fass fuel pump stops working at high elevation
#1
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#4
3,000 is far from "thin air" and I can't see how the slight difference in atmospheric pressure would cause your lift pump to stop working. You should probably start thinking electrical problems or an issue with the pump itself. Call FASS and describe your issues to them, they may have a workaround.
In MT I run at 5,000+ ft above sea level 24/7, and I never have issues when I drive to lower elevations (1,500 to 2,000 ft).
---AutoMerged DoublePost---
To be a little more specific:
At 700 ft above absolute sea level, you are at 99 kPa (Kilo Pascals) meaning you have approximately 98% oxygen availability per atmospheric unit.
At 3,000 ft, you are at 91 kPa, with 90% oxygen availability.
Barely enough of a difference to make a carbureted engine hiccup, let alone an ECU regulated modern engine.
In MT I run at 5,000+ ft above sea level 24/7, and I never have issues when I drive to lower elevations (1,500 to 2,000 ft).
---AutoMerged DoublePost---
To be a little more specific:
At 700 ft above absolute sea level, you are at 99 kPa (Kilo Pascals) meaning you have approximately 98% oxygen availability per atmospheric unit.
At 3,000 ft, you are at 91 kPa, with 90% oxygen availability.
Barely enough of a difference to make a carbureted engine hiccup, let alone an ECU regulated modern engine.
Last edited by tangodown; 11-27-2011 at 03:29 PM. Reason: Automerged Doublepost
#5
#6
Another possibility is not the elevation change, but the angle of your truck. Does it happen on a full tank just as regularly as a half empty or quarter tank? If the FASS pump is unable to siphon fuel from the tank it may be starving the engine. Do you have any fuel rail sensors that would give you an idea of how much fuel you are getting to the injection pump in the first place?
I'm just thinking, driving around in town = fairly flat and little to no hills... driving up the mountains = 6% grades or better, here in MT anyway. So that may be another possibility.
I'm just thinking, driving around in town = fairly flat and little to no hills... driving up the mountains = 6% grades or better, here in MT anyway. So that may be another possibility.
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ok guys i think i might have it narrowed down to the old relay for the stock fuel pump whoever installed my fass ran through that then to the pump i was gettn 12 V on the line comming into it but i didnt have my other meter to test continuity on the ice cube relay i messed with it a little bit went and ran it and it ran fine for couple miles then barely was runnin when i pulled back up to the house it just didnt sound like the pump was running full bore like it was when i left the house.
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