Thanks Paul,

If I have a look at fuel pressure readings on my IID tool, would it be noticeable if that sensor was out of spec?

David. 1997 Range Rover 4.6 HSE in Oxford Blue with Ash Grey Leather
1997 Range Rover 4.6 HSE in Rioja Red with Lightstone Leather
2006 Range Rover Supercharged in Zermatt Silver with Jet Leather
2007 Freelander i6 HSE in Izmir Blue with Ebony Leather
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior

dhallworth wrote:

I did a compression test this evening, it was stone cold and it was performed dry.

Cyl 1 - 200
Cyl 2 - 200
Cyl 3 - 250
Cyl 4 - 200
Cyl 5 - 250
Cyl 6 - 250

I’ve read online this evening that they’re supposed to be carried out with the engine warm so I’ll get it warmed up and see how we go from there.

I’d expected the numbers to be a bit more even then that but there’s none of them that are alarmingly low.

dhallworth wrote:

The old plugs are filthy, however, the car has been run several times over the last couple of days whilst changing plugs/coils and monitoring some live values on the diagnostics. Due to this it’s not been off choke for the last several starts.

Once it had warmed up last night and settled down I did around 12 miles in it with the new spark plugs in. They were absolutely spotless when they were removed again this evening to do the compression check.

dhallworth wrote:

Thanks Paul,

If I have a look at fuel pressure readings on my IID tool, would it be noticeable if that sensor was out of spec?

David.

dhallworth wrote:

Thanks Paul,

If I have a look at fuel pressure readings on my IID tool, would it be noticeable if that sensor was out of spec?

David.

Sorry for the slow response to this, the weather has been in the evenings meaning the enthusiasm to go and have a look at the car has been lacking!

Fuel pressure seems to hover around 385kPa which is around 55psi. I think I saw it as low as 375 and as high as around 400 when giving it a blip of the throttle.

When you start the car and it's sitting at around 1200rpm on cold start there are no misfires. When the car comes off choke and drops to 800rpm is when the misfires start to occur. If I lift the revs back to 1200rpm they stop. This is visible when watching the misfire counter on the IID tool.

Once the coolant temperature had reached around 45 degrees Celsius you could drop the revs to idle (around 800rpm) and it would sit there as smooth as silk and the misfire counter on the IID tool wasn't registering any misses at all.

Whatever is causing it only seems to cause it when it is cold. 1997 Range Rover 4.6 HSE in Oxford Blue with Ash Grey Leather
1997 Range Rover 4.6 HSE in Rioja Red with Lightstone Leather
2006 Range Rover Supercharged in Zermatt Silver with Jet Leather
2007 Freelander i6 HSE in Izmir Blue with Ebony Leather
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior

I did a cold start today.

0 PSI before I engaged the starter motor


On initial startup the fuel pressure spiked to 69 PSI

Then it dropped almost instantly 61 PSI


The interesting thing to note is that the RPM dropped to ~800 RPM before the fuel pressure dropped.

It took a few seconds for the pressure to drop to 55 PSI


The RPM drop seems to be attributed to the Throttle position

14.1% --> high idle

3.5% --> low idle

High Idle


Low Idle




Other things to note

MAF (Lb. / Minute) = 0.80

MAP (Inches of Hg) = 9.7




Thanks

Paul

Note: the 9.7 inches of mercury measured by the MAP is on the absolute scale.

We live in a 29.9 inches of mercury world (approximately)

The nine inches isn't relative to the typical pressure here on this planet.

It is relative to the pressure in deep space.


So if you are accustom to using a gauge that reads ZERO at 29.9 inches of mercury

Then that gauge would show that my LR2 has 20.2 inches of Mercury of Vacuum



I am pointing this out because your ODB tool may show the relative Vacuum instead of the absolute pressure

So don't be alarmed if you have 20 instead of 9.7

This is just a frame of reference difference


Thanks

Paul

David,

You convinced me to get a tool that can count misfires

I found something with a lot of capability for not much cost. (my research says it can count misfires)

Autel AL539B OBD2 Scanner 3-in-1 Code Reader Battery Tester Avometer for 12 Volts Batteries, Full OBDII Diagnosis and Circuit Starting & Charging Systems Test


It will arrive in a few days and I will look for Misfire counts from a cold start.

I will do this on my LR2 3.2 and my S80 3.2

I really appreciate your help to make me think about this.



Note: I have a spare set of sparkplugs and 6 ignition coils on the shelf so if I find anything I already have some spare parts.

The Volvo 3.2 has a new fuel pressure sender but the LR2 has its original part.
Both have their original MAP sensor and MAF sensor.
Both have original fuel injectors.
And both have Denso Iridium Power sparkplugs (the set on the self is from Volvo and they are Denso Iridium TT Plugs)


Take care

Paul

David,

My package arrived and I have my new diagnosis tool.

Unfortunately the tool arrived after my daughter had taken the LR2.

But the S80 is here parked outside.


Time to test a cold start.

I hooked up the Autel tool to the Volvo got to the Misfire menu and then I turned the engine on.

The tool gave me two choices

EWMA MISFIRE COUNTS. (I believe that this is live data)

MISFIRE COUNTS LAST (I believe that this is from the last start)

I have to check one cylinder at a time

For today’s cold start. ZERO MISFIRES

For the last start I had ONE MISFIRE on cylinder 3. All others had zero


Hopefully this helps


As I wrote above I wanted this capability to stay out in front of problems.

Thanks for bringing this up


Happy Holidays

Paul

Last edited by p_gill on 21st Dec 2021 2:15 am. Edited 1 time in total

Thanks Paul, I didn't get a chance to get near the FL2 this weekend so will likely try and get a better look at it over the holidays.

Weekends just seem to disappear in a flash around here these days!

David. 1997 Range Rover 4.6 HSE in Oxford Blue with Ash Grey Leather
1997 Range Rover 4.6 HSE in Rioja Red with Lightstone Leather
2006 Range Rover Supercharged in Zermatt Silver with Jet Leather
2007 Freelander i6 HSE in Izmir Blue with Ebony Leather
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior

David,

I am learning how to use the tool

EWMA = Exponential Weight Moving Average (This is effectively the average for the last 10 times you starter the engine)

Last = The most recent time you used the engine (if you check the data before you start the engine it is the number of misfires from the last time you started the engine and it resets to zero as soon as you start the engine)


Here is my data for the LR2 that I collected before starting the engine

Cylinder..........EWMA (counts)..........Last (counts)..........

Cylinder #1..............0.........................0..........
Cylinder #2..............0.........................0..........
Cylinder #3..............0.........................1.........
Cylinder #4..............1.........................3..........
Cylinder #5..............1.........................0..........
Cylinder #6..............1.........................1.........

These are obviously very low misfire counts.

However it is interesting to note that cylinder 4, 5 and 6 have more misfires than cylinder 1, 2, 3. The PCV routes the blow by gases to cylinder 6 then 5, 4, 3, 2, 1. So if any oil gets by the Valve it will tend to affect cylinder 6, 5, 4 more than 3, 2, 1

I did replace my PCV around 100,000 miles and looking at this data I am glad I did.

This is so much better than waiting for things to get so bad that the CHECK ENGINE LIGHT comes on.


By definition the LIGHT is too late.

I want to be proactive not reactive.



Take care

Paul

Just to put another update on here...

Due to the weather and work commitments we opted to send the Freelander to the local LR specialist to get looked at.

They've checked the new plugs that we fitted and noted that they're not oily.

They've swapped the injectors from Cylinder 5 to Cylinder 6 and the fault stayed with cylinder 6.

They've done a compression test with the engine warm and advised that all compression readings are well within and towards the top of the acceptable range.

They've put fuel cleaner and engine flush through it too.

They've also checked the fuel pressure and advised that it's fine too.

Still, there's a misfire on Cylinder 6 until the coolant temperature reaches around 45 degrees.

They're thoughts are that it could possibly be a sticking valve that's causing the problem. We're at the point where it's not worth paying them to take the head off it as we were going to be selling the car anyway.

They don't believe that the PCV is causing it but I'm thinking of changing it on the off chance that it cures the fault as I'm pretty much out of ideas otherwise. I don’t see how a PCV fault would clear when the temp rises slightly either though.

Is this the correct part for the PCV? LR023777.

https://www.island-4x4.co.uk/covercylinder...37847.html

David. 1997 Range Rover 4.6 HSE in Oxford Blue with Ash Grey Leather
1997 Range Rover 4.6 HSE in Rioja Red with Lightstone Leather
2006 Range Rover Supercharged in Zermatt Silver with Jet Leather
2007 Freelander i6 HSE in Izmir Blue with Ebony Leather
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior

Looks like it, the round item being the PCV, as I understand it.

A couple of slightly less expensive options here:

https://www.lrdirect.com/lr023777-cover-cylinder-head

Let's hope that it miraculously solves the problem for you, David.

Tim

Dave,

LR023777 is the correct part number

These are know to fail after about 10 years.

If you want to check to see if the PCV is causing a problem then remove the oil fill cap when the engine is misfiring.

A bad PCV will apply too much intake vacuum to the engine crankcase. If you remove the cap and the PCV is bad the engine will likely stall. If it starts running significantly differently I would replace the PCV.


As for the sticking valve.

The 3.2 has variable valve lift and if it doesn't switch from the high lift to low lift then it would act like a sticking valve.

The Solenoid that switches from low lift to high lift may be broken (other have experience this failure)

I don't know if the valves are in low lift or high lift on a cold start and I don't know if it switches when the idle drops down.



The engine should run if you disconnect the Solenoid (there are two) but the horsepower will be very limited and disconnecting the solenoid will set the check engine light.

I just had my emissions test done so I can try this out if you are interested.

Let me know

Thanks

Paul

Thanks Paul,

I’ve ordered the PCV today so hopefully that’ll be here one day next week. I’ll swap it out and if that makes no difference will look at the solenoids.

Just a shame it’s not logging a code for anything useful!

David. 1997 Range Rover 4.6 HSE in Oxford Blue with Ash Grey Leather
1997 Range Rover 4.6 HSE in Rioja Red with Lightstone Leather
2006 Range Rover Supercharged in Zermatt Silver with Jet Leather
2007 Freelander i6 HSE in Izmir Blue with Ebony Leather
2012 Range Rover 4.4 TDV8 Autobiography in Baltic Blue with Sand Interior