Hey y'all ?

I am wondering if I am really noticing something, or is it just my human failings.

When I first start my '82 240D (EGR disconnected, I think...) I idle it high (yeah, us 240D guys have the little Idle raising screw =) for a few minutes and after its been driven a few miles I let the idle back down. Valves were adjusted 2k miles ago, all glow plugs test good, small exhaust leak somewhere around the manifold. Timing chain strech is either 4 or 5 degrees- I need to re-check (I'm not sure I did it right). Last diesel purge routine about 5k ago.
To get to the point, the car always seems faster (accelerating) when the engine is below 80C on the temp meter. After the engine is at operating temp, it seems that the car doesnt accelerate as fast (and requires more pedal to keep up with traffic on the highway).

Am I imaginging all this ? Is the timing chain stretch doing this ? Flush with ATF a couple times ?

Thanks in advance
-John

__________________
2009 Kia Sedona
2009 Honda Odyssey EX-L
12006 Jetta Pumpe Duse
(insert Mercedes here)

Husband, Father, sometimes friend =)

Slower than when cold? Just about impossible. If my driveway was uphill to the road I would have to get out and push my 240ds when cold. The heavy cold oil load seems to be the problem in my case so guess will have to change to synthetic. Really though Have never studied how the idle adjuster is linked to the main linkage but are you reducing linkage transfer extension when you turn down the idle? Regardless of that, one test that I always do as a matter of course is to set the idle control at full right position. Then get a helper (some attractive woman strolling by would be nice). Have the helper depress the pedal fully while you make sure your linkage transfers motion enough to fully activate the pump linkage. Have found wear in some of mine requireing either adjustment or repair of the linkage. Just a thought. Quick and cheap to check though. Five degrees stretch equates to a possible 6 degrees of pump delay if timing chain pulls from cam side and pump has never been retimed. Every little bit helps with this model as owning two myself learnt. A couple of other things come to mind right away. Partially clogged fuel filters is high on the list and a long shot being the valve clearances. If they were too tight cold as the block warms you would start to decrease clearances further. Resulting in one or more valve staying partially open. Since you checked your chain stretch I imagine you covered the valve clearances?

Technically, physics wise... if your valves are too tight you could get this symptom .

Yes leathermag, I was reluctant to mention the valve thing as to start with the valve is going to still have a much greater volume to deal with at increasing speeds than it had at slower. This I thought would mitigate the slightly non totally seating valve or valves somewhat as the engine warmed up. But if they are adjusted too tight or even too loose they should be put at spec. anyways. Also I suspected he had a dial gauge to calculate the chain stretch and might have closed up # 1 valve clearance to calculate the stretch. Perhaps forgetting to open it up after. I have done worst at one time or another. Again just some thoughts as I do not always communicate very well. One upside for him personally is the possible attractive lady helper. I just think he will be happy that he got his linkage checked out at that point even if it does not help the fundemental problem.

It is a long shot... but thought I would mention it because it is a short distance from that ( if it is happening ) to a burned valve... The time the valve spends against the seat is a major part of cooling it. Once you do not have good contact then that valve expands more than it would usually do at operating temperature.... a feedback situation which can cause major work to be needed.

Again I totally agree with you leathermag although it has also been my observation that it seems to take a little more time to burn a valve in a diesel than a gas engine but my observation may be in error. Used to get tired of pulling older gas engine mercedes head in early 60s to deal with burnt exhaust valves. The adjusters where too weak to hold and tended to decrease clearance slowly all the time. Mercedes wanted them checked regularily and if a thread reader has one of the earlier straight gas sixes before the m130 engine they should take note. Perhaps the four banger as well but I have no knowledge. Check every ten thousand miles without fail. They increased the interference fit on the adjuster to the point it took two men and a boy to adjust them it seemed. It stopped the problem but I have to remove the rocker now to get any adjustment movement on some of my early 70s gas engines. Straight onto adjuster with socket rather than offset crowsfoot type wrench required it seems.

When I checked the valves, #3 cyl was tight both intake and exhaust- It's better now... (#3 glow plug was also shot...). I think the rest of the valves were on the "tight end" of the spec, but maybe I'd be best to go back in there and check- It was only my second time adjusting valves when I did on this car 2k ago.

I can look at the linkages. I dont think that the idle adjuster has anything to do with the problem, but I wanted to let you guys know how I "warm up" the engine- if definitely runs rougher (not abusive, doesnt quit, but notably rough) when it's just started up.- (I normally drive away with the idle raised...) I just leave it up to get the thing started easily and warm up quicker.

Maybe I can listen more closely- if the motor sounds more klattery when cold could that be telling me something ? I know then when warm it almost sounds clock-like (FWIW diagnosing sounds on the internet...)

__________________
2009 Kia Sedona
2009 Honda Odyssey EX-L
12006 Jetta Pumpe Duse
(insert Mercedes here)

Husband, Father, sometimes friend =)

That may not seem like much difference... if it affected just one cylinder.. but you only have four of them and you don't have many cubic inches to start with.... every little bit helps...

I'd be tempted to check the compression myself-the 240Ds are so weak to start with that any kind of ring or valve problem would drop the power. My 300D has a similar problem in that it tends to idle roughly hot, but is very smooth cold(am waiting for warmer weather to try out my new compression tester and adjust the valves). Angel, I had chances to buy 240Ds (would love a manual trans) but I sort of drive for a living here in the 'nati and these lunatics around here practically push my Powerstroke work van off the road!

__________________
1982 300DT 190K (Diesel Purge + synthetic oil=smoothness at last!!!)
2004 Ford E-350 6.0 L PSD 227K
2006 Dodge Ram 3500 SRW HO Cummins 4X4 48RE 42K (brute force tow vehicle)
2005 Scion xB wife's rolling pop can
1993 GMC Sierra C3500 6.2 142K

Is the pump possibly retarded? Combustion efficency increases with temperature may have the effect of even more apparent abnormal delay (it's real) causing the less power when really warmed up symptom. Also a rough cold idle is symptomatic of a late delivery as well. One could mark present location of pump loosen it up and move top of pump towards block to check for improvement (advances timing I believe but not sure if I have the direction right) or just check pump timing to start with. Again it's cheap and not too bad to do in comparison to the pumps on volkswagens for example. Retarded pump timing also hurts cold starting to some degree I think as well. Just a few thoughts after your further clarification and my thinking about it. But again maybe you have already done the pump timing? If you think it's all in your head just ask your wife for instant verification. My wife would not hesitate to help me either. The only thing I proved to myself by listening to a 240d at idle warm up from cold to 80c is that yes hearing does indeed fail with age to some extent. Actually it is normal for it to quiet down somewhat during warm up unless you have massive wear somewhere. Just my opinions.

I have not checked IP timing. I'll do that when next I am able- it should have been on my list in the first place.

I'll have to dig this thread back up (it'll be on page 19 by then...) when this issue come to closure (hopefully by finding that my timing is off)
If it is, then wow, my car will be MUCH nicer to drive...all the time...

I was gonna go visit my buddy (he lives 4 hrs away) this weekend, maybe I'll bring my tools and make him hang out inder the hood of my MB with me =)

-John

__________________
2009 Kia Sedona
2009 Honda Odyssey EX-L
12006 Jetta Pumpe Duse
(insert Mercedes here)

Husband, Father, sometimes friend =)