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  #1  
Old 08-16-2009, 02:24 AM
Tony 12's Avatar
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Location: Barossa Valley, South Australia
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W123 280E- Won't Run Hot

Hi all.
I haven't been around for a while, but now getting back into my cars and I need help.
My Australian 1979 W123 280E starts and runs ok cold, but once it warms up, it misfires under load, then stalls and won't restart.
If you can get it to restart, you need to hold the accelerator wide open to keep it running.
I'm out in the country and don't have access to pressure guages, but I do have another running '79 280E that I can take parts from.
So far I have replaced warm up regulator, fuel distributor, cold start valve, ignition coil, distributor, spark plugs and leads. And yet the problem persists.
Can anyone offer any advice what to try next, please?
Many thanks in advance.
Tony.

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76 W116 280SE
74 W107 450SLC
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82 W123 280TE
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  #2  
Old 08-16-2009, 09:24 AM
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Location: Hampton Roads, Virginia
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Just a guess, but if you can run when cold, then the enrichening circuit is working, and your car is leaning out when the cold start shuts down.

Verify by looking at exhaust and see if it is blowing black smoke. If it's clean, your leaning out too much, if it's black it's getting too much fuel.

Given what you've swapped so far, might be low fuel pressure...

Jim
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  #3  
Old 08-16-2009, 07:13 PM
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Thanks so much for the input, Jim.
Are you suggesting I try the pump or is there some other item that may affect fuel pressure?
Actually, the pump is easy to do, so I might just do that anyway.
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Tony
76 W116 280SE
74 W107 450SLC
88 W124 300E
82 W123 280TE
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  #4  
Old 08-16-2009, 10:24 PM
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And the accumulator, and change the filter.
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'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe
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  #5  
Old 08-16-2009, 10:33 PM
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Location: Barossa Valley, South Australia
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Thanks Chuck
I actually discounted the filter as it looks very new.
From the outside...............
Will give it a shot.
Thanks again gentlemen
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Tony
76 W116 280SE
74 W107 450SLC
88 W124 300E
82 W123 280TE
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  #6  
Old 09-12-2009, 11:55 PM
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Join Date: Jan 2004
Location: Barossa Valley, South Australia
Posts: 71
Well............... you guys may not believe this................. :?
I decided to spend the day sorting this problem and it is now fixed.
The one thing I failed to mention was that when changing ignition distributors, I broke the rotor off the donor car, so used the original. That turned out to be critical.
However, (and this is the weird bit) after changing the rotor the car still wouldn't start. Fiddling this morning, I touched the air flap with the ignition on and noticed that I heard the fuel pump relay but not the pump. :?:
Turns out that the relacement pump off the donor car decided to stop working at the same time as I put the new rotor in. :shock:
So, back in with the original pump and all is right with the world again.
I'm confident now that it was just the rotor all along, but because it gave the sensation of running rich, I had spark, I had replaced 99.9% of the ignition components and the running problem occured every time the temperature gauge hit 87 degrees, I assumed it was fuel related.
Thanks to all for taking the time to offer suggestions.

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76 W116 280SE
74 W107 450SLC
88 W124 300E
82 W123 280TE
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