I had a chance to get out and try to diagnose the issues with the RRS. As I was trying to record the values with the Gap Tool, after running about 10 minutes, the truck evened out and ran without any misfires. I did a 3 miles lap and all seemed well. Took another shorter lap and bam, CEL and Reduced Engine Performance came back again. I had the codes showing all cylinders were misfiring. I checked the readings with the Gap Tool and could only find the misfire on Cylinder 6. I did my best to record the information accurately. No doubt some of the listings are mislabeled. I did note the the MAF readings were quite different, 7920/8640g/hr to 10800g/hr. Note sure if that is significant. I could not get any reading other than 0 on the Long Term Fuel Trim on the misfiring RRS. Fuel Rail Pressure on the misfiring RRS was 2900 vs. 3190 kpa on the Black RRS. Fuel Level % on the Grey RRS was 31.8% vs. 62% on the Black. (fuel pressure % on the black was 34.6%, there is a chance that I misnoted the numbers). It would be nice if you could just do a full dump from all of the reading from the Gap Tool, if there is, I can't seem to figure it out. I hope that some of this information is helpful. Very odd the way that it smoothed out and the misfires stopped for 15 minutes or so.

Grey 2010 Range Rover Sport 5.0 liter Direct Injected Engine (Misfiring Truck)

Throttle Position Sensor

Sensor 1 Sensor 2

-31.1 -30.5

Short Term Fuel Trim

27.3 24.2

Short Term Fuel Trim

+/- 1.56 +/- 1.56

Short Term Fuel Trim %

21.1% 19.5%

Long Term Fuel Trim

All Zero 0

Fuel Rail Sensor

1.10

High Range

3,000 +/-

Low

2.3v

Fuel Rail Pressure

2,900 +/-

Fuel Level Input

31.8%

Fuel Injector Width

1 .00139
3. .00139
5. .00140
7. .00140
2. .00168
4. .00166
6. .00168
8. 00168

Mass Air Flow

4.5g/s

5,678
Earlier Reading was Bank 1 - 7920g/hr, Bank 2 - 8640 g/hr

Combined Misfires

127 (all on Cylinder 6)

Cat 1 Cat 2

1739 1739

MAF

1. 7920/8640

2. 7920/8640

Fuel Rail

2800 kPa

2900+/-

2.34v/3000kPa

Black 2010 Range Rover Sport 5.0 liter Direct Injected Engine (Running Perfectly)

Throttle Position Sensor

Sensor 1 Sensor 2

-31.3 -30.4

Short Term Fuel Trim

24.2 24.2

Short Term Fuel Trim

+/- 1.56 +/- 1.56

Short Term Fuel Trim %

29.7% 23.4%

Short Term Fuel Trim

3.12-7 3.12-6.25 ( earlier reading, Bank 1: -4.69%, Bank 2: -3.91%

MAF

1. 30.8 2. 1.15

Long Term Fuel Trim

-2.34% 3.12%

Fuel Rail Pressure

3190 kPa/1.15v

Fuel Rail Pressure Low

2.30v

Fuel Pressure %

34.6%

Fuel Pressure Input

62%



High Range

3,000 +/-

Low

2.3v

Fuel Rail Pressure

2,900 +/-

Fuel Level Input

31.8%

Fuel Injector Width

1. 158 5. 172

2. 160 6. 172

3. 162 7. 172

4. 162 8. 172

162 167

Mass Air Flow

Bank 1 - 10800 g/hr, Bank 2 - 11160g/hr

Combined Misfires

127 (all on Cylinder 6)

Cat 1 Cat 2

1739 1739

MAF

3. 7920/8640

4. 7920/8640

Fuel Rail

2800 kPa

2900+/-

2.34v/3000kPa

Air Flow MAF

10800 g/hr 10800 g/hr

 

On the short term fuel trims, I can’t really tell which readings are which:
Short Term Fuel Trim
27.3 24.2
Short Term Fuel Trim
+/- 1.56 +/- 1.56
Short Term Fuel Trim %
21.1% 19.5%

Not sure what those first and second readings correspond to as there are no units. The % numbers are way high (I assume these are positive values). Both short and long term fuel trims should be within +/- 5%. But are the two numbers bank 1/bank 2? That doesn’t make a lot of sense to me because the injector pulse widths are way higher on one bank than the other. Also, you seem to be showing high short term fuel trims on the truck that’s running perfectly, which doesn’t make any sense. So, I’m thinking something is off in the readings. Try to record these values at idle, engine warm:

1. Short term fuel trim (STFT) Bank 1 (%)
2. STFT Bank 2 (%)
3. Long term fuel trim (LTFT) Bank 1 (%)
4. LTFT Bank 2 (%)

Then look at the values holding steady at about 2000 RPMs (in park - not driving). A vacuum leak will show high positive fuel trims at idle and they get smaller as you increase RPMs. A fuel delivery issue (shortage of fuel) should show high fuel trim at idle that gets worse with increasing RPMs. A leaking injector should show negative fuel trims - might get better or worse with RPMs depending on the problem.

With your injector pulse widths being different on the two banks, you should see some high positive or negative fuel trim readings on one bank.

As for fuel pressure, I usually look at these readings:

1. Fuel rail pressure commanded Bank 1
2. Fuel rail pressure commanded Bank 2
3. Fuel rail pressure actual Bank 1
4. Fuel rail pressure actual Bank 2

You want the actual fuel rail pressure to be close to the commanded rail pressure.

As for the MAF readings, they will vary from one another some as you drive, but you don’t want to see one or the other dropping to zero, or spiking up really high. The rule of thumb at idle is 1 g/s per liter, so your combined reading of 4.5 g/s doesn’t seem so far off to me for a 5.0L V8.

You can also take a peek at your o2 sensor readings. Look at voltage. Once the engine is warmed up, sensor 1 (pre-cat/lambda) on each side should go up and down in a smooth wave from about 0.1 to about 0.9 and back again, over and over. Sensor 2 (post-cat) is not used for fuel control, but you can peak at that one also - should be steady at about 0.5-0.7v.

One tip: when you are reading live values, most things should be changing a bit -especially when you increase RPMs. If it seems like things have frozen, hit the gas and see if you can get it to move. Go to a value you know should move with RPM - like STFT or fuel rail pressure. If it’s not moving, the GAP tool might be frozen. I’ve had this happen, and it turned out to be the OBD pins on the car getting weak.

 

I just had a thought on the 15 minutes of smooth running - wondering if your engine temp isn’t coming up fast enough, or isn’t reading correctly. The car doesn’t go into closed loop fuel control until it his operating temp. Often, misfire issues happen either before closed-loop fuel control, or after, depending on the problem. If this problem is showing up after 15 minutes, could be your car is going into closed loop really late, which could indicate a bad T-stat or coolant temp sensor. From a cold start, your engine should be up to operating temp of about 190-200F within about 7 minutes. While your warming up your car for the above tests, you could monitor your engine coolant temp with the gap tool to see how long it takes to warm up.

 

I did a hard reset and got a few different numbers. As an extra bonus, my remote that had quit communicating with the truck is now working again. Not sure what causes it to lose communication, but glad it works. Any ideas are appreciated.

After the reset I still had a very noticeable misfire.

The only codes that it is showing that are engine related are P0306.00 (AE) and P0316-00 (AE)

I tried to write down the numbers that I got from the Gap Tool, again, I wish that there was a way to download the entire live scan results without having to save each individual reading.

MAF Volumes
Side 1 12,000 and Side 2 12,000 (up from around 8,000 and 8,600 from earlier reading)
Fuel Injector Pulse Width were both banks were in the 140 range (137 to 142) down from 170 in earlier readings
Oil Temp 194 f (outside air temp around 70 f)
Oil Volume showed 5.8 Liters (dash gauge was right in the middle, down a quart +/-)
Misfires showed 838, 70 this session all on Cylinder 6
Fuel Level Input 29.8%
Fuel 549 kPa
Fuel Rail Pressure jumped around in the 3800-3900 range, dropped as low as 3200
High Pressure 4100 kPa
High Pressure Fuel Rail voltage 1.33v
Mass Air Flow Sensor 1. -30.9, 2. 1.12
Duty Cycle (I have no idea what that is) 34.1% and 53.9%
O2 Sensor Output voltage 1. .645 v and 2. .895 v
Low Pressure Fuel Pump voltage 23v
Bank 1 - 21.9%, (with a low of 18.5%) Bank 2 - 28.9%
Throttle Position Sensor 1. 031.3, 2. -30.5

I am not smelling any fuel from the exhaust. I do note a hint of coolant, but that may be residue from the radiator swap a few weeks ago. I cleaned it up pretty well, so the coolant smell is a bit troubling. No coolant leaks that I have seen. I am noting what appears to be an oil leak coming off the rear passenger side, probably the valve cover gasket, tough to see from under the truck, seems to be leaking down across the starter motor case. Still have a small leak from what seems to be the tube connected to the top of the brake vacuum pump. As I understand it, no oil should be in that line, that should only be air, is that correct. I believe Abran mentioned that if it is leaking oil from that tube, ,there is likely an internal seal failure in the pump, time for a new vacuum pump. I hate throwing any money at this truck if the motor has a catastrophic issue......Thanks again, the feedback is greatly appreciated. Phil

 

Pretty tough to make anything out from these values the way they are listed. It’s interesting that your injector pulse widths are now the same. Your increased airflow suggests the engine was not at normal idle. Did you run these readings cold or after the engine warmed up? Are those two o2 readings from bank 1 and 2, or from sensor 1 and 2 on a single bank? Was sensor 1 moving up and down like it should?

I assume this line: “Bank 1 - 21.9%, (with a low of 18.5%) Bank 2 - 28.9%” is short term fuel trim, but can’t tell if positive or negative (are those dashes or negative signs?). If your long term trims are still zero, then you’ve definitely got some kind of fuel mixture problem going on, but it seems to be affecting both banks when your misfire is only in one bank. Did the fuel trim change when you increased the RPMs? Very odd that you wouldn’t have a code for values that high (or low). If these are positive fuel trim values, the one thing that immediately comes to mind is your PCV diaphragm. Cheap and easy to change, but you need to have one in hand before you pull the old one off as the old cover will likely break when you remove it.

As for downloading the data, you can record live data on the tool and then look at the recorded data later - you also can share it with yourself for viewing. The data is presented as a graph that you can scroll.

You mention no fuel odor from exhaust, but some coolant smell - is that from the exhaust? If so, you might take a sniff of your coolant reservoir (after it cools) to see if you smell any exhaust or see any bubbles.

Any fuel smell from the engine compartment?

Definitely need a new vacuum pump. If you want to confirm the condition of the engine, you could just take it someplace for a compression and leak-down test. Not sure how much they would charge, but shouldn’t be terribly expensive.

 

I have been on the road for a few weeks and haven't had a chance to dig into the RRS any further. I moved it when I got home and it was running very rough. Checked the codes and have misfires on every cylinder. Could the vacuum pump be causing these issues if it were pulling oil due to a bad seal?

P0301-00 (01) Cylinder 1 misfire
P0302-00 (01) Cylinder 2 misfire
P0303-00 (01) Cylinder 3 misfire
P0304-00 (01) Cylinder 4 misfire detected
P0305-00 (01) Cylinder 5 misfire detected
P0306-00 (01) Cylinder 6 misfire detected
P0307-00 (01) Cylinder 7 misfire detected
P0308-00 (01) Cylinder 8 misfire detected
P0300-00(01) Random misfire detected
P313-00 (01) Misfire detected with low fuel
P0316-00 (AF) Misfire detected on start-up (first 1000 revolutions)

 

There have been reports of a failed vacuum pump causing oil to be pulled into the intake on the V8 motors. I think the pump leaks oil and the engine vacuum must suck it up through the vacuum port. But those events were accompanied by occasional large amounts of smoke. I assume you’re not seeing smoke, right?

With misfires on all cylinders and a low fuel misfire code, I’d still be looking at fuel pressure, though I’d first check that PCV valve to make sure it’s sound.

 

Thank you I will check that out. No smoke to speak of. Phil

 

SUCCESS! The Range Rover Sport runs great. Simple problems are the best. I changed the plug and coil on Cylinder 6. No more misfires and no check engine light. Thank you all of the suggestions. I ordered the plug and coil from FCP Euro. NGK plug and the Bosch Coil. Phil

2010 Range Rover Sport 131k miles

 

Glad you got it sorted and thanks for posting back. Always great to see the solution.