Pajero Owners Club of South Africa

Hi everyone.
I am technically disadvantaged, so I need pointers from the people in the know, please. Have looked through the various threads, but I cannot seem to "marrry" the engine symptoms with those mentioned in other threads.

Bought my Paj LWB blister fender Feb last year, 165k, engine was redone due to piston through the block. According to me the engine was doing fine(ish), have power, but lacking somewhat as I expected it to have even more oomph though. Heavy on fuel like you cannot believe! Then the front oil seal at the crankshaft blew. Took it in for repairs, and the mechanic told me that the "crank shaft sensing blade" is suspect as it have other holes drilled in it and he did not trust the situation. So he fitted a brand new crank shaft sensing blade. Since then the engine is less powerful than a 1600 cc engine! He re-checked the timing belt and timing. All fine according to him. Mechanic says it is ECU.

Discussions with various people pointed to ECU-related problems, although no engine management light comes on ever. Took it to SAC, they re-checked the timing and timing belt, confirmed that it is correct, also said ECU. Needless to say, I had a SAC chip installed. Motor is doing wonders now, however, between idle and 1000 rpm (when the chip kicks in) the engine is still extremely rough. Fuel consumption before and after the chip is unchanged. Battling to do real slow crawling below 1000 rpms, because the engine either pulls itself dead on a "definitely not serious" incline or does not react when I step on the accelerator. Takes literally a second or two before the engine responds. The moment the revs fall below 1000, the engine battles. When the chip is unplugged, this erratic behaviour is carried on over the 1000 rpm mark and the engine is back to 1600 engine territory.

Before I take out the ECU to have it checked (at a small fortune), can you give me some pointers where to start looking for possible other sources of the problem(s)? I had someone check all the electrical components' resistences, wattages, volts, etc, and it seems to be fine. Which confirms no lighting up of the engine management light.

Questions: What precisely is the function of the "crank shaft sensing blade", and can it be fitted in more ways than one? From what I could see, no, it cannot, but I am not sure. I.e. can it be that the machanic has indeed fitted the new one incorrectly?

I still feel that the motor is underpowered by at least 15Kw. The dyno measured 92 Kw on the rear wheels after the chip was fitted vs 62 Kw before!

Any ideas? Or is it the ECU that has effectively packed up? I know that the chip can only do so much from an in-efficient ECU.

Thank guys, your input is highly appreciated.

Can the people simply not install a new ECU and see if it works? If it does, you pay for it. If it doesn't, the ECU goes back on to the parts shelf. The labour charge in this "test" shouldnt be all that much.

Have you scanned the ecu to see if it has error codes? Maybe it is just in limp mode.

That will be my last resort, as the agents are very "stuck-up" regarding the method of testing. They want me to book in the vehicle and run the full diagnostic testing procedure. Depending on what the outcome of that testing is, will they fit a new ECU. If the testing does not indicate that the problem is with the ECU, then they do not want to put in a new one just to check. They argue that the ECU is then not new anymore. (I know, it is a load of nonsense!) Hence me trying to do all I can outside the agents until I really have nowhere to go but the agents.

What I am really scared about, is the methodology being applied, that is, fitting new parts where a possible problem might be until the problem has eventually been found and cured, ending up in huge unnecessary bills. I am very allergic to agents, I must confess. I am yet to have a bad experience with Mitsubishi-Motors, but their response as described above has put of me off, big time! I am quite happy to pay for the labour, but the "red tape" and policies and procedures are unbelievable. I am not aware of somebody that has a working ECU somewhere. Tried various scrapyards to find an ECU to do the test myself, but to no avail.

Maybe, just maybe, someone on this wonderful forum has experience the same problems in the past and can pinpoint the most likely cause immediately.

4ePikanini wrote:Have you scanned the ecu to see if it has error codes? Maybe it is just in limp mode.

If it was in limp mode, then the engine management light should have come on, indicating some sort of problem, or am I mistaken?

Thanks for the replies Simon and Marius, much appreciated.

It is one of these types of problems where you sit on the stoep with your pipe in your mouth, chewing the cud over this problem and going over the logic of it all!

I'm not familiar with the mitsu OBD system but my 2000 passat had a o2 sensor fault and oil level fault ( luckily turned out to be a bad sensor ) that didn't trigger a CEL.

This is just a long shot but have a look at the spark plugs in the motor, they should be the plug with an r in the coding indicating a resistor plug. If the plugs are not resistor type it does mess the ecu around especially at lower rpm range. I realise that these are a schlep to get to but it might just be the source of the problem

Thank you Henk, will definitely explore this route as well.

I had the vehicle tested twice at two different places with the MUT II diagnostic tool. No fault code, no "limp mode", no error, no nothing!

But maybe, just maybe, we have located the problem. I eventually managed to borrow another ECU. Engine performs better than with my ECU with the Unichip UNplugged on both ECU's, but not as good as when the Unichip is plugged in (which is understandable). So, I definitly have an ECU problem. However, when the Unichip is UNplugged, I do not have the erratic problem between idle and 1000 rpm on either ECU's, but then I do not have any power either. So, it seems that the Unichip is actually causing the erratic behaviour! I've been in contact with SAC and will see them tomorrow.

Man, chasing this problem is like hunting. Take it one step at a time ...

Thanks for all your responses, gentlemen, much appreciated.

Hi how did you get on with the ecu.Hate to say it but the exhaust isnt blocked is it

Digger, no the exhaust is not blocked.
There is definitely something wrong with the ECU, albeit not to the extent that it is totally useless. What was also discovered which add to the problem, are the butterfly valves in the inlet manifold. The bushes are worn out causing extra air to be sucked into the manifold as what the ECU actually registers via the air flow sensor, effectively causing a weak mixture. This is much more prevalent at idle stage than high revs. At higher revs there is no erratic behaviour.

I read on some of the other forums about the butterfly valve issue, but due to lack of time have not been able to read up some more on it.