I have read all the posts on adjusting the rack dampener bolt. I still feel confused about it.
I have adjusted mine all the way out and then back in until it touches. I have had it all the way in, and every spot in between.
I do not notice any change in idle smoothness. The only thing I have noticed is, now when I increase the idle slightly with the stop lever the engine has a surging quality, and also idles roughly when I let off of the gas and brake to a stop while driving.
Could someone post a proper way of adjusting this?
I feel like mine wants to be all the way in, but I read that that was incorrect???? Many thanks to all respondents.

There are 2 versions of this "bolt". The silver is original & is weaker than the Replacement cad(gold) one. If you have a rough idle then this is a starting point. Loosen the jam nut until the bolt will move by hand! With engine running slowly run bolt back in until it touches the rack. At this point the engine should smoooooth out a bit. No more than 1/8 turn on in. tighten jam nut. That is the basic adjustment. BE CAREFUL!! the oil cooler lines can be HOT.

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Thanks Doc, So what should I think if mine was all the way in(no gap between locknut and adjusting bolt), to begin with? Also, should I replace mine with the newer better bolt. Mine has a wear mark on the end of it from where it touched the rack all this time. If I start at the basic adjustment spot, and I keep having this rough idle when I come to a stop, should I keep turning it in a little at a time until it no longer does this? Thanks So Much!

I would start with new bolt as they are ONLY $26.50, that is if the one in your car is silver! not gold.

Thanks, I'll give it a shot. Mine is silver.

If the rack dempener bolt is turned too far in, it will cause the idle to dip when you rev the engine and let off the gas. If the new bolt doesn't sure the problem with idling and/or starting, adjust the valves and for the cold weather, leave them slightly on the loose side. I also prefer to adjust valves with the engine dead cold.

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Regards,
Aaron

Bill, I also have no detectable difference in adjustment at idle.

I also have a hard time understanding what changing my bolt to a different bolt would do.

I do notice however, that if I adjust the bolt with the idle up slightly, using the stop lever, I can increase or subside a surging quality in the idle.

Aaron, I think, just explained why my engine idle will dip and become slightly irregular when I let off of the gas while driving and I coast. It was strange at first, to have my engine so quiet, I had to turn off the radio, and air to see if It was still running!

My question now, is what would happen if the bolt were too far out?

....It will cause a rough idle. You have to turn it in 1/4 turn or less at a time, give the engine gas, then let off and at the point when the engine doesn't stumble when you let go of the throttle that's where you want to tighten the jam nut. It takes some time and a good ear, but you'll get it!

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Regards,
Aaron

Thanks Aaron!
I was on to that method originally, and now I will redo my setting with full confidence!! I had noticed the stumbling when I was setting it, because I was grasping for any change anywhere, I started revving it. It's nice to know the correct procedure.

Hello Gang! I searched the data base to see if I could find answers to my problem and found these. I've been reading these posts because it seems to relate somewhat to my problem.. but not quite sure if adjusting the bolt will solve everyting.

When I start my 82 300D-T in the morning (whether plugged in all night or not), I get an idle so rough that the engine will cut off if you don't continue to press on the accelerator. I have to put the car in neutral at stop signs/lights to avoid the engine shutting down. When the temp gauge increases, I do not have the problem anymore. Could this be "automatic choke" problems? I did notice yesterday morning that while cold and in park, the rpms are 800 (Haynes recommends idling speed setting at no more than 1000) and the engine seemed to "miss". If it were spark plugs, I'd say one was misfiring. On my 76 D I had the turn-screw swith inside the car that changed the idling speed for just such events. What can I do to this one to smooth everything out?

Also, once the car is warm I have a "surging" in the engine while at stop lights/signs. Only once could I detect a small amount of movement in the tach, but you can clearly hear the engine go "vroom" about every 5 secs. It only does this after the engine is warmed up, and does not do this in neutral or park. Does this mean it's related to transmission problems, or due to idling speed adjustment, or what?

Any help will be greatly appreciated. Thanks.

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Nello Tare

1982 300D (266,001 mi.) looking and running great

Previously owned:
1976 450 SLC
1983 300D
1976 300D
also
1982 Jaguar XJ6 (loved, but gone)

Not sure if this helps, but my 240D has a better cold idle when I just completed an oil and fuel filter change... I don't know why, but it does. Of course I have the manual choke knob but I am so scared of breaking it... I generally just let it warm up with the soft idle before taking off.

Silverbullet,

Thanks for the info. I had posted my problem under this thread and when I didn't get a response I re-posted it as a separate thread about "rough/surging idle". Benzmac gave me some instructions regarding what to look for. rough idle/surging So far I've not had time to check the car out, so I do what you do.. just let it warm up before driving. I will replace the fuel filter soon like you stated and maybe that will help also. Again, thanks for the response.

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Nello Tare

1982 300D (266,001 mi.) looking and running great

Previously owned:
1976 450 SLC
1983 300D
1976 300D
also
1982 Jaguar XJ6 (loved, but gone)