79 SD idle is rough with some misfire. Have no idea when valves were last adjusted. Is that th elikely source?

I'm replacing 2 bad GP's tomorrow. That should address the rough start, but idle is rough after warm as well. Would like to adjust the Rack Pin. On the 79 I do not see the Pin as it has been described on the boards. What I have found is a long screw with a nut at the base that is situated on the motor side of the IP (bottom). I find no mention of this item in the Haynes, so I'll give it a try. It looks as if the nut gets loosened and the screw adjusted...

The next procedure will probably be the valve adjustment as this car is a recent acquisition with TMU and no maintenance records.

I plan on replacing the timing chain also. SHOULD THIS BE DONE WITH THE VALVE ADJUSTMENT, WHILE THE COVER IS OFF? Again, I have no notion of the condition of the current TC, but replacement seems the prudent course. Motor and transmission mounts will follow.

I am learning about the diesel machine as I go along. The most difficult aspect to figure so far is that heat retained in the engine, combined with the pressure provided by the pistons in the cylinder are what ignite the diesel fuel for each explosion. I had assumed that the plugs stayed heated...

mc - after the engine is at operating temperature and the glow plugs have gone off it is the extreme heat of the compressed air when the piston is at top dead center that ignites the fuel. The glow plugs help put a little heat in there prior to the engine getting up to temp.

__________________
Jim

Thanks, Bill. I'll keep searching for the rack pin. Idle speed seems to be fine, about 7K rpm when warm.

Now that's what I would call a fast idle !

__________________
Palangi

2004 C240 Wagon 203.261 Baby Benz
2008 ML320 CDI Highway Cruiser
2006 Toyota Prius, Saving the Planet @ 48 mpg
2000 F-150, Destroying the Planet @ 20 mpg



TRUMP .......... WHITEHOUSE
HILLARY .........JAILHOUSE
BERNIE .......... NUTHOUSE
0BAMA .......... OUTHOUSE

Found Rack Pin and adjusted with no real difference through entire range (1/8 turns at a time). Has the end of the Pin been worn down?

Idle adjustment bolt is frozen. Nut at bottom is veyond my capaity (with current tools) to reach. Can anyone tell me the size of that nut (79 SD, 617.195)? I'm sure that I can find a deep socket (real deep!) to reach. Idle can sit at about 5K rpm and sometimes sits at about 7K. With a minor punch to accelerator, it seems to settle back down to 5ish.

I think you missed Palangi's comment about the idle being too fast. 7k would be equal to 7,000 RPM....and I would agree - that's a really fast idle. Surely you mean 700 RPM???

__________________
1976 240D
1987 560SL
2007 E320 Bluetec
1998 C280 (now son’s car)
1982 240D Manual - Sold

Yup. Missed it. I feel like the new guy at the club and I keep having trouble with the secret handshake.