Stalls on idle in gear

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68er

68er

68Dart GT
Joined
Feb 9, 2008
Messages
345
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Location
Sarnia Ontario
Working on my car still lol like we all are....

Here is the situation: My 340 has a decent lumpy cam. It came with the car so I do not know the lift on it... Others that have been working or hearing it seem to think its a street/strip purple cam in the 455 t0 485 range...

Earlier this year I had to replace a rod and lifter and most recently changed the timing chain as it was stretched more then it should of been... We detected this when trying to set up the timing.. We noticed when moving the crank the rotor was lagging and not moving soon enough...

So the current situation is this:

Car is running nice once its moving along. Tons of RPM and want to go go go... but when it warms up or if the day is hot I cannot get it to idle in gear... always have to pop it into neutral when approaching stop light or sign... PIA...

The carb is a 600 Holley with vac secondaries. Is been pulled apart cleaned and put back together. Mechanic says its good...

[ I do notice the mixture screws on the side of the bowls are not very responsive when turning them ]???

Pulled the plugs and they are a golden brown on all of them.. I suspect this it dry and means the setup is too lean...??

I do not have a mechanical adjustment distributor so the timing is set like normal off the damper with gun.

I have done a ton of reading here on FABO .. From what I read I suspect 3 things

1: Carb mixture screws and idle circuit are not working right... [ this might include the accelerator pump ]

2: Timing : need a distributor that can be curved and have mechanical advance setup... [ I can have mine taken into Jim Speed shop in London Ontario and they can curve the factory distibutor for 75 ]

3: a fuel issue , maybe gas is too hot entering the carb on low idle ?

My mechanic wants to up the jet size from 70 to 72 but he already went from 68 to 70.... I think jumping to more sizes will just increase the gas usage and not correct the stalling...

I was recently at the Bothwell Carshow in Bothwell Ontario and chatted with a carb expert.. He says I need to get the carb working first before
determining any further.. He suspects the front idle circuit is dirty or plugged in one of the areas... this is why the mixture screws are not responsive.

Okay enough of my rant...... im looking for your input and experience too so I can further my testing...

Hoping to fix this before MoParFest..... :) !!!!!

thanks in advance FABO

Houston

:burnout:
 
At idle what is the timing? Idle speed?

If it's not around 14-16 at a minimum, it's likely not enough.

You may need to adjust the mechanical advance in the distributor to limit total timing to a reasonable number.
 
I had the same problem with my Dart. I spent hours recurving my distributor and playing with the timing. I rebuilt the Carter changed the jets and rods and it still stalled at idle.
One day I went out bought a new Edelbrock 750 put it on right out of the box and problem fixed.

Kenny
 
Carb adjustments are secondary to timing. Get your timing set properly then tune the carb. Do you have a vacuum gauge? Dial timing light?
 
Badsport said:
Carb adjustments are secondary to timing. Get your timing set properly then tune the carb. Do you have a vacuum gauge? Dial timing light?
Click to expand...

Will be driving over to my buds tomorrow. He has a SnapOn digital timing light.. and Vac Gauge too...

I got the timing set by ear right now. Basically drove and moved distributor until it had no more detonation on increased speeds through the gears.

Being a factory Distributor we will set it as best we can and check the vac..

I will report back with this result...

Also forgot to mention I did put a 600 Carter on it that is rebuilt and it too stalls at Idle in gear... so I guess this might rule out carb for now...

thanks
 
In my experience, when an engine runs OK in neutral and stalls when you go to drive, the idle mixture is too lean. That was a continual problem with my 60 Dart 225 with factory cam until a new carb fixed it. I have a Holley Projection in my Newport w/ O2 sensor so I can adjust the mixture easily and can reproduce easily. I find it needs to run a bit rich at idle. Besides the carb, a vacuum leak can cause a lean idle.
 
My 67 cuda did the same thing I thought it was carb turned out the stock converter wasnt working well with my cam put a 2200 stall in it and its great now. I also had 600 holley went with the new 770 street avenger I like it but there was nothing wrong with the 600 other than adjustments are funny on them. Use the vacume gage.
 
if the mixture screws have no effect on the idle then the primary side is open to far need to turn carb over and open secondry side until you see the transfur slot this will let you pull fuel out of the backside let close the primary side and your mixture screws work will help idle and stalling
 
burr said:
if the mixture screws have no effect on the idle then the primary side is open to far need to turn carb over and open secondry side until you see the transfur slot this will let you pull fuel out of the backside let close the primary side and your mixture screws work will help idle and stalling
Click to expand...

I missed the mix screws not doing much. That is usually an indicator of not enough initial timing causing too much throttle blade opening. Guys using the total timing method usually fall into that hole.

I wouldn't mess with the secondaries yet until you have a known initial timing setting that is adequate for the cam/engine. Until then, messing with the carb is a waste of time. XE262-268H are usually in the 14-20 range depending on the engine and that's similar to what he think he has in the engine.
 
Okay timing is set. Still not running very good in gear.. being a cool day here it was not acting up like on a real hot day.
We sampled a few dif carbs today and its looking like its not timing or carberation as the poor idle remains once in gear....
THe motor has no issues when you take off... runs like a bandit...


So tomorrow we are going to do a leak down test and gets some %'s

THen we will go from there ....
 
if its a big cam maybe the converter is pulling it down in gear? I know mine did the same when cracked helped out, was a pain but we got it. It needed a lot of initial, as much as possible and a high idle, like 900-1k
 
crackedback said:
Where is initial set?
Click to expand...

I believe its 15 area and total is 35 area.. Or its 16 and total 36

I don't remember exactly.. But it runs good and takes off great just a bust on idle in gear.

Once he is finished the leak down test we can determine things from there.
 
Set the idle mix screws with it in gear at the idle speed you want. What is fine in park is lean in gear. In gear is what really counts here, IMO. If the rpm drop from park to in gear is big, more than about 100rpm, ideally less than 75, something isn't right.

You might also disconnect everything that is vacuum related from the, plug that stuff and set it up. Then hook one thing at a time back up and note any change. Sometimes the PCV or power brakes are a vacuum leak.
 
Suspected issue was found... #3 cyclinder came back at 40% in the leak down test. But the compression in the cylinder was okay.

All other cyinders were just under 20%..

Earlier this season I had a rod go in #3 so defenately something there not right..

However we put a different 600cfm carter on it today and messed with the timing again.

To get it to run in gear on idle we are 18 initial and total 36. This will do for now before I decide over winter what top end changes I will do.

It is running in gear at idle now... there is a miss in #3 as the intake valve is not closing all the way on idle but does in higher RPMs...

So this is fine for now... future changes are going to come....

Happy we got it to run for now...

Thanks for all the inputs
 
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