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  #1  
Old 11-28-2010, 06:18 PM
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Idle Hunting Behavior on 617 Turbo Engines

Hello,

Since I got it, on random occasions my 82 300CD would "hunt" a bit for an idle. Generally it seems when cold or nearly cold, in cooler temperatures but above freezing. It is a random thing, and seems to be related to finding the right idle speed after very low loads, like going from D to N or the AC cycling.

I took a video on my phone. Listen as the sound is more telling than the tach needle. Any thoughts/ideas?

And this was done after driving a while (drives fine) after reaming/replacing GPs and changing the spin-on fuel filter...

Link is here:
http://www.youtube.com/watch?v=-TGfKXp_-d0



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Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
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  #2  
Old 11-28-2010, 06:35 PM
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Adjusting the rack dampener screw fixed my hunting.
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1985 300SD 99K
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  #3  
Old 11-28-2010, 06:44 PM
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I have had a very small intermittent fuel line air leak do the same thing.

I also have had a weak lift pump do that as well.
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'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car
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  #4  
Old 11-28-2010, 07:59 PM
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OK, makes sense. Need to dovetail this into the other thread on IP springs then...
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
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  #5  
Old 11-28-2010, 09:00 PM
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Quote:
Originally Posted by JHZR2 View Post
OK, makes sense. Need to dovetail this into the other thread on IP springs then...
I think you're adjusting a bunch of things at once and you could well be running into two issues which are interacting with each other. An air leak combined with a slightly out of adjustment rack screw can cause the bad starting and idle hunting you are experiencing.
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-------------------------------
'85 300D, 'Lance',250k, ... winter beater (100k on franken-Frybrid 3 Valve Kit)
'82 300D, 'Tex', 228k body / 170k engine ... summer car
'83 300TD Cali Wagon 210k, wife's car
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  #6  
Old 11-28-2010, 09:10 PM
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May be true...

I had idle shake and the hunting since I got the car. Starting wasnt perfect either, but generally no big deal. Adjusted rack damper to fix idle, made starting tougher, no real fix. Pulled rack damper out and starting got easier, still have the shake.

Tested (cold) compression, got good numbers, though #4 may be off a tad.

Not sure if the #4 cylinder or a possible air leak would be the culprit. I dont noticeany air leaks, though it did seam tough to reprime the system after changing the secondary filter...
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
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  #7  
Old 11-28-2010, 09:39 PM
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Quote:
Originally Posted by JHZR2 View Post
OK, makes sense. Need to dovetail this into the other thread on IP springs then...
Why not start a new thread, and tie them all together by linking to the other threads you already have on the same subject? The mods will really like that.
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83 300 D turbo 297K runs great. SOLD!
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  #8  
Old 11-28-2010, 09:46 PM
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Location: New Jersey
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Ill figure it out. Thought all were jsut different separate tweaks that needed to be made...
__________________
Current Diesels:
1981 240D (73K)
1982 300CD (169k)
1985 190D (169k)
1991 350SD (113k)
1991 350SD (206k)
1991 300D (228k)
1993 300SD (291k)
1993 300D 2.5T (338k)
1996 Dodge Ram CTD (442k)
1996 Dodge Ram CTD (265k)

Past Diesels:
1983 300D (228K)
1985 300D (233K)
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  #9  
Old 11-29-2010, 01:21 AM
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Location: Grand Rapids, MI
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The idle hunting is generally a weak or poorly adjusted rack damper bolt in combination with not quite the right idle speed. Each engine/IP seems to need a unique adjustment of idle speed/rack damper bolt to find the sweet spot where it doesn't hunt or shake.
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  #10  
Old 11-30-2010, 03:00 AM
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wow, such a subtle thing to notice -- hunting idle. i never thought to look at that. where is the thread on adjusting rack dampeners (with pics, please)?

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