Hi all... please help save my sanity!!!!

I did write a previous post on the issue, but have opted to write a new one as there were some red herrings in the previous one, but I will update it with a link to this.

So... having enjoyed several years (unusually) of trouble free driving, I have an issue with what feels like a misfire. This can happen when crawling around a carpark and then anywhere up to around 2000revs when accelerating or cruising.

The issue rarely if ever, happens from a cold start and tends to happen if you have driven somewhere then stop for a period of time (can be 5mins or an hour). When you start again and pull away you will get the 'misfire'. It can sometimes happen on the first journey of the day, but only when you have been driving for an extended period.

No fault codes are logged.

Notable points:

- Sometimes it will do it once, then drive fine for the rest of the journey. Other times it will do it throughout that second 'warm start' journey.

- It will normally feel very violent, however, on occasion you get more of a sensation that you are accelerating in waves of holding back, then accelerating.

- When you get the violent 'misfire', it is often accompanied by a turbo flutter.

- You can observe the erratic behaviour on the rev counter.

- On occasion during a journey where it is particularly bad, it will then get worse and worse and try to stall when you are at a standstill.

- The issue first reared it's head on a long journey, having filled the tank up to the brim from nearly empty. However, this has been going on for nearly 5 months now, so I'm guessing bad fuel would be gone by now.

What I've tried so far (at a cost of £1k):

- Multiple fuel system and injector cleaners and 'Wynns Dry Fuel'.

- New crankshaft position sensor.

- Garage carried out Turbo clean.

- Garage fitted new Turbo Actuator.

- Garage also fitted new crankshaft position sensor (saying the new one I fitted was faulty).

- Full service including new fuel filter.

- All intercooler hoses were replaced 6 months before issue started after bottom long hose split.

- Removed and cleaned MAF sensor.

- Removed and cleaned MAP sensor (on throttle body) - This was very grimy but made no difference.

I am now at a total loss; neither my trusted local garage or a nearby Land Rover specialist know what to do next.

My thoughts are that it could be the fuel pump, but these look to be £1200 so really don't want to try that on a whim.

Any thoughts or suggestions would be very much appreciated as this is driving me absolutely insane and I have lost confidence in driving any type of distance.

Thank you all in advance!

Tom.

Probably a long shot but......
I had similar problems, though possibly not as violent as yours, which did indeed turn out to be th Crank position sensor. Whilst I appreciate that this has been changed twice, what about testing the wiring to the CPS plug and connectors.........
As I said a long shot ........
Good luck

Is just removing and cleaning the MAF and MAP sensor going to rectify a faulty sensor?

Possibly better to replace them.

Can't believe something causing so significant a missfire isn't logging a fault code?
What system is your tame mechanic using, although you'd think any land-rover specialist would have the right equipment to diagnose it? Very frustrating you having to spend money throwing parts at it hoping it might fix it. This could be so many things. Are the new parts fitted decent quality oem?
Do keep us updated as to the outcome. Landrover - turning owners into mechanics since 1948

2014 Orkney grey Freelander SD4 GS.
2004 Zambezi silver Discovery 2 Td5 (Gone)
1963 Surf blue Morris Mini Minor Super de Luxe (my little toy)

I'd suggest the CPS plug is faulty.
The plug on mine wasn't making a perfect connection, giving similar dropout to the engine.
I ordered 2 plugs, as the shipping was more than the plugs. I've since discovered that the plugs are rebuild able, as they come apart easily, and the pins are available from ebay.
 Hyundai Ioniq 5 Ultimate. The family car.
2009 Rimini Red SE TD4. Gone.
2006 Tonga Green i6 HSE. Gone.
Audi A5 convertible, my daily driver.
1972 Hillman Avenger GT, the project.

As Nodge says look at the connectors.

I am sure that, as the forum's 'fleet' of FL2s become older, the need to consider checking electrical connections and condition of wiring harness will become more and more important.

I am sure that with all the vehicle movement as we drive harness/connector damage will become more likely than 'solid state' module failure.

I am unsure of how long for, and/or how many times, an intermittent fault has occur before it is logged as a pending or solid fault.

Obviously 'Intermittent Faults' are very hard to find, and a thorough inspection of harness and connections is the way to start.
(Reseating all plugs and sockets 'Carefully' is a good first step, and repositioning slightly the harness may cure/find the fault as the second step) FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 79k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)

Hi all,

Many thanks for your replies.

Grimdog / Nodge68 / IanMetro - With regard to the CPS, as I now have 3 of them I'm wondering if I can bend the pins on one of them slightly so that it makes a tighter fit when the connector is plugged into it? I will have a go at that today.

Bobupndown - I'm unsure as to the diagnostics they have to be honest. What I can say is that it large red handheld touchscreen, about the size of an iPad.

FL2ukkent - Very, true. My next plan was to replace them (see below update).

UPDATE:

Knowing I had a long journey yesterday, I ordered a replacement MAF & MAP from Euro Car Parts (I know!) yesterday. My logic being that if the problem occurred, I could change the parts there and then to see if it helped.

The drive to Euro Car Parts took approximately 30mins and it drove flawlessly there. Stopped and was in the shop for 10mins. Within 10secs of pulling away the violent missing began. Pulled over and fitted the MAF then drove and it was even worse and nearly stalling so swapped back to the original. I didn't swap the MAP as I really struggled to refit the original when I cleaned it and I'm concerned that it's cross threading so will try that later.

However, within about a mile of driving the issue stopped and I drove about a further 20 miles no problem.

Was at customer for about 4 hours so car fully cooled. Drove no problem for about 20 miles, stopped for a short time, drove again and problem occurred.

It really does seem to me that this is about a warm start. I can't believe for example, that if I hadn't stopped at Euro Car Parts, the problem would just so happen to have started at that very moment if I'd just kept driving; it has to be related to the act of stopping and starting warm.

I will certainly tighten the CPS connection, the only thing is, it just seems too coincidental that the loose connection only ever rears it's head in the very particular set of circumstances above.

Thank you all once again... being able to discuss this here is about the only thing keeping me sane right now!!!!

[/quote]

Bobupndown wrote:

Can't believe something causing so significant a missfire isn't logging a fault code?
What system is your tame mechanic using, although you'd think any land-rover specialist would have the right equipment to diagnose it? Very frustrating you having to spend money throwing parts at it hoping it might fix it. This could be so many things. Are the new parts fitted decent quality oem?
Do keep us updated as to the outcome.

Tominator wrote:

Hi all,

Many thanks for your replies.

Grimdog / Nodge68 / IanMetro - With regard to the CPS, as I now have 3 of them I'm wondering if I can bend the pins on one of them slightly so that it makes a tighter fit when the connector is plugged into it? I will have a go at that today.

Bobupndown - I'm unsure as to the diagnostics they have to be honest. What I can say is that it large red handheld touchscreen, about the size of an iPad.

FL2ukkent - Very, true. My next plan was to replace them (see below update).

UPDATE:

Knowing I had a long journey yesterday, I ordered a replacement MAF & MAP from Euro Car Parts (I know!) yesterday. My logic being that if the problem occurred, I could change the parts there and then to see if it helped.

The drive to Euro Car Parts took approximately 30mins and it drove flawlessly there. Stopped and was in the shop for 10mins. Within 10secs of pulling away the violent missing began. Pulled over and fitted the MAF then drove and it was even worse and nearly stalling so swapped back to the original. I didn't swap the MAP as I really struggled to refit the original when I cleaned it and I'm concerned that it's cross threading so will try that later.

However, within about a mile of driving the issue stopped and I drove about a further 20 miles no problem.

Was at customer for about 4 hours so car fully cooled. Drove no problem for about 20 miles, stopped for a short time, drove again and problem occurred.

It really does seem to me that this is about a warm start. I can't believe for example, that if I hadn't stopped at Euro Car Parts, the problem would just so happen to have started at that very moment if I'd just kept driving; it has to be related to the act of stopping and starting warm.

I will certainly tighten the CPS connection, the only thing is, it just seems too coincidental that the loose connection only ever rears it's head in the very particular set of circumstances above.

Thank you all once again... being able to discuss this here is about the only thing keeping me sane right now!!!!

Quote:

It's difficult to tighten the CPS plug connection, as the pins on the CPS actually spread the pins in the plug. They are are tin coated, and do suffer from corrosion and spring tension loss.
Replacement of the pins is the only cure.
I ordered gold plated pins to give a longer life. I also used plenty of di-electric grease to seal the plug from water and air.



Your replacement MAF caused more issues because you can't just replace sensors or actuators on the air path, without carrying out an air path calibration, which configures all the values from the various air path sensors and actuators.

Would either of these do the trick?

https://warwickts.com/5521/Delphi-Scima-FC...nector-Kit

https://www.amazon.co.uk/CONNECT-37593-Ele...amp;sr=8-1

Many thanks.

Tominator wrote:

In terms of the air path recalibration, does this require a diagnostics tool, or is there a routine that I can perform myself?

One of my three Code readers can do an Airpath relearn but since I use them all at the same test sessions I can't remember which one, most likely the Gap or the AP200

Last edited by I Like Chips on 4th Dec 2023 6:53 pm. Edited 1 time in total

So, yesterday the vehicle did not miss a beat for the first time in months.

This included starting from hot and proceeding to drive from south of Bristol to Cardiff, then stopping for a few minutes, before starting again to move parking space several streets away. In this scenario I would have put money on experiencing the misfire, but everything was fine.

It then also performed fine on the reverse leg of the journey.

The temperature yesterday was significantly lower than it has been recently, not getting out of single figures.

So could this indicate that the issue is to do with ambient temperature, and if so, what would be affected by that?

Thanks once again in advance for your input.

P.S. I've ordered up the components to make off the replacement CPS plug.

Hi all,

I am now convinced this is ambient temperature related. For about a week, I had only driven in temperatures about 5c and below, with no issues. Yesterday, I drove when the temperature was up around 9c and the issue occurred.

Would anybody be able to suggest what that might be?

I'm thinking it may be a sensor, but not sure which would be affected by ambient temperature.

Many thanks in advance for your help.