Running 4 bar map sensor, BUT, BIG but...

This is a big but! In future I would NOT use bosch part number 0 281 002 316 http://rb-aa.bosch.com/boaasocs/index.jsp;jsessionid=9090D6556F63A10AF31888AFA73270C7.sundoro?ccat_id=110&prod_id=203

It turns out the reason for the implasuible correlation error was due to a voltage difference between how this sensor reads pressure through voltage and how the stock 3 bar sensor reads it. Not sure on the exact symptoms, but it needed a resistor incorporating into the wiring to take out half a volt to allow the sensor to work in my car.

One side effect now though is my mapping is now making more boost than it did before. Sometimes over 2.5 bar overboost and between 2.2 bar and 2 bar of sustained solid boost, compared to 1.8 before. Car does feel a bit faster though.

There HAS to be a 4 bar sensor out there which does not need this resistor work as both my tuner and the auto-spark doing the work had not seen this before and the tuner had mapped 4 bar setups before.

Is it possible that http://rb-aa.bosch.com/boaasocs/index.jsp;jsessionid=9090D6556F63A10AF31888AFA73270C7.sundoro?ccat_id=110&prod_id=203 is NOT the correct 4 bar sensor to use and there is a different model number which is more plug & play for these engines?

Hi Jason what was it that gave you reference to this 4bar sensor in the first place , and if it were someone on this forum had they actually used it on there setup themselves!!

Is there a way your tuner can rescale the MAP table in your tune to correspond to this MAP sensor voltage?

what's the Bosch p/no of the standard item? Have you compared characteristics?

I'm a little confused. The map sensor linearization in the software correlates pressure to voltage. If voltage is different then you should be able to just alter the voltage there (when you find these values and set them into a map the voltage will be in the axis description). If you have figures I could try to fix it for you....either that of there's something I'm missing here.

Thing is, my mapper has mapped 4 bar sensors plenty of times and this voltage thing has never cropped up. It seems whatever sensor I used was probably not the right one. Someone here must have swapped 3 bar out for 4 bar, and been able to just "plug & play" so I am curious as to what part was actually used.

PS: I was told the part number I got by someone on here - don't recall who but I assumed it based on prior knowledge. Now I need to actually find someone who has done the conversion with no resistor needs, and it's worked right away.

You propably wouldnt be able to run a 4bar sensor in place of 3bar without remap in the firstplace. My original 012k ecu was ok with 2.5bar->3bar but 012bd was in the limp mode at start most of the time. So either youre calibration is off or you got yourself a 12v sensor

All it needs Jason is rescaling with the matching voltage i know your tuner may have done 3bar to 4bar map sensor changes before but were they not with 1.8 20v motors i.e petrol motors and not diesel motors which he hasn't done before!!

I've got the same sensor as jason (but haven't fitted it yet)

Reccomended by numerous people on this forum.

If it doesn't even plug in correctly without butchering the wiring, it seems a bit daft to fit it if I'm going to have issues (which I won't know until I've fitted it and got it at the tuners - too late by then)

If we know of a definate plug in sensor (no matter whether it needs re-mapping or not - which it will) then I'd rather spend another load of money and get a different one.

I have a new map to upload from my mapper now which is supposed to work OK without the resistor in place. So I shall be experimenting one evening this week.

That whole resistor thing sounds fishy... The whole point of getting a 4bar map is to get more headroom for boost that ecu sees and can react to. You can wire your 3bar sensor inline with a resistor and you end up with more boost and wrong info sent to the ecu. So if you put the resistor inline the sensor it will indeed just fool the ecu to see LESS preasure. And that will lead to a limp mode even more likely. What you need to do is calibrate the MAP sensor in the software so it sees the right preasure all the time. Simple mod if you know the voltages at different preasures from your new sensor. And find the damn spot in the code where the sensor linearisation is

I'm going to use VEMS 4bar sensor with my own car. Cheap and it even had the calibration voltages stated at their website. You will have to cut the wiring loom but thats a given since you will be hard pressed to find a sensor with same connector that the OEM sensor has. http://shop.vems.hu/catalog/product...d=121&osCsid=7d923a240158976da844f7ab7f6d6cc9

Youll need the 5v sensor.

I really wanted to stick with Bosch. I shall get there in the end, but wondered what others had achieved successfully.

If you just go to a decent tuner there's no problem of making ANY linear 0-5v pressure sensor work with the ecu..

tell your pro-tuner to look in the hexdump in 16bit for the sequence 200; 3000..

Rub87 said:

If you just go to a decent tuner there's no problem of making ANY linear 0-5v pressure sensor work with the ecu..

tell your pro-tuner to look in the hexdump in 16bit for the sequence 200; 3000..

Click to expand...

Never have any problems with 4 and 5 bar MAP just re-calibrate ECU for new MAP sensor and it works as hell!!

StingrayRT said:

Never have any problems with 4 and 5 bar MAP just re-calibrate ECU for new MAP sensor and it works as hell!!

Click to expand...

So there's a 5bar MAP available too. I might be needing one.

maybe 10 bar is more something for you., check on the link to the Bosch site

shadowmaker said:

So there's a 5bar MAP available too. I might be needing one.

Click to expand...

Shadow the best thing you could do with yours is just connect the map/maf sensor in free air no housing and just mount the sucker to the front of your Van JOB DONE!!...............lol .

I think he'll already have an airspeed indicator for when he's exeeding the measuring range of the oem tacho.. ^^

shadowmaker said:

So there's a 5bar MAP available too. I might be needing one.

Click to expand...

ask and you shall recieve.

http://tunertools.com/proddetail.asp?prod=AEM-30-2130-75

or better price

http://www.zeitronix.com/installation/mapinstallation.htm

just odered bosch one, 55€ for 4bar version, the one ith 12mm hole..

Have you got a number for me rub?
Or get me one

Johan

0 281 002 576, plactic connector housing 1 928 403 736.. ordered mine already

Hey devon, my 4 bar sensor is in, and it works perfectly no errors etc.. Pressure in vag com also is able to show op to 4000mbar

It's only the linearisation, nothing else.. (to let it work without dtc)

Rub87 said:

Hey devon, my 4 bar sensor is in, and it works perfectly no errors etc.. Pressure in vag com also is able to show op to 4000mbar

It's only the linearisation, nothing else.. (to let it work without dtc)

Click to expand...

Which exact part number have you got please?

Now that would be telling

devonutopia said:

Which exact part number have you got please?

Click to expand...

The one from post #22..

but the one you have should work just the same.. it's all in the tune..

Rub87 said:

The one from post #22..

but the one you have should work just the same.. it's all in the tune..

Click to expand...

He just hasn't found a proper tuner as yet!

Looking at the specs of the 2 sensors, they do seem to be slightly different. If my new map doesn't work, I'm going to go and get this sensor instead.

You got PM..

0 281 002 576, plactic connector housing 1 928 403 736

is this plug and play? or does it need some mapping...

also can you buy less than 100 contact pins!?