Hi

I need a new or working used MAP sensor for my 1972 MB 280SE 4.5

As I have learned, they are very expensive new so info on where to find a used one is most welcome.

Another alternative is to have it repaired.

All help is very welcome at this stage, the car is useless right now....

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1974 MB 230 4 cyl auto Sold
1973 MB 280SE #12004
1970 MB 230/8 #53280
1970 MB 300SEL 6.3 #4509 sold
1968 MB 300SEL 6.3 #0335
1972 MB 280SE 4.5 75k miles sold
1971 MB 230/8 60k miles sold
1972 Volvo 142 60k miles sold
1969 Opel Rekord 1900 sold
1974 L508D Camper

There was only one company I ever heard about who repaired these MAP sensors.I do not believe they still provide this service as the aneroid modules are no longer available.
There are a number of used parts sources available,but I have no idea what they would charge for these rather rare items if they had one?
I do most of my parts shopping at the "pull your own parts" auto wreckers here in northern CA.If you have access to these type yards I'd start there.
If you don't have easy access please PM me with specific part number,model and year of your car.I'll do my best to locate you one as these cars turn up from time to time.
As a side note,are you sure the MAP sensor is defective? They can be adjusted for altitude compensation by an allen screw under the black cap on one end.Mine was WAAAAY out when I got my car making it barely run.

I have a pile of those sitting on my shelf from when I owned a 4.5. Hit me up by PM and we can talk.

__________________
With best regards

Al

Hi

The part number printed on the sensor is Bosch 0 280 100 100.
Is this what is needed?

As I have fule pressure, injectors are all working and I have a good spark on all plugs this is my next try.

It quite suddenly started to misfire, and I have consulted "expertise" on the matter....

Is it the same MAP sensor in the W107 350/450SL?

This car was never sold new here in Norway where I live, there is only a handfull present in Norway so the scrapyard-methode does not apply here ;-)

Tom

__________________
1974 MB 230 4 cyl auto Sold
1973 MB 280SE #12004
1970 MB 230/8 #53280
1970 MB 300SEL 6.3 #4509 sold
1968 MB 300SEL 6.3 #0335
1972 MB 280SE 4.5 75k miles sold
1971 MB 230/8 60k miles sold
1972 Volvo 142 60k miles sold
1969 Opel Rekord 1900 sold
1974 L508D Camper

Yep same as the 450SEL SL to 1975.

__________________
With best regards

Al

You got mail

__________________
1974 MB 230 4 cyl auto Sold
1973 MB 280SE #12004
1970 MB 230/8 #53280
1970 MB 300SEL 6.3 #4509 sold
1968 MB 300SEL 6.3 #0335
1972 MB 280SE 4.5 75k miles sold
1971 MB 230/8 60k miles sold
1972 Volvo 142 60k miles sold
1969 Opel Rekord 1900 sold
1974 L508D Camper

Have you checked the two resistance values on the sensor?

Is the vacuum hose good?

__________________
Chuck Taylor
Falls Church VA
'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

Hi

The vacuum hose looks good.....

I have a description for the MAP sensor for Porche 914, dont't remember the Bosch-number, and there is a test procedure for the MAP sensor there.
Not sure if it also applies to my car.
I have a vacuum pump and a manometer to measure vacuum available at work, so I might run a test to see if values are correct.
Do you know what terminals to measure between and what values to expect?

__________________
1974 MB 230 4 cyl auto Sold
1973 MB 280SE #12004
1970 MB 230/8 #53280
1970 MB 300SEL 6.3 #4509 sold
1968 MB 300SEL 6.3 #0335
1972 MB 280SE 4.5 75k miles sold
1971 MB 230/8 60k miles sold
1972 Volvo 142 60k miles sold
1969 Opel Rekord 1900 sold
1974 L508D Camper

Usually when the MAP sensor goes wrong it is the internal copper (?) membrane that cuts iself on its periphery. As a result it cannot measure vacuum properly anymore as air is going through and the symptom is a car running way too rich, with black smoke each time you floor the gas. I'm not sure misfire in one of the symptoms, as action of that device influences rich or lean mixture via the calculator on all the cylinders at the same time. You should find a way to have it tested before replacing it. You don't want to spend a fortune on a new one only to discover later the problem is somewhere else. But given the high probabilty for it to go wrong, mainly due to age, it is adviseable to have a good one readily available on the shelf (or in the trunk). I believe the 3.5 and 4.5 are different. Normally they are paired up with the calculator and they both should have a round sticker of the same color, yellow or green for ex.

A good starting point is to measure CO at the exhaust. Should be around 4 at idle and go down to nearly 0 when you put gas. If that's the case you have good chances that your MAP sensor is doing OK (of course you can act on richness at idle through the knob on the calculator).

To measure the coil's resistance, unplug the MAP connector. Measure on the MAP side.

7 & 15 (outside terminals) = 90 ohms
8 & 10 (inside terminals) = 350 ohms

These values do NOT change with running conditions. The MAP sends an inductance value to the ECU which uses it to adjust the fuel mixture.

__________________
Chuck Taylor
Falls Church VA
'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

4 at idle?? That sounds very high
I believe the specification for my 74 California car is 1-1.5% Max.
I imagine CA specifications might be a little tighter than federal...but not lower by 60+%
I'd love to find a relatively cheap CO meter.The least expensive I've found for a portable unit was in the 400-500$ range.

The W108's were pre cats and less bogged down then the later models. I scored a CO analyzer on CL for about $250. You can get a brand new Gunson's gas tester for about that much on Amazon or Ebay.

__________________
With best regards

Al

Here is a cool tool you can install for real time measurements.

http://store.summitracing.com/partdetail.asp?autofilter=1&part=EDL-6593&N=700+115&autoview=sku

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Tony H
W111 280SE 3.5 Coupe
Manual transmission

Past cars:
Porsche 914 2.0
'64 Jaguar XKE Roadster
'57 Oval Window VW
'71 Toyota Hilux Pickup Truck-Dad bought new
'73 Toyota Celica GT