Griffith MIL light

[kabaman]

All, I've just replaced some bits and pices on the car and I've disconnected the throttle sensor, AFM, had the injectors cleaned. I've put it all back only to be confronted with a "MIL" warning light and the fuel pump doesn't prime.

I've started measuring resistances of meters at the ECU...Strangley the AFM reads about 9V across the sense pins which sounds worng.

Does anyone know if there's a cheap bit of kit to read fault codes? If the AFM is faulty will it throw up the MIL light? Anything else I should check next. I can see this taking me some time to ge to the bottom of so any suggestions would be most welcome.

Thanks,

Neil

[kabaman]

Update: Pin 2 from the ECU seems to be an issue here. ECU has batt (unswitched) voltage and ignition (switched) voltage but pin 2 does not deliver 12V. Does anyone have any details of the ECU itself so that Ican figure out what should be happening and is possibly going wrong in the ECU?

Cheers,

Neil

[kabaman]

ECU Pin 2 shows around 8.7V. Even if I manually operate the fuel pump relay the fuel pump never runs so that suggets to me that there's no positive supply there to be switched. Hmmmm investigations continue.

Neil

[Ballistic Banana]

There is a good who advertises in the classifeds for the hire of his fault code reader £10 for a week i think, think it was Richard

I take it you have checked the relays and fuses? Also did you change the AFM...I'd be checking everything you have changed wiring wise.Check the inertia switch has operated too( just above the back of the glove box, an easy check) Is the immobilser working?

BB

[lwt]

Inertia switch or one of the two silver relays dangling near the ECU would be my favourites. Even when you have it sorted, the MIL lamp will stay until the code is cleared out of the ECU (remove power from it by pulling off the huge connector for a few seconds then refit).

Ian.

[blitzracing]

9 volts is an odd figure to get, as both the main relay and fuel pump relay only switch 12 volts on or off. The main relay feeds the AFM, whist the fuel pump relay feeds the pump and lambda probes, but only for a few seconds on power up and then when the engine runs. If something is dropping 3 volts due to high resistance (like a relay contact) Id expect some heat to generated as the current drawn is quite high.

fault finding guide here for the Range Rover (less the TVR immobiliser)

http://www.g33.co.uk/images/PDFS/14cux_fuel_inject...

The MIL light is an odd one, as even with a sensor unplugged or failed the ECU should be in get you home mode and the pump should still prime. This is a very basic funtion of the CPU starting within the ECU. As a matter of interest if you remove the fuel map chip the pump runs contiously if you want to run continuity tests. Id unclip the injectors just to make sure you cant inadvertantly get fuel into a stationry engine. Also check for 5 volts across the temp sensor (s) as this will show at least the the ECU is providing power.

[kabaman]

I think 9V suggests things are horribly wrong - coupled to that the fact that pump doesn't even prime.

The ECU isn't driving the main or fuel pump relays at all. I could have a crack at debugging the ECU if only I could find a circuit diagram for it. So far internet searches for an internal ECU diagram have failed.

[Ballistic Banana]

Can you not test at the back of the ecu? Steve Heaths "The Bible" has a diagram of what spade is what then follow the wire out through the plug and then test at the wire?

Just a thought

BB

[kabaman]

Yes I have been testing at the back of the ECU. I'm wondering now whether I might have failed to reconnect a ground connection somewhere and hence something has lost its ground reference. I'll check that the ground connections are grounds. I seem to remember a ground connection on one one fuel rail mounts to the inlet manifold on the driver's side. Does anyone else have one of these connections? It's possible I've failed to reconnect a ground after having the trumpet base off and injectors out etc. Fingers crossed...

N

[kabaman]

Found the bugger, a ground I'd failed to reconnect to the inlet manifold taht the fuel rail legs go to. Re-connected and everything's good!

Except that idling speed is way too high....I can feel a new thread coming along.

Cheers,

Neil