Hello I change motor 4,2 1985 year and now i can't start it ! i don't have voltage at injectors check ground but nothing

i change ignition coil and amp for ignition new balast

check injectors but theres is nothing !
car stay before 13 years without starts

maybe someone know where i can try find + for injectors

Thanks

thank you!

 

I have spark!

 

Have a read here: -

Fuel injection and the Jaguar XJ6 4.2 Series 3 / AJ6 Engineering

The injectors are fired all together twice per engine revolution. This is done by the ECU earthing the injectors that have a voltage supplied to them at all times. The length of the earthing period hence decides how long the injectors are open and hence how much fuel is injected. The whole system is analogue, there is no fuelling map or anything like modern systems. The key event that triggers the injectors is the supply of a pulse to the ECU from the ignition system. Without this pulse nothing will happen. This pulse is supplied from a wire running from the coil negative terminals.

It might also be prudent to check the earths attached to the rear of the inlet manifold as these can stop the system working if not making a good earth. Also check the engine earthing strap, but if the engine is cranking over OK this would seem OK.

Doug Dwyer who posts on here may also give some info as he runs these cars. I sold mine in 2003

 

"+" voltage for the injectors originates from the 'main relay' on the firewall and then goes to the injector ballast resistor which is on the RH of the engine compartment, well forward and down low.....approximately across from the power steering pump.

The main relay has the following wires:

Brown -- constant battery "+" voltage
Black -- ground/earth
White -- 12v with key 'on'
Brown/slate -- 12v with key 'on'. This is the output that supplies voltage to the resistor pack and the injectors

Take some test light or voltage readings and post back

The brown/slate wire splits into to branches so you'll see two brown/slate wire at the the resistor pack. Check connectors for corrosion.

Also check for the bundle of 5-6 ground/earth wires are the rear of the water rail. Nothing in the fuel injections system will work if they are loose, dirty, or not attached

Also check the white/black wire that runs aft along the water rail, originating from the coil "-" post. It provides a trigger signal to the fuel injection ECU

Cheers
DD

 

thnx i will check this )

 

tnx its works ))