[DirtyDan]

Originally Posted by ringoism

There is definitely no risk of engine damage

For what it is worth, I have driven about 60,000 kilometers with my 2013 Thar with the air mass sensor unplugged and EGR blocked off....absolutely no problems.

I have driven about 35,000 kilos on my 2018 Thar with the air mass sensor unplugged and the EGR blocked....absolutely no problems.

I get a big increase in responsiveness and a very noticeable increase in rate of acceleration.

[ringoism]

Originally Posted by DirtyDan

I have driven about 60,000 kilometers with my 2013 Thar with the air mass sensor unplugged and EGR blocked off....absolutely no problems.

Thanks Ken, was thinking of you when re-reading this thread, glad to see you're still active here. Had seen your similar comment earlier.

I looked into the official (PDF) service manual for Getaway, realized it's NOT a full 5v signal that gets sent to the ECU when MAF disconnected, as some here claimed. What actually happens is that when the ECU doesn't receive an airfllow signal in the expected range of 0.5-5v, it is just switching to a default map which assumes: 1) 20°C ambient on the integrated temp sensor (which is close enough a good part of each year in the hills), and 2) "normal" fuel metering based on engine rpm and throttle position. Being that engine displacement is a fixed volume, then assuming a fresh air filter, unclogged intercooler, and decent overall engine condition, this assumed default airflow should be reasonably close to ideal within a moderate altitude range with "average" weather conditions, etc, etc.

Everything here then points to OE mapping problems, not hardware. We should remember that this development happened pre-Three Idiots, hill touring was more limited. And most hill folk themselves were more pragmatic on one hand and typically lower-income on the other, and would have favored (as many still do) more rugged vehicles and the good old DI's of whatever form than Scorps and CRDe Thars, which at some level (good as they are) really were originally intended for greater comfort, quiet refinement - and posing!

For the <5% of customers who were going to drive the hills in a CRDe, it probably wasn't deemed necessary to send teams to do the extended R&D, etc. As you mentioned, down in Punjab people loved these, had no issues.

Maybe therefore Team Mahindra, without much actual testing and tweaking, just got the fuelling compensation for altitude totally wrong, such that the default map runs better.

It is also possible that even BS3 norms weren't so easy to conform to with that particular engine (though DI's did it with full manual fuel systems and longer strokes), and that they were simply forced into compromises.

Whatever, on a well-maintained car running at anything but extreme altitudes/ temps, the map should be expected to run fine and is not going to damage things any more than running carburetors and manual diesel injection pumps would have in the day, 99+% of which never were compensated for altitude & temp! Throughout most of automotive history, vehicles ran on mechanically-fixed "default maps" pretty well most of the time with no issues - and that's what a CRDe with a disconnected MAF/temp sensor gives us!

Btw I am doubtful now that adding a resistor in the MAF wiring (as a few mentioned incl. me!) would help matters - because if the voltage output isn't within the specified range, a code will trigger, and it's going to switch into the same default map anyway. Depends how far away airflow at idle /max speeds put us away from 0.5v or 5v in unaltered form I guess, could be a little wiggle room there that could make a difference but may or may not be enough to make a real impact. Worth a look maybe, will try and measure this real-world operational voltage range one day.

Anyway this "Everymod" that some of the VAG guys are doing on YT generally appears to add the resistor to the fuel rail pressure sensor, which tricks the ECU into thinking pressure is lower than actual and that it must compensate by increasing pump output pressure and/or lengthening injector pulse width. Tuning boxes do the same in a potentially more sophisticated way. Hence more power - and smoke, and presumably fuel consumption when "in it", depending how badly you try and trick it or how smart the tuning box maps are.

I was wondering how your Thars have run at really high altitudes and/or really extreme temps.

I'd imagine that without mass airflow compensation, engine would run a bit too rich at high altitude. And without temp info would assume less dense air than actual at super low temps and meter too little fuel. Which come to think of it might help winter FE at the expense of some peak power.

Technically the wire to the airflow portion only could probably be clipped / have a switch added, and the temp signal lead left alone if that seemed beneficial. Pinouts are there in the manual, it would be an easy job if selectable normal (closed-loop) operation was sometimes desired or offered benefits in FE or whatever.

Whatever, it's really a shame it wasn't mapped right WITH the compensation functional. Getaway runs so effortlessly and transparently now, no need to downshift all the time below 1500-1600 rpm's, no need of severe clutch abuse, can lug it down easily to 1000-1200rpms and it will pull cleanly from there. Still no real power till boost comes in till later, but at least it isn't faltering / falling on its face anymore. And I think I'll almost never have to use 4Low just for getting started on inclines now.

Wish I'd done this earlier, wifey wouldn't have roasted the clutch that fateful night, and I'd have saved ₹4600 on the new disc...

-Eric