NM Pajero Hex files

Technical information, definitions, advice, and support for factory ECU remapping, aftermarket systems, and much more.
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ross79
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Engine: 3.5-Litre 6G74 V6 24V SOHC
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NM Pajero Hex files

Post by ross79 » 11 Mar 2017, 16:34

I am having problems with my 2000 model NM Pajero.
Car is completely stock apart from improved mufflers.
Despite running 98 octane it detonates under load.
I installed a new oxygen sensor that fixed the problem for a couple of days before it returned.
I then installed a new set of spark plugs which again appeared to fix the problem until it returned a few days later.
Incidentally the old plugs looked blistered indicating it's running lean.
I have tried running it with o2 disconnected but it doesn't help.

So I ended up buying an open port cable to adjust the factory tune BUT I cannot find a definition / hex file to suit.
The ECU number is: MD369177

I have tuned a number of cars so I understand the concept and consequences.

WytWun
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Posts: 539
Joined: 09 Apr 2011, 23:22
State: Australian Capital Territory
Model: Mitsubishi Magna TJ AWD
Engine: 3.5-Litre 6G74 V6 24V SOHC

Re: NM Pajero Hex files

Post by WytWun » 11 Mar 2017, 20:14

ross79 wrote:So I ended up buying an open port cable to adjust the factory tune BUT I cannot find a definition / hex file to suit.
The ECU number is: MD369177

I have tuned a number of cars so I understand the concept and consequences.
If you have the cable and have installed the ECUFlash software, the first step is to read the ROM from the car and save it. Yes ECUFlash will complain about not having a definition, but you should be able to ignore that and continue on to save the ROM file.

I have reason to believe that ECUs with that part number have MH8305 (aka SH7055) chips and to properly read the whole 512kB ROM will require using a custom read-template (aka vehicle type type definition) file with ECUFlash - see the first post in this thread for the Evo 7 GT-A/Magna one which should do the job for you if I am correct. Once you have the ROM, definition work can commence.

I have to say that I seriously doubt that any attempt to make adjustments to the ROM will help - you have some other systemic issue which is compromising the ECU's ability to control the fueling. I can't offer much direct experience, but at the very least I would be checking the following based on my knowledge of these ECUs' code:
- fuel pump/inlet filter
- fuel filter
- fuel lines
- fuel pressure regulator
- MAF
- PCV valve and plumbing

I have also heard that holes in the exhaust system between the cylinder heads and the catalytic converter(s) can affect the extra oxygen sensor's mixture interpretation - while it seems more likely that this would make the sensor read lean (making the ECU add fuel) it might also make the sensor read rich thus causing the ECU to reduce fueling to compensate.

The several day lag after fitting the new oxygen sensor before the return of the problem relates to the adjustment (often called "learning") by the ECU of the low, mid and high long term fuel trims (LTFTs) after an ECU reset via battery disconnection. Having disconnected the sensor, you need to again reset the ECU by disconnecting the battery (or unplugging the ECU from the harness with the ignition OFF and reconnecting it if that is more convenient) to clear the learned LTFTs. Without this ECU reset, the ECU continues to use the learned LTFTs even in the absence of the oxygen sensor, which I think is why you didn't see any improvement by simply disconnecting the oxygen sensor.

If you also purchased a copy of Evoscan, you should be able to log the ECU - if the high LTFT is significantly positive compared the mid and low LTFTs, that would tend to confirm the ECU is trying to deliver more fuel under load than normal (this might be more indicative of a fuel system problem), if it is significantly negative compared to the mid and low LTFTs that would mean the ECU is cutting fuel under load (which might be more indicative of an oxygen sensor reading richer than it should).

stumagoo
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State: Western Australia
Model: Mitsubishi pajero
Engine: 3.5-Litre 6G74 V6 24V SOHC
Transmission: 5 Speed Manual

Re: NM Pajero Hex files

Post by stumagoo » 24 Apr 2017, 13:23

hate to say it buddy but there are not a lot of definitions out for the Paj, I was going to look at doing the NM one day but still have not got around to buying a new cable.........

As suggested I would consider looking into other possibilities as well, these engines are designed to run without detonation so anything from a dud ecu temp sensor to a bad fuel filter has the potential to cause problems.

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rush
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State: South Australia
Model: Mitsubishi Magna 1998 TF
Engine: 3.0-Litre 6G72 V6 24V SOHC
Location: Adelaide

Re: NM Pajero Hex files

Post by rush » 24 Feb 2018, 08:32

Was there any outcome with this? ANyone manage to find a XML for the NM Pajero? I am chasing one if someone has it

WytWun
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Posts: 539
Joined: 09 Apr 2011, 23:22
State: Australian Capital Territory
Model: Mitsubishi Magna TJ AWD
Engine: 3.5-Litre 6G74 V6 24V SOHC

Re: NM Pajero Hex files

Post by WytWun » 25 Feb 2018, 20:49

rush wrote:Was there any outcome with this? ANyone manage to find a XML for the NM Pajero? I am chasing one if someone has it
If you email me the ROM, I may be able to assemble a fairly basic one from a disassembly but it won't be as complete as my Magna definitions as I don't have much time at the moment :(

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