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DISCOVERY TD5 - ECU
jimmyjoebob - 9/1/15 at 10:39 AM

Suspected ECU failure - misfire present with fault codes reading peak charge too long for one of the injectors, and two other injectors reading open circuit.

Sent off for analysis and all input/output circuits checked out ok but inconclusive test as no real time simulation could be performed.

Can anyone recommend a company that can definitively test it?


pewe - 9/1/15 at 11:01 AM

I used these guys some time ago.
They were very helpful and prices reasonable.
ECU Testing
HTH.
Cheers, Pewe10


DW100 - 9/1/15 at 11:21 AM

The most effective, definitive testing is done on the car. Using something like a Picoscope.

None of the ECU testing companies I've come across have any facilities for simulating anything like true running conditions.

Most can't even run them in the true sense as you have found out.

I would be running tests on the wiring loom for open circuits and shorts etc.

Then testing outputs both at the injectors and ECU with picoscope to pin down the fault.


jimmyjoebob - 9/1/15 at 11:21 AM

Thanks for that Pewe10


jimmyjoebob - 9/1/15 at 11:31 AM

Thanks DW100.

The injectors were replaced with known good ones and the ecu recoded. The misfire was still present with the same codes re-recorded.
The ECU was removed for testing whilst the engine bay loom has been removed and visually inspected.

I will try to collect the loom so I can work my way through it as you suggest


Dick - 9/1/15 at 12:12 PM

Only ever had to replace the discovery ecu when it has oil ingress so would say has it got oil in it would be my first check.
Now the wiring loom is different kettle of fish we have replaced loads of these


jimmyjoebob - 9/1/15 at 12:25 PM

Hi Dick,

The ECU showed the beginnings of oil ingress.

The in-head loom was replaced within the last 200 miles with a genuine LR item. The engine bay loom is the original however. The car has had the EGR removed by a previous owner.


Dick - 9/1/15 at 01:00 PM

The removal of the egr is the best thing you can do. If the loom has been replaced check the plug connection as the pins push back. Oil in the ecu can be the death of them this was an early problem with the discovery.
The oil would travel down the internal of the wiring . ODD yes but true
If you still need it checking then bba say they can do them
Good luck


Slimy38 - 9/1/15 at 01:21 PM

quote:
Originally posted by Dick

The oil would travel down the internal of the wiring . ODD yes but true



Sadly not unique, my friends old Passat died in the same way. It wasn't something I'd heard before (and just seemed totally bizarre), but it cost him a fair bit to fix.


jimmyjoebob - 9/1/15 at 01:23 PM

Thanks Dick.

I have spoken to several ECU testing places and it's the real time simulation of injector running that most can't do


kevmcdo - 9/1/15 at 05:32 PM

What year is your td5?

When you replaced the in head loom did you flush out the lower part of the loom, it can take a few days to clear if spraying the connector plug where the top loom connects.

I may have a known good loom in my garage that was removed from a good running 02 plate.


jimmyjoebob - 9/1/15 at 05:42 PM

Hi kevmcdo,

It is a '53 plate TD5 manual.

It was pretty thoroughly cleaned but i'd be interested in buying your spare. If you can u2u me a price incl p&p I'd really appreciate it!


perksy - 9/1/15 at 08:43 PM

Have you tried ATP ?

www.atpelectronics.co.uk


Had an intermittent ECU fault on a Rover K series engine and their test rig simulated the loads etc and found the fault


jimmyjoebob - 11/1/15 at 12:14 AM

Hi perksy,
I'll give them a call next week.
James