Thread: ENGINE SYSTEMS FAULT......HELP

Only guessing but perhaps one or both turbos (my 2nd doesn't seem to operate at 110-115 kph) is/are being backed right off on any reduction in throttle and therefore needing to build pressure from scratch again. A risk with software patches, regardless of whether they are for a commercial computer system or for an ecm, is that sometimes they are not sufficiently tested to be sure that no unintended actions occur. Regardless, I'd be following this up with a dealer.

Originally Posted by Disco4SE

Graeme, I was backing off very slightly rather than taking my foot off completely. In the past, the vehicle would back off slightly in sync with my foot pressure.
Now it is backing off to the point where I have to apply the accelerator to maintain speed.

Any clues??????????

Cheers, Craig

Had my D4 back to the dealer today to check out the 'backing off the accelerator' problem. When I phoned them last week, they thought that the patch that Blacklocks Albury did, may not have been installed properly. Either that or they may have knocked a hose / wire etc.

When the mechanic hooked it up to the analysis machine, a heaps of code faults appeared???? At this stage he suspected a problem with the battery. With that, he took it for a test drive with lights, air con, etc going to try and drain as much power as possible.
Upon his return, he found that the battery was showing very low voltage.

The end result was replacing the battery with a new one. The mechanic said that he has seen this happen at around 100K but not at 80K.

Apparently the Disco's depend on high voltage and can suffer various problems if battery is faulty.

Would appreciate others comments on this.
BTW: I have a dual battery system.......Redarc with Optima battery.

Cheers, Craig

Originally Posted by Disco4SE

The mechanic said that he has seen this happen at around 100K but not at 80K.

Planned obsolescence after end of warranty kicked in a bit early!

Is the negative terminal for the dual battery system connect to a vehicle earth or the main batteriy negative terminal?

If to main battery negative terminal than this can cause the problem you describe.

Originally Posted by RoverLander

Is the negative terminal for the dual battery system connect to a vehicle earth or the main batteriy negative terminal?

If to main battery negative terminal than this can cause the problem you describe.

I'll have my auto elecrtician check it out (the one that set up the dual system).

Cheers, Craig

Originally Posted by Disco4SE

I'll have my auto electrician check it out (the one that set up the dual system). Cheers, Craig

Your electrician might think that grounding to the body does not matter or does not make sense. He is almost correct when he says it does not make sense, but it does matter.

Normal vehicles ground to the body pretty much as an after thought and for the most part, primarily to the engine block. I can only assume that the computers that are strewn about the 3 do not like that technique as I would anticipate that there would then be millivolt currents running thru the body.

You run into that in aircraft where you have shielded cables. You can only ground a cable shield on one end - ground both ends and currents start to flow in the shielding and the radios pick it up.

You have probably noted that there seem to be an inordinate number of proper ground studs throughout the 3. Land Rover must think they are needed, as at some point, the cost of providing them adds up.

My second battery mounted in the "other side" battery box using the Traxide system is grounded to a nearby stud that Land Rover provided. For a third battery, now that is when it would get interesting.

Originally Posted by RoverLander

Is the negative terminal for the dual battery system connect to a vehicle earth or the main batteriy negative terminal?

If to main battery negative terminal than this can cause the problem you describe.

Roverlander, I had my auto electrician chack out all connections etc. The second battery negative is connected to the chassis, not the main battery earth.
The redarc system is working how it should.
Its obviously the battery.

BTW: The auto electrician mentioned that he has had a few recent model Mercedes etc come in with buggered batteries.

Cheers, Craig

That's the third D4 with a RedArc system I've heard of that's killed the battery. Are they rated to handle the D4 charging voltages and currents? Or are they not being installed correctly?

Cheers,

Gordon