Retraced all wires and all is good in da' hood!
Plug wires--- Good!
Cap and rotor----Good
Adjusted timing----No improvement. (should you get any rotation play when grabbing the rotor and twisting it?)
Adjusted carb-----Seems to be good, It didnt help much trying to lean it or richen it.

Here is what I am wondering about, this carb was on another car prior to mine (challenger) I think. The accellerator pump was unable to come all the way to its resting pos. making it idle to high and be unadjustable due to linkage restrictions, so I moved it one hole, now I am concerned that this may be part of the prob.

Also since I have installed the new tank, the filter up by the carb doesnt seem to have much fuel in it until after about 30 minutes of running. But the one back at the tank is constantly full. The vent for the system in my valiant is a tube that is at the top of the filler neck and drains openly near the frame rail.

Any help or ideas is much appreciated! thx :thumbup:
 
First off did you set the idle mixture screws with the car warm and idleing in gear? If not you need to do that. I always set idle mixture witha vacuum guage and set it to the highest reading....this will aslo give you the info you need for a power valve or in your case the metering rod step springs. Have you taken carb cleaner and sprayed around the intake and carb to check for leaks? I have seen where leaks show up when warm because of the the metal expanding and contracting. I used to run an Edelbrock carb and I hated it...never ran right. What is you fuel pressure at idle when warm? Do you have a return line? If not the fuel could be deadheading in the line and getting hot and the fuel pressure drops and this can cause a operating temp idle problem. What fuel pump are you running?
 
So, if it idles slow, set your timing first, then set your carb. No problem... That';s why all the adjustments are on it. You have seperate idle speed screws. the hot idle (slow) has the slotted end pointing straight forward. The cold idle (fast) has a screw that faces more down tha forward, and it's on the driver's side linkage. I find it easiest to shut the car off, open the throttle by hand, and adjust it a little, then fire the car up to make sure it's where I want. Also unplug the electric choke while you set the fast idle, or it will be trying to open every time you fire the car. Just make sure to plug it back on and let the thing warm up before resetting the slow idle. Once you have the speed(s) where you want them, use a vaccum gage to set the mixture for the highest smooth vaccum reading at your rpm. Also keep in mind that as youi adjust, the speed may increase or decrease. You have to adjust until it's all dialed in. Just for reference, I've been tinkering with my truck's carb a little here and there and it still needs some tweaking to be right after about 2-3 hrs of 20 minute adjustment periods.
 
Thx Guys!
Ill give it a try. Like I said I havnt had the car for about 9 years nor' have I been wrenching in about the same amount of time so I have lost some of my intuition! lol However I can say I was also not aware of the corrent way of setting the carb up. I have always done it ol' school red neck way. Adjust it til it runs better! lmao :tool:
So Ill borrow a Vacuum guage and give it a couple of tryes and see what I get! Thx again!
 
Ok here is the update to this.
First Ill start with some issues I found. I realized durring the last time I drove it, that if I kept the choke pretty well closed that it ran ok, idled better and all (still not a great idle but better). Then today I went to adjust the timing and carb and I could not get it to start for anything! So upon inspecting things I realized that when I pumped the throttle that NO FUEL was squirting into the venturies NONE! So I am thinking that I have a bad accelerator pump, which would also cause the crappy idleing (am I correct?). I noticed I have a "dead" spot as I try to bring the idle up slowly. The dead spot is imidiately off of the idle screw.
So, I went and bought the rebuild kit for my edlebrock. I have yet to rebuild it. However! I did eventually get it started and then went forward with adjusting the timing and the carb. Ok more issues concerning the timing adjustment.
So I adjusted the carb first and maybe I shouldnt have but it wasnt running very well so I got it better before atempting to time it. Here is where the problem lies. I put a quality timing light on it and the timing mark on the balancer was wayyyy before "0" (refering to clock position it was probley 12:30 or so) I have an advance style light and had to advance it about 40* according to the light, but according to the timing cover it was more like 20* or so. SO what I did was adjusted it til it came to "0" and my idle had dropped way low. so then I brought the idle up and drove it around for a few minutes. it idled better but still a lil' low. And thats when I had to stop tinkering for the night. Any help would be much appreciated!!!!
SORRY ABOUT THE NOVEL!!!!!!!!! LOL. :sleepy3:
 
First off your timing should not be at zero. It should be somewhere around 10-12 before tdc. And remember to unplug the vacuum advance when checking the timing. It sounds like your timing was probably close to begin with and now you have it retarded WAYYYYY back so it's going to be a real dog. Get the timing set back to where it should be first. The accelerator pump has no affect on idle whatsoever. It only gives the engine a shot of fuel when accelerating. Thus the name accelerator pump. If it's not working it will cause the bog you mentioned though. Rebuild the carb and make sure and clean it real good with carb cleaner inside and set all the settings right to spec. per the paper work that comes with the rebuild kit and then adjust it like the other guys said and you should be good to go.

BTW: If it idles better with the choke half way on sounds like it's running lean. After the rebuild start with the idle screws out about 1 turn more than they are now.
 
hey thx very much. I only had a chiltons that was up to 1972 so I didnt even have specs for timing for the 360. Just basicly guessed off of the 340 for 72. As for the accelerator pump it is causeing me issues when trying to start obviously, and what you said makes perfect sence as far as idle goes. Which explains why it will run once started. I see you have a 360, so 12 degrees btdc is where its supposed to be ayy? thank you Ill straiten that out tomorrow! Hey do you know how I can check to see if my balancer outter ring has shifted at the rubber part? Like is there some way that it was indexed or was there something that may be lined up that I can check?
I just ordered the balanced flex plate from summit so I can get my trans issues sorted.
 
No problem. Actually 10-12 degrees is just close enough to get you into the ballpark. I forgot you mentioned earlier that you have a advance type timing light. With that you can get it real close. What you really need to get it to is about 34 degrees total timing. That is what it should read when you have the vacuum advance disconnected and the engine revved up to about 2800-3000 rpm in neutral. Then lock your dist. down and hook the vacuum advance up and your good to go. Actually my 360 timing is set at 16 before but that's because I have a Mallory dist. that has adjustable advance and need more initial timing and less advance for my larger cam. As far as checking the balancer goes. The only way I know to do that is do a good visual inspection on it and check with a dial indicator. I believe if it actually came loose enough to slip it won't be straightand since the 360 is externally balanced it would probable vibrate bad if it slipped. The mechanical way to check it would be to use a dial indicator to find TDC on piston #1. When #1 is on TDC the balancer should be on zero. If you don't have the tools to check that the visual is all you can do.

I see what you mean about the acc pump causing hard starting since it gives no pump shot.
 
Well Im going to do a lil' checking because I do have a bad vibration but I have been thinking that it may have the wrong converter (built in HS, didnt know any better) Hence the flex plate being ordered. Im going to have the motor out soon so Ill check the balancer then. Ill be putting J heads on it at that time as well so Ill be able to set it to tdc while the heads are off pretty easily. Im going to have to read up on this timing light a lil more and make sure I get it all set correctly. Thx for the general idea on the specs. I guess I need to get a book for a dodge truck or something to get some decent specs on the motor. Sorry bout the PM it was incredibly late here and I didnt realize. Thx for your help. Donnie :thumbup:
 
Keep after it. You're making progress. It can take a little bitt o get a carb dialed in right. Sounds like you're getting closer.
 
OK guys well I want to thank all who helped!
I was able to get a few minutes and play with it a little more today and I have it pretty well dialed in compared to before.
I set the timing to 12 btc and then adjusted the carb to a good and stable vacuum of 21 or so. The car idles great and doesnt die at a stop sign.
Although here is something I ran into today when setting the timing. I pulled the vacuum line off of the dist. and to my surprise I couldnt feel any suction. I had it connected to the vacuum port on the left as you are facing the carb. I moved it to the other one on the right as you are facing the carb. This is the port that I checked the vacuum at. Am I wrong in thinking both of them should be equall? Or did I have it correct, and that perticular port increases in vacuum as the rpms go up? :thumbup: thx again guys
 
Good deal Donnie. Sounds like you've got it doing alot better. The one vacuum port is called ported vacuum and it does not have vacuum at idle. It is where the dist gets connected and it only has vacuum when the throttle is opened past idle. The other port will have full vacuum at idle. It's generally not used for anything but a good place to hook up a vacuum gauge. Everything you found is normal.
 
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