Technical Doblo diesel 1.9 JTD cranks, coughs, but no start

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Technical Doblo diesel 1.9 JTD cranks, coughs, but no start

brecklandmotorco

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Hi all, first newbie post, with a headscratcher. Hopefully a solution may help others too.


Doblo 1.9 JTD 53 plate, 120 odd thousand on the clock, reasonably well looked after, but has had a recent catalogue of EML coming on, limp mode, then miraculously clearing itself. Was taken to another repairer a few months ago, when I was busy, who reported a crank sensor fault, replaced the part, and it seemed "cured". It also shows an immobiliser light occasionally, on starting attempt, but isnt doing so at present. It came to me for non starting a month ago, but on going to collect it, wouldnt you know, it started fine, and despite keeping it for a few days, to try to provoke it in various situations, it wouldnt not start. Needless to say, no codes or EML (Im checking with a TRW Easycheck). Cleaned the ECU connections, relay connections, bled the filter water trap, checked voltages and connections.
So NOW we have a problem... Customer called, vehicle wouldnt start again. All warning lamps function as normal on switch on, tank lift pump can be heard priming, glow plugs cycle as expected. Crank the engine, and it 70% of the time coughs. like, crank crank brrmph... stalls, back to cranking. It will fire and run on Easystart, as long as you "feed" it, but I dont like doing that...
Fuel delivery with ignition on, to filter good, and down to high pressure pump. Found a thread on fuel pressure sensor voltages, although figs given didnt seem clear (recommended to set multimeter range to 2v and one fig was given as 5v!), but interpreting the bad grammar and typos, the pressure reg seemd to indicate there was fuel pressure. But still no start. Fuel pressure sensor and fuel pressure regulator replaced with known good items from my local scrappy taken from a known running vehicle. Still no joy. Fuel union from back of hi pressure pump slacked off, at ign on, but no cranking, some flow of fuel. On cranking theres no discernible increase in fuel flow, either at the common rail union, or at an injector pipe union. Id expect a "fair squirt" at those unions on cranking.
So given that its STILL giving me no codes to get to grips with, nor let me do live readings (which might show fuel rail pressure), it says the ECU "is not supported", can anybody give me any ideas?


Is the lack of codes indicative of an ECU fail, or an immobiliser fail? Would an immob fail still allow cranking, and trying to start? (Id think not) So can the lack of sufficient fuel pressure be diagnosed without codes or live scanner data? Anyone solved this or a similar fault?

Any help appreciated.
 
Hi, download multi ecu scan for free and get a cheap cable . Once it's talking to the ECU have a look at the parameters , worth looking at fuel rail pressure first , needs about 200 bar to start.
If the key or code light goes off when key turned on then immobiliser should be turned off. Multi ecu scan will confirm if key recognised.
 
My 2004 Doblo JTD has become difficult to start. I changed the fuel filter, it started. Next day still difficult to start. Easy start works. Runs well once it starts.
Could it be the fuel lift pump?
 
It turned out to be the crankshaft sensor, sorted. Caused us some problems as we broke down in Spain, orange warning light came on so fault code stored.
 
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