Cylinders 1,3,5,7 misfire

[Roger Ramjet]

2001 D2 SD bought as a fixer, great body and clean but would not run.
So far
fuel pump module (made it run, rough but running)
Crank and cam positioning sensors
throttle position sensor
Mass Air sensor
coil packs, wires and plugs
intake manifold gasket
valve cover gaskets
new fuel injectors
cleaned all the fuel lines and such
anti knock sensor (helped a lot)
all four O2 sensors
idle air control valve
Now I consistently get a multi cylinder misfire for 1,3,5,7? One bank on drivers side. It is eating fuel. idles like crap and will occasionally surge in rpms, I have no clue where to go from here.

 

[JUKE179r]

Welcome to the forum.
What fault codes are you getting? are your spark plug wires in the correct order from the coil pack?

 

[rovercanus]

What O2 sensors did you use?

 

[mlnnc]

In my personal experience, confirmed at least a few times by others on the forums, you likely have a bad upstream O2 sensor on Bank 1.

I know you said all four O2 sensors are new, but several of us have had sensors that were bad out of the box. And I know too that some say a bad O2 sensor can't cause misfires, but the upstream O2 sensor is the only component shared by all four cylinders on each bank.

My truck had misfires on all four Bank 2 cylinders about 5½ years ago. I replaced the upstream O2 on that side and all the misfires disappeared.

Also, some have reported better results with sensors made by Walker instead of Bosch. I've not needed to change a sensor since reports about the Walkers being a better choice have emerged so I haven't tried them, but I have personally had 2-3 Bosch sensors be bad right out of the box.

 

[Discomania]

I promise you, a bad O2 sensor can make your vehicle run like CRAP. I had a 4WD of another manufacturer (ahem) once and had it in for an exhaust leak repair. They managed to damage one of the O2 sensors and told me to bring it back the next day and they'd fix it. I could barely make it home, it ran so poorly. Nowhere near highway speeds. The ECU relies heavily on data from those sensors.

 

[discostew]

Unplug the o2 sensor on that bank and see what happens.

 

[Swedjen2]

We anxiously await your considered reponse.

 

[pdxrovermech]

the o2 sensor is likely good. ive been running into a melted plug connection back by the coolant reservoir lately. specifically the power feed to the O2 sensors that runs through it.

 

[Roger Ramjet]

sorry for the slow reply. The holidays have eaten into my time. I also have a 2003 discovery that runs wonderfully (most of the time) This 2001 is drinking gas like crazy as well and idles terribly (all are likely related, I am going to get into the O2 sensors and plugs and wiring this weekend. I'm also wondering if there could be a bad ground wire to the injector rail? Would that be symptomatic of what I have here?

 

[Swedjen2]

As you know, it's always a good idea to keep the grounds on a Land Rover as clean as possible. Even the ECU ground wire.
Esp. the steel ground connections to any aluminum anywhere. After years of thermal recycling and moisture, galvanic corrosion rears it's ugly head, leading to sadness and regret.

 

[JohnB]

Do you ever get an knock sensor code or pending code? last time I was working on my engine I know I squished the harness for the knock sender under the ac mount. Mine runs fine but every once in a while get a knock code and misfires on 1,3,5,7. when I get some time going pull the ac mount and open that wire loom to see if something is rattled.