I love Rovers!

So I took the new 2010 Range Rover Sport 5.0 for a test drive out on the freeway, the first couple of miles went great, was driving well, had tons of power, (actually seems to have more punch than our other 2010 Range Rover Sport with 90k miles). Then the check engine light came on and started flashing along with the reduced performance message starting flashing. The truck was noticeably misfiring and had very little power.

I pulled over and checked thing, no leaks, just a rough idle. Shut it down and waited a few minutes, started it back up and the lights were still flashing. Got off at the next exit and turned around to head back home. After a 1/2 mile, the reduced performance light went out. About 1/2 mile later the check engine light went out. Still seemed to have a misfire. Got about a mile from the house and the check engine light came on solid, no longer flashing, truck ran really rough and didn't have much power. Got home and plugged in the Gap Tool.

I got the following code related to the Cylinder 6 misfire. Ideas? Bad plug, bad or clogged fuel injector, bad coil. Head gasket? I have noticed that when I start it up and let it idle, after a few minutes the engine gets less smooth and starts to run rough, fairly subtle, but noticeable. It hadn't thrown any codes prior.

(Last week, the truck also threw the remote not communicating code. It was not communicating when I first got it two months ago. Put a new battery in the remote and it still didn't work. Then out of the blue, could have disconnected the truck battery, and it started working again, now, it just isn't working again, I have no idea what caused it to start working and then to shut down, I cleared the code and it came right back).

thanks, looking for ideas, I really don't want to take it to the shop if I don't have too, some of the local indy shops are getting as pricey as the dealers. Phil

2010 Range Rover Sport HSE 5.0
Stornaway Grey with Black Interior
131,969 miles


PCM-Engine Petrol

• P0306-00 (AE) Cylinder 6 misfire detected
• P0316-00 (AE) Misfire detected on start-up (first 1000 revolutions)

BCM-Body Control

• U0214-00 (2F) Lost communication with the remote function actuation
  ( on 05-08-2021 07:58:49 at 131969 mi )

 

You listed the big three. I just replaced an injector on my Volvo that stuck wide open - you could blow through it like a straw. Are you noticing any white or black smoke from the tailpipes (and note whether at startup, when hitting the gas, etc)? Is the misfire worse when you first startup, or when you hit the gas hard? Maybe look at the fuel trims (see if you’re rich or lean on either side) and look at fuel rail pressure (actual vs commanded, compare right and left rails). Otherwise, the usual swap coil packs to see if the misfire stays on 6, replace plugs - see if wet or oily - if not recently done. Injectors after that as they are more of a PITA and more expensive. With a head gasket, you should see white smoke and maybe a drop in coolant level or coolant in the oil (turns light brown/thicker with swirls or a mayo appearance).

 

No smoke, white or black. It runs great at start up, after a few minutes I notice a vibration in the engine, rpms stay the same. I had driven it about 8 miles to drop it to an electrical shop a couple of weeks ago. No issues out there or back. I had driven around the neighborhood, 4 miles or so several times on test runs, no codes or cel. The cel and reduced performance kicked on for the first time last night on my freeway test run (similar route to the electrical shop). I did get on it a bit after about a mile on the freeway. No coolant in the oil. I will look at the fuel trims, if I can figure that out......I do have the Gap Tool but it is much more sophisticated than I am.....I just got the truck so I don't know the history. Looks like it has new front lower control arms and overall is in nice shape. It has an oil leak or two, still sorting those. I thought one was the brake vacuum pump, but the more I check it, the more I think that it is coming from the hose connection on the brake vacuum pump, rather than the pump gasket. It has another leak up near the oil filter housing, but I don't think that is the source. I will try swapping the coils and see if that changes anything. If that is the culprit, any recommendations on a replacement coil. FMP Euro and Atlantic British each have replacements for about half or less than the OEM part. Land Rover is very proud of its parts......the story continues........

Does the fact that the engine vibration/rougher idle doesn't start until it warms up indicate anything? This is the first time that it has thrown the two misfire codes, even though, I have noticed the engine vibration/rough idle since I first got it. Phil

 

You mention the brake vacuum pump, and that is something that occurred to me, but thought I’d ask about smoke first. We’ve had a number of reports on these forums of the brake vacuum pump developing a leak that ends up dumping oil into the intake (the vacuum line apparently is connected to the pump and the intake - both assist in providing vacuum to the brake and EVAP system). It’s bizarre - and my 2016 does not have this system - but seems like the vacuum pump starts leaking oil, maybe loses it’s own suction, and the engine vacuum then just sucks oil from the pump right into the intake under certain conditions. Anyway, I thought maybe you’re getting some oil into the intake and it’s fouling the plug. But, these reports usually come with the occasional cloud of smoke out the tailpipes.

Rough idle after warming up sometimes points to an issue with the closed loop fuel control. (Apologies in advance if I’m stating things that you already know). When the engine is cold, the air/fuel mixture is set by fixed stored values. Once the engine warms up, it goes into a feedback loop whereby the oxygen sensors tell the ECM whether the fuel mixture is too rich or too lean and the ECM then adjusts the mixture. There are several components to this feedback loop and a problem with any can give you a rough idle: MAF sensors, 02 sensors, fuel injectors, HP fuel pumps, engine coolant temperature sensors (there are two that work together). Both open and closed loop fuel control also relies on only metered air entering the engine, so rough idle also can be caused by a vacuum leak (maybe PCV) or a bad purge valve. Knowing whether the engine is running lean or rich can help track down which component might be failing. The fuel trims are in the gap tool under live values. You want to look at both long term and short term fuel trims (you add them together to get actual fuel trim at any given moment) for both left and right banks. Negative fuel trim means rich condition, and positive fuel trim is lean condition.

Key, here, though is the code for just cyl 6. Many of the above components can cause rough idle with misfires on multiple cylinders on one or both banks, but typically will not cause a single cylinder misfire. Still, you might have a couple things going on - the rough idle and cyl 6 misfire might be two separate problems. The other possibility here is a valve issue.

No advice on the coil other than I’ve seen reports that the car is picky about which type of coil. Some just don’t work.

Oil leaks - the vacuum pump seems to be quite common. If you’re seeing oil at the hose connection, its probably an internal leak - so new pump time. I have heard of the oil filter housing leaking as well, but much more common (unfortunately) is the valve cover or timing cover. On that side of the engine, the oil can drip onto the alternator and ruin it as well.

Welcome to the club - looks like you’re getting the full experience.

 

One step forward and several steps back. I swapped the coil on cylinders 6 and 4, here is what I got.......hold on to your seats...PCM-Engine Petrol

• P0301-00 (01) Cylinder 1 misfire detected
• P0302-00 (01) Cylinder 2 misfire detected
• P0303-00 (01) Cylinder 3 misfire detected
• P0304-00 (01) Cylinder 4 misfire detected
• P0305-00 (01) Cylinder 5 misfire detected
• P0306-00 (AF) Cylinder 6 misfire detected
• P0307-00 (01) Cylinder 7 misfire detected
• P0308-00 (01) Cylinder 8 misfire detected
• P0300-00 (01) Random misfire detected
• P0313-00 (01) Misfire detected with low fuel
• P0316-00 (AF) Misfire detected on start-up (first 1000 revolutions)

Ran horribly and the reduced performance light came on. Finished the lap around the block, got home and swapped the coils back, Then I only got the same two original misfire codes. P0306 and P0316.

For what it is worth when I just scanned the OBD, my Gap Tool didn't pick up on the codes, I used a generic code reader, and it showed the two codes P0306 and P0316. The truck idled smoother in park and neutral, when I put it in R or D, it was really rough, almost felt like there was a drive train issue, although when I drove it I did not notice any driveline problems. I am leery to run it much at this point, When the misfires showed on all cylinders I was afraid that I have thrown a timing chain, so odd that when I swapped the coils back, I only got the two original codes.

Thanks so much for the input, engine performance is not my specialty.

By the way, getting the coils out on the driver's side is pretty easy. My truck had an insulation pad over the valve cover. I removed that, just wedged into place I then removed the side of the driver's side box that covers the brake fluid master cylinder. Made it pretty easy to get 4 and 6 out, I didn't try 2 or 8...... .

 

Very odd result. When you swapped the coils, you didn’t accidentally mix up the wires did you? Coils swapped, but wires stayed where they were? Aside from that, I can think of no earthly reason swapping the coil pack between two cylinders would cause you to go from a single cylinder misfire to all 8 cylinders misfiring.

When you put it in reverse or drive, your engine loads up as compared to park/neutral because you’re powering against your brakes. That would require more fuel. So, could be a fuel delivery issue someplace. Take a look at those fuel trims and maybe check fuel rail pressure.

 

the coils were plugged in correctly. I was shocked at the codes that showed all 8 cylinders misfiring. I will check the fuel trims. I was sure that I had thrown a timing chain when all 8 cylinders were misfiring. They joy of owning a Range Rover/Land Rover.............

 

I plugged in the Gap Tool again last night. Initially, I had misfires on all 8 cylinders. I cleared them and then only had the P0306 and P0316 codes. Truck was running rough. I cleared the engine adaptations and it seemed to smooth out. I pulled out of the driveway and it started to misfire again. Threw the check engine light.

Per my Gap Tool, the fuel injector pulse widths were as follows:
1. 0.00139
2. 0.00168
3. 0.00139
4. 0.00166
5. 0.00140
6. 0.00168
7. 0.00140
8. 0.00167

The air flow rate from mass air flow sensors
1. bank 1 - 7920.0 g/hr
2. bank 2 - 8640.0 g/hr

do those numbers tell us anything? Phil

 

Those pulse widths are interesting. Your odd cylinders have shorter pulse widths than the evens (about 0.00140 vs 0.00167). Higher pulse width = more fuel. So, the engine is either trying to lean out the the odd bank by pulling back fuel, or richen the even bank by adding fuel.

Since your problem appears to be on cylinder 3, I’m guessing your are running rich in the odd bank and the engine is trying to reduce fuel by reducing the pulse width on that bank. You should be able to verify by looking at fuel trims. If the car is running rich in the odd bank, you’ll see high negative fuel trim on bank 1 (odd bank). If it is running lean in the even bank, you’ll see positive fuel trim on bank 2 (even bank). Running rich (if that is, in fact, what is happening on bank 1), means that your O2 sensors on that bank are sensing too much fuel in the exhaust and telling the PCM to back off on fuel supply by reducing the pulse width. Just the opposite if running lean.

All this is interesting, but doesn’t tell you the cause. A bad O2 sensor could be reporting the wrong mixture. A stuck-open fuel injector will cause a rich condition. And any other reason for a misfire (failed spark or lack of adequate combustion) will cause unburnt fuel to be dumped into the exhaust causing a rich condition. A failing HP fuel pump will create a lean condition on one bank. Any of these things will cause the PCM to adjust the pulse width.

Those MAF readings don’t tell you much other than they are reasonably close to one another at that particular reading. To diagnose MAFs, you really need to graph performance over time and compare the two sides, and see what each is doing at different RPM levels. But the fact that you seem to be having one cylinder misfiring reliably and pulse-widths down on one bank suggests its not a MAF (which affects both sides of the engine).

I think the first thing I’d try is looking for spark on that cylinder 3. If no spark, check for voltage on the coil.

You could also look at fuel trims to see if you are rich or lean on one bank or the other, and compare fuel rail pressure. If you are rich on one bank and have lower fuel rail pressure on that bank - that would strongly suggest a leaking injector.

Looks like you posted up in Landroverworld.org as well - please add these new results and try to get some more feedback there too.

I welcome any input on my logic from others in the forum as well - please let us know if I’ve missed anything. Let’s help get this one sorted out.

 

Wow! @jlglr4 I commend you! You are giving great, comprehensive advice.

2 things I’ll add.

- you can watch live data for the misfires on GAP. That might help.

- can you smell fuel? If so, maybe throw a new fuel injector at it.

Often times the simplest, most direct explanation is the correct one, the whole Occam’s razor thing.

good luck Phil.