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Discussion Starter #1
Hey guys, I've got a pretty basic question (at least I think it is)... I've got a SBF single turbo car with the classic FAST system. I made a cam change and now the issue I am having is with the base fuel curve. The graph is map vs rpm. With the car idling the green bubble in planted on the very bottom row of the graph. It moves side to side with engine rpm change but it will not move up and down (increase/decrease in MAP Kpa). The map sensor is reading 50-60 kpa of pressure at idle. So the bubble should be on the 3rd or 4th row and not buried on the bottom row. The car stumbles on initial throttle and even dies (too much fuel). I try to take fuel out on the base fuel curve but it has NO effect on the issue. If I rev it up and keep it at a constant rpm (2000 or 2500) it starts popping through the exhaust and the green bubble is still pegged on the bottom row. Any advice or tips you guys could give me would be greatly appreciated. I'm at a loss on this one.
 

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With the ignition on and the engine off, where does the bubble sit at? It should be at 99kpa

Have you tested the map with a pressure source to see if it responds?
 

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Discussion Starter #3
The bubble sits at 1 (bottom left corner) on the fuel base curve map. On the main dashboard the map reads 50-60kpa at idle. I will check the main dashboard value tonight with the car off. I called FAST and they think that the dashboard being used for the fuel base curve doesn't have map kpa selected for referencing. I forgot a small tidbit of information... if I open the base spark curve, the map sensor operates like it should. At idle the bubble is about 3-4 rows up and moves with rpm movement. I will do some more checking tonight and see what I can come up with. Thanks for the help Dustin.
 

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Check to make sure the map is set up for your 2 or 3 bar map sensor and also make sure it isn't in alpha-n mode. It should be in speed density.
 

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Discussion Starter #5
Check to make sure the map is set up for your 2 or 3 bar map sensor and also make sure it isn't in alpha-n mode. It should be in speed density.
Yep! I checked both of those at the track last night. They were both good. I'm going to check the dashboards tonight and see if I can at least get the map to read on the base fuel curve chart.
 

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EFI/N2O JUNKIE
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Send Kgiblin a PM and I bet he can quickly help you with your problem. Makes no sense that your "bubble" is moving-around correctly in your Timing Map and not in your Fuel Map.
 

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Discussion Starter #8
I figured it out. I had selected dashboard 1 for my base fuel curve which had 10 sensors on it. Apparently if you run more than 8 sensors it could affect the way some of them read on the chart. I reset the dashboard with only 6 sensors that I actually needed on the base fuel curve chart and now with the car off it sits at 99 like its supposed to and moves while the car is running. Thanks for the help guys. I really appreciate it.
 
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