[Nick Gibson]

Perhaps your EGT gauge is reading incorrectly. I cant think of anything else.

Hi Marius

This was my last port of call so to speak, I have spoken to Brian Cotton at madman and there is a "K" type thermocouple voltage (not resistance) lookup table to test the probe itself. He said you need an accurate thermometer and an oil bath heated up to 200 deg C. You would then take readings at 10 minute intervals as the oil cools down and note the bath temperature & voltage out-putted by the thermocouple. One could then compare the two by using the lookup table attached and see if it is accurate.

Eish. Need to find a thermometer to do the test...

[Nick Gibson]

You have basically checked everything! What does the intercooler look like? Have you cleaned that to assist in getting cooler air in, although I suspect a blocked intercooler should lead to lower power and not higher EGT.

How was your EGR blocked off? Blanking plate? If it is easy to remove it might be worth running it with EGR active ( no blanking) and comparing to blocked off results. I am led to believe that an active, proper working EGR will actually reduce heat in the combustion area and "may" just reduce EGT's as a result? Or am I wrong? I have often wondered if my blocked EGR is not causing my heat buildup after my rebuild when towing on extremes but has not yet gone the route of testing it. It was blocked off the same time as the rebuild having been left alone for many years to do it's designed thing.

If it is any consolation I believe that the 4m41 engine is very well controlled electronically to prevent high egt's so should be able to protect itself sufficiently in this regard.

I wonder if the MUT-II tool can read the EGT as well from the engine management system? Maybe worth your while to ask and if it does to take a drive with one and compare to your Madman readings.

CATS

HI Cats.

Thanks, I do believe the Mitsubishi ECU is quite careful with fueling of the motor and thus quite EGT friendly - seems I am the only one with the the High EGT problem with the 4m41 motor.

Inter-cooler, it has been removed and cleaned out with petrol & prepsol quite early on (last year) - before I fitted the EGT probe. I also 'combed' the fins a bit to improve airflow through the cooler. No cracked or dings in it and seem to be well protected behind the LYNX bash plate.

EGR, I have simply temporarily disabled it by removing the vacuum pipe from the actuator and blocked it with a bolt. I have not done it permanently yet, it did not change the EGT's at all. I am still of two minds when I come to the EGR removal/blanking.

I am seriously looking for a diagnostics tool that will allow me to see what is happening with my van (as yoou say - possibly estimated egt's ??), but the OEM MUT II unit is just too expensive for my needs right now, and there aren't any aftermarket units available...

Nick

[Roelf_le_Roux]

Hi Nick,
I think Snoopy's overheating problems were traced (to some extent) to the aftermarket bumper. I cannot help but wonder what effect your Lynx bash plate has on the intercooler efficiency.

[larry007]

Hello Guys - what are high EGT's?

idle temp?
normal driving temp,
highway 120 - 130km/h
full throttle uphill?

GK

General consensus is that high Exhaust Gas Temps refer to 700'C+.

In my findings:

Idle - less than 200'C, most gauges ignore less than 200'C
Light use in town - 250-350'C
Light use on Highway - 350-450'C
120kph on Highway - 400-500'C

And then when pushing the motor by towing, speeding or going up a mountain pass, keep an eye on the temps to keep it under 700'C. I never felt comfortable going over 600'C for extended periods of time.

I remember towing a loaded holiday trailor on a mid-summer day in the Karoo with a head wind. I was running 580'C @ 90kph on the slightest of inclines over lunch time. As we dropped down to DeDoorns at 3PM, all was back to normal again. Afterwards I realized that if I didn't had the gauge, I would have kept going at 110kph without knowing the extreme temps I was expecting the motor to handle. When ambient temps are high, everything takes longer to cool down, so I am almost certain damage would have been done.

[Ritteling]

General consensus is that high Exhaust Gas Temps refer to 700'C+.

In my findings:

Idle - less than 200'C, most gauges ignore less than 200'C
Light use in town - 250-350'C
Light use on Highway - 350-450'C
120kph on Highway - 400-500'C

Thats consistent with what I see. Also from a madmanII system with the probe on the exhaust manifold before the turbo, thus reading a combined temp for all 4 cylinders.

I have had my alarm, which is set at 700, beep at me 2 or 3 times. in all occasions I was cruising on 130kph speedo with the speed control set - then hit an uphill pass. the speed control tries to do its job and the temp jumps quickly. Its actually quite easy to hurt the engine when you're 'just cruising along' on the open road.

[Nick Gibson]

Been doing some more research... this video is what I am sure I could achieve (similar readings) if i tried hard enough. I Have hit 770 deg C once...

https://www.youtube.com/watch?v=hPpjy5leniM

from here:
http://www2.pajeroclub.com.au/forum/sho ... post433199

Anyone else have seen vaguely similar readings as in the video?

ps. How do you embed a YouTube video? I seem to be struggling, the embed function does not seem to work?

EDIT. It seems to have worked somehow...

[Nick Gibson]

Following on from these threads:
https://www.pajeroclub.co.za/forum/viewtopic.php?t=3731
and my exhaustive EGT fault-finding I think I might have found the problem. My Pajero pulls like and absolute train up to about 90kph (lots of grunt), but loses steam from 100kph onwards. Overtaking is sluggish and painful at times with my EGT alarm screaming at me from time to time. I think my pump has been re-installed in a slightly retarded position.

Symptoms of a retarded injector pump timing: High low down torque, low chamber pressures, low high end power & high EGT's
Symptoms of advanced injector pump timing: Lower EGT's. higher chamber pressures, higher power in upper rev range, noisy idle.

Apparently the Covec VRZ injector pump retards its timing even further at the higher rev (3000RPM on-wards) range to lower the pressures in the cylinder, I believe the high EGT's I am experiencing are due to the injection being retarded so much that it does not have a chance to combust completely in the cylinder and get expelled into the exhaust still burning = High EGT's? Add to that low high end power as un-burnt energy is being sent down the exhaust as heat instead of driving the piston donwards?

I believe I have ruled everything else out, is my logic sound or am I missing something here?

Should I advance it a mm or two?

[Nick Gibson]

Have some more feedback on my issue.

I have had a lumpy rev at about 1500 RPM with a bit of engine vibration, and I also have had a persistent slight diesel smell about my van for a good while now. Got under my van and found a slight dampness around the back of the injector pump where the injector pipes connect. Seems one of the union nuts on an injector pipe was not snugged up correctly when they re-installed my pump - (see yellow highlighted pipe).

Injector pump pipes

Unfortunately the only way to snug up the injector pipe in question without removing all 4 of them, was to access it from underneath the vehicle by removing the starter motor. I tightened it up with 19mm spanner, some double jointed dexterity is needed, and all was good.

I also found the the short rubber leak off hose (No. 7) was rock hard and had perished and was also leaking a small amount of fuel. This is the diesel injector leak off hose that returns the un-injected fuel back to the injector pump to be sent back to the fuel tank to be re-cycled. It is used for cooling the injectors.

I had to remove the whole steel pipe from the banjo fitting at no. 9 to fit a new hose due to access issues. Seems the fuel is VERY hot coming from the injectors and had 'cooked" the cheaper hose used by CL diesel, allowing fuel past the spring clamp as it could not seal anymore; as it was not pliable. I replaced it with a better quality hose supplied by them and will see how it holds up.

End result:
My EGT's have come down at least by about 50-80 deg C, seems the one cylinder was not performing as it should causing the other 3 to work MUCH harder thus increasing the over-all EGT's. On a usual hill where I used to hit about 730 Deg when flooring it, I now max out at 650-670 deg C. Still a bit high but in the 'safe(er)' zone now. Engine no longer has the lumpy idle and seems to pull alot better.

Must say I am Happy Chappy!

[Ritteling]

End result:
My EGT's have come down at least by about 50-80 deg C, seems the one cylinder was not performing as it should causing the other 3 to work MUCH harder thus increasing the over-all EGT's. On a usual hill where I used to hit about 730 Deg when flooring it, I now max out at 650-670 deg C. Still a bit high but in the 'safe(er)' zone now. Engine no longer has the lumpy idle and seems to pull alot better.

Must say I am Happy Chappy!

Hello Nick.

Great to see that you have sorted out your problems. Thanks for the informative posts!


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[Ritteling]

Been doing some more research... this video is what I am sure I could achieve (similar readings) if i tried hard enough. I Have hit 770 deg C once...

Seriously high egt's. I take my foot off after 700 degC


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