So this morning, upon start up, after a few minutes my idle started to climb rapidly in the manner of a runaway diesel. I shut the car down, waited a few moments, and drove the car off (82 300sd) and then parked with the car at a normal idle. Again, the idle began to climb rapidly (only in park) what gives? It does ,for the first time, a tank full of bio diesel (versus diesel) and has been running great on this . . .could this have anything to do with the runaway idle? What might cause this situation, help! Thanks!

how high does it go to?

If it was a run away you would not be able to shut it off without using a Co2 fire extinguisher into the intake or a chunk of wood to block the intake....

it just starts to climb faster and faster, I am able to shut it down with the key -

Does the accelerator move when this happens? I'm wondering if the cruise control actuator connected to the linkage is trying to activate. Had a POS Ford that would do that.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

99 W210 E300 Turbo Diesel, chipped, DPF/Converter Delete. Still needs EGR Delete, 232K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Gone and still missed...1982 w123 300D, 1991 w124 300D

does it keep climbing, or does it peake out?

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82' 300SD

I just checked and cannot seem to duplicate climbing idle situation. I am going to keep an eye on this and will also check air cleaner, turbo play, and oil consumption, etc. to ensure that I do not have all the elements to create a runaway diesel scenario . . . .thanks!

if it did "peak out" what would that indicate?

If you were able to shut it off with the key, it is not a runaway diesel. So you have no need to check for these elements in your troubleshooting of the problem (although it wouldn't hurt just so you can get to know your car better). Maybe your accelerator linkage needs adjustment. While in drive, the TC+trans presents enough load to the engine to keep the RPM low. When shifted into neutral or park, the load goes away, and the engine will rev higher and higher. It takes a surprisingly small amount of pedal to do this, so if your linkage is adjusted wrong, it could happen.

If it "peaked out" at somewhere around 4800RPM, then the governor in the IP is taking over.

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Dale

http://i52.photobucket.com/albums/g1...MG_2277sig.jpg

1990 300D 2.5 Turbo -155k
2000 E430 - 103k
2014 Jeep Grand Cherokee Ecodiesel 4x4 - 11k
2014 VW Passat TDI SE - 7k Bro's Diesel
2006 E320 CDI - 128k Pop's Benz

Pre-glow - A moment of silence in honor of Rudolph Diesel

Thanks, just seems odd that linkage adjustment would change overnight like that . . . . have to keep an eye on this !

My 82 300SD started to do this same thing two days ago....did you find the problem? Is there a simple fix? Is this common?

How high is your idle?

Don't know if anyone's still reading this thread a month hence, but my 78 240d also has this problem intermittently. Sometimes it idles out of gear at a nice even low speed, but just as often it starts low and after 30-40sec. it sort of shivvers a bit and runs up into higher RPMs and stays there. I do think my linkage is sort of sticky (though i did grease it last year..at every point i'm not certain?), and engine mounts are hilariously worn. I have new, but haven't gotten up the courage to change them. The one thing is, though, when the idle runs up higher, I'm not sure that the linkage actually moves. If it were not to move in this event, then would this mean the IP is becoming strange? I have been using biodiesel of various concentrations and used Mobil 1 15w-45 (being synthetic) on the last oil change, this one shell 10W-40, as its getting cooler out.

I had this problem on my W116 SD... it was caused by the cable for the vacuum cruise actuator backing out of the connector for it, and getting stuck partially out on the return to idle. It happened a time or two driving down the road... takes a little more effort to stop when the engine is at 1300 RPM and there is a stopped car ahead!

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John Robbins
'05 E320 CDI - 240k
'87 300TD - 318k