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Technical Crank sensor on its way out?

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Technical Crank sensor on its way out?

vhtr

vhtr

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Joined
May 15, 2016
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Hello there!

It's a terrible shame to write my first post with such a negative subject but I really need your help.

My car is a 1999 Mk1 75SX.

Symptoms are as follows:

-Sometimes it takes an extra second of turning the key to start.
-Sometimes there are noticeable "notches" in the powerband under heavy
accelerating.
-Last couple of days it has started to flash the engine warning light and
stalling.
Fortunately it stays running if I apply some throttle and stalling ends after
a minute or so.

All these symptoms are quite sporadic but steadily getting worse.
I think the problem is the crankshaft position sensor but I would like to hear
your opinions on the topic.

Greeting from probably the most inhospitable place for an Italian car, Finland :D
 
Yes, it could be your crank sensor. However, it could be a fault elsewhere such as the ignition leads or a coil, or just a faulty plug. Check for obvious faults, but is probably worthwhile changing the crank sensor anyway.
 
Thanks for your reply, I've owned the car for just over a week now and I changed the leads because one the old ones was damaged and grounded itself on the rocker cover.

The seller told me that he had changed the plugs in the autumn and the car had been unused for the winter so they SHOULD be all good, I might pick new plugs anyway when I go to get a new sensor. If neither of those helps I then take a closer look on coils but when the car runs normally, it pulls very nicely so it's hard to believe that weak spark would cause the problem
 
flisko said:
i would plug it to a computer clear old errors and scan again to see what it will show
Click to expand...

This model year isn't OBD compliant so that must be done at a Fiat dealer? I'm very new to Italian cars as I've only owned Volkswagens before. :worship:
 
Thanks a ton! I will get the adaptor ASAP, I didn't know you could read OBD by simply changing the connector.

Sadly due to my job I'm away from home 5-7 days a week and I need my car every day so it's pretty tricky to fix the car on the fly. I guess I'll try the crank sensor and if it doesn't fix the issue I will have to get the code reader. Well, the code reader will be handy some time in the future so I'm buying one anyway.
 
Last edited:
Don't start "throwing" parts at it in the hope of fixing the problem!, It will end up costing you more! You could try crank sensor, coil pack, etc etc but a plug in will at least give you an idea of the problem. Remember the saying "If it's not broke don't fix it", there may be nothing wrong with the crank sensor. Bite the bullet and get the codes read.
 
I'm painfully aware of that Digger, it's just that my situation is quite difficult since I have to drive forth and back to work every day and my nearest Fiat dealer is 50km away from where I live when I'm working. Of course I could use public transport but my workplace is a bit unusual so there isn't such thing available.

But now I'm just thinking out loud, I try to get an idea how to solve this and get back to you when I know what was the root of the problem. Thanks for your time, this forum made a pretty damn good first impression on me from the start.
 
you need this to read/clear codes.. http://www.ebay.co.uk/itm/152024589202

throw away the disc if it comes with one and download this (its free) http://iaw-scan2.sourceforge.net/

Bear in mind that if it is the crank sensor the ecu generally will not report the crank sensor as the problem unless its completely and utterly dead, and the car clearly won't run at all. It usually just reports 'multiple misfire' or a coil failure when the crank sensor is dying. Just don't follow the software blindly basically.

Do pull the plugs and see how they look - whether they look like they were really changed recently? are they black and sooty or really white and or a nice brown or grey colour like they should be.

As you have changed the leads it could be as simple as one is not on properly - again software would prob report a coil failure in that case. So make sure they are all on properly proplerly - you can pull back the boots so you can see they are properly clipped on then push the boots back down over the connections after.

Also have a look at the crank sensor, is the bolt that holds it in screwed down properly, is the sensor really dirty and covered and crap. Clean it up if so. follow the wire and look for any damage, check the connector for dirt or corrosion and that the metal clip is present that holds it together.

What you describe does sound like crank sensor kind of symptoms but its not defo that - although its never a bad thing to have a spare. I'd consider just buying one and if it makes no difference swap the old one back on and keep it in the car as a spare incase you need one when out ;)

Best of luck, keep us posted :)

And lastly, :wave: welcome to FF!
 
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blu73 said:
you need this to read/clear codes.. http://www.ebay.co.uk/itm/152024589202

throw away the disc if it comes with one and download this (its free) http://iaw-scan2.sourceforge.net/

Bear in mind that if it is the crank sensor the ecu generally will not report the crank sensor as the problem unless its completely and utterly dead, and the car clearly won't run at all. It usually just reports 'multiple misfire' or a coil failure when the crank sensor is dying. Just don't follow the software blindly basically.

Do pull the plugs and see how they look - whether they look like they were really changed recently? are they black and sooty or really white and or a nice brown or grey colour like they should be.

As you have changed the leads it could be as simple as one is not on properly - again software would prob report a coil failure in that case. So make sure they are all on properly proplerly - you can pull back the boots so you can see they are properly clipped on then push the boots back down over the connections after.

Also have a look at the crank sensor, is the bolt that holds it in screwed down properly, is the sensor really dirty and covered and crap. Clean it up if so. follow the wire and look for any damage, check the connector for dirt or corrosion and that the metal clip is present that holds it together.

What you describe does sound like crank sensor kind of symptoms but its not defo that - although its never a bad thing to have a spare. I'd consider just buying one and if it makes no difference swap the old one back on and keep it in the car as a spare incase you need one when out ;)

Best of luck, keep us posted :)

And lastly, :wave: welcome to FF!
Click to expand...

Thanks for the warm welcome! :)

I found the reason when I looked around the engine bay, the wires from the crankshaft position sensors plug are damaged. I mean the wires from the cars side of the plug to the ECU.

Luckily my collegue has the needed tools for
the job so we now do just a quick fix (cut the wires and replace them with standard flat female connectors to the sensors plug) and next week we redo that bit of wiring between ECU and the original plug.

To be honest I didn't expect such an easy problem but I'm not going to complain about that! :cool:
 
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Yeah, they're super simple but everyone who knows I bought an Italian car has told all the horror stories about them that they can think of.

Hopefully when that is sorted we will get along better, one thing I've learned about Puntos is that they're great fun to drive! You get the feeling of speed and power without the hassle of actually having either :D

And I've even fallen in love with the tacky 90's wood trim my car has! It really is a pleasant thing to travel in, even though my driving consists about 85% of motorways
 
That's true, but where I live Italian cars have a terrible reputation, I guess because people can't take into account that a car from southern Europe could need some extra care to work in the freezing north.

But anyway,before this goes more off-topic I'll leave and post more when I get the problem sorted. Thanks again guys for the great advice!
 
Situation update, the car spent the last few days with the car electricity specialists and has now a new wire between the crank sensor plug and ECU. That bit is fixed and the car runs great but yesterday it cut out on the highway.
I coasted to the side of the road to check what was wrong, when I saw nothing extraordinary I turned the key and drove off. I have no idea what is wrong this time, they installed the new crank sensor at the garage so it's hard to believe the problem would still be in that section of the Punto's electric system.
 
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