Td4 injector

I bought a td4 2003 Freelander which the previous owner said was getting increasingly difficult to start. Once started it ran ok with no apparent mis fires.

I replaced the low pressure fuel pump and filter and checked the fuel regulator O ring which was fine.

I did a leak back test and number three injector pushed out masses of fuel compared to the other three.

I bought a second hand injector and put it in. The engine starts now no problem but rough idles and is miss firing around the 2000 Rev range.

I have run the engine for about five minutes to see if the ecu would learn the replacement injector in. It is better than right at the beginning but still not right.

my question is - will the rough running improve if I give the ecu more time or is the second hand injector also probably shot ?

or do I have another problem ?

any advice welcome. Thanks

Does your misfire happen on or off load?

Off load.

Alloy said:

Off load.

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That's called the 2k misfire and is pretty common, but almost impossible to cure.

Nodge68 said:

That's called the 2k misfire and is pretty common, but almost impossible to cure.

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Any advice ?

Alloy said:

Any advice ?

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I gave up looking on mine, and couldn't definitively put it down to one particular item.
Many other's have also given up looking too, unfortunately it seems to be some issue on this engine, in the Freelander, and other vehicles the engine is used in too.

Nodge68 said:

I gave up looking on mine, and couldn't definitively put it down to one particular item.
Many other's have also given up looking too, unfortunately it seems to be some issue on this engine, in the Freelander, and other vehicles the engine is used in too.

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I am not sure it’s that. The engine was running fine but not starting. I changed the injector after leak off test. Now it starts on the button but initially will not respond to the throttle staying at about 1000 revs. Leave it long enough it will Rev up but with misfires and knocking on idle. It’s undrivable.

my dilemma is is the secondhand injector also knackered or is it likely to be something else bearing in mind I have changed low pressure fuel pump and filter and checked regulator o ring.

also the other question is does the ecu learn in new injectors and maybe it will clear over time ?

any advice ?

thanks

Alloy said:

any advice ?

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If it's undriveable, then it's not the 2k misfire, which is only there when the engine is revved off load, or sometimes just detectable when going down a slight hill, on a trailing throttle.

In you case, I'd suggest the replacement injector has an issue.

Tx

does the ecu learn in new injectors ?

tx

Haven't seen anything to suggest that the ecu learns at all. It might do and adapt to a driving style but doesn't need to do anything to accept a new injector as they are not programmed in any way.
I'd agree with above, replacement is faulty, or the O ring or copper washer leaking. Did you replace them as the washers compress??

Why not unplug the replaced injector and if engine is much the same there is your fault?

Makes sense. Do I simple take the electrical connector off or fuel supply and returns ?

tx

Alloy said:

Tx

does the ecu learn in new injectors ?

tx

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No. It doesn't really need to learn the injectors as such, and doesn't need to be programmed with injector specs like later diesels.

On the TD4, when the engine is running, the EDC monitors the evenness of pulses from the crank sensor, so is able to apply a compensation value to individual injectors, adding or removing fuel volume as required. However this compensation is only needed up to about 1500 RPM, above which any slight changes in injector characteristics aren't an issue, as the flywheel will smooth out any imbalance.

If you have an injector issue, then some advanced diagnostic equipment can give the injector compensation values on screen, which can be used to identify if an injector is a long way out.

However as your misfire only started after that injector was installed, it stands to reason that the replacement injector is causing the issue.

Alloy said:

Makes sense. Do I simple take the electrical connector off or fuel supply and returns ?

tx

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Only unplug the injectors when the engine is off, as damage can be caused to the engine, EDC or injectors, if the engine is running, when the plug is removed.
You leave the fuel lines alone though.

That’s brilliant advice. Thank you.

one final thing. Despite assurances from the seller that the secondhand injector would fit my manual td4 I see that it is actually different where the nozzle fits the main body. The new (secondhand) one has a cross plus a tube with tiny disc spacer but the 4 originals have neither the cross design or spacer arrangement. I attach photo. Would this explain the problem?

the original product number is 0445110049
The secondhand nu is 0445110130.

thanks

49 is manual and 130 is for an auto I am pretty sure.

As you have had the injectors apart are you sure that everything went back as it should? I have an auto running a set of 4 x 049 injectors no problem. What an odd one does to the ecu I am unsure.

I'd conclude that the replacement is duff or incompatible and get a known good one. Save time in the end!!