Not starting (turning over but no ecu light or fuel pump)

[tomperkins]

I've got a 2004 S3 with a 1.8 k-series and an emerald ECU.

 

The cars not starting, it's turning over but there's no light on the emerald ECU and the fuel pump is not kicking in.

All the fuses are good and I've tried a brand new MFU to try to fix with no difference, so MFU is good too.

Any ideas of where to start?

[Shaun_E]

Crank position sensor? The Emerald needs a certain cranking speed before it will start the car - the light on the ECU goes green when it can see the required crank speed.

[vertew]

My 2003 roadsport had a habit of doing this periodically.  Suggest:

• check that the inertia switch hasn't tripped / gone faulty.
• if fitted -- check connections to battery master switch / isolator - on my 7, the high-current connections were fine, but the smaller spade connections (that connect the fuel pump I believe) were not tight.  Also the earth was dodgy and the lead to the resistor fell off in my hand on disassembly.  I've now replaced the entire switch + cleaned / re-crimped all connections.
• (obviously) check that the immobiliser is disarmed.

I'm fairly sure fixing the master switch addressed the problem for me.

[Myles]

When you say there's no light, is that literal? The LED should show red until rotation is recognised - at which point it will turn green unless I've taken leave of my senses. If you've no light at all, the emerald has no power....

[Jonathan Kay]

As Myles says.

Done any recent work on it?

Check inertia switch and connections including earths and trace feeds with a multimeter.

If you get to the point where you have the ignition light on but the fuel pump doesn't run then check the feed voltage to the pump or run a jump lead to it to test.

Jonathan

 

[7 wonders of the world]

If your running an Emerald and it's been installled correctly you will have 2 positive feeds 1 constant and 1 ign fed though these are often bridged to make 2 ign fed supplies, with ign on you should have the red light on the emerald if not the ECU has lost its feed.

It has no connetion with inertia switch or pump, simply ign fed live, when mine lost its feed mid way through a mapping session I traced it to yet another duff solder conection in the Rover loom !!

you can donwnload the pinnout diagram etc from Emerald and set to work with a multimeter and a pin probe.

Try  a wiggle test to see if with the ign on you can get thered light to flickle - this will give you an idea as to which area of the loom the falut lies.

 

[tomperkins]

Thanks for everyone's comments, glad the helpful nature of the community still exists on the new site.

There's no light at all on the ECU so it sounds like we can conclude its a power issue to the ECU rather than a sensor not working.

I'll take a look with a probe and have a look at the wiring diagrams and see if we can work out what's going on.

[oilyhands]

Pins 11 and 28 should have power when the ignition is on. Check the earth from the ECU (pin 29) .

Oily

 

[tomperkins]

So we found the problem. Turns out someone had installed a connector in the look that runs through to the block that connects to the ECU. This was giving a dodgy connection. We replaced this with a sound connection but there was still an issue somewhere further up the line between the ECU and the ignition. We therefore ran a bypass connection from the ignition to the loom going into the ECU solving the issue.

Thanks for everyone's thoughts on this one.

[Jonathan Kay]

Well done, thanks for the update.

Jonathan