So I was digging into the dash of my e320 wagon trying to "fix" my combination stalk when I came across this strange box with a knob on it



timing reset? magic mpg increaser?

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77' 300D, "Cartman" SOLD @ 150K (didn't know what I had)
83' 300SD, "The Superdon" 325k+ @ 28mpg
95 E320 wagon, "Millennium Falcon" 231k+ @ 24 Mpg
95 E300D, "Sherley" 308k @ 33.69 Mpg, currently anticipating a head
99 Suzuki Intruder "Trudy" @ 45 mpg

I think that's what's called the MAS relay? I believe it's related to the fuel pump.

-J

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1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Correct, a MAS relay, the knob is for removing the relay.

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I noticed the same when I had the dash apart on my '95 E320 wagon. I thought it was related to the security system.

The MAS relay is supposed to be behind the battery IIRC. If this is under the dash, it might be a similar looking device.

But first thing comes to mind is the MAS relay for me too. This controls the fuel pump, among other things.

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http://farm8.staticflickr.com/7271/7...144c3fc1dc.jpg

engine control unit.

Attached Files

15-2193.pdf (95.7 KB, 185 views)

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77' 300D, "Cartman" SOLD @ 150K (didn't know what I had)
83' 300SD, "The Superdon" 325k+ @ 28mpg
95 E320 wagon, "Millennium Falcon" 231k+ @ 24 Mpg
95 E300D, "Sherley" 308k @ 33.69 Mpg, currently anticipating a head
99 Suzuki Intruder "Trudy" @ 45 mpg

Not a MAS relay unit!!

That is the ODB1 diagnostic module that records check engine information.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Cool What fuel injection system would a 95 E320 have? Are they LH Jetronic or were they still CIS?

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

HFM-sfi

Hot Film Management

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

I'm going out on limb here but i guess your car is a California version of E320 and this a diagnosis control unit with the part number A0155454332. Just shoot me if i'm wrong.

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600SEL '91
300E 4Matic '88
240D '83
280SE '77
350SE '73
The most complex systems can fail in the simplest way.
Contra verbosus noli contendere verbis, sermo datur cunctis, animi sapientia paucis.

i don't believe in the lord! He's never bought me a Mercedes Benz.

sfi = sequential port injection in this case?

Does the fuel injection computer also control the ignition system?

-J

__________________
1991 350SDL. 230,000 miles (new motor @ 150,000). Blown head gasket

Tesla Model 3. 205,000 miles. Been to 48 states!
Past: A fleet of VW TDIs.... including a V10,a Dieselgate Passat, and 2 ECOdiesels.
2014 Cadillac ELR
2013 Fiat 500E.

Yes, & Yes

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Yes & No, it is a 104 with SFI, but the ignition was not integrated until ME-SFI

BTW the LH-SFI and HFM-SFI are essentially the same, the only real difference is the mass airflow sensors, the LH being hot wire, and HFM being hot film.

I wouldn't argue about the control unit until I saw where it is. Based on where I believe it is I still think it's a MAS, MBdoc could be right, it's definitely not the engine control module though
Gilly

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Click here to see the items I have up for auction at EBay

Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold)

Oh I see what you are saying, no the MAS is not the engine control unit. MB can be very flaky on their descriptions, N16 is the MAS, which is NOT the engine control unit. In that drawing the engine control unit would be one of the larger control units towards the top of that drawing.

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Click here to see the items I have up for auction at EBay

Click here to see a photo album of my '62 Sprite Project Moneypit (Now Sold)

So wouldn't that actually make this Motronic?

-J