Guys, I need some help...


The morning after my wife filled the tank I started getting a misfire. Got the codes read at Advanced and called out 3 & 7 misfire. Since I have 140k on the LR3 I decided on new plugs and Lucas fuel treatment. No help. Still 3&7 misfire. Got 2 new ignition packs and threw them in thinking that was going to be for the win. Wrong. There is still a half a tank of suspected bad gas I am trying to run out before I get fresh stuff.


Any suggestions? Fuel filter? Injectors? Anything I'm overlooking?


I appreciate it!


Late,
Scott

 

Oooohhh... Atacama Sand Metallic? You're going to make Abran jealous. But, on to your problem.

You've started with the right things I think. Though, I would swap coil packs next time to see if the misfire follows the supposedly faulty packs instead of just replacing them. Might save some money.

Sounds like you've addressed the spark variables, so now you're down to air and fuel. I'm not sure how you'd consistently have misfires on two specific cylinders with an air issue, so I would focus on fuel if it were me... which is what it sounds like you're doing. Lucas fuel treatment is not the same as a full BG injector cleaning service. If nobody else has suggestions, I would try the BG injector cleaning first to see if it helps.

Are you experiencing drivability issues or are you just getting codes that state misfires on those cylinders? I've had a coil pack fail, and I can tell you that even with one cylinder not firing, engine performance is severely impacted. Can't imagine what two would be like...

Also, if you have bad gas, I don't know if something like a fuel stabilizer or octane booster might help with the remainder of the tank, but you may want to give it a shot.

 

Scott-

I had a similar issue with 2 misfires popping up at once. As it turned out mine was a single coil pack failure which also induced a misfire code in a different cylinder, even though that coil pack was okay. I documented in this post: https://landroverforums.com/forum/lr...message-76119/

Two more coil packs failed on my LR3 within a few months so I replaced the remaining originals and I haven't had any problems since then. I hope this helps you with your problem.

-Rob

 

Damn, love that color. I still think there is a non metallic color that is in the sand category. Good luck with the misfires.

 

This is an interesting one..

Misfire codes, but no lean / rich codes?

I mean.. unless it's a REALLY bizarre random fault causing these things (which are typically very time consuming and tough to track down, plus expensive!) I'd suggest looking at the injectors.

I'm basically at the same point with my engine (not the same symptoms at all though) but I've ruled out a lot of other things.

ONE thing you might want to do is replace the ignition RF interference capacitor / condenser P/N LR004160 (around $30 usually).

Land Rover actually updated the design of the unit since the 05-06 models, so some engineer somewhere must have seen something he didn't like. It sits just underneath the engine cover and is a 10 min swap tops.

I only say this because the power feed for all ignition coils is fed through this capacitor - so it's about your last shot at this being an ignition issue.

 

All, I appreciate the insights and feedback.


I am leaning towards a fuel issue since I believe bad gas is what caused this mess in the first place, and I have replaced the most common spark related issue. It seems like an air issue is unlikely, but definitely still a possibility.


This weekend I am taking the fuel rail off and doing a check/cleaning of it and the injectors. It seems very straight forward and not a very involved job. I have some Seafoam at the ready to soak/clean the injectors to solve this issue.


As always, I will update with my progress, and hopefully, a resolution.

 

Let us know how it goes - that would be a very unlikely cause (most of the "bad gas" stories are myths these days, it's almost impossible with the various checks, certifications, etc all along supply routes..) plus if it's just contaminated it should either go into limp mode, knock protection / ignition retard, or not run at all. A 2 cyl misfire due to fuel would be really odd - can't think of something you could pump that passed the filters and injector screens then clogged 2 injectors..

 

Just to be sure, which coils did you replace? 3 and 7 are 2nd and rear most on the passenger's side.

Persistent misfires on these, are usually coils, and they will throw erroneous cylinders(no combustion in on cylinder means lower rate of compression in the next to fire)

Is the MIL flashing? Do the codes come right back? Can you feel it misfire, or just getting the codes?

 

GOOD POINT!
I totally forgot about this, not only are the cylinder ID / locations weird on these, they are DIFFERENT for some years AND different between ECU ID and mechanical ID.

I ran into this when I did my plugs - glad I took a picture of the actual layout of all 8 plugs on the ground before I labeled them because I labeled them totally wrong haha.

 

FYI, this is a useful video explaining cylinder numbering and firing order for the different land rover engines. LR3 V-8 engine is around 3:05 in the video.

Firing Order And Cylinder Numbers For Land Rover Engines