Member Since: 13 Dec 2016
Location: Limerick
Posts: 111
Disco 3 Woes!! help!! :D
Hi Lads,
Appologies in advance for the long windedness of this but I want to be thorough in order to give a decent representation of the faults.
I picked up the Discovery 3 last week, previous owner stated it stopped on the motorway and refused to do any more than idle. He brought it to a mechanic who apparently had the injectors tested, and all were ok, he also checked both timing belts were still intact.
I arrived to collect it, plugged it in.
-it appeared to only run on 3 cylinders (drivers side bank), barely idling, no response from accelerator pedal.
-All injectors showed 999 (im assuming this is pressure related but not sure?)
-The rail pressure was fluctuating between 34-36MPa (a bit low i think from research but unsurprising seeing as it barely idled).
-With it barely idling, I was able to unplug the front injector on the P/Side with no change in engine note, but as soon as i disconnected the front one on the D/Side, it died.
Loaded it and brought it home, been messing with it since.
-I have found that turning it over it will try on a few cylinders to start, and the starter wont labour as much, so while the engine is being cranked, i can disconnect all 3 P/Side injectors with no change to this (my reasoning is that the starter would struggle more if one of those injectors was firing).
-So, i have swapped all 3 injectors on the P/Side with known good injectors, no change.
-I have cracked an injector and cranked to prove good fuel pressure to that bank.
-I have checked for lift pump pressure (approx 0.4bar, not ideal but surely enough for it to start and idle?)
-I have checked continuity between the injectors and the ecu plug, all good.
-Fuel filter looks new, previous owner stated the mechanic replaced it (Mahle filter).
-I have run an injector on the p/side bank, outside the cylinder, it doesnt fire.
My current best guess is the ECU is fault and not firing the P/Side bank of injectors, so getting that tested today, but has anyone got any suggestions or come across these symptoms before?
Cheers in advance!
Lockey
13th Dec 2016 10:47 am
Lockey
Member Since: 13 Dec 2016
Location: Limerick
Posts: 111
Heres a look at the logged codes when i plugged it in originally
13th Dec 2016 5:40 pm
Lockey
Member Since: 13 Dec 2016
Location: Limerick
Posts: 111
Anyone?? Starting to run out of ideas now. Have tested compression, all good. Now swapped all injectors and no change, ECU has been checked and is good also.
21st Dec 2016 9:58 am
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10365
ensure there is fuel pressure in the passenger rail.
That rear rail could be broken.
or
put a test lamp on a passenger injector and see what happens when you crank.
either no electric supply or no fuel supply
Last edited by Pete K on 21st Dec 2016 1:14 pm. Edited 1 time in total
21st Dec 2016 1:12 pm
Lockey
Member Since: 13 Dec 2016
Location: Limerick
Posts: 111
Have cracked the injectors on the p/s rail and proved fuel pressure is present
21st Dec 2016 1:14 pm
kiwirich
Member Since: 02 Oct 2011
Location: Sydney
Posts: 99
Maybe
Hi Lockey,
From the Wiring diagram, all the injectors are fed from the same supply.
If you have any working then they all should work electrically.
You've already swapped them over and proven the Injectors themselves.You've also checked the ECU (In another vehicle?)
I think you're only left with a Wiring fault i.e.. one side not supplied at all
I'd be looking for a crap connection somewhere.
RichardHONI SOIT QUI MAL Y PENSE
22nd Dec 2016 1:15 am
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10365
Having looked at the wiring diagrams, each injector wire goes directly back to the ecu.
There are no joints.
There is nothing common to one bank.
24th Dec 2016 11:58 am
kp
Member Since: 27 May 2011
Location: Sticking the Ex back in the skanks bin
Posts: 2824
It Deffo sounds like a wiring issue to me.
If you have
Removed an injector from the head
Left it plumbed in and plugged in
And it fails to fire then the electrics need looking at.
Test each of the injectors on that bank and see if there is any power going to them.
If there is a common area the cables for that bank pass over or route thru then check it.
Also check that you have continuity from the ecu to the injector ends and while wiggling the cables as during starting and engine running lumpy or taking up power it will move a little on its supports and flex cables.
If the ecu is the issue you have the choice of either sending it off for repair or trying another ecu once the security by of its is sorted FFRR Owner, very nearly became a D3 owner
Test piloted a new D4 XS SDV6.. Gone and being forgotten i hope!!
D4 HSE 10MY
D4 XS 11MY
SSRR Destroyer *2
24th Dec 2016 2:24 pm
Lockey
Member Since: 13 Dec 2016
Location: Limerick
Posts: 111
@kiwirich:
According to the auto electrician i brought the ECU to, each bank of injectors is fed of a separate driver, so one for each bank, regardless, he said the ecu was fine so no issue there.
As you said, the injectors have been proven to be good, so my money is on the wiring having a short somewhere causing one driver to shut down a bank when is senses an issue. everything is pointing towards an electrical fault and not a mechanical one.
@Pete K: Yep, totally agree, all wires to and from the ECU for the injectors are on seperate pins going into the ECU, but you'll notice, each bank is wired to a seperate plug, and each bank is then powered by a seperate driver on the PCB.
What was suggested by the AutoElectrician was that the two wires going to an injector could be rubbing against each other, and have shorted, ecu would pick up on this and shut off a driver on the effected bank.
@KP: Agreed, tracing the wiring is next on my list of things to do continuity is good but as mentioned above, it could be a short, continuity would still look good with a short so its looking like il have to trace each wire individually.
Looking forward to getting back to working on it soon, been in hospital with a collapsed lung since Xmas eve
28th Dec 2016 1:35 pm
kp
Member Since: 27 May 2011
Location: Sticking the Ex back in the skanks bin
Posts: 2824
To be totally honest if the injector loom is its own and can be bought as such I would just do that unless it's £300 or something sillier as the pulse bursts across those wires are super short timing wise and not a massive amount of power either so will be hard to prove out.FFRR Owner, very nearly became a D3 owner
Test piloted a new D4 XS SDV6.. Gone and being forgotten i hope!!
D4 HSE 10MY
D4 XS 11MY
SSRR Destroyer *2
28th Dec 2016 3:04 pm
M3DPO
Member Since: 22 Sep 2010
Location: Notts.
Posts: 8103
My understanding from experts on here it is catastrophic to unplug injectors and turn the engine over
One item that connects the two banks is the cam shaft drive chain at the rear of the left bank looking from the front, this has been known to snap, could it have jumped a tooth?It can when others can't,
It will when others won't,
It goes where others don't.
Last edited by M3DPO on 28th Dec 2016 4:01 pm. Edited 1 time in total
28th Dec 2016 3:50 pm
Lockey
Member Since: 13 Dec 2016
Location: Limerick
Posts: 111
Hey M3DPO,
Can you elaborate? cant see why this would have any negative effects
28th Dec 2016 3:53 pm
M3DPO
Member Since: 22 Sep 2010
Location: Notts.
Posts: 8103
Read Robbies reply in the post below, he is no.1 on here in this subject, I'm sure he will be along shortly to offer advice: http://www.disco3.co.uk/forum/topic101658.html?highlight=InjectorIt can when others can't,
It will when others won't,
It goes where others don't.
28th Dec 2016 4:12 pm
Lockey
Member Since: 13 Dec 2016
Location: Limerick
Posts: 111
Ah i see what the potential issue is!
Thankfully i havent had this issue occur but can see how it would seriously wreck an engine
Cheers for the heads up!
28th Dec 2016 4:21 pm
M3DPO
Member Since: 22 Sep 2010
Location: Notts.
Posts: 8103
-All injectors showed 999 (im assuming this is pressure related but not sure?:
The above measurements can only be taken at tick over, anything above 900rpm gives a 999 reading.It can when others can't,
It will when others won't,
It goes where others don't.
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Starting to run out of ideas now. Have tested compression, all good. Now swapped all injectors and no change, ECU has been checked and is good also. 
