NT Pajero wont accelerate

[craigs_r75]

Problems with 2010 NT Mitsubishi Pajero Diesel Auto Trans.


The Pajero goes into a sort of limp home mode but there is no engine Malfunction indicator.


Just took it for another drive after disconnecting battery for 10 minutes (to see if something would reset). We drove for 20 minutes with no problem in busy stop start traffic, and half way home it started playing up. One thing I noticed this time was that if I kept the rev's up above 2500 RPM by changing gear manually it drove ok, and its only when the rev's drop say at a stop light, that it has a problem. It was necessary to floor the accelerator to clear whatever is the problem and after 5 seconds or so it would clear and rev up then by keeping the rev's up I could drive it. It is also interesting that the engine rev's freely when in park.


Here are the symptoms I have seen over the last month or so.

1. It does nothing when push accelerator.
2. Often it will drive very slowly as if it is in limp home mode, but not always. In these cases it is not possible to drive at all.
3. The engine never stalls and can always be started easily with no throttle and idles nicely.
4. Mostly it will accelerate strongly if put accelerator to floor and hold there for maybe 10 seconds, only works on 50% of times.
5. Have never had problem when towing 2.5 tonne caravan.
6. Most often occurs when moving off from stopped.
7. The engine light never comes on, and checking the OBD2 reader there are no fault codes.
8. First occurred about 1 month ago, when pulling out from T intersection, Pajero got into middle of crossroad and engine did not respond. We drove to side of rode, pushed throttle a couple of times and when then able to drive away.
9. It was ok for some weeks during which we travelled away with caravan, did maybe 1500Km.
10. Then when driving to Greensborough from Doreen had problem. Struggled home. Bought a new fuel filter and fitted, and car was good for another 2 weeks, part of which was another caravan trip of 1000Km.
11. A few days later during local driving same problem again.
12. Even though fuel filter looked ok, I changed it again and it was immediately playing up again, so I don't think it is the problem even though it seemed to fix it the first time.
13. If leave for a day, it seems to drive ok for half and hour or so.
14. A couple of times the engine has not shut down for an extra 1 second when the problem is occurring and switch off ignition, but normally shuts off immediately.
15. The is no shortage of power at any time when everything is ok, Even when the problem is occurring and you put the foot to the floor, it will spin the wheels when it takes off. So I think it is unlikely to be a blocked inlet manifold.
16. The problem hasn't occurred when the engine is cold and we have towed on 36 degrees days through heavy traffic without problem.
17. The problem is getting worse and has happened the last 4 times I have driven it. It now seems to most likely happen after the car is run for about 15 minutes in light traffic (stop start driving).

Actions taken

1. I removed the top part of the inlet manifold to see if it was full of soot, it didn't seem too bad, I scraped about a cup of soot out and replaced it. As the manifold and EGR valve didn't seem too bad, I didn't bother pulling off the lower manifold and injectors.
2. I have cleaned the air flow sensor with CRC spray.
   
   
3. Looking at the ECU there doesn't seem to be any power chip or anything fitted.
   
   
4. When the Pajero is giving the problem, the OBD reader doesn't show any fault codes, but it shows the non-continuous monitors (EGR, O2 sensor, Catalyst etc) are NA?? only the Comprehensive Components (CCM) are working.
   Is it worth getting Mitsubishi to connect their analyser to see if possible to get any more detail?
   
   
5. Could it be the ECU??
   - Can I fit a second hand ECU. The locks etc all seem to be working ok
   - Is it possible to reload the software in the ECU or refresh it somehow?
   
   
6. The engine check light on the dash comes on and always goes out correctly when the engine starts.
   
   
7. Could it be the throttle body, air flow sensor or fuel injection. What could be faulty but not give a fault code?
8. Could it be a blocked exhaust?
   
   
9. There seems to be a few connectors under the bonnet that do not connect to anything, is that just because it is a common harness with petrol engine, or is there something missing? There is one near the fuel filter, and 3 near the air filter and 1 near the fuse box?

Car purchased 6-7 weeks ago from Toyota dealer in Geelong and I don't know any previous history and I have done about 3000Km since purchasing it.


Does anyone have a clue as to what is happening

[nj swb]

Not a clue.

Suggestions:

Set up an OBD monitor (Torque / Ultragauge / Scangauge) to monitor the following parameters. Try to get a feel for how they behave "normally", and look for any abnormal behaviour when the car is playing up.

• Pedal (I think I'm monitoring Pedal E) - see if the signal responds properly to the pedal at all times.
• Commanded EGR & actual EGR (or EGR Error?) - perhaps the EGR is "laggy" at times, but responds before the ECU logs an error?
• Throttle Position (changes with EGR) - if the throttle plate is closed at the wrong time it could be strangling the engine?
• Fuel rail pressure - mine changes dramatically depending on load, see if yours drops away when it should be high? Although I would expect fuel pressure problems to log a code.

As much as it would be nice to have it sorted out by professionals, I wouldn't trust a Mitsubishi dealer to diagnose and fix this, much less a non-Mitsubishi dealer.

Good luck.

[spot01]

Car purchased 6-7 weeks ago from Toyota dealer in Geelong and I don't know any previous history and I have done about 3000Km since purchasing it.

I'd start with the dealer you purchased it from, assuming it is covered under s/hand warranty:

https://www.consumer.vic.gov.au/cars/buying-a-used-car/warranties

[craigs_r75]

Thanks for the thoughts.
Unfortunately the OBD reader I have is just a $20 cheapy from China and cannot do any logging.
The car is not covered by the normal warranty as it has 166000Km's.

[spot01]

[QUOTE=craigs_r75;571152] When the Pajero is giving the problem, the OBD reader doesn't show any fault codes, but it shows the non-continuous monitors (EGR, O2 sensor, Catalyst etc) are NA?? only the Comprehensive Components (CCM) are working. Is it worth getting Mitsubishi to connect their analyser to see if possible to get any more detail?

Interesting these are NA when the problem occurs - are they different when running properly?
I wonder if there are some codes the generic ODB reader isn't picking up?

[dhula]

Are there any other lights on/flashing when you are having problems, eg the ESC light or TC lights

Take some pics of the disconnected connectors you are referring to. Knowing what they are may help point in the right direction. When taking the pics include a little of the surrounding area to give some context as it will help identify the connector.

You say you cleaned the MAF with CRC, did you use proper MAF cleaner or something else in the CRC brand.

Has the in tank filter been checked/cleaned/changed

Have all the fuel lines etc pre engine been checked for leaks to ensure an air tight seal

You say that you disconnected the battery to see if anything reset, did you follow the correct steering angle setup procedure.

[craigs_r75]

Lots of comments received thankyou. I will try to comment on each.

1. The administrator suggested some area's to log to see if there are any problems
   - Pedal position and throttle position. I suspect the pedal is working correctly as when I drive in manual gear mode to keep the rev's up, the throttle is smooth and even from small movement to large movement.
   - The EGR. Maybe I should fit a new (or maybe second hand one) to see if it fixes the problem. If it was faulty what would happen. I'm not sure how it affects performance. Its obviously lets some exhaust in at low speed/rev's. If it stayed open when trying to accelerate from low rev's would it cause the problem I'm seeing? Is there any way to temporarily disable the EGS ( by shorting wires etc) to verify if that is the problem?
2. The monitors on the OBD are always the same, engine running, not running, with and without the problem.
   
   
   
3. I do wonder about my cheapy OBD reader (although I've used it on other vehicles and its worked fine) and was thinking about getting Mitsubishi to plug there's in. I understand that the Mitsubishi one has extra features. Even if I had to pay something for their time I might get some useful information.
   
   
   
4. There are no other lights lit up or flashing when the problem occurs, all the lights show up when turn the ignition on and disappear once the Pajero is started.
   I haven't changed the intank filter. Is there one? It could possibly be something like that as the first time I changed the engine bay filter it seemed to make a big difference for a couple of weeks. There is no leaking fuel, but maybe its something I should check further. Is it hard to change the intank filter.
   I didn't follow any “follow the correct steering angle setup procedure “ but the Pajero seems to be driving fine.

[nj swb]

OK, I previously missed this one:

14. A couple of times the engine has not shut down for an extra 1 second when the problem is occurring and switch off ignition, but normally shuts off immediately.

Delayed shut-down can be a symptom for those who have drilled holes in their throttle plate to compensate for an EGR blanking plate. On shut down, the throttle plate closes to restrict airflow to the engine, preventing "run-on". A hole in the plate allows more airflow, so the engine can "run on" momentarily after shutdown.

This extra run-on you're experiencing could be related to operation of the throttle - in this case, not closing properly when it should.

If it is sticking for whatever reason, and sticks in a restricted position, that could also cause engine problems.

It's a long shot, but confirming that it's moving smoothly should be a reasonably simple job.

[kiwi1973]

OK, I previously missed this one:


Delayed shut-down can be a symptom for those who have drilled holes in their throttle plate to compensate for an EGR blanking plate. On shut down, the throttle plate closes to restrict airflow to the engine, preventing "run-on". A hole in the plate allows more airflow, so the engine can "run on" momentarily after shutdown.

This extra run-on you're experiencing could be related to operation of the throttle - in this case, not closing properly when it should.

If it is sticking for whatever reason, and sticks in a restricted position, that could also cause engine problems.

It's a long shot, but confirming that it's moving smoothly should be a reasonably simple job.

It's common to have this delayed shut down due to open throttle plate when their is an issue with the vehicle. However, if this is happening and causing the car to behave like this, then presumably there must be a fault code stored too.

[flyboy]

I’d be checking the fuel tank too.

Plus the tank internal screen as someone already suggested.

You could have crud in there which is intermittently covering the tank outlet filter screen.

[kiwi1973]

This does sound like a really odd one. A few thoughts:

I wouldn't necessarily assume that the issue cannot be related to a blocked manifold just because the car has plenty of power when things are working ok. This demonstrates that the manifold isn't sufficiently blocked to affect performance, but doesn't tell you if there is carbon buildup affecting the tube line up to the MAP sensor (on firewall near fuel filter), which in turn controls boost and thus has the potential to significantly affect engine power production.

I was very surprised to read that certain OBD2 parameters are shown as N/A when the issue is occurring. My first thought was that this might indicate something serious with the ECU, but on further reflection I am minded to wonder if something is up with your OBD2 reader. Have you had the fault occur at a time when the OBD2 reader was unplugged? (If you leave it in all the time then I suppose you won't have tested this). Another thing that makes me wonder about your OBD2 reader is that your delayed engine shut down is almost always associated with an engine code - which caused me to wonder if you're not seeing a code perhaps because something is amiss with your OBD2 reader rather than there actually not being a code set. If there actually is a code that you're just not able to read, then getting to that code could be half way to resolving this.

And one further thing, if you're using Torque have you read up on these forums about the best connection protocol to use? Sometimes the auto mode sets a protocol that can acutally cause issues with the transmission. It may be worth trying at least changing the protocol settings and maybe try changing to a new/better OBD2 reader.

This fault could also point to a faulty accelerator pedal position sensor, though those don't usually seem to give any issues.

[craigs_r75]

Hi, I just had a closer look at the throttle body and butterfly. It all seems clear (no soot or anything) and seems to move easily and smoothly with the accelerator pedal, there are no ridges or anything on the body. When the engine is switched off the butterfly shuts completely and after a short time goes to the rest position (approx. in middle).

Mind you this is on a cool motor when everything is working ok, but it looks ok. The engine never seems very hot and the temperature guage never goes above half even towing on a 36 degree day.

I mentioned that the delayed shutdown has occurred twice in maybe 200 times, so maybe we are reading to much into it, I just mentioned it for completeness.

I had a look at the map sensor (I assume your talking about the vacuum connected sensor between throttle and EGR) removed the line and sensor, blew air through it, it all seemed like new.

I have tried the OBD reader when car is running, stopped. The fault occcurs in all these conditions, and no error or engine light appear.

Is it worth getting Mitsubishi to reload the software in the ECU if this is possible, I'm a software engineer (and a enthusiastic motorcycle tinkerer for 4 days a week since I retired 10 years ago) and I tend to look for these things.

[craigs_r75]

Forgot to mention that the fault occurs when the OBD reader is not connected as well (normally the case).

[Allan2]

Is it a petrol or diesel engine?

[geopaj]

Is it a petrol or diesel engine?

First line of the first post...

Problems with 2010 NT Mitsubishi Pajero Diesel Auto Trans.