I replaced my MAF and the M104 now appears to be working properly. No flat spot or hesitation anymore! However, I should add that it is still a bit notchy and less linear in acceleration vs. the M103. In particular around 3000 RPM it appears there is a marked burst of power. Sort of reminds me of very mild turbolag. I still think the M103 is smoother, but let's face it - time to move on. At least with this M104 working properly now it is much more enjoyable!

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

I experience similar behavior in my 94 E320. Just dropped in new plugs and it still has a 'non-linear' feel. How much was the MAF and did you pop it in yourself? The m104 definetly starts putting out the power around 3400 rpm- from there it rockets to the redline.

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94 E320
71 350SL

Did the MAF fix your starting problem? My ' 94 E320 had the same kind of problem, only without the hesitation under acceleration. My car had 206K miles and would still pull right up to redline very smoothly. It was a blast to drive. Now I'm driving a ' 99 S420 which I love, but sort of miss the E.

I have no starting issues whatsoever, just the slight feeling of hesitation. I haven't gotten around to changing the air mass meter yet, but I feel like it is getting worse so it will be time soon. Just have to cough up the couple hundred bucks for the part..

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94 E320
71 350SL

That is the point where your variable length intake runners/valve timing kicks over to the higher RPM setting.

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Jonathan

2011 Mazda2
2000 E320 4Matic Wagon
1994 C280 (retired)

Exactly....my W124 E320 had a slight bump when this happened, sort of like a turbo kicking in.

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Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

The M104 in my friends S320 is smooth as butter to redline.

Your plugs are probably dirty or something.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

On a 104 HFM/SFI , if you DON'T feel the Runners change length and the cam advance , THEN there is something WRONG..this is a Performance power-plant, and when Engine Management calls for the power/load intake runner matching and cam valve advance mapping , it is a noticable change ...don't compare the power/torque range habits of a 104 to a 103 .... 104 HFM/SFI is a full electronic, distributorless, high performance engine and has nothing in common with a 103 engine.
They are light years apart.

Thanks Arthur, I feel much better. Like I said, it is smooth as glass now. It just seems to have a performance notch around 3000 RPM where a sort of turbo boost kicks in. After researching more of the technical aspects of the M104, this now makes sense. However, though primitive in comparison, I still love the M103. You are correct, though - they are light years apart.

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

gmercoleza-

Is this the part you are referring to as the MAF? AKA mass air meter? Thanks, J

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94 E320
71 350SL