Last edited:
Engine slow return to idle.
- Thread starter 68Nwprt
- Start date
The Horvaths
Young man with a cowboy hat
Are you referring to starting while parked, or after accelerating when driving?
stubs300
Senior Member
Or just blipping the throttle while sitting in the driveway?
That's exactly what I mean. Sitting in driveway in park. Hit the gas and rpm comes up fast but takes three to four seconds to slowly return to idle. It's not a big deal just curious if any one knows why.
Last edited:
stubs300
Senior Member
All that rotational energy has to go somewhere and that takes time. I think all engines take a few seconds to wind down, there's no way it can do it instantaneously. What RPM are you buzzin it up to? I wouldn't worry about it.
Thanks for the input. Coming up to around 3500.
70bigblockdodge
Old Man with a Hat
See what " of hg your vacuum is coming in at. Should not come on til 7-8" and all in by 10" or so
Not sure what you mean by this. What is inches of hg . Sorry.
Does appear to be stretched some, also I don't have a safety spring. I'll look into that. Thanks.
70bigblockdodge
Old Man with a Hat
Inches of mercury or vacuum.
Are you referring to timing advance.
He is. Your modern DD uses ignition timing to correct idle speed all the time, it only changes airflow to make larger corrections. Also any small vacuum leak may lead to this complaint/symptom... or it could be perception.
Timing tests are covered in the FSM, with specs. Vacuum leak diagnosis gets iffy when your chasing a smaller leak that isn't really messing with idle too much. My best test for a leak without having to go shopping is to spray a heavy mist of water at all intake/carb gaskets on a warmed engine with a stable idle... you should hear a small rpm change if the water temporarily seals a leak. Keep in mind vacuum leaks could come from HVAC vacuum controls, brake components... anything with a vacuum hose. If you buy a selection of vacuum test caps you could easily block off all the external (to the engine) vacuum lines and verify if the issue is still present.
If you have no other issues with acceleration, cruising spark ping or operating temperature, you can simply continue to drive too...
Last edited:
Thanks for your input. Sounds like good advice.
Last edited:
70bigblockdodge
Old Man with a Hat
I was trying to remember which way it effects, I believe it is too light of spring pressure will make it come on early and stay on too long which is what is happening to yours. a 3/32 allen wrench in through the nipple will adjust CCW will tighten ( make it operate at higher inches of mercury) CW will make it come in earlier/lower vacuum. I think you will need CCW, but I would measure it with a hand vacuum pump.
Thanks, I'll try that today. I had a feeling it was a vacuum issue just not sure which way to go with it, since pretty much everything is new. I don't believe I have any vacuum leaks, but it is possible so I will take cantflips advice and check that also while I'm in there.
Similar threads
