Technical Sensor problem

[Dale Jenkins]

Hi guys I recently aquired my fourth mk1 punto...this time a 55sx! I had two 1600 sportings and a 60s in the past and thought rather highly of them especially concidering the way people slate them for no reason...especially my sportings, they gave alot of cars a good run for their money! Anyways iv had the 55 for about a week and the first few days it drove spot on untill it just lost all power whilst driving down the dual carriageway and cut out! I quickly used my initiative at the side of the road and established that everytime I turned the ignition on I could no longer hear the fuel pump kiking in. I turned my attention to all possibilities only to discover it was the sensor situated under the fusebox in engine bay. (dont know what this is called) Everytime this problem occurs I fiddle about with it and pull the plug off and then plug it back in and bobs ur uncle...it drives for a few blocks and the problem occurs again and the engine cuts out! What do I do guys? Please help...is this a common fault with the 55? Would it be a cheap fix? Can I run the engine with the plug to the sensor unplugged (after iv started it ofcause) in the meantime whilst I try getting it sorted? Mk1's are starting to get rare round my ways but have been to the local breaker and spotted a mk1 60 team with everything still on it....so can I grab the sensor off that or will it not be the same as the 55sx? Please, any information or help will be much appreciated thanks.

 

[s and b]

hi dale
under the fusebox doesnt make sense to me
are you sure its not the crank sensor on the end on the engine by the alternator that you are waggling?
if it is change it
i dont know if the scrappy yard one fits but you could always take a phone photo to compare i would be surprised if it was different mind

 

[Dale Jenkins]

Hi s and b...sorry about my explanation as to the where abouts of the sensor. If it makes it any easier, I am refering to the sensor plugged into the fuel injection manifold?? Its on the right hand side of the air filter box, about a 1/3 of the way down towards the block. Another explanation is its above the sensor that is on the gearbox. Yes I do gather the 55 and 60 engines are very similar so I will be surprised if does not fit either. At the moment I am adamant that it is that sensor causing the problem...but fingers crossed!

 

[blu73]

is the end of the sensor blue? the bit the wire clips onto??

 

[fingers99]

Could be the main relay? White (but sometimes black) box about the size of two conventional relays (in effect, that's what it is).



The bit with the red circle: punto 55/65, Cinq 1108, early Sei 1108. (Illustration is from Seicento manual -- I can't remember the location on the P55/60.)

Crank sensor is more likely the problem, but easy peasy to test. When conked. remove a spark plug, lay it on top of the cam cover. Crank the engine. If there's a spark, it isn't the crank sensor. If no spark, remove the air filter conver. Crank the engine and watch for fuel dribbling onto the throttle butterfly. If fuel, it isn't the crank sensor. If no fuel and no spark 98% it is the crank (aka TDC) sensor.

Note that the fuel pump switches itself off as soon as the fuel rail reaches the required pressure and will stay switched off until the pressure decays. But no fuel pump tends to indicate main relay.

Hope that helps, but a picture from you would save a lot of guessing, effort, etc.

 

[Dale Jenkins]

Hi guys....
Yes blu73, that was the sensor I was referring to....and it was definitely not the crank sensor or any other one for that matter! In actuall fact I feel quite embarrassed as I went down to my local breaker this morning and aquired and fitted that sensor from a mk1 60 team and the promblem still persisted! I then put two and two together and thought, since my lights and everything else in the car stayed on when the engine cut off that this must be an earth problem! I then checked the earth and it appears that the mechanic whom the lady refered to android l used to service this car just weeks before I bought it, was either a cow boy or just wanted to do her over because not only had he over crimped the earth to the lug that is connected to the gearbox but he also over tightend the lug so much that it had been rounded off and split!!! The earth was hanging on by its last string! I felt like kicking myself! Earth should of been one of the first things I checked but hay hoe, the car is up and running better than ever...thank you guys very much for your help

 

[blu73]

well at least its sorted now.. just for your info that blue sensor is the coolant temperature sensor, which the ecu uses to adjust the amount of fuel to inject