Any idea why my EFI resistor block would get very hot with the key on engine off. Thanks.

 

Erm, because a resistor works by turning too much electricity into heat and a lower output?

 

Unlike you, Daim, my knowledge of the electrics in the injector system is rather sketchy to non existent. But it occurs to me, as the engine is not running, even though the ignition is on, why would there be anything in the injector circuit in the way of current at all, as the injectors would not be activated by the ECU?

 

Yes with the engine not running the ECU is not switching the injectors so there should be no current flow through the resistor pack.

Injectors have 12volts supplied when ignition is switched on, ECU works by switching the injectors to ground. My guess is you either have a short in the ECU or in the wiring harness between the resistors and ECU.

You did not say if you actually had an issue?

 

It's my understanding that the injector solenoids are a 'normally open' construction meaning they open when 12V supply is removed. This corresponds well with a hot resistor pack with ignition on, but engine is not started as the solenoid then will be activated full time to keep closed

 

Iirc this is also noted in the HE/facelift manual as a not to do. That is for instance why the car has ignition OFF, AUX and ignition ON. Same goes for the ABS unit...

Normally the resistor pack would be cooled via air flow through the engine bay.

They are getting warm as they are waiting for the signals from the ECU regarding the injection point. Basically in standby untill the engine is turning ans the trigger via sensor etc. is triggered.

​​​

 

Thanks for the help. Engine barely runs. Will start with throttle held wide open but floods so bad that it has actually filled at least one cylinder to the point of making it difficult to turn over. Injector harness checks as follows - all 12 connectors have 12.5 volts at one pin and slightly less 11.8 at the other. Nothing shows zero ohms to ground in either the harness or the injectors themselves. Thanks again.

 

yes they have 12v supply but if you measure its on both sides 9f the injector so no current is flowing. It requires the ECU to switch one side to ground.

An injector noid light will tell you if this is your problem. You don't need to start the car.

 

That must mean that at least some injectors are staying open. This can only be caused by:

• faulty injector (very unlikely but obviously possible if all else fails)
• ECU fault keeping an injector open (equally unlikely but possible)
• injector loom shorting to earth, in spite of your tests saying it is not. This is by far the most likely cause of over fuelling.

 

I missed your post as it must have been the same time as mine.

Greg has it.

As the resistor pack is hot and the car is flooding the problem will be either

1 Shorted wiring from resistor pack to ECU
2 ECU failure

Disconnect the wiring from the resistor pack and ECU the wiring MUST be disconnected at BOTH ends. Then meter all the wires at the resistor pack connector to ground they all should have no continuity.

Continuity in any wire means shorted wiring
No continuity means ECU is bad

 

Looking at the wiring diagram, till 2 am, I have the wrong relays at the main and pump. Standard ones will cut 87a. Need the kind with 2 - 87s connected instead of 87a. Found them on Amazon for 13 bucks. Will post results. John.