Thread: Puma 2.4 - Random power loss + engine cut

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.

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.

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.

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?

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

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?

Originally Posted by MD5

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!

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.

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



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??





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

Brian.