Idle issues when in gear

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Ed Kelly

Ed Kelly

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Location
Columbus Oh
My Wagon has developed an issue at idle when the car is in gear. It will idle around 700 rpm and then drop to 400-350 rpm. It won't die just shake, a tap of the gas will bring the idle back up.

225 /6 push button automatic.
Pertronix II and Pertronix coil
New cap, rotor, plugs and wires
Carb was professionally rebuilt
New fuel filter
No vacuum leaks
Vacuum at idle is 22 in park and in drive it is 20.

What should I be looking for?


Pic is just cool..lol

20190621_201222.jpg
 
Worn out, sticky butterfly's? Lots of return spring spring pressure?

When my torque converter took a crap my car wouldn't idle in gear.
I had to up the N idle to stay running in gear before I realized I had a trans issue.
 
My former ‘71 model \6 would do the exact same thing when it would start to run out of valve lash until I started using lead substitute. May or may not be your exact issue, but may be something you want to check.
 
Ed Kelly said:
My Wagon has developed an issue at idle when the car is in gear. It will idle around 700 rpm and then drop to 400-350 rpm. It won't die just shake, a tap of the gas will bring the idle back up.

225 /6 push button automatic.
Pertronix II and Pertronix coil
New cap, rotor, plugs and wires
Carb was professionally rebuilt
New fuel filter
No vacuum leaks
Vacuum at idle is 22 in park and in drive it is 20.

What should I be looking for?


Pic is just cool..lol

View attachment 1715353347
Click to expand...
I'd look at a voltage issue, sounds like coil is affected , maybe regulator dips the voltage.
 
Love your wagon ! My 76 Aspen with a slant does the same thing and it also diesels when I shut it off in park but not in R .I have set the timing to an advanced position to raise the idle so I can back off on the throttle screw. It made a huge difference and stopped it from running on when shut off in P. Still runs kinda rough when idling in gear but running is smooth as silk. I'm still chasing my tail over this problem .
 
The problem is not a failure to use lead substitute, so don't fret (or spend) about that. The problem is likely electrical/ignition- or fuel-related, and the mentions of valve lash are wise, too. Follow tune-up parts and technique suggestions in this post, do a careful valve adjustment, and Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download.
 
I have worked on it some today. I adjusted the timing, something I failed to do after installing the Pertronix. The timing was way off, I now have it set at 8 degrees before tdc. The distributor will not any further to set in at 5 degrees. The throttle return spring would not pull the throttle closed all the time, so I replaced the spring and reset the idle and fuel mixture, using a vacuum gauge and I have 20 degrees of vacuum in drive at idle. The needle bounces just a touch, again I am assuming a valve adjustment will help that.

I just got back from a 30 minute stop and go cruise with a small stretch of highway at 60 mph. It seems to run pretty well now and idles in gear good. I still have a slight miss that could be do to the valves needing adjustment.

Thanks for all the help and advice.
 
Ed Kelly said:
I have worked on it some today. I adjusted the timing, something I failed to do after installing the Pertronix. The timing was way off, I now have it set at 8 degrees before tdc. The distributor will not any further to set in at 5 degrees. The throttle return spring would not pull the throttle closed all the time, so I replaced the spring and reset the idle and fuel mixture, using a vacuum gauge and I have 20 degrees of vacuum in drive at idle. The needle bounces just a touch, again I am assuming a valve adjustment will help that.

I just got back from a 30 minute stop and go cruise with a small stretch of highway at 60 mph. It seems to run pretty well now and idles in gear good. I still have a slight miss that could be do to the valves needing adjustment.

Thanks for all the help and advice.
Click to expand...

thanks for the follow-up. Too often we don't get any feedback, so there's no real resolution.
 
Vacuum advance, or hose, on your distributor my be leaking, cause erratic timing. Easy to check...
 
Ed Kelly said:
I now have it set at 8 degrees before tdc. The distributor will not any further to set in at 5 degrees.
Click to expand...

You'd need to loosen the 2nd bolt, the one that holds the hold-down plate to the underside of the distributor body, to rotate the distributor body relative to the plate and get the adjustment range you need. Both ends of the plate are slotted, so if you run out of room in the short slot where the hold-down plate bolts to the block, adjust the other bolt in its longer slot. That means either pulling the distributor or having the secret decoder ring.

The throttle return spring would not pull the throttle closed all the time, so I replaced the spring
Click to expand...

Good. That's a safety issue.
 
also check you wires and coil.

Car would do similar. Hv lwad from coil would arc occasionally to lv posts on coil. Hv lead wasnt seated in there properly. Easy to see at night
 
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