Idle, hesitation, poor performanc - tech bulletin

Apologies if this is old news, but I have come across a LR Tech bulletin 00052 dated April 2007. The faults must therefore have been occuring well prior to this.

This relates to complaints of:

1. hesitation,
2. poor performance,
3. poor idle,
4. poor starting

The cause is corroded contacts at the fuel rail pressure sensor & ecu.

The fix requires harness YMQ503320 , sensor STC4768, O ring MYX000040
The harness replaces the existing wiring from the ecu to the sensor.

So if you have any of these symptoms and have eliminated the maf sensor, please consider this fix before condeming the injectors or anything else.

You could try some switch cleaner on the pressure sensor contact. If this makes a difference, then the above parts should cure it.

Ron

Hi Ron,

Thanks for the info, and about this subject, I think I've read somewhere in the past of someone who replaced this harness already. I think there was some hassle to replace but in the end all went fine I believe.
Take care and cu.

willo said:

Hi Ron,

Thanks for the info, and about this subject, I think I've read somewhere in the past of someone who replaced this harness already. I think there was some hassle to replace but in the end all went fine I believe.
Take care and cu.

Click to expand...

I think this fault explains why some owners have difficulty in curing those symptoms. In some cases £1000s have been spent changing everything from HP pump to injectors, to ecu to little or no avail.

I wonder whether the 75 & ZT suffer from the same problem as every so often one is encountered with similar symptoms that the owner has given up on.

I think I have also come across another rare fault today. Namely, a sticking egr valve.
The owner (who has owned it from new) had had a new Hp pump & ecu but found today that the garage had secretly blocked the egr actuator pipe off. When he unblocked it the car broke down 1/4mile from home and the egr valve was red hot. (he could not drive it at more than a walking pace.)

I suspect that the original fault was caused by it sticking open and replacing the Hp Pump & ecu had in fact been unnecessary. If stuck wide open, at low rpm the engine will suck hot exhaust gas through the valve (heating it up) and as the boost pressure climbs, air will bypass the engine and pass straight into the exhaust manifold, where it will also prevent the turbo reaching normal speeds. The maf signal will be reduced further affecting the performance.
In addition, when starting, because the maf signal will be very low*, starting becomes difficult as well. (*the engine sucks in exhaust gas instead of air)

We live & learn as they say.
Ron

One for the Q's and A's section, please MODS..

The Mad Hat Man said:

One for the Q's and A's section, please MODS..

Click to expand...

i have a feeling It's already there but I've just added it again anyway.

Ferk this may just be my problem.
See my thread
http://www.landyzone.co.uk/lz/f9/wits-end-88808.html
Will try this at home.

Hello
I am new to this forum and I am trying to find out what is wrong with my wifes Land Rover Freelander -03 mod TD4.
The problems we experience is that the idle is very unstable when we start the engine. Goin from 500rpm to 7-800 rpm at a very rapid interval.
We have had the car to a Land Rover repair center here in Norway and they say it is the injectors (2 of them) needing to be replaced. The costs would be £1500-2000:doh:
But since the problem sometimes seems to be absent (rarely) I doubt that the injectors are the problem. Also the engine responds very hesitatingly to the throtle. But at speed the car runs normally.

Do you think this problems can be connected to the issues in this service bulletin?

Sorry for my bad english but I hope I have made my self understandable.

Hope you have some ideas to share with me
Thank`s

Sandvik said:

Hello
I am new to this forum and I am trying to find out what is wrong with my wifes Land Rover Freelander -03 mod TD4.
The problems we experience is that the idle is very unstable when we start the engine. Goin from 500rpm to 7-800 rpm at a very rapid interval.
We have had the car to a Land Rover repair center here in Norway and they say it is the injectors (2 of them) needing to be replaced. The costs would be £1500-2000:doh:
But since the problem sometimes seems to be absent (rarely) I doubt that the injectors are the problem. Also the engine responds very hesitatingly to the throtle. But at speed the car runs normally.

Do you think this problems can be connected to the issues in this service bulletin?

Sorry for my bad english but I hope I have made my self understandable.

Hope you have some ideas to share with me
Thank`s

Click to expand...

I think to have seen on here that "ginny" took the contact off, sprayed it with WD40 and on the way home the car went on better as new, so why not try this yourself ? As far as I can see it's just a question of unplugging a plug, check whether the contacts are corroded and spray some contactcleaner or WD40 on the contact and in the plug and test ?? Good luck.

Think I may have this issue cheers Ron !

What engines are affected by this wire harness fault?

Bmw td4