MAF sensor high volts Help - Alfa Romeo Forum
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(Post Link) post #1 of 22 Old 02-11-07 Thread Starter
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MAF sensor high volts Help

Hi all,

I currently have my 156 2.0 selespeed with an engine diagnostics centre. So far he has fitted a MAF sensor which was faulty but has informed me that there is a problem with the voltage which caused the old one to burnout. He has tested the voltage to the sensor and is getting readings of 12V and he says it should be no more than 5V. Has anyone got any views to what could be causing the high volts.

Cheers.
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Re: MAF sensor high volts Help

nominal supply voltage is 14v.

the supply voltage range is 8-17v

http://www.guzzimental.com/documents/alfa/Bosch%20HFM5%20Sensors.pdf

tell him i said he's an idiot
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(Post Link) post #3 of 22 Old 02-11-07 Thread Starter
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Re: MAF sensor high volts Help

LOL, will do after I get the car back..
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Re: MAF sensor high volts Help

as above wildman, range is 8-17 volts, after the car been standing for 2yrs i'm not surprised the maf has gone.Was the maf the problem with the injector light.
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Re: MAF sensor high volts Help

just been and checked mine 13.6v engine off 14.2 engine on.
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(Post Link) post #6 of 22 Old 02-11-07 Thread Starter
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Re: MAF sensor high volts Help

Cheers mate, think I will need to give him a ring.
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Re: MAF sensor high volts Help

2 years!?! Probably a spider sitting on the hotwire and when you turned it on fried it and the MAF ...
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(Post Link) post #8 of 22 Old 02-11-07 Thread Starter
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Re: MAF sensor high volts Help

New update, gave the diagnostic centre a ring and he reckons that he is able to clear the fault codes with the engine off but within five seconds of starting it again the engine management light comes on again. He also said that the new MAF sensor is giving all the right readings and the engine is running better. He also thinks that the ECU is seeing something different to the MAF sensor (At this point my brain really started to hurt). Dont know if this helps but the car did originally run out of petrol due to faulty fuel gauge and never ran right since.
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Re: MAF sensor high volts Help

New Fuel filter, and cleaned or replace the injectors sounds like you have crud in them
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Re: MAF sensor high volts Help

There is no servicable fuel filter, it is part of the fuelpump inside the tank.
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Re: MAF sensor high volts Help

It sounds to me as though your diagnostic man hasn't had a lot to do with alfa's. they are a law to themselves,
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(Post Link) post #12 of 22 Old 05-11-07 Thread Starter
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Re: MAF sensor high volts Help

Many thanks for everyones input, the alfa turned out to have a major elec fault which they fixed. She is now purring like a kitten.
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Re: MAF sensor high volts Help

Out of curiosity - what exactly was the fault? Did they tell...
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(Post Link) post #14 of 22 Old 05-11-07 Thread Starter
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Re: MAF sensor high volts Help

No they did not, they fitted a new MAF sensor which was the route of the poor running. But the voltage output was too high so they said if left would burn out the new sensor in a couple of days. On my receipt the repair description is as follows; REPLACE AIR MASS METER, LOCATE AND REPAIR TO ECM WIRING FAULT. The work was under taken by an AUTOTEST centre. Sorry its not more specific.
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Re: MAF sensor high volts Help

so is she on the road now wildman
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(Post Link) post #16 of 22 Old 05-11-07 Thread Starter
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Re: MAF sensor high volts Help

Yes mate kind of, Just got to change the cambelt and then she's in for a dam good spanking.
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Re: MAF sensor high volts Help

ECM wiring fault probably means that they wiggled the ECU connectors.....maybe there was some corrosion or even damp.
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Re: MAF sensor high volts Help

A previous owner of mine saw fit to cut open various rubber boots on connectors and jam probes into various wires. This and the fact that they left the wires exposed gave me what appeared to be a MAF failure.

I cut a MAF connector and a length of cable for a scrapyard and soldered it in place of my damaged connector. The thing is I had to look at a few cars in the scrapyard as they all seemed to have cables damaged in the same way. ...This obviously wasn't the reason they were in the yard though, sadly nearly all are crashed in some way.

Check how these lot have been checking the MAF voltage, if they've damaged the wires you could end up with problems later.

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Re: MAF sensor high volts Help

Quote:
Originally Posted by gazza82 View Post
2 years!?! Probably a spider sitting on the hotwire and when you turned it on fried it and the MAF ...
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hi there.i have alfa romeo 146 ts
model 98 i testing the signal of maf
it given me between 6 and 7 volt i
make the complete ecu resetting
and its the same ..any ideas please
i'll be thankful.
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So what's the problem? Flat spot, performance, etc.

MAFs are funny ... they can be failing but not show up on a diagnostic ...
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yes ..big flat spot. rpm going up and down beside the car is turning off when its cold and a lot of gas spending ....i check the oxigen sensor its ok.also changing sparkpkugs ....?
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