Td5 ECU swap using Nanocom

[d1scv]

Put simply- my Td5 auto 2001- is down on power, and tends to misfire when cold. Chucks out grey smoke,when cold.

Checked all the usuals:

Maf- good readings

Map- good readings

Cylinder balance OK- apart from when misfiring at cold.

Have noticed that track 3 on the throttle hardly varies with the engine running. Moves OK with just the ignition on.

No sign of oil in the harness.

So- want to trial a known good ECU using nanocom.

Not going to try changing the map.

Can anyone give a guide as to how to 'learn security' and possibly write injector codes using nanocom.

Nanocom site very vague about exactly how to change ECU. Thanks Tony

[BogMonster]

I would change the injector harness and not bother with anything else until you have done that. After that I would look at the fuel pressure.

To make a Td5 run with a replacement ECU you only need what you describe - security code learn and write the correct injector grades. At a basic level nothing else is required as long as the ECU is right for the age of vehicle (pre 02 or post 02).

I don't think the pedal will be causing the fault - if the ECU can't make sense of the pedal output it trips a "driver demand" fault code and defaults to idle, so pressing the throttle has no effect at all.

[d1scv]

I would change the injector harness and not bother with anything else until you have done that. After that I would look at the fuel pressure.

To make a Td5 run with a replacement ECU you only need what you describe - security code learn and write the correct injector grades. At a basic level nothing else is required as long as the ECU is right for the age of vehicle (pre 02 or post 02).

I don't think the pedal will be causing the fault - if the ECU can't make sense of the pedal output it trips a "driver demand" fault code and defaults to idle, so pressing the throttle has no effect at all.

Thanks for your suggestions.

I forgot to mention that my ECU has no faults logged. Which is making me wonder.

Would not either the harness or fuel pressure problem throw up a fault or at least bad cylinder balance.

The red plug and cylinder head plug are both clean

[BogMonster]

You will usually not get faults logged with either harness or fuel pressure - though if the plug on the head is clean that makes it less likely but still not impossible.

How long have you had the vehicle / do you know when/if this harness was last changed? Unless it has been done recently I would still suspect it, oil showing or not, and the official story that it only happens to early vehicles is bllx.

[d1scv]

You will usually not get faults logged with either harness or fuel pressure - though if the plug on the head is clean that makes it less likely but still not impossible.

How long have you had the vehicle / do you know when/if this harness was last changed? Unless it has been done recently I would still suspect it, oil showing or not, and the official story that it only happens to early vehicles is bllx.

I am going to have to bit the bullet here and replace the harness, just to clear up the possibility. Don't know if it's been changed, but there is not a trace of oil at the ECU.

Will also carry out a fuel pressure test as you have suggested.

May I also crank up the question.

Nanocom shows my injectors as:

NG GB 3-G-A

BE GF 4-H-*

NL GD 6-K-*

NB LD 5-J-*

NN LN 5-J-*

Injectors are actually marked:

NGGBG

BEGFH

NLGDK

NBLDJ

NNLNJ

If we take No 1 injector [for example] where has the '3' and the 'A' come from.

If I could get a grasp of this I'd be in able to walk on my own!

[cipx2]

.... there is not a trace of oil at the ECU.

...

Hang on a bit.

There are two looms/harnesses:

- the injector loom/harness - the one BM speaks about and the one that should be checked/replaced first as it's the root cause; it costs about 40 pounds

- the engine harness - the one that the injector loom connects to and goes to the ECU.

Usually the misfiring or other glitches occur when there's oil in the injector loom but the oil doesn't get that far as the ECU. So checking for oil presence only at the ECU doesn't exclude "the oil in the loom fault".

In case you didn't do that already, you should check for oil in the connector in 14th picture you'll find in this thread: http://forums.lr4x4.com/index.php?showtopic=42788

I second the 2 things you should try:

-replace injector loom - given you know nothing about it, even if it's not at fault, sooner or later it will give up, so it will be 40 pounds well spent.

- fuel pressure (fuel pump in the tank, faulty pressure regulator etc)

[d1scv]

I second the 2 things you should try:

-replace injector loom - given you know nothing about it, even if it's not at fault, sooner or later it will give up, so it will be 40 pounds well spent.

- fuel pressure (fuel pump in the tank, faulty pressure regulator etc)

Thanks, I will be replacing the injector loom- even though I can see nothing wrong. Have already fitted new pump/ injector seals etc.

Will be checking fuel pressure. Probably will replace regulator just to eliminate.

Still trying to understand the detail of trialing another ECU. I've just got it locked in my head that this is where my problem is.

But I do not discount any ideas. Tony

[BogMonster]

Yes sorry I meant the injector loom, not the main harness (which is about 500 quid)

Fuel pressure should be 4bar/58psi we check it by taking out the fuel temp sensor and putting in an adaptor.

Injector grades - no idea - T4 shows the 5 letters but maybe it filters the extra info, I've not used a Nanocom - maybe that is normal.