TD5 no start woes...Nanocom RPM while cranking.

Hi All

I have a 2001 D90 TD5 which has just decided not to start overnight. The fuel pump runs as normal and it cranks with enthusiasm but makes absolutely no attempt to start. I've hooked up the Nanocom and all looks normal except that the engine RPM reads 0 when cranking. Suspecting the crank position sensor, I've changed it - still 0 RPM. I've now checked the wiring fro the sensor to the ECU (continuity on both wires and 1.3k Ohms at the ECU end, which feels about right). The fuel pumps appears to be working okay although I don't have a pressure tester (pumps about 1 pint of fuel at the regulator in about 5 seconds). The injectors all click audibly when use the Nanocom test function and there's no sign of oil in the ECU end of the loom.

Is it normal to get 0 rpm when cranking or is that definitely my issue?

I'm out of ideas...and assistance much appreciated!

Hi it appears as though the crank sensor is at fault although it isn’t as you have checked it, I would say your ecu may be faulty

Discodevon said:

Hi it appears as though the crank sensor is at fault although it isn’t as you have checked it, I would say your ecu may be faulty

Click to expand...

Thank you. That would certainly make sense as I can't find anything else wrong.
Any idea what RPM it should show when cranking?


Luckily, I had my ECU rebuilt a couple of years ago and it now has a lifetime warranty! I'll send it for testing...

Damon482 said:

Any idea what RPM it should show when cranking?

Click to expand...

You should see above 250rpm to start

sierrafery said:

You should see above 250rpm to start

Click to expand...

Thank you, both. I think that's definitely the issue, then, as Nanocom shows 0 whatever I do. Saves me pulling the fuel system apart looking for a problem.

An aditional test you can do as you already know where the wires from the CPS ar going is to measure voltage on the wires while cranking, you should get around 3V AC if the circuit and sensor are OK and then you can definitely blame the ECU

ECU failure seem to be more commonplace now, although when mine failed the fuel pump didn't run

Do you get the engine management light when you turn on the ignition?

lightning said:

ECU failure seem to be more commonplace now, although when mine failed the fuel pump didn't run

Do you get the engine management light when you turn on the ignition?

Click to expand...

When my ECU packed up last time, everything was totally dead. This time everything seems normal except not starting. Fuel pump runs, no EML and no faults on Nanocom.

I presume I check the CPS voltage by 'backprobing' the plug while it's attached to the ECU?

Damon482 said:

I presume I check the CPS voltage by 'backprobing' the plug while it's attached to the ECU?

Click to expand...

For a relevant result you'll have to unpin the wires or try with ECU unplugged

If there's no EML when you turn on the ignition, then it's probably the ECU

The EML should come on when you turn on the ignition, then go off after a few seconds.

lightning said:

If there's no EML when you turn on the ignition, then it's probably the ECU

The EML should come on when you turn on the ignition, then go off after a few seconds.

Click to expand...

Apologies...I misunderstood. The EML comes on initially as normal, but then goes out.

Thanks for the advice.

I've recently learned that the ECU can be faulty while still behaving as if everything is OK (apart from not starting the engine, of course).

It'll communicate with the Nanocom and show no error codes, and the fuel pump will run and dash lights will be as expected, but it will crank all day, and just won't fire up

BulletBrindle said:

....but it will crank all day, and just won't fire up

Click to expand...

Which is normal as long as the rpm reading is 0 and no need to crank it in vain untill you get above 250 regardless of what's at fault

Solved!!

ECU returned having been repaired under warranty and now starts first time again.

Thanks all for your advice. This forum never fails me.