Thread: Engine power loss/limp mode TDV8

Sounds like my 3.0 experiences unfortunately - keep revs low with minimum throttle, up-shift manually to get the most out of the miserly fuel allocation then wait for the next down-hill run to get some speed up.

I'm heading into the Simpson in a few weeks so have acquired a spare solenoid for the secondary turbo isolation valve because a few have started to fail and if mine goes then limp-mode wont be of any use on the sand-hills. The 4.4 has a similar solenoid but has to be bought with all the vacuum tubes so I'll see if the 3.0's can be used on a 4.4 if it doesn't get used on the 3.0.

I would be interested in knowing in what way your EGR valve has failed and any ideas as to why. I wonder if too much time running on light throttle leads to it clogging or if there's a design deficiency, noting that the valve has been superseded and fitted to the L405's 4.4 even by the end of 2012.

Can EGR valves be removed or bypassed with the newer diesels? Eg 3.0, 3.6 or 4.4?
I'm assuming a customs map would be required.

I don't know whether the 3.6's can be blocked but the 3.0 cannot and I suspect the 4.4 neither without triggering engine faults. The 3.0 compares MAP values with MAF values and EGR percentage open and flags a fault is the equations suggest that something is amiss and with the 4.4 being of the same generation, I suspect the same rules will apply. However there are sources for ecm maps for both the 3.0 and 4.4 that effectively disable the EGR valves in normal use but the valves still have to physically move when checked at start-up or shut-down, possibly achieved by having altered the minimum coolant temperature for EGR to be used to an excessively high temperature.

I looked into blanking plates for the 3.6 and they're not available. I assume from that it's not a good idea.

A few weeks ago I noticed on the 3.6 higher fuel consumption, a bit of black smoke and soot build up on the rear plastic mud flaps.

My mechanic suggested a product called Revive engine/turbo/EGR cleaner. Now the motor is quieter, more responsive and not leaving soot on the rear mud flaps.

Maybe this might help.

Originally Posted by Graeme

Sounds like my 3.0 experiences unfortunately - keep revs low with minimum throttle, up-shift manually to get the most out of the miserly fuel allocation then wait for the next down-hill run to get some speed up.

I'm heading into the Simpson in a few weeks so have acquired a spare solenoid for the secondary turbo isolation valve because a few have started to fail and if mine goes then limp-mode wont be of any use on the sand-hills. The 4.4 has a similar solenoid but has to be bought with all the vacuum tubes so I'll see if the 3.0's can be used on a 4.4 if it doesn't get used on the 3.0.

I would be interested in knowing in what way your EGR valve has failed and any ideas as to why. I wonder if too much time running on light throttle leads to it clogging or if there's a design deficiency, noting that the valve has been superseded and fitted to the L405's 4.4 even by the end of 2012.

The 4.4 has only the one EGR, yes?

I'll carry your query to the dealer re why it failed, but beyond that you're all leaving me behind technically, and I'm in no way interested in interfering in factory settings by blanking valves etc on a near new car.
It may or may not be clogged due to light throttle use, I don't know. Most of my driving is in the city, relatively short distances - 15km or less - so that may have something to do with it, although the it does get some good long runs in, many hundreds of kms at a time. I would have thought that any potential problems would be picked up with the SDD scan at each six monthly service. (Yes, every six months, event though I might do only 5,000km in that time).
I just want the thing to run as it should, the way it was meant to when it left the factory.

As an aside, I suspect that such is the rate of advance in technology, and the equally rapid integration of computer science with mechanics and physics, it is little wonder that even the most well trained LR technicians struggle to keep up. Particularly when such advances and integrations can be deployed almost instantly around the globe. So I appreciate the knowledge this forum gives me, going into discussions with the dealer's technical people, it pays to be able to at least talk a similar lingo.

Yes, just a single EGR valve drawing exhaust gases from the right exhaust manifold.

No warning can be obtained for an EGR valve that is getting close to sticking from excessive carbon or corrosion build-up. However your's must be stuck hard or has broken parts to fail permanently and without any previous incidents.

Originally Posted by Graeme

Yes, just a single EGR valve drawing exhaust gases from the right exhaust manifold.

No warning can be obtained for an EGR valve that is getting close to sticking from excessive carbon or corrosion build-up. However your's must be stuck hard or has broken parts to fail permanently and without any previous incidents.

Is there any point in trying Revive as suggested by one of the guys earlier in this thread?

If the vehicle is still covered by warranty then I'd get it replaced rather than try to make it work again. You'll get the latest version of the part and it can start its life all over again from new as they don't last forever. Perhaps they'll decide that the attached EGR cooler needs to be replaced at the same time, which could be a good move if there's any corrosion from the exhaust heat.