Author Topic: Help, don't start.  (Read 945 times)

Offline Tonyxxx86c

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Help, don't start.
« on: March 01, 2016, 09:01:24 pm »
Hi, I used the last time on January 3, after I unplugged the positive battery cable and put the battery trainer. End of January I decided to use my g40, but not started. If I turn the key switch on the instrument panel lights, but the fuel pump don't priming,  the starter motor work.  Check the relais and work,  connect direct fuel pump and work,  with direct connection the engine don't start.  Igniton coil i have changed in december 2015 and work in my another 86c AAU,  but the spark don't have power. last round i have changed the knock sensor with a new parts but don't start.

Can help me?

Offline G40supercharged

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Re: Help, don't start.
« Reply #1 on: March 02, 2016, 08:03:33 am »
The fuel pump is primed by the ECU when power is first applied to it. The ECU does not have any power when the ignition is switched off. Power is applied to the ECU by one of the two relays that are fitted next to the ECU. The other relay is controlled by the ECU to turn on the fuel pump. The ECU will only turn on the fuel pump at start up for priming and while the engine is turning. The ignition (and fuel injectors) are fired by the ECU when it gets a signal from the hall sensor in the distributor.

As you do not have any priming of the fuel pump and no spark as well this suggests that there is no power to the ECU. It is likely the problem is the relay that powers the ECU. (If there was a spark but no fuel it would be the fuel pump relay.)

The knock sensor will not affect the car starting only how well it runs. 

Offline Tonyxxx86c

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Re: Help, don't start.
« Reply #2 on: March 02, 2016, 08:19:26 am »
It is one of two relays that is near the ECU?

Offline G40supercharged

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Re: Help, don't start.
« Reply #3 on: March 02, 2016, 01:10:30 pm »
Yes, it is one of the 2 relays mounted next to the ECU. The other is for the fuel pump. They are 2 different types of relay. Try taking them out and cleaning the contacts.

Do you have a wiring diagram for the car?

Offline Tonyxxx86c

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Re: Help, don't start.
« Reply #4 on: March 02, 2016, 01:47:44 pm »
the relays (4 and 5 pin) and the contacts are tested and works.  yes i have a diagram

Offline G40supercharged

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Re: Help, don't start.
« Reply #5 on: March 02, 2016, 11:14:04 pm »
Check that you have power to the relay when the ignition is switched on. There is a permanent 12V to the relay plus 12V from the ignition switch to turn on the relay when the car is on. It may be there is a fault in the ignition switch. (The contact in the switch that controls the starter motor is different to the one that powers the ECU relay.) It is also worth checking if there is an immobiliser fitted that can stop the power to the ECU. If there is power to the ECU and nothing is working it may be an ECU fault.