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156 2.4 jtd will not start

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7K views 30 replies 7 participants last post by  nathanrobo 
#1 ·
Yesturday i had mscf light come on but the car started and seemed to be running ok i stopped and started multiple times with no problems. Today however it refuses to start the batteries ok there fuel in on holiday in cornwall 300 miles from home any suggestions
 
#8 ·
Normally a small yellow light in the top right of the panel between the speedo and rev counter - should illuminate when you turn on the ignition then almost immediately go out as the code is read by the immobiliser.....

You say you've vhevked the relays - have you checked the wiring into the relay mounting blocks? - as with my JTD that wiring corroded and caused a failure to start.....
 
#11 ·
i had a mechanic come out today and with the aid of easy jet got it going he then reset the ecu so no more mscf light however today afyer 300 mils home i stopped the car and when i tried to start it (it was still warm by the way) it would not start engine light came on . eventually it started with a bit of throotle but light light still on. when th emechanic read the codes the was no mention of crank sensor problems any ideas
 
#15 ·
What mileage / age is your 156? I have had this issue aswell with an 8 yr old 2.4 JTD with 250k km on the clock;

car turns over fine but doesn't catch
sometimes starts when warm with a bit of throttle, often leaving a blinking glo-plug light on the dash
starts with a squirt brake cleaner in the air intake
once running seems fine

My mechanic told me it is the plugs needing replacing, however as it happened I was selling the car on to someone for parts (I had pranged it) so I explained the problem to the buyer and they went away happy so I never found out if swapping out the plugs would have solved the issue

in the interim I drove it for about a month, 500km a week and just a squirt of Wurth Brake cleaner (5 euros fo a can from my mechanic) in the air intake every time I wanted to start the engine. Not that I'd reccommend doing this for an extended period as I'm not sure the effect on the engine but certainly in a pinch (and to get you home where your mechanic can sort it for you) it worked for me.
 
#18 ·
I think the crank sensor will be causing the problem, the squirt of brake cleaner gets the engine spinning a bit faster so theres a higher voltage at the crank sensor, enough to trigger the injectors to fire..
 
#20 ·
I had same symptoms, 2.4 JTD 10v

Tied all the usual, in the end local Bosch Diesel agent determined it was a faulty injector causing mayhem. New one in, passed diag, problem never returned.
 
#22 ·
cheers dave when my fault codes were read i was told i had a po683 preheating unit problem. however have looking for this specific code it doesn't seem to exist. so i assumed possible wrongly that the preheater unit is a glow plug. How ever on reflection it could be the relay as its all the same circuit. A relay costs less so i will probably replace this first and see. I can always return the plugs.
 
#28 ·
thanks dave are you suggesting it my be the ecu Powertrain - Computer and Auxiliary Outputs - ISO/SAE Controlled
Description
Glow Plug Control Module to PCM Communication Circuit

but just a note on the car been an alfa owner for 3 years 156 2.0 ts but owning a 2.4 (4weeks) is just nothing but pleasure despite the minor issues with diesel technology
 
#30 ·
I'm just thinking if the car is cranking over fast, but it is not firing up (and the code light is out), then chances are it isn't getting fuel. All it needs to start is compression and fuel at the correct time, it shouldn't particularly need extra heat at this time of year, especially as you mention in post 13 that the car failed to start when it was already warm. Also in post 10 you mention there was fuel at the injectors - well the injectors will not open unless it is getting a signal from the crank sensor..
 
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