Pajero Gen 3 DiD Altitude attitude
Posted: Sat Feb 06, 2016 1:18 pm
Pajero gen 3 DiD 3.2 2002 180 000km 
Smoking missing.
After a nightmare experience, I combed through ”Engines and Engine Management” section on this forum for the relevant threads on smoking and sudden loss of power problems, I found not less than eight members that experienced this phenomena, all of them from a high altitude visiting the Kruger at a low altitude. Problems were resolved when they returned to higher grounds!
We had a similar terrifying experience last week.
Some background: Left Gauteng [ altitude1630m], going down the Abel Erasmus pass between Orighstad and Hoedspruit , we landed behind a heavy loaded truck with six vehicles behind him. Not a chance of overtaking….. crawling down using transmission to assist in breaking [ mentioning this could be relevant, I don’t know!] As we came to the bottom of the pass , what a relieve! ……….. Clear open road, however that’s when the trouble starts: loss of power plus heavy black smoke, could not even see the cars following me. Accelerating pulled me out of the smoke but as soon as we reach 120km/h and started to cruise, the black smoke in abundance with the loss of power started again. Cruising between 1500 and 2000 revs worsened the matter, keeping the revs around 3000 improved the situation. In those crisis sweating / bank balance moments, and option was mentioned that not enough oxygen for the fuel to have proper combustion, hence discharging unburned fuel . Smoking and puffing we arrived at the lodge in Hoedspruit [alt. 450m]. After a couple hours of sweating the following morning, we found through reasoning, common-sense and experimenting with all the available knowledge and options that by removing and blocking the vacuum pipe to the idling [top] diaphragm on the throttle unit solved the smoking and loss of power problem. At the time we did not know what the actual function of the two diaphragms were. We had absolutely no problem driving back to Gauteng. Arriving back home I replaced the vacuum pipe…………… no smoke, no loss of power. I had no warning light [CEL]at all, neither during the smoking nor with the vacuum pipe removed and blocked. Matter of fact my fuel consumption improved to 9,7 lit/100km, still have to control and confirm this with the vacuum pipe blocked off again.
Back home I jumped onto the forum, searching, investigating and found very valuable topics and discussions that confirmed our reasoning, arguments and findings. BUT the big question is…. why is that happening, what is the cause,?? We deactivated the idle diaphragm that cured the symptoms but not the problem. Evidently the air flow gets choked causing the unburned fuel smoke etc. We simulated that by closing the butterfly in the throttle unit manually.
What initiated this process? Low altitude, higher pressure, airflow meter >ECU > solenoid open-vacuum on diaphragm > butterfly closes > choking airflow to engine. Diesel still gets injected with not enough oxygen to do proper combustion.
What roll does the EGR play in this? What about the pajeros that lives in low altitudes? Is there a link between higher kilos, age and sudden drop in altitude and EGR soot build up in the manifold?
I am not a mechanic although I am mechanical minded and have some years behind me and a bit of common sense.
Disabling the idle diaphragm does not solve the problem it! It merely stops the symptoms.?
Now, 800km after this nightmare and she is purring like a kitten without a trace of smoke.
Smoking missing.After a nightmare experience, I combed through ”Engines and Engine Management” section on this forum for the relevant threads on smoking and sudden loss of power problems, I found not less than eight members that experienced this phenomena, all of them from a high altitude visiting the Kruger at a low altitude. Problems were resolved when they returned to higher grounds!
We had a similar terrifying experience last week.
Some background: Left Gauteng [ altitude1630m], going down the Abel Erasmus pass between Orighstad and Hoedspruit , we landed behind a heavy loaded truck with six vehicles behind him. Not a chance of overtaking….. crawling down using transmission to assist in breaking [ mentioning this could be relevant, I don’t know!] As we came to the bottom of the pass , what a relieve! ……….. Clear open road, however that’s when the trouble starts: loss of power plus heavy black smoke, could not even see the cars following me. Accelerating pulled me out of the smoke but as soon as we reach 120km/h and started to cruise, the black smoke in abundance with the loss of power started again. Cruising between 1500 and 2000 revs worsened the matter, keeping the revs around 3000 improved the situation. In those crisis sweating / bank balance moments, and option was mentioned that not enough oxygen for the fuel to have proper combustion, hence discharging unburned fuel . Smoking and puffing we arrived at the lodge in Hoedspruit [alt. 450m]. After a couple hours of sweating the following morning, we found through reasoning, common-sense and experimenting with all the available knowledge and options that by removing and blocking the vacuum pipe to the idling [top] diaphragm on the throttle unit solved the smoking and loss of power problem. At the time we did not know what the actual function of the two diaphragms were. We had absolutely no problem driving back to Gauteng. Arriving back home I replaced the vacuum pipe…………… no smoke, no loss of power. I had no warning light [CEL]at all, neither during the smoking nor with the vacuum pipe removed and blocked. Matter of fact my fuel consumption improved to 9,7 lit/100km, still have to control and confirm this with the vacuum pipe blocked off again.
Back home I jumped onto the forum, searching, investigating and found very valuable topics and discussions that confirmed our reasoning, arguments and findings. BUT the big question is…. why is that happening, what is the cause,?? We deactivated the idle diaphragm that cured the symptoms but not the problem. Evidently the air flow gets choked causing the unburned fuel smoke etc. We simulated that by closing the butterfly in the throttle unit manually.
What initiated this process? Low altitude, higher pressure, airflow meter >ECU > solenoid open-vacuum on diaphragm > butterfly closes > choking airflow to engine. Diesel still gets injected with not enough oxygen to do proper combustion.
What roll does the EGR play in this? What about the pajeros that lives in low altitudes? Is there a link between higher kilos, age and sudden drop in altitude and EGR soot build up in the manifold?
I am not a mechanic although I am mechanical minded and have some years behind me and a bit of common sense.
Disabling the idle diaphragm does not solve the problem it! It merely stops the symptoms.?
Now, 800km after this nightmare and she is purring like a kitten without a trace of smoke.