I've looked in both the owners and service manual, both suggest that 1,2,3 are on the passenger side (US) and 4,5,6 are on the drivers side. I changed my spark plugs today and I am getting a misfire in one of the cylinders, the code says cylinder 2 however I can find no problem. I put back the old spark plug after the failure, tried testing resistance on the cable (was not out of range), I am getting a spark from both the cable and the plug independently, both on the new and old, both have the correct spacing, I have also tested resistance on all the other cables, and I have tested cylinder 4 plug in the same manner as I did number 2. At this point I am thinking I am missing something obvious, all the connections are tight, is my cylinder map correct, or have I been wrong all this time?

 

This is from my manual - hope it helps
Cylinder arrangement V6 petrol, numbers 1 and 4 cylinders at front of engine when engine is viewed from rear
Cylinder numbering Number 1 cylinder - right hand bank; Number 4 cylinder - left hand bank

 

I'm not familiar with the 4.0L V6 in the LR3s but if it has a coil on each plug like the 4.4L V8, swap that #2 coil to a different one and see if that's the issue. Conversely, if it has old school wires, see about swapping cylinder #2 with another wire that is similar in length.

Just a thought.

 

After becoming frustrated I ended up pulling out all the plugs and testing them individually, I found poor continuity on plugs 3 and 4 and replaced them. I don't know why the computer thought it was cylinder 2.

For those searching in the future this is the alleged cylinder order, map, diagram etc viewed from the top down, front being towards the bumper and rear being towards the cabin...

V6 4.0 LR3

(front)
1 4
2 5
3 6
(rear)

 

As frustrated goes, the AB explanation at 1:20 on the video https://www.roverparts.com/resources...-firing-order/ shows Land Rover engines up until recently? with their cylinders and firing orders. Since I have the 2008 Ford Ranger engine in my 2007 LR3, I thought I could use the Ford 4.0L SOHC V6 diagram, but it shows 1 2 3 on passenger side from front towards firewall and 4 5 6 from front on driver's side towards firewall. When diagnosing a misfire on #4 I wound up using the AB video to find out where #4 in Land Rover terminology for the Cologne 4.0L SOHC V6 is located. Unfortunately I started out using the Ford diagram and that was not what the Land Rover use of that engine deemed correct. Really confusing and frustrating!

EDIT: I see SoCal Rob at https://landroverforums.com/forum/lr...e-83095/page3/ found the AB video back in 2017!

 

 

X2! Only reason for posting so much is that it took a dog's age to replace the #4 ignition coil, all because of using incorrect information.

Page 1155/4829 of “Land_Rover_3_Discovery_2006-2009_Repair_Manual” (Published 11 May 2011) starts with “Engine - V6 4.0L” and the chart line is “cylinder numbering”. A picture of the cylinder numbering (verifying previous post by 5280) is on page 1159/4829.

General Specification

Type 4.0 litre, 60 degree 'V', petrol engine, single overhead camshaft per cylinder head,

2 valves per cylinder

Cylinder arrangement V6, when looking towards the rear of the engine, cylinders 5 and 6 are at the rear.

Cylinder numbering Number 1, 3, 5 cylinder - right hand bank; Number 2, 4, 6 cylinder - left hand bank

Bore - nominal 100.4 mm (3.952 in)

Stroke 84.4 mm (3.322 in)

Capacity 4009 cm􀃱 (244.5 in&#1048817

Firing order 1 - 2 - 3 - 4 - 5 - 6

Compression ratio 9.75:1

Direction of rotation Anti-clockwise viewed from rear of engine

Maximum power 156 Kw (209 bhp) @ 4750 rev/min

Maximum torque 346 Nm (255 lb-ft) @ 3500 rev/min

Dimensions:

Length 669 mm (26.3 in)

Width 712 mm (28.0 in)

Height 747 mm (29.4 in)

Maximum permissable cylinder head warp

0.08 mm (0.003 in)

Engine oil pressure:

At Idle 1.8 - 2.0 bars (180 - 200 kPa) (26.0 - 29.0 lb/in)

At 3500 rev/min 3.3 to 3.6 bars (330 - 360 kPa) (48.0 - 52.0 lb/in)