Member Since: 03 Sep 2021
Location: L117ad
Posts: 8
Traditional Cascade Failure
Hi All
Wonder if you can shed some light on a Disco 3 with a random Cascading Fault / limp mode.
It’s very random and can happen after 1 mile or 10 miles and doesn’t really matter if your full sending it or driving like miss daisy it throws the typical Transmission Fault - Limited Gears Available. Suspension Lowered. Engine System fault. All the usual.
I have done:
Full Service Including new fuel filter
Found the bad splice in passenger sill loom and it was not even connected. Repaired. This Cleared some instrument cluster codes etc
Found evidence of water ingress in the TCM plug hole - PCB is fine and cleaned the pins and removed all the oxidation/water corrosion all looks clean and reinstalled. Same issue.
Cleaned all sensors I can get to on top and sides of engine. MAF etc
After clearing all codes - There’s a few codes stored after the limp mode event and they are;
Any help would be appreciated!
3rd Sep 2021 5:19 pm
aja4x4
Member Since: 14 Apr 2019
Location: Westbury
Posts: 2459
This is quite a common fault and be caused by a number of faults, i think the most common one is a failing low pressure fuel pumpAndrew
D3 2.7tdv6 2005
D4 3.0 SDV6 Commercial died and gone to LR heaven
D5 3.0 SDV6 HSE
3rd Sep 2021 6:10 pm
Daley2021
Member Since: 03 Sep 2021
Location: L117ad
Posts: 8
Managed to clear some more codes - only have one on engine ecu now
Injector control pressure too low
Hpfp?
One of these must be triggering the shutdown just need to eliminate them 😕
3rd Sep 2021 7:54 pm
aja4x4
Member Since: 14 Apr 2019
Location: Westbury
Posts: 2459
What fuel filter did you use? These vehicles can be a bit fussy.
You need to check your Lpfp first as its a common failure and will directly influence the high pressure pump.
D3 2.7tdv6 2005
D4 3.0 SDV6 Commercial died and gone to LR heaven
D5 3.0 SDV6 HSE
3rd Sep 2021 10:20 pm
Daley2021
Member Since: 03 Sep 2021
Location: L117ad
Posts: 8
Fussy to say the least!
Spent a few more hours on it yesterday. Found a bit of a diesel leak on both sides of the engine.
One of the fuel pipes to an injector was loose on the left side. Tightened up. Dry now.
One of the fuel pipes to another injector on the other side at the fuel rail was loose. Tightened. Dry now
The main fuel feed to the fuel rail on the right was loose. Tightened and dry now.
It’s now quite happy under heavy load tbh and doesn’t really go into limp when your giving it some beans - get about 6 miles of driving but when giving it some slight throttle when low down - it errors then. Does seem fuel related tbh and the lpfp is looking like the culprit.
Fuel filter fitted was a Mann filter - made no odds really it went in to limp soon after.
Current codes:
You can clear all codes and drive for 5 mins and before the limp event there are still no codes present.
When it goes into limp the above codes are stored.
On red light - pressing the little bleed valve on top out fuel - but gunna crack on with that guide you sent and try isolate whether it is the lpfp dropping pressure now and again when not under heavy load. When running the fuel rail pressure sits around 25000kpa and climbs to around 40000kpa around 2500rpm - it gives a false of security that the fuel system is fine but something clearly isn’t!
Otherwise it pulls like a train and shifts through all her gears no problem - hard to think something serious is wrong considering how well it behaves out of limp. after finding all the usual splices etc, brake switch looks clean and fresh - unplugged and replugged all the connectors under glovey and they look brand new.
Thanks All
4th Sep 2021 11:13 am
BradC
Member Since: 29 Apr 2019
Location: Perth
Posts: 118
I had similar symptoms and it turned out to be the HPFP. Specifically the PCV was "sticky". If you gave it a decent boot there was never really an issue, but a gentle request for more juice would see the PCV stick resulting in various faults.
Best explained as "cruising on the flat with cruise control on and then hitting a gentle incline". Would trigger it every time.
I spent weeks watching it on the Gap IID graph view before I pulled the trigger on the HPFP.
Just a random anecdotal data point for you.
4th Sep 2021 11:25 am
Daley2021
Member Since: 03 Sep 2021
Location: L117ad
Posts: 8
Thanks mate
Indeed replicating giving it just a gentle throttle does throw the error straight away more or less
If you drive like a mad man it’s fine!
During take off fuel pressure:
Just before limp
During limp event
Vehicle now showing Transmission F/ Engine System Fault / Suspension lowered etc
Then the pressure climbs again - at pace
4th Sep 2021 6:17 pm
BradC
Member Since: 29 Apr 2019
Location: Perth
Posts: 118
Yeah, the characteristic is the PCV shooting up to %55 and the pressure not materially increasing (or dropping because the car really wants more). If it sits there for ~2 seconds you get the fault. With the Gap I was able to watch the live graph and when I saw the valve spike open I could get off the throttle before the fault happened. I could then stab the throttle hard and get it past that point.
Not entirely "keeping ones eyes on the road" however. I found once it faulted it took another couple of seconds for the fault to "cascade" so I could cycle the ignition to reset the ECU and keep rolling (mine is a manual) before the fault hit the other systems.
5th Sep 2021 3:11 am
Daley2021
Member Since: 03 Sep 2021
Location: L117ad
Posts: 8
Thanks for your reply Brad
Really does sound far too similar - I do now suspect the hpfp blipping as it drops to 13000kpa when it throws the error which is way below what it hovers around at idle (24k 25k kpa)
Hpfp looks like a pig to replace 😒 trying to weigh up the cost of the stress of trying to do it myself vs paying another poor soul - how much did yours cost all in mate?
5th Sep 2021 11:16 am
BradC
Member Since: 29 Apr 2019
Location: Perth
Posts: 118
I did it myself.
All in it was about $1750 AUD for a brand new pump, pair of high pressure lines, the single use bolts and a new rear belt and tensioner. Took me about 9 hours over 4 days (never having really wrenched on the car before) and numerous beers, but 3 of those were trying to figure out how to get the the bloody crankcase breather chamber out.
I reckon now I could do it in 5 and if you know a teenage double jointed russian gymnast to do some of the work you could cut another hour off.
I was quoted $2.5k to get it done, so I didn't save a lot but I learned enough to make it worthwhile and I positively know it was all done correctly.
Edit: I could have saved some $$$ sourcing the pump from the UK, but the extra for "available in 2 hours" and 2 year local warranty trumped cost.
5th Sep 2021 1:48 pm
Daley2021
Member Since: 03 Sep 2021
Location: L117ad
Posts: 8
That’s quality the double jointed Russian gymnast haha - getting down the back of these v6s is a nightmare.
You can pick up second hand hpfp for stupidly cheap or a refurbished hpfp for a reasonable price too here local to me in uk.
I’m gunna test the pressure at the lpfp today for a laugh and go from there
5th Sep 2021 4:29 pm
BradC
Member Since: 29 Apr 2019
Location: Perth
Posts: 118
I made up a gauge adapter for the schrader valve and cable-tied it to the drivers side windscreen wiper, then went for a long drive to reproduce the fault just to make sure the fault wasn't the low pressure side.
I saw (and still see) it drop into vacuum on a full beans 3rd gear pull up a hill, but it never budged when the fault occurred. In fact I could comfortably drive the car with the low pressure fuse out entirely with a fault only occurring if I really put the boot in.
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
not even connected. Repaired. This Cleared some instrument cluster codes etc
