Defender TD5 ECU issue

Locko · Nov 10, 2019

Hello,

I have a Landrover TD5 ECU NNN000120 that will not trigger injectors after is got a bit wet!

I dryed it out and found 2 transistors (IRL 540n) they were burnt out, I replaced them and they blew again straight away.

Any ideas why or what to check?

EeEk · Nov 10, 2019

No but if seen the "not trigger injectors after is got a bit wet!" before. I just swapped the ECU. had a look in the old one but didn't see anything obvious.

v8landyman · Nov 12, 2019

Why have you disconnected the big Rifa capacitors?

Locko · Nov 12, 2019

v8landyman said:
Why have you disconnected the big Rifa capacitors?

I disconnected them to test them both at the 1000uf is charged to 80v by the two transistors switching rapidly....

anyway ecu fixed now some other small issues now fixed too...

1 crank sensor signal was terrible om the scope so removed it to find it full of water ( now surprise ) and replaced

2 drained water from inter cooler that was full.

3 replaced 4 dead glow plugs (shouldn’t stop it starting but needed doing all the same..

thought I would test the fuel as it was in water a long time and this is what I found....

the sample on the left is from my 300tdi... the sample on the right is from the TD5 !!

Locko · Nov 12, 2019

I’ve now drained the tank and will replace the fuel filter tomorrow and fill with fresh derv and see if it starts... I think it will!!!
Next time I go deep wading I will take the 300tdi

Locko · Nov 25, 2019

Ok......

Still won’t start, replaced the fuel pump and checked pressure by removing fuel temp sensor and measuring a constant 4 bar

any ideas much appreciated.

I’m at my wits end !

Locko · Nov 25, 2019

This is the crank signal I am getting does it look ok?

Locko · Nov 25, 2019

Well I’ve been out in the wind and cold all day and it still won’t go!!!

Anyone out there got any ideas at all????

HELP

Si Click · Nov 25, 2019

What DTCs are you getting?

Given that your intercooler was full of water are you quite sure the engine was not hydrostatically locked?

Locko · Nov 25, 2019

Si Click said:
What DTCs are you getting?

Given that your intercooler was full of water are you quite sure the engine was not hydrostatically locked?

Hi,

Thanks for your reply... I removed the glow plugs before attempting to start it but there was only water in cylinder number 1.

I get crank sensor noisey?

Si Click · Nov 25, 2019

Locko said:
Hi,
I get crank sensor noisey?

There's your problem right there. The ECU will allow the engine to crank but will not fire the injectors unless it has a clean crank position sensor signal.
If you put a new one in then it may be the screened wiring that is full of water. It may all dry out on its own, but you may have to run a new screened cable from the ECU red plug to the sensor.

So was the vehicle parked when it flooded or did you drive into it? If the engine was running when water got into No 1 cylinder the pressure could have done all kinds of damage.

Locko · Nov 25, 2019

Si Click said:
There's your problem right there. The ECU will allow the engine to crank but will not fire the injectors unless it has a clean crank position sensor signal.
If you put a new one in then it may be the screened wiring that is full of water. It may all dry out on its own, but you may have to run a new screened cable from the ECU red plug to the sensor.

So was the vehicle parked when it flooded or did you drive into it? If the engine was running when water got into No 1 cylinder the pressure could have done all kinds of damage.

hi,

I have replaced the sensor twice, once with a cheap on and now I have a OEM one... new connector and screened cable running direct into the back of the red plug.

i drove into water but stopped the engine when the water came into the footwell.

runs fine on easy start with no nasty noises?

I can see a good sensor signal on the scope

gymmaniac · Nov 25, 2019

injectors blocked?

Locko · Nov 25, 2019

gymmaniac said:
injectors blocked?

They could be but the ECU will not fire them... they have been manually actuated on the diagnostic machine

Si Click · Nov 25, 2019

If you are getting a DTC of crank sensor noisy then for whatever reason the ECU is not seeing a clean signal. Does it run fine if you bump start it? If so this would point to the sensor and cable being OK, but perhaps you have damaged the starter. In some cases, even if the engine is turning over fine, electrical arcing from the solenoid contacts can cause interference with the crank sensor signal and prevent start. However, if you start without using the starter it runs happily. You might want to pull the starter, check the contacts and install a £10 solenoid repair kit, or at least dry it out.

Locko · Nov 26, 2019

I have replaced the starter for brand new one after reading that it can cause interference... it made no difference at all.

Locko · Nov 26, 2019

Si Click said:
If you are getting a DTC of crank sensor noisy then for whatever reason the ECU is not seeing a clean signal. Does it run fine if you bump start it? If so this would point to the sensor and cable being OK, but perhaps you have damaged the starter. In some cases, even if the engine is turning over fine, electrical arcing from the solenoid contacts can cause interference with the crank sensor signal and prevent start. However, if you start without using the starter it runs happily. You might want to pull the starter, check the contacts and install a £10 solenoid repair kit, or at least dry it out.

I will try bump starting and let you know

Si Click · Nov 26, 2019

Did you replace the starter after the flood? If so that will not be the cause.
When you replaced the crank position sensor wire did you fix the screening to a terminal and fit into pin 16 on the ECU?

Locko · Nov 26, 2019

Si Click said:
Did you replace the starter after the flood? If so that will not be the cause.
When you replaced the crank position sensor wire did you fix the screening to a terminal and fit into pin 16 on the ECU?

hi thanks for your reply.

yes I replaced the starter after the flood.

I connected screen to pin16 on the red ECU plug and sensor to pins 13 and 36 and have also tried swapping the sensor wires around?

Locko · Nov 26, 2019

It’s driving me round the bend!!!!
Im going to sell it .... any offers?

Defender TD5 ECU issue

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