Puma 2.4 - Random power loss + engine cut

[MD5]

Hello Everyone.

First of all, thanks for taking to the time to look at this post and sorry for my poor English language. I'm looking for help and ideas to fight a very random engine problem in my Puma (2.4 engine).

Basically, the vehicle runs normally but sometime, under very rare circumstance, (usually after a few thousands kilometers or several weeks/months), you'll suddenly feel a slight hesitation as the problem kicks in and pushing the vehicle at pretty much any speed after that point makes the vehicle jerk on and off like the engine is cutting out completely. It never cuts out completely unless you bring the vehicle to idle during one of these cutting out episodes and then will it idle for a few seconds and then die.

The attempt to restart the engine immediately after the shut down always fail. Each time I must wait about a minute and then the engine start without hesitation.

After engine restart, I can drive on the street but most of the time after a few kilometers the failure happen again.

After 2 or 3 power loss + cut off and restart, the problem disappear for weeks or months.

This vehicle never has any fault codes logged at all or warning light on the dash. Nothing useful to track the problem. Also the problem is not related to the EGR because actually I run a BAS Remap that disable it.

At the moment, the following components was replaced and work carried out , most under warranty:

1st repair attempt:
- MAP + MAF sensor
- Turbo replacement :o
- Tank breather valve replaced
- All plugs and connectors in the engine vane cleaned and verified
- ECU software update
- EGR replaced
Problem still present

2nd repair attempt:
- fuel tank cleaned, some dirty inside
- fuel suction hose from tank to filter head replaced
- fuel filter head replaced
Problem apparently solved for 10 months / 6000 km's

Some weeks ago the problem was back again, now my Defender is stopped in a friendly Land Rover assistance 465km far from where I live, I'm out of warranty. They are trying to discover what's wrong but due to the extremely random nature of the fault it's a very hard if not impossible task. At the moment they are made a very accurate static diagnostic and live engine data recording but everything is within specs and the engine is always running fine.

What do you think about this problem ?
Could be due to a random malfunction of any of the following components ?
- VCV Valve on the pump
- PCV and Pressure relief valve on the common rail
- The fuel pump itself

Any help will be greatly appreciated, thanking in advance!

Mario from Italy

[87County]

I hope that someone of knowledge of Pumas posts a reply to your question soon.

Your written English is very good Mario, better than some that we see which has been written by "English" speakers. :)

[william mcallan]

Hi Mario
Have read your blog with interest, I was having the same concern recently with intermittent bad flat spotting at 1800-2000 RPM, poor gear change etc, but never a cut out completely situation. I too have a BAS re-map and it to date has fixed the flat spot and turned the driving the Puma into a pleasant experience.
I am an ageing mechanic but in my opinion I think that it is fuel related, the fuel rail pressure would certainly be a good place to start looking at, without DTC’s it is unusual problem and will make it difficult to track.
Owing to the number of successful BAS upgrades out there I would rule out ECU problems, however Peter at BAS is very talented/helpful and has enormous experience with Landrover, I think an email to him with a copy of your blog is a good place to start. The cost of just changing parts would have to be an absolute last resort.

[chook73]

My first thought is possibly a cut out due to overheating, does the air conditioning cut out just prior to the engine?

Is the cut out during heavy working conditions such as pulling up hills, hot days etc?

It might be worth getting a scanguage or engine monitoring device like that and just to keep an eye on temperatures and key components.

[MD5]

Thanks for your help attempt!

I forget to wrote some useful details.

The problem most of the time happen while driving on steep uphill roads or with a fairly engine load and high RPM, but nothing exaggerated. I think I was not close to a possible engine overheat condition. The onboard ScanGauge show a cooling fluid temperature between 90/100 °C and a CHT temperature between 100 and 110 °C

Aircon was always off

Probably a dumb question, but what exactly happen when the engine overheat ? It simply loose almost all the power and cut off or the ECU introduces a loss of power that still allows to drive the vehicle?

[The Cone of Silence]

MD5,

When mine overheats, the engine doesn't die out, but it does go into limp mode, so regardless of how much I press the throttle, the revs do not change....they stay very low. I've had this happen at 10kph up a very steep hill and 110kph up a gentle but long motorway climb with a full load.

When this happens I always pull over to the side of the road or even just slow right down and leave the throttle off. Within seconds, the temp cools enough to get going again. I found that this only started happening once I'd been away driving through huge muddy puddles and blocked up the radiator fins with mud!

I don't have a scangauge so I'm afraid that I can't tell you what the engine and coolant temperatures are at the time.

Bobby

[chook73]

Same as Bobby said here, the first key is at a water temp 110deg the air con cuts out and then at 114deg (or 116deg) the engine goes into limp mode. I have never pulled over when it has happened so I am not sure if it cuts out when the vehicle stops but you loose all power.

If you have a scan gauge and your 100% confident that the water temp is not getting over 100deg then it wont be overheating however your situation (climbing hills or heavy engine loads) and your symptoms sound very much like overheating needs to be considered further.

Do you have a larger intercooler and/or spotlights?

[Naks]

The problem most of the time happen while driving on steep uphill roads or with a fairly engine load and high RPM, but nothing exaggerated.



Yeah, ECU is cutting power to the engine to save it. Get a bigger intercooler and your problem will go away!

[Lorryman100]

Hi Mario,

first off sorry about not replying to your pm but I have just seen it in my inbox and I didn't get an email notification to let me know I had a pm.:redface:

The dealer can isolate the immobilizer through the 10AS by disabling a couple of options in the settings menu.

https://www.aulro.com/afvb/images/imported/2013/07/615.jpg

Just remember that with this disabled you will have no immobilizer function at all and the steering lock and ignition barrel can be forced to allow the defender to first start then run. The immobilizer stops the defender starting unless it receives a valid mobilization code from the key fob because it isolates the starter and injector circuits. Also by disabling the immobilizer you also lose the passive immobilizer which would shut the engine down after about 5 minutes unless it receives a valid mobilization signal from the key fob.

As to the recent engine power loss you may have already answered the cause of the issue by saying that you have seen the CHT as high as 110 degrees C. The IPAC doesn't move the temp gauge needle up into the red until the CHT reports a temp of 105 degrees C. Above that the EMS will bring in the overheating strategy to protect the engine from damage. The strategy involves reducing the engine power by limiting the revs and torque available in an effort to reduce the engine temp. It would feel like the defender was almost kangaroo-ing as the temp fluctuated near the high limit meaning revs limited when hot and as it cools the engine gets full power again only to go back into overheat as you make demands on power again and so on etc etc. I would first off clean the CHT terminals and plug in electrical contact cleaner and then see if the problem persisted, if it did I would change out the CHT sensor and see if that helped. Another point to note as well is that it could be your driving style that is putting the engine temp into the red? Low revs and high gears under a heavy load will make the engine work harder using more fuel to keep up with the operator demands maybe exasperated by the remap?? This means a hotter burn which increases CHT temps quicker than higher revs in a lower gear where the fan is turning faster cooling the coolant faster keeping the system at a lower temp cooling the cylinder head quicker??

https://www.aulro.com/afvb/images/imported/2013/07/616.jpg

https://www.aulro.com/afvb/images/imported/2013/07/617.jpg

A bigger intercooler would allow the engine temp to be lowered by about 5 or 6 degrees ( My new Alive intercooler reduced my CHT by this amount but I stay in a cooler environment.), so may help your issue?

The last time we traced the same fault you are experiencing now to the filter head and fuel pick up line being contaminated with detritus and the dreaded black silicone gunge blocking your fuel pick up at the filter head. Did you check the fuel system for leaks, especially for heat expansion of the fuel lines? If the symptoms are exactly the same as before get the independent to disconnect the fuel line at the pump and using the fuel bleed tool syphon the diesel into a glass jar and look for contamination at the pump inlet head. The dealers may have replaced the fuel lines and filter head from the tank but did they also check for contamination at the pump side of the fuel lines?? If you read over the emails/pm's I sent you the last time you will see how the pump operates and that the VCV would not log a DTC due to fuel starvation but would log a DTC if there was an issue with the fuel rail pressure (eg: P1169) rail and pump temp sensor as these fall under the emissions control criteria which leads me to think the issue is temp related (CHT) or you have contamination within the fuel pipe from the filter head to the pumps inlet valve(admission valve). Just my tuppence worth :BigThumb:

Brian.

[MD5]

Thanks all for the information and help attempt!
And special thanks to Brian for the enormous help given in the past!

About the possible overheats, when the problem kicks in there are nothing wrong in the instrument cluster including the water temp gauge always near half.
The last time that the problem occurred I was on a street with no traffic so I took the opportunity to better understand what happens during the malfunction.
If I try to accelerate, the engine sobs and does not increase speed. After released the accelerator and pushed the clutch, the engine after a few seconds of hesitation turns off.

At the moment my Def is BAS remapped with a large intercooler fitted (it's the one from chiptech.at, really a masterpiece), silicon hose and a high flow sport catalytic converter.

This morning I received a phone call from the LR workshop. They tested the behavior of the engine along some steep roads and recording parameters during operation has not revealed any problem.

They replaced again the fuel filter + filter head. They also replaced the CHT sensor (very cheap) and made the injection system learning and matching with the ECU.
I'm pretty sure that they skip to check the pump side fuel lines, I will ask for this kind of check.
No useful DTC's stored except something related to a faulty brake switch found many time in the past. They are waiting for replacement switch to fix this issue.

What exactly is the process of the injection system learning ?

About my driving style, the BAS remap adds power and torque but without exaggeration, I specifically requested a relaxed map to avoid excessive stress to the gearbox and other transmission parts.
With this map the engine has much pull at low revs and that as Brian wrote may cause overheating. I will urgently adopt a different drive style!

[The Cone of Silence]

MD5

Definitely not an overheating cause, if your temperature gauge is still at halfway.

When mine goes into limp mode, the needle always goes very rapidly north. When it comes down, after a few seconds, that's when I get the throttle response back.

I've pulled over to a complete stop before and the engine kept running....it doesn't turn itself off.

Mine is also remapped and with an Allisport intercooler. When I was installing the new intercooler, I cleaned the radiator with a garden hose for ages and this, together with the new intercooler, seem to have stopped the problem happening so often.

I hope you find the cause of the problem soon mate. Don't forget to keep us updated!

Good luck

Bobby

[alan48]

Hi all,
my son's 2.4 90 Puma has twice had to be flat topped truck home due to cuuting out or initially no throttle response at all, and despite sometimes going for a few more ks dies completely--it is extremely dangerous to be passing a truck and suddenly find all power gone--ie NO repsonse to depressing the accelerator. First time is was a faulty fuel sensor that took ages for the LR service centre to deal with as no faults showed up on the diagonistic readouts, the second time it was the temperature sensor and again no faults showed, but gauge did show overheating --which it certainly was not. Both times the car had recently been pressure washed so maybe thse sensors don't like getting wet--not a good advert for a LR though!

[MD5]

Thank you all for your suggestions.

I would tend to rule out the possibility of overheating, in any case, the CHT sensor has been replaced.
When I mounted the large intercooler I also cleaned the radiator from the engine side. I did not find it clogged, just some dirty on the bottom anyway now it's like new.

After reading what's Brian wrote and suggest, I believe that the most likely cause is that of a problem in the low pressure section of the fuel intake.
I called the shop to ask if they could check and clean the feeding tube section from the pump to the filter head.

As a DIY maintenance, it's ok to remove the fuel filter, detach the quick release coupling from the pump, and spray the fuel feeding tube with brake or carb cleaner and then blow it with compressed air ?

@Alan48: I fully agree with you about how dangerous this kind of failure can be. My nightmare is that the engine stops in a motorway tunnel without emergency lanes...
Which is the fuel sensor that you described ? It's the VCV (Volume Control Valve) on the fuel pump ?

[MD5]

Some update about my issue, I'm very sad :(

Yesterday I took the vehicle from workshop and drove 465 km to return at home.

The following repair was made:
- CHT sensor replacement
- Fuel filter head + filter replacement
- Tank and fuel lines cleaning + blowing using a very effective tank cleaner
- Total fuel draining and filtering, it was ok, very few dirty inside
- Fuel pump learning
- Immobilizer fully disabled

Engine run really fine for the entire 465 km highway trip, average cruise speed between 105 / 110 km/h, weather temperature was fairly hot, +32°C and sometime +35°C but engine temp (CHT and cooling fluid) was always like expected even with aircon on. CHT Max peak = +105 °C.

To arrive at home, I have to take a 300 mt steep uphill road, I usually drive it very slow in 1st gear with engine at 2000rpm. Just a few meter from the parking the engine quickly loose all power and die. No way to restart it for at least 10 minutes.

No DTC stored except P1935 -Brake switch/sensor signal- fairly common on my Defender

I take the video of the ScanGauge display during the various restart attempt, apparently there was no fuel pressure on the rail. I kindly ask if someone could decode some useful information from the two YouTube videos, expecially from the FPd (Fuel Pump Duty) and FPr (Fuel Pump rail) gauges

Video 1 - restart attempt after about 30 seconds from cut-off
Defender Puma restart failure - 1 - YouTube (http://youtu.be/zCiOAENxIeE)

Video 2 - restart attempt after about 2 minutes from cut-off
Defender Puma restart failure - 2 - YouTube (http://youtu.be/ZzBuhxFvkGI)

The 3rd video will show the ScanGauge values in normal condition, when the engine in turned on and then off without problem
http://youtu.be/3W5Rk6b2Do8

Thanking in advance for any help!

[MD5]

Hello,

Just an update about my defender issue.
I opted a very drastic solution. At the beginning of August I asked the LR assistance to replace the following components:

- Fuel/injection pump with VCV valve
- The entire common rail with both valve/sensor at the end
- All the fuel lines from filter head to engine
- The entire engine wiring assembly
- The ECU

I then drove for about 1000km trying to repeat the conditions that generated the problem (low fuel, steep road, highway etc.). Everything went fine. At the moment I'm fairly happy :).

My engine, previously, in normal condition run very fine, but now, with the all the new components throttle response is in some way improved. Another incredible thing happen is that fuel consumption decreased dramatically (from +- 7km/l to +- 10km/l).

Hoping that the problem is finally solved, I keep the finger crossed!

[sashadidi]

I hope it fixes your problems, were those parts replaced under warranty???

[MD5]

I hope it fixes your problems, were those parts replaced under warranty???

No, I had to pay for everything :mad::mad::mad:

Vehicle standard 3y warranty was expired Sep-2012.
I tried to ask a warranty extension since the problem was complained when the Defender was under warranty but no lucky.

The only thing I get for free is a courtesy car for one week :eek:

[justinc]

The problem appears to be centred around fuel supply to the HP pump and then the common rail. The possibility of a faulty High pressure pump on its suction side is very high, to test the theory the pump can be pressurised with a low pressure lift pump from the tank.


Glad it is finally all sorted out :)

JC

[MD5]

I also think that the problem was caused by the pump, probably in the suction/low pressure section. In that section there are a non serviceable filter and a bypass valve that may be the culprits, who know.

To save money I bough a refurbished "exchange" pump, so the old one was returned to the supplier. No way to test or dissect it to see if something is wrong.

I hope now the problem is finally solved!

[Neptune]

Hello,
Is a problem solved or till day you have it?
Thanks

[MD5]

Hello,
Is a problem solved or till day you have it?
Thanks

Touching wood and keeping finger crossed, I can say that more than one one year later and about 30.000 km after parts replacement everything run fine.