Car wont start!!!!!

Technical Area Engine, Transmission, Exhaust etc
2

Hi all,

Posting up on behalf of my father in law regarding his mx5 2.5 2002 02 1.8 unsure of exact model as he is not here to ask [:)]

Recently he went on holiday leaving his car stood for 2 weeks but he disconnected the battery. When he returned he turned the car over and left it to tick over but didnt take it on a run. From what i understand the next day he came to start it nothing happened, which he believed was possibly down to the battery being flat as he has had similar issues like this before. He charged the battery and connected it back up and nothing happened not even a booster pack would do anything. All that happens is the lights on the dash light up on position one of the ignition as you would expect but when trying to start nothing happens at all, no turning over or anything and the dash lights dont seem to fade they stay reasonably bright.

He has had his friend who is a very knowledgable mechanic out to have a quick check and all the signs from what he has said point to the ecu being fried due to their being an excessive amount of water where the ecu is positioned, there is clear rusting on the casing of the ecu but when opened up the circuit board seems unharmed (to the naked eye). He also said that when they first checked the car there was signs of a spark (but still no turning over) but no spark now.

Obviously an ecu is expensive thing to be changing so i was just wandering whether anyone has come across a similar fault before, or any ideas which may be able to help in diagnosing the fault

 SORRY FOR THE ESSAY

 Many Thanks

 SAM

3

any advice is appreciated

 

cheers

4

First port of call would be try a known working battery, I had a similar fault on a previous car, drove 100miles stopped car, wouldn’t turn over even with a jump, lights etc working ok though, RAC chap put a known good battery on it and it started first time, only advice offered to a reason was that the plates had dislodged and were shorting on each other? I’m Thinking the spark is a red herring - this is triggered by the can angle sensor so without the engine turning over the trigger for spark wouldn’t happen? (happy for someone to prove me wrong though), also the starter circuit is a direct feed from the battery to the starter motor, switched by a circuit from key switch (via immobiliser) to the starter solenoid, so unless the ecu has the immobiliser built in to it the engine should at least turn over if the ecu is faulty, so I would check the immobiliser circuits also!

5

 cheers for the advice mate

 

have also posted this up on another mx5 forum to see if i get anymore ideas to try