General Map sensor question (to add to the list )

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General Map sensor question (to add to the list )

Neil75

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Thanks for looking at yet another one of my clutching at straws questions re punto maintenance , if I unplug the map sensor on my 1.2l petrol punto and the engine runs smooth (which it did) and then I plug it back in again and my rough idle returns does that more than likely mean that the map sensor need replacing or cleaning ? , I know it sounds obvious but could It also be hiding something else and unplugging the sensor hides the real problem ?
 
map sensor need replacing

When you unplug your MAP sensor the car will run on 'default' settings.

I had a problem with my car (not a Punto..) whereby it was kangarooing, jerking and cutting out but would restart immediately.

I did the same as you did - unplugged the MAP sensor and found that the car ran 'okayish'. Changing the MAP cured the erratic running altogether.
 
Ok , slight issue here ,not much of a problem , new Map arrived ,
I removed the old one and screwed new one in , (kept old one ) car was running slightly rough and engine light stayed on , however I know it takes a while to go out. So I lifted bonnet up to make sure all was ok , turns out I hadnt clicked plug in for map 100% so it wasnt actually connected (dumbass)
. Problem now is , I then plugged in new Map and car dies 5 seconds after start up , revs just fall and then it cuts out , will disconnecting battery in order to reset settings help ?, or do I have a dud sensor? , ill try to put the other one back in later to see if that works.
 
just to confirm a map disconnected will revert the ecu to factory default ie get you home but will most likely be running rich thus using too much fuel and killing your lambdas and cat
if you have replaced the map with a quality working replacement then once plugged in it should work
you probably need to clean the engine out now if there's too much fuel in the plenum causing stalling by revving it up but don't go nuts
light should show as fault if unplugged it will usually go off i think after so many cranks but a reset tool would be preferable
by the way swapping parts without checking live data to confirm part is not working is parts darting ie hoping you get 180 its not ideal unles you have the parts to hand and they are free
you really need a half decent fault code reader that reads real time whats happening or use multiscan connected up to a windows based laptop
i use a launch crp129 these days as it does many cars and also does abs and airbag fault codes

hth
 
Thanks , have high quality code reader, no codes showing , no lights on dash ,
have replaced plugs, leads , air filter , exhaust as it needed doing anyway and still misses slightly when idling , doing about 31mpg , garage when changing exhause said it wasnt a misfire , has just gone through mot so im assuming all engine supports are good. cleaned throttle and still rocks slightly on idle
have re gaped plugs and doesnt make any difference , no loss of water, oil.
its a complete mystery , is losing a few drips of oil from behind coils on side of block., however coils are working 100%
 
what about live data
what is map showing
on a simpler note connect a vacuum gauge
maybe you've got a faulty valve
look for 18 to 21 on tickover see what happens on blip
 
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