Trying to set idle and due to dieing when in gear after it gets warm. Need help.

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YoungDart75

YoungDart75

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Ok guys ive been digging through most of the idle threads that have been posted on here and i keep coming to a few common fixes to try and get this thing fixed but dont seem to be having much luck.

Car was running and idling fine before, i had an issue with the float on the car and ended up rebuilding the carb and putting in a brass float. I followed the procedures in the manual about setting everything up to spec. Car ran fine for a little bit then the ECU crapped the bed and that was replaced. I set the timing back to 0 TDC and the car started up fine but died off after hitting temerature and being placed into gear/nuetral.

I bumped the timing back to where "the engine likes it" per some advice on another thread. Basically letting it idle until it warmed up, It began to start idling rough so I bumped the timing up as it picked up a few rpms and began to smooth out.

Shortly after that i took it for a drive and when i get to a stop it wants to fall on its face unless i keep giving it gas. Ive been looking through this for some help. But it seems the PO has always had the throttle position solenoid wire unhooked while hes had it which causes issues when trying to set idle. Also i noticed in this picture it has the accelerator pump link in the bottom groove of the rocker arm but mine has always been in the top groove. Is that an issue as ong as the distance measured is still correct?
[ame]http://u225.torque.net/cars/SL6/docs/Holley_1945.pdf[/ame]

I also saw this on the side of the solenoid and it says dont use solenoid or screw to set idle. So right now i dont really know where to proceed from here. Any help would be appreciated. Thanks in advance.

 
I would put a little more timing advance than that. You may have a vacuum leak. The solenoid is there to shut the butterfly closed when you shut the key off for pollution control as I remember.
 
Right now when at normal temp shes at about 5-6 degree's BTDC, the third notch on the timing cover. So basically no need to mess with it when setting curb idle/fast idle then?

Having the hardest time getting this thing to idle properly.

Ive gotten some better results adjust the curb idle screw today and it seems to be better but when i put it in drive or reverse to pull in or out of the garage it will try to die shortly after.
 
Ima thinkin the low-speed circuit is too rich.Do the mixture screws do anything? Is the choke blade standing vertical after warm-up.Did the Accelerator discharge check valve make it back into its cavity?
By now the spark plugs may be sooted up. I would pull a couple and look them over.I have often had to replace sooted up plugs.I have a feeling the float level is too high, making idle pull-over too easy.

Here are a couple of quick tests;
1) With engine idling and warmed up, air cleaner lid off, slowly bring a rag over the airhorn, but not enough to stall it. If the rpm goes up, as the airflow is restricted, the idle is lean.Conversely, if it wants to stall, its rich.
2) If the test shows rich, figure out a way to stop all fuel flow into the floatbowl,of the idling engine. This is usually done by clamping a rubber line. If the idle speed begins to rise(give it 15 to 20 seconds), Shes rich alright. Reset the floatlevel to lower the liquid level, and go back to #1.
3) If the test shows lean, first check for an external vacuum leak. Check every/all rubber lines that attach to the carb, and every device that those rubber lines lead to. Some devices include; the EGR valve, the charcoal canister, the choke pull-off, the brake booster,the nox valve and the heat stove.Check every single vacuum operated device. This is usually done by pinching those hoses and noting the idle responses. If any pinch results in an rpm change, repeat it to verify the change,then inspect the device. Then spray water all around the carb base,on the base gasket,looking for a change in rpm.
I left the PCV off the list because it will cause a change in idle rpm. Expect it to be small tho.
The charcoal canister is a special consideration.It is a controlled vacuum leak. But its not supposed to be sucking air at idle. If you crack the curb idle screw too far, the port for it may signal the canister to begin purging.If you determine the engine to be lean, make sure the canister signal line is hooked up to the correct port.It must not see vacuum at idle.Its also possible for that canister to become loaded with fuel vapors. If it purges too early it can send the carb into a rich state,. so again, make sure the signal line is hooked up right.
If,and only if, no vacuum leak is found this way, then;
4) You can try increasing the float level, then go back to #1
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5) if nothing seems to work, I would check/adjust the valve lash, and do a compression test.If you have a bad intake valve, firing compression into the intake manifold,You can waste a lot of time on the carb.
(If it was me, I would do this second(right after proving the canister signal line), cuz I have the tools, the time, the training, AND I have chased my tail around a time or two, to believe this should often be the first, go-to.)
If/when you do the compression test, (I always do a Ctest before the lashing, and again after),and you get some wide variations in the numbers,then I go to a leak-down test. I go to the cylinders with the lowest numbers first.I first determine where the air is going.If its going into the crankcase,its bad rings and we're done.But if its a valve,I reduce the air pressure into the chamber, and put the piston down in the hole. Then I take a mallet and spank the valves several times. This, hopefully, crushes or dislodges any carbon that may be preventing the valves from closing.If the numbers come up,then I re-lash those valves, and repeat the LD test.If the numbers just wont come up,and especially if there are more than one cylinder with low readings,attributable to valves, then it would seem the head needs work.

But as a parting shot, the rag and clamp trick usually gets to the bottom of it. Good luck
 
YoungDart75 said:
Right now when at normal temp shes at about 5-6 degree's BTDC, the third notch on the timing cover. So basically no need to mess with it when setting curb idle/fast idle then?

Having the hardest time getting this thing to idle properly.

Ive gotten some better results adjust the curb idle screw today and it seems to be better but when i put it in drive or reverse to pull in or out of the garage it will try to die shortly after.
Click to expand...

When you are checking the timing you are removing the vacuum line to the distributor and blocking the line from the engine, right?
The three notches you see when checking the timing are actually showing advanced and not retarded?

The accelerator pump rod being in either hole won't have any effect on the idle.

When it's warmed up and the choke is fully open put the parking brake on and let it idle in gear then adjust the idle mixture for the highest rpm or the highest vacuum reading if you have a gauge.

It might be helpful if you could post a video with sound of it running and what it's doing.
 
Do you still have a thick insulator type gasket between carb and manifold?
 
mguner said:
Do you still have a thick insulator type gasket between carb and manifold?
Click to expand...

Yes the carb rebuild kit had a brand new one in it and it went on with the rebuild.

kman521 said:
When you are checking the timing you are removing the vacuum line to the distributor and blocking the line from the engine, right?
The three notches you see when checking the timing are actually showing advanced and not retarded?

The accelerator pump rod being in either hole won't have any effect on the idle.

When it's warmed up and the choke is fully open put the parking brake on and let it idle in gear then adjust the idle mixture for the highest rpm or the highest vacuum reading if you have a gauge.

It might be helpful if you could post a video with sound of it running and what it's doing.
Click to expand...

Yes I am removing the vacuum line from the distributor and blocking it off. It has Before TDC and After TDC, mine is 3 notches Before TDC which is where it seemed to pickup rpms and then level off.

Ill try the idle mixture trick. It seems like its about midway out right now. Ill try and get a video posted but everytime I try to share one on the forum theres an issue posting the link/getting it to work.

Also compression test was 120 across all 6 cylinders +/- 5.
 
Ill do the video this weekend sometime. I left the car sit for a few days and i went back out to fire it up and do the video now and my battery magically only register 1.3V so slow charging it now. Never had an issue with the battery doing that before. Especially since its only a few months old.
 
Uploading the video now. But bringing the rag over it causes the rpms to climb up. I have the mixture screw already backed out pretty good too. Once I took it off the rpms dropped and as soon as I took the rag off.

[ame]https://youtu.be/nfbY8zSSB-E[/ame]
 
Well i adjusted the idle screw and the mixture a little bit more today in order to make it a little richer and she responded very well and i did a couple tests of putting it in gear and it never died once. So ill test it again tomorrow and take her for a drive and see.
 
Started up and idled just fine again today. No issues staying running when put in gear again so for now id say this thread is closed.
 
Annnnnnd its back open. Idling in the driveway/garage is fine, even when putting git in gear. I drove about 30 minutes to an event yesterday with no issues. I stayed at the event for about 2 hours and then drove home. About half way home I got to a light and she died on me. She fired right back up but as soon as I put it back in gear without idling it up manually she died. So I basically finished the rest of the drive(basically with a police escort who liked the dart) two-footing the brake and gas to keep her from dying again. I think this week I'm going to start looking at all the vacuum lines and see if there are any issues.
 
AJ/FormS said:
The charcoal canister is a special consideration.It is a controlled vacuum leak. But its not supposed to be sucking air at idle. If you crack the curb idle screw too far, the port for it may signal the canister to begin purging.
Click to expand...

Since your issue seems intermittent, transient conditions would be my first suspect. AJ's info above and in his post prior is very useful. It sounds like time to try and isolate the various items which could contribute to your issue.

But, for continuity sake, what is your current timing? Current idle mix adjustment (# of turns out from lightly seated)? How many turns in on the idle adjustment?

Your rag test indicates lean, which could definitely be the cause. If you're lean, then it could be that you're rich more often than it should be (charcoal canister issue, perhaps) and thus your mixture changes when that source of enrichment goes away. OR it could be that something in the carb is clogged and not delivering fuel the way it should. OR it could be a vac leak. A spray bottle of water or carb cleaner should help you root out vac leaks fairly quick, but disabling/plugging the various ports on the carb would be a good place to start.

As others have mentioned: float level and seat/needle may be a good place to check, but probably after checking the 'easy' things first. It may be newly rebuilt, but it's easy to overlook something or measure float level/drop incorrectly. You mentioned installing a brass float, was the original not brass? If not, did you use the float drop/level that came with the new float? If not, that could also be an issue. If the new brass one is more or less buoyant than the old one it will change your actual bowl level.
 
Should also mention;water. Up here in Manitoba,Canada, water is a constant battle . It seems the Alcoholized gas has an affinity for water, and sucks it right out of the atmosphere.
EFI cars have a more or less closed system, so they remain relatively unaffected.Furthermore their EFI pumps keep the fuel constantly circulating.
Not so with our older carbed cars with vents everywhere.The water likes to collect in the bottom of the fuel bowls, and cause low-speed problems. At highway speeds it seems to go through almost unnoticed.They make chemical additives to reduce this puddling of water.
At least on most motorcycles and ATVs we can drain the carbs pretty easily.
 
Well i pulled the cannister out today just to get a look at it while the battery is charging back up. The bottom filter on it is pretty dirty. Not quite sure how clean it would be or how when replacing it is advised. But ill try your method of the ports tomorrow. Also the current timing is right at 6 degrees btdc (third notch on the timing cover). I checked and reset the float level when I installed the new one as well as all of the choke adjustments that were recommended after rebuilding a carb. Idle mix is about 6 turns out from it being snug.
 
It seemed a little far out to me which is why i havent driven it since this whole issue started. What is the average setting for most? Could be leaking vaccum out of there with it being loose too. Ill check for vacuum leaks elsewhere as well. Ill post updates tomorrow after i mess with it.
 
I turned it back into where its 3 turns out from being seated. It fired right up and is idling fine. In the garage and cycling through the gears it holds without stalling but barely. Plugging any of the ports that run to/from the charcoal cannister have no effect what so ever. Un plugging the port that leads to the bottom of the air cleaner causes the rpm to rise a little but then reconnecting causes it to fall back to its normal idle. Unhooking pcv stalls it and it shuts down. Unhooking and plugging the port to the vacuum diaphram does nothing. Unhooked either of the lines from the "tree" on the intake manifold causes the car to studder and then reconnecting it goes right back to normal.
 
Good video
Do I see occasional puffs of smoke rising up out of the carb?
Is there any chance you set the valve lash too tight?

1) A too-tight valve lash, may not let the engine build enough compression to make the power required at low rpm to keep itself running, in gear. If you have solid lifters and you can't hear them clacking, chances are very good that the lash is too tight.
2) The rag over the carb seems to point to a vacuum leak. Often this will require a large curb-idle opening to provide the fuel to go with that air, to prevent a stall. This can then expose the vacuum advance port, which will then bring in some advance. All well n bad, but it idles with no load. Then when you put it into gear, the sudden drop in air-speed through the carb, drops the vacuum advance out, and then it stalls.
3) Another possibility is that the transfer ports are over-exposed due to a too-far-open throttle.They then can run dry at idle with the high vacuum, as the engine draws air around the blades through the t-ports.This condition is usually caused by insufficient idle-timing, but may also point to a vacuum leak.

Heres how I would attack this;
1) If I did see puffing out the carb, its time for a leak-down test. If for some reason, one or more intake valves are not seating closed during compression, it will be impossible to tune this beast.This is common on hi-mileage engines, as the valve spring pressure goes away, so you might as well check those if you take the valve cover off.
2) Lash the valves, Set the T-port sync., crank up the timing to get 550 rpm,and adjust the mixture screws with the engine running to best,smoothest,most stable,idle. Next go hunt for a vacuum leak. The slantys I've had, like to pull air in at the head. EGR valves can leak right through the diaphragms.Hunt.If you prove that there are no leaks, then;
3) prove your TDC timing mark, using a piston stop. Prove your centrifugal advance system is operating correctly;that is, smoothly up and down the rpm range, and no sticking.My slantys all liked plenty of idle-timing.
If you wish to leave the idle-timing up around 8* to 12*, you will have to limit your power-timing back to 32* to 36*

To set the T-port sync; pull the carb off, flip it upside down.With the throttle stopped against the speed screw, the transfer ports should appear as square to slightly rectangular.If you have A/C, that solenoid is a throttle-kicker. Make sure the throttle is properly parked.
Good luck.
 
Those thick fiber base gaskets are notorious for warping, even new ones, I would spray wd-40 or water around the base gasket and see what it does while running. I had a slanty do that years ago. It would surge at part throttle and die out in traffic at stop lights. Turned out those little steel grommets in the gasket were bottomed out from being re-torqued several times and the gasket had a slight gap between the mounting ears on the carb to base. Replaced it and voila, problem went away.

Try spraying around the intake manifold ports too, common place to have an air leak. Definitely looks like an air leak from your video.
 
You know what, I just thought of somethings. all this nonsense started after the new float went in, right? And the new float was brass. Was the replaced one also brass? Cuz IIRC,the float settings are different between brass and nitrophyl.Perhaps the fuel level is too high or it's not stable. What if perhaps the perceived float problem was really a float-valve problem? Hmmmmmmmmmm

EDIT; OOPs, I reread the thread, and forgot this was previously asked and answered.
 
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