Altitude related boost (or is it fuel) cut?

~Barn~ · Postby **~Barn~** » Sat Jul 28, 2012 9:14

So the wife and I drove to Las Vegas last Friday in the MS6 (returned this morning), and I noticed that when I would get on it - not even WOT, just accelerating into higher boost - my car would jerk abruptly, and the power would cut-out.

It seemed to only do this while I was in the mountains of Colorado and parts of Utah though (?). While I was down in the flatlands of NV & UT, the car was fine and felt exceptionally powerful. Now that I'm back home to DTC elevation, again, the car feels powerful and fine. But both ways in the "mountains" of Summit and Eagle counties, I had this problem.

What is it about driving at elevation that caused me that power-cut? I've never experienced it before driving spirited up in the mountains, but my car may not have had the same setup at the time (read: no Testpipe, different Cobb map versioning).

Thanks in advance for the insight, and any thoughts on how to maybe correct it!

Justin · Postby **Justin** » Sat Jul 28, 2012 9:14

I'm not seeing high flow fuel internals on your mod list. You may be running short on fuel. Was it worse on the uphills, or just in general? Any idea what your AFRs looked like?

~Barn~ · Postby **~Barn~** » Sat Jul 28, 2012 9:14

No, I don't have any internals, but I've always been able to maintain ~1700psi at WOT, with the stock pieces. This is of course when I've datalogged here in town, and not at altitude. Regrettably, I don't know what my AFRs were looking like at the time. Once it happened about 3 or 5 times, I just tried to drive more conservatively, since the power-cut was so jarring.

Colombia28 · Postby **Colombia28** » Sat Jul 28, 2012 9:14

Sounds like fuel cut. I get it every now and again at the track. I too don't have upgraded fuel internals. Though it's never happened to me on the street.

~Barn~ · Postby **~Barn~** » Sun Jul 29, 2012 9:14

Um.... I think I made an idiot mistake. (Don't install maps when you're tired!). I'll make a point of driving up into the mountains in the coming days, and see if it continues to happen.

Justin, I believe you were on the mark, to ask me about my AFRs!

Justin · Postby **Justin** » Sun Jul 29, 2012 9:14

Cool, glad to hear you may have a solution. Keep us updated!

RichB · Postby **RichB** » Mon Jul 30, 2012 9:14

Yea, it sounds like you were getting fuel cut because you were reaching your boost limit at a higher altitude. I've seen boost limited to 12 PSI at a certain altitude on some maps which is unnecessary. All you have to do is adjust your tables and you should be fine...

Altitude related boost (or is it fuel) cut?

Altitude related boost (or is it fuel) cut?

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