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#1
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Light surging/missing at WOT high RPMs
1982 240d four-speed manual. 223,000 miles
When accelerating at WOT (should this be WOA?) I sometimes gets a light, but noticeable surging in power output and/or a feeling that maybe the engine is missing/not hitting as hard as it should at high RPM. It's most noticeable in second gear but I've felt it in third as well. I've never felt it in first, but maybe in fourth with a load on. It seems a little down on power. Acceleration times to 60 seem to be getting longer as well. I replaced the primary clear filter, it was looking kinda gross inside but flowed well after I pulled it. Thinking maybe the secondary spin-on filter should go next. It has 12,000 miles on it. I've had a spare one available for a while but was missing the washers that get replaced on the bolt. They just arrived so that's going to happen next, but if there are any other suggestions, they'd be welcome. I'm supposed to be driving the car from St. Louis to International Falls and back in a couple of weeks, and with the cartop carrier on it it doesn't seem to maintain highway speeds very well. I recently used the car to haul 1800 pounds loaded in a trailer (combined weight) from Tulsa to St. Louis and it worked out great, seemed to run easier hauling the trailer than with the relatively light and aerodynamic cartop carrier on. And because I enjoy looking at pictures, here it is with the cartop test fitted. 1800 pounds towed. |
#2
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I ussually think of high speed miss as valve problems.But we have injectors also.So it could be fuel flow.Maybe screen or filters dirty.
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1999 w140, quit voting to old, and to old to fight, a god damned veteran |
#3
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Yeah I was thinking/fearing that as well a bit. Maybe valve float, but I'd expect a lot of smoke out the rear if they were floating/bouncing and I'm not seeing that. In fact, the car smokes very little. Even at night with another car's headlights behind me, I don't see much smoke. This makes me think it's running lean and thus a fuel issue. It's due for a valve adjustment now, but I don't expect they're massively out of wack.
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#4
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Change your fuel filters first and then test it. If it is still acting up, adjust the valves and test it again. If it is still acting up, check the fuel tank screen and possibly do a diesel purge.
Good luck. Glenn
__________________
2012 Mercedes ML350 Bluetec 91K (hers) 2005 Corvette 55K (fun car) 2002 VW Jetta TDI 231K (mine) 1998 Volvo S70 T5 Turbo 196K (kids) 1994 Ford F150 4WD 249K (firewood hauler) 1983 Mercedes 300D 376K (diesel commuter) |
#5
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Well a new spin on filter seems to have done the trick. Funny thing about it, I called the local dealer to order the washer and o-rings for the spin on filter. Picked them up but only recieved two o-rings. They said the computer shows that's all there is. I took it apart, found the crush washer damn neer welded at the top of the bolt and one flattened out o-ring on the shaft. The shaft seemed to have seat for a second o-ring. The two o-rings I had replaced the small flattened out ring perfectly and the other mystery ring the dealer gave me fit the empty seat on the shaft just fine. Put it all back together with the two o-rings and the old crush washer, pumped the primer forever and it fired right up with no leaks.
Anyway all my complaints have been resolved, so I'm happy if confused about what I've been told and what I found. |
#6
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Glad to hear it is working well for you. Anytime a diesel starts to run funny at higher speed or under a load, the first thing I check is fuel filters.
__________________
2012 Mercedes ML350 Bluetec 91K (hers) 2005 Corvette 55K (fun car) 2002 VW Jetta TDI 231K (mine) 1998 Volvo S70 T5 Turbo 196K (kids) 1994 Ford F150 4WD 249K (firewood hauler) 1983 Mercedes 300D 376K (diesel commuter) |
#7
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Yeah, this is my first diesel engine and we've been together about 12,000 miles so far. So we're still very much still getting to know each other. Next up is a valve adjustment and a new oil pan gasket because it appears mine no longer wants to keep the oil on the inside.
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#8
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Sounds good. When you adjust the valves, if it comes down to it, a little on the loose side is better than too tight. Good luck .
__________________
2012 Mercedes ML350 Bluetec 91K (hers) 2005 Corvette 55K (fun car) 2002 VW Jetta TDI 231K (mine) 1998 Volvo S70 T5 Turbo 196K (kids) 1994 Ford F150 4WD 249K (firewood hauler) 1983 Mercedes 300D 376K (diesel commuter) |
#9
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Boy they really run nice with fresh filters and topped of with valves adjusted.
That looks like a pretty big trailer for a 240D but it must be able to do it. What kind of trailer hitch are you using?
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Junqueyardjim Christianity, if false, is of no importance, and if true, of infinite importance. The only thing it cannot be is moderately important. C.S. Lewis 1983 Mercedes W123 240D 4 Speed 285,000 on the road with a 617 turbo, beautiful butter yellow, license plate # 83 240D INDIANA 2003 Jaguar Type X, AWD. beautiful, good mileage, Mom's car, but I won't let her drive it! |
#10
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Quote:
Here's a shot of it, sorry I don't have anything from the underside. (click for bigger) I can get one if you're really interested. The trailer is the smallest U-haul rents. 4x7 and weighs 630lbs by itself. I had it loaded with a fully-dressed AMC 401ci v8 engine plus some miscellaneous AMC parts, also there were two riders in the car. The 240d could run 75mph indicated on flat ground without flooring it (but it was close!), there were some hills that results in slowing to 50mph, but overall it did the job quite nicely. I drove it from St. Louis to Tulsa empty, and back with the engine and parts loaded all in one day. |
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