General No Spark at plug

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General No Spark at plug

Michael D

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Nov 2, 2007
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Stirling
Hi , Out of the blue on Wednesday my scie would'nt start in the morning , the engine turned and turned but not even a cough or splutter from it , when I came back in the evening and tried it , first turn and started , ran here and there and it was back to normal , next day thursday ok ran perfect , next day Friday was an action replay of tuesday , would not start , later on I tried again , started and it was fine all night , Saturday morning no joy turned and turned the engine , not even 1 fire-up or cough or splutter , took plugs out = no spark , anyone had this strange behaviour ? saturday evening still no joy !
Cleaned crank sensor and visual but nothing seems out of place.

Suggestions\advice please anyone , would be appreciated , thanks
 
sounds like it could be a faulty crank sensor,,,,was there no spark on any of the cylinders?? if its only on 2 then could be one off the coilpacks or H/T leads.
 
Hi , Thanks for the reply , I only tried 2 plugs for a spark in between trying other things i.e. checking leads etc. it's quite difficult to chack for a spark working on my own as I had to ask a neighbour to turn the key while I checked , maybe I should have taken the lead cap of and tested the HT lead's on there own as I should not be trusting plugs at this stage but 4 going at the same time ? The crank sensor was really quite dirty but seemed to clean up well , do you know if there is a way to test this on it's own because really at this stage it could be any of a few things , trial by elimination seem's to be the strategy here . but it's knowing which area is most likely . Thank's again .
 
you can check a cranckshaft sensor with an ohms meter, if your getting a very high resistance then there could be a break in the coil inside the sensor but if it is doing this intermintantly then this may be hard to find.
depending on sensor type ohms can range between 500-1500.
if i remember correctly
 
you can also check the H/T leads for a break down in the same way using an ohms meter, shortest to longest you would want to exspect around 4.7, 5.7, 7.6 and 8.5 ohms for the longest set on the (20k) setting on the meter (for the cinq sporting).
just incase you wanted to no ;)
 
but remember if you do as above the connector will have to stay on and you will have to prod into the wires to test using the meter,,,usually you would remove the muliplug and test directly to the sensor.
:)
 
Sorry did,nt see reply there . Not chewed but wondered if they are known to knacker internally and if so would the symptom be no spark at all at the plugs as this is what's happening , Can anyone give me a rough breakdown of what the crank sensor really does so I can get a grip of the theory side of it's workings as my knowledge consists of the old school of distributors and points etc.
Typical job's I've done on my scie are > Clutch cable , Thermostat , Rocker Gasket , Brake Shoes so I am adaptable , I just need to know where the problem is as I dont really want to replace anything unnecesary as this takes time/travel/money and it's crap when one replace's the wrong part.
Also if there is a conclusion to this scenario I will document it and also post the symptom's AND fix on Fiatforum so if anyone has this problem , information will be there for them. I have read a lot of problem's people have with their scie's/cinq's but not many people post the fix to the problem once thy have it sorted . Thanks again ..
 
Sorry did,nt see reply there . Not chewed but wondered if they are known to knacker internally and if so would the symptom be no spark at all at the plugs as this is what's happening , Can anyone give me a rough breakdown of what the crank sensor really does so I can get a grip of the theory side of it's workings as my knowledge consists of the old school of distributors and points etc.
Typical job's I've done on my scie are > Clutch cable , Thermostat , Rocker Gasket , Brake Shoes so I am adaptable , I just need to know where the problem is as I dont really want to replace anything unnecesary as this takes time/travel/money and it's crap when one replace's the wrong part.
Also if there is a conclusion to this scenario I will document it and also post the symptom's AND fix on Fiatforum so if anyone has this problem , information will be there for them. I have read a lot of problem's people have with their scie's/cinq's but not many people post the fix to the problem once thy have it sorted . Thanks again ..

it tells the engine the rpm and the top dead centre position from this the car knows when to inject and when and witch plugs to trigger either 1 and 4 on top dead or 2 and 3 on 180 from top dead wasted spark system

so if this part is faulty in any way or the wiring for it it plain and simply wont run because it wont spark or inject

if your car is not injecting also and the ecu has power light comes on and goes off and so on then it's a likely cause

if the car is injecting fuel but is not sparking check the common 12v feed to the coils from the injection relay
 
Thank's , littlepip17 , fingers99 , fordcosworth , rallycinq , Had another look today but could,nt hang around as in "easter loadsa thing's to do and no car to do it in , typical ! lol !.
Any way I took the hoses of (incoming+outgoing) the carb and there is petrol going and coming from the carb , but when I turn the engine there is no smell of fuel so it seems like a double whammy regarding * Quote so if this part is faulty in any way or the wiring for it plain and simply wont run because it wont spark or inject *Unquote .. So I would see what is happening here .
At the beginning of this I had to figure out wether this was spark or fuel related , but it is both , so this would suggest a new crank sensor would be the one to try , so I will order one tomorrow , meanwhile the bus to work for me till friday and I will be back on FF with the result. Thank's Pepe's for your help and support ..
 
Re: No Spark at plug *SORTED

Update - Replaced crank sensor and the car is running fine again , thanks to the guy's who helped and for advice .

The readings which I measured from the new crank sensor before I fitted were * 696 ohms and continuity was .314 mv , there are only 3 pins to measure. so if anyone wants to know what the exact reading should be , this is it , also the one I took of measured zilch .. Thanks again ..
 
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