Diagnosing a non start


Staff member
Deal, Kent UK
A3 1.4 TFSI 150 COD
I thought it would be good for us to have a thread on how to diagnose a non starting engine. Feel free to add your tips and suggestions to this thread.

1) Is the starter motor turning over. If you just hear a clicking but no whirr then the starter motor is probably the issue. Sometime the solenoid will stick, a swift blow to the starter motor will sometimes free it up. The starter motor is pushed onto the flywheel when engaged. If the starter is spinning up freely without turning over the engine then the relay that pushes it into place has probably siezed up.

2) Is there fuel in the tank and battery power? If the lights dim when the starter is used then the battery is probably almost flat. The fuel gauge is not always accurate so be sure to rock the car and check the tank for fuel this way. Being on a steep incline sometime prevents the fuel from reaching the pickup.
I had this last week on a shop car park. The +ive had come loose on the battery clamp, there was enough connection to light up the dash but not enough to provide power to the starter! Did get some funny looks when l lifted my fibreglass bonnet of the car too! :lol:
Check battery connections 1st also earth connection from the starter.

on more modern cars - if your just getting a clicking when trying to start then check the voltage. most cars have a cut off of some sort to prevent the voltage dropping so low that central loking etc doest work.
have had this in both my car and dads. could open the door even the leccy windows half worked but there wasnt enough juice for it to even start the starter just clicking of the relays.
if its an auto , check & move selector through the quadrant to check its in park/nutrual , sometimes this is the answer to what appears to be a flat battery .
funny how this came up

recently my car is hard to start, last week it started when cold no problem
when i took it for a drive and it was warm, it wouldnt start until it cooled down again

so i called my mate
he took a wire, and connected it to the fuel pump via a fuse,
car fired up straight away, but if you dissconect the wire, it would cut out

we thought it was the fuel pump, but we could hear the pump prime with just the key
problem is the relay, its burned out, and when the car gets hot it dosent work

so, another thing to check if the car wont start

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