2011 LR4 Misfire/rough idle

LarryK said:

Hey Gang, new forum member here. I purchased an 11 LR4 a few weeks ago. Has 72K on it. Drove great for 2 weeks and that was it since I have had it. Have replaced the low and high pressure fuel pumps, all 8 injectors, and the crankshaft position sensor.
Still have a hard (long) start when cold and after some unspecified amount of time when running, I get a rough idle, check engine, and reduced performance warning. Definetly shows some improvement on power with the new parts but it only ran 60 or so miles before acting up again. Codes are showing misfires. After injector replacements, I did get a code for the Cat Converter one time but hasn't re-appeared. I'm several thousand dollars in and have the same result. The classic definition of insanity... Any thoughts from the group on this? Has anyone tried the Coolant Senor replacement and had the same effect as OP above? Any direction on next steps would be very helpful.

Click to expand...

LarryK : It's been a while since I've had that coolant sensor replaced and it's been extremely hot here in Los Angeles so I rarely get an actual cold start to truly test if my issue is gone. HOWEVER, there have been some mornings in the low 60's when I drive to the barn and I get a very faint chug chug while it's running cold (in drive). I don't get any readable misfires or restricted performance codes yet but I'm still not convinced that my sensor was the only issue. Otherwise, she runs stellar. Yes, this is the definition of insanity!!!

Hi,
new to the forum, concerned and hopefully I can get some advice before throwing $ away. Picked up a 2012 LR4 a couple of months ago. Perfect condition or so appears, drove only about 500 miles, no issues. Then short drive to store in rain, on way back, check engine light and restricted (?) driving light. Rough ride home. Codes read misfires even numbers and random. Smoke from exhaust. Had my guy check at the house and he says oxygen sensors look fine and are not reading as issues (guy that sold me it says sounds like that according to his mechanic when I called him). He is pretty sure it is the fuel injectors and wants to change those next week. Not cheap. Fine to do them but worried it will not be the problem. When the car running in driveway while he was checking things- hitting the gas hard sprayed fuel out of the exhaust pipes!!!
Any thoughts would be appreciated.

unburnt fuel in the exhaust is due to the misfire. it will go away once you solve the actual problem. however, this would mean fuel supply is most likely not a problem.

did you scan with an IID tool? or generic? IID may give you more specific codes. if its related to a module IID may tell you.

since your codes are all even cylinders (they are all on the same bank) and it you were driving in the rain when it happened..... makes me think a wiring or module issue. possibly not supplying spark to those cylinders.

Injectors is a $2000+ job. there are plenty of things to check before that.

check wiring. follow the harness for that side of the engine. wiggle it around. make sure nothing is loose or damaged.

Just as preventative, do these things....DIY for under $150.
clean MAF sensors.
clean throttle body.
replace spark plugs.
replace PCV valves...although usually only idle is affected.
move a coil from an even cylinder to a odd cylinder. see if the problem follows. this is most likely not going to help, but cant hurt to try.

I really feel you're looking for 1 part that affects the entire even side. it will be intake (MAF), injectors...not likely (wiring) or spark (wiring)

michael ****** said:

Hi,
new to the forum, concerned and hopefully I can get some advice before throwing $ away. Picked up a 2012 LR4 a couple of months ago. Perfect condition or so appears, drove only about 500 miles, no issues. Then short drive to store in rain, on way back, check engine light and restricted (?) driving light. Rough ride home. Codes read misfires even numbers and random. Smoke from exhaust. Had my guy check at the house and he says oxygen sensors look fine and are not reading as issues (guy that sold me it says sounds like that according to his mechanic when I called him). He is pretty sure it is the fuel injectors and wants to change those next week. Not cheap. Fine to do them but worried it will not be the problem. When the car running in driveway while he was checking things- hitting the gas hard sprayed fuel out of the exhaust pipes!!!
Any thoughts would be appreciated.

Click to expand...

I’d say if you think it’s injectors, try some good injector cleaner like BG44. Best purchase I ever made was a gap iid tool. Has helped me identify and fix some seemingly big issues inexpensively. If you have to do the injectors, it’s not too bad of a job if you do it yourself. The injectors themselves are not cheap though

I heard it is a big job 6-8 hours. Told story to a few different repair guys all agree sounds like injectors staying open. But their are other reasons. Also read fuel injector cleaners do not work. Anyway waiting for more advice before I decide move to make. Drove it for gas yesterday np, drove it to a couple of stores today np. Did not hit gas hard though, no smoke from exhaust when I stopped.

michael ****** said:

I heard it is a big job 6-8 hours. Told story to a few different repair guys all agree sounds like injectors staying open. But their are other reasons. Also read fuel injector cleaners do not work. Anyway waiting for more advice before I decide move to make. Drove it for gas yesterday np, drove it to a couple of stores today np. Did not hit gas hard though, no smoke from exhaust when I stopped.

Click to expand...

Injector cleaner is a part of LR service and at least should be done annually to keep it running smoothly. BG44 is definitely worthwhile.

I’ve done the injector replacement myself. Not a bad job. Took about 4-5 hours.





Sent from my iPhone using Tapatalk

I borrowed the scanner from auto zone and it gave me those codes. also my mechanic came over and ran it in driveway for a couple of hours monitoring it on some device and whatever code detector he had.
he was convinced fuel injectors. When I called Land rover dealer advisor immediately said fuel injectors when I told him what it did. Also a Land rover specialty mechanic over phone told me the same. Neither mentioned any other possibility.

michael ****** said:

I borrowed the scanner from auto zone and it gave me those codes. also my mechanic came over and ran it in driveway for a couple of hours monitoring it on some device and whatever code detector he had.
he was convinced fuel injectors. When I called Land rover dealer advisor immediately said fuel injectors when I told him what it did. Also a Land rover specialty mechanic over phone told me the same. Neither mentioned any other possibility.

Click to expand...

I’d try injector cleaner first. Dirty injectors (because it is direct injection) can cause misfire just like a bad injector.

michael ****** said:

I borrowed the scanner from auto zone and it gave me those codes. also my mechanic came over and ran it in driveway for a couple of hours monitoring it on some device and whatever code detector he had.
he was convinced fuel injectors. When I called Land rover dealer advisor immediately said fuel injectors when I told him what it did. Also a Land rover specialty mechanic over phone told me the same. Neither mentioned any other possibility.

Click to expand...

All great advice. I will tell you, from my own journey, that my #3 and #5 misfire was not fixed until I replaced the injectors. All spark plugs and ignition coils were replaced, but the new injectors solved the problem. Lrbritishparts on eBay has some great deals on injectors, ~$140 for bosch, and they verify fitment by VIN.

If the injectors are stuck open, they can be dirty, or internally fouled. It's hard to tell, but after trying the easy fixes, I would just replace them.

my guy was ready to change injectors but could not do it for a couple of weeks, I had some doubt as it has been driving perfectly since he checked it and cleared codes. So now I brought it to local land rover dealer to get diagnosed. Been sitting there 2 days now without them looking at it, pathetic. I did see the bosch injectors online for as low as $85 each and I know a guy that cleans carbs and also said he cleans injectors quite often for a Land rover dealer- so I guess they clean them and put them back in sometimes. The genuine LR injectors are expensive. Oh well will wait and see. Funny now my kids chrysler had misfires- changing plugs tomorrow. Coincidence but gas purchased at separate times.