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Matt
Matt, Mechanical Engineer
Category: UK Car
Satisfied Customers: 21095
Experience:  BEng hons Mech engineering, in auto industry 22 years
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My Vauxhall vectra 1.9 cdti 2007 won't start. Fob key works

Customer Question

My Vauxhall vectra 1.9 cdti 2007 won't start. Fob key works fine as battery has been changed. Please help
JA: Have you changed a battery before?
Customer: Yes I have
JA: What is the model of your '07 Vauxhall?
Customer: Yes
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: A mechanic tried fixing it, we have changed most of the things as he said the diesel was leaking
JA: Anything else you want the mechanic to know before I connect you?
Customer: The car won't start
Submitted: 1 month ago.
Category: UK Car
Customer: replied 1 month ago.
I have been told, there is a fuel cut so diesel is not entering the engine.
Expert:  Matt replied 1 month ago.

Hello

I'm assuming that the engine turns over OK on the starter so that aspect is OK

I'd check that you're getting full power to the glow-plugs, they pull a lot of current so take care when checking but see if the relay is clicking when the ignition is turned on first and also check the fuse if this is OK check to see if the engine earth strap is also OK.

If the plugs haven't been changed in the last 20K then they may have to be replaced.
You can test the glow-plugs with a multimeter by measuring the resistance across the plug ( between the power connection and the body) it should be around 4-8ohms if its tending to infinity / open circuit the plug is faulty or by using a clip on current clamp, either on the supply wire to glow plugs or onto engine earth, with glow plug light on you should see 15-20amps for each glow plug fitted, 4 cylinders would be approximately 60-80amps.

Also if its not injecting at all then check the connections to the crankshaft sensor, unplug it and check for corroded contacts and broken wiring, and consider fitting a new sensor - do the same for the cam position sensor

If the EGR valve is stuck open then this too can effect starting so try disconnecting it to see if this helps or changes anything

Could also be an injector leaking fuel back through the overspill pipe, so not getting enough fuel pressure to tell ECU to fire the injectors, this is trickier to find and you’ll need the garage to do a ‘run back’ test to identify which one is the issu
Lastly it’s also worth considering fitting a new fuel filter as if only slightly blocked this can lower fuel supply pressure and choke the main pump, the pump will be more sensitive to this when its cold as diesel thickens considerably with low temperatures.

Customer: replied 1 month ago.
I have beeen told the mobiliser needs decoding
Expert:  Matt replied 1 month ago.

well thats possible

if the dash is lighting up normally and the engine is cranking however then this normally means the immobiliser is off