Technical New MAP Sensor... now stalling at junctions

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Technical New MAP Sensor... now stalling at junctions

DrumRollChris

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Just as the title says really. If anyone has been on here recently you will find me in past threads... solved the problems occurring with a new MAP Sensor. Disconnected battery for 2 hours to do a relearn with the new sensor installed and worked magically! EML still remained on even after battery being disconnected but when out after 15 minutes (been on solid light for 2 weeks before then every time the engine has been on).

Now that problem has been fixed I took it out for a 30 minute drive (relearn) and in the last 5 minutes of driving home I was coming up to a few junctions where the battery and oil light popped up, with my revs down at 0rpm... although I could still pull away on one or two occasions?! I did stall a good few times though...

Possibly charge the battery? Been under a lot of load recently due to constant stop start during diagnosis and repair.

All earth points checked as I know this is a common fault.

Has never occurred until fitting new MAP Sensor/disconnecting and then reconnecting battery so any ideas folks? Cheers :)
 
i have exactly the same problem. i decided it must be down to a faulty new map sensor. the strange thing is i put the old one back in, and the stalling has gone, and the original starting problem has not come back. its been a week of driving with the old sensor back in.
the only thing i noticed when changing the sensors was the new one has thicker pins in the connector, this got me looking at the slots in the plug, and they look a bit wide for either set of pins, so I've bent them all inwards with a pointed knife. maybe this has cured the problem.
 
What are the symptoms of faulty MAP?

My mechanic checked it with diagnostic while driving and says everything is ok. But...

I've seen it is all dirty and I cleaned it as much as possible, but I have a feeling that engine cuts off while changing gear, like the revs go fast down.
And I have to mention that my consumption in city is around 26-26mpg :(
This is too high by my opinion.

Also engine sounds little rough until 2000 rpm, like it is struggling, I hate that noise, especially comparing to 1.9 JTD in Stilo. It goes, it goes up to 4500rpm, just I have a feeling it does not have power in low revs you have to push it little harder. Does not feel so smooth like above 2000rpm.

It is 1.9 MJTD Sporting engine.
 
Changed it back to the old sensor just out of curiosity and the EML came on straight away.... very rough idiling and bouncy revs, that being said I did not experience a stall when idiling. Decided it was too dangerous to go out and test the old sensor again... New one works wonders, apart from stalling everytime you need to change down to 1st/2nd gear... haha

Bad MAP Sensor covers everything Bingodalton it might not show up on the dash as an error code but definitely worth the £12.75 I paid for a new one... cleaning it doesn't really do much as it is a pressure sensor and the mayo you found won't affect the reading directly (although the oil has probably penetrated the electronics and frazzled them... you could maybe give the throttle body a clean? Not so much the butterfly valve but more the side walls as oil residue can become lodged and makes the throttle more restricted. I have a garden hose pipe as a breather hose until tomorrow when the new modified part is delivered. Genuinely think it is just a poor design by Fiat but oil can get anywhere! When was the last service it got? Check spark plug tips to check for lean/rich fuel mixture.
 
Came to the conclusion one of the two lambda sensors are on its way out... plus this is a very common fault. Does anyone know how to diagnose which one would be at fault? One plugs directly past the heat shield at the front of the engine and one after exhaust manifold. Would rather find out which one has gone rather than dish out for two new ones when I only need one as they can be rather pricey...
 
might have an air leak on the intake side leading to incorrect mixture get some carb cleaner and spray it all around the intake manifold area including any vacuum pipes.
 
The smaller breather hose at the back of the air box has a small split on it at the end of the hose... ordered the new modified part. going to do the carb cleaner trick at the weekend. Also got a new oil breather hose, spark plugs, oil filter.
 
the small part of the breather hose that goes to the manifold attatches to a very small tune blow through the tune to make sure its not blocked I think it is the air bleed for the idle control valve
 
DrumRollChris, the last service is done almost 8.000km ago, but it is behaving like this since I bought the car...and that was 8.000km ago. :)

Throttle body and EGR cleaned, and EGR is closed, but not eliminated in software. Before that, car would kangaroo sometimes when i start really slowly.

Not really sure what to check. Mechanic guy says MAP is good, readings are good comparing to expected ones, but for me, consumption is really bad, and I have that feeling of stalling when I change the gears.

It starts fine, never had a problem if I wait for the fuel pump to buzz out. If I try to start it earlier problem can happen. (excessive temperature,...).

I think here we do not have such a cheap MAP. What is your engine? I don't have spark plugs :), it is a diesel.
 
Going to try and get the throttle body off tomorrow, give it a good looking over... would it give easy access to the idle control valve? And it's a 1.2 8v Bingodalton maybe a lambda sensor? That's my next purchase next time I get paid....
 
Found out a way to stop it stalling at junctions... stay in the higher gear right until around 1000rpm, just as you feel like the engine doesn't like it and then disengage the clutch and drop down to second if going round a corner/ first to come to a complete standstill. I do not however know if this could do damage long-term. Still haven't actually found the root cause, still geared towards the pre-cat lambda sensor....

With 93.5k miles on it, it looks like the pre-cat has been changed previously but not the post-cat.
 
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