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D u a l s t a r
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Discussion Starter #1
I installed a APEXi EL boost gauge this weekend. It seamed to be working. I would read a negative pressure at idle. And would get about 0.75 kg/cm2 (10.5 psi) at WOT. So I thought everything was great. Then to day I was sitting in the car waiting for the carwash, listening to music with the motor off. The line I taped for power to the gauges was active. Suddenly the boost needle started to move. It went up to about 1 kg/cm2 (14 psi). I thought it would fix it's self after I started the motor, but no. Driving back from the carwash the guage was reading 1.5-2 kg/cm2. And the reading at idle shows a positive manifold pressure. The guage boddoms back to it's highest (lowest?) negative reading when I turn off the power. but once the power is back the bad readings are still there.

here are some pictures:

motor off


motor idle


motor reving out of gear
 
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Make sure that the hose that you have running to the gauge is not cracked or leaking. mine did this once and i found out that the the hose cracked at the gauge nozzle. but then again on my old greddy boost gauge used to just go haywire all the time showing weird boost readings and positive manifold pressure. I scrapped that one and got a new one.
 

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D u a l s t a r
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Discussion Starter #3
1/4mile in style said:
Make sure that the hose that you have running to the gauge is not cracked or leaking. mine did this once and i found out that the the hose cracked at the gauge nozzle. but then again on my old greddy boost gauge used to just go haywire all the time showing weird boost readings and positive manifold pressure. I scrapped that one and got a new one.
Yea I checked the hoses. One did have a tight bend, so I moved then around. It didn't make any difference. This is a brand new, electronic gauge. I guess it could be broken. Anybody have a better idea?
 
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try hooking the guage up to a known pressure source like off of a air compressor and compare the readings with what is supposed to be going out. that should give you a good indication if the gauge is not working correctly...
 

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pics no good!
 

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D u a l s t a r
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Discussion Starter #7
1/4mile in style said:
try hooking the guage up to a known pressure source like off of a air compressor and compare the readings with what is supposed to be going out. that should give you a good indication if the gauge is not working correctly...
With the sensor unpluged from the boost line (just reading the outside air) the gauge read about 1 kg/cm2. Shouldn't the gauge be reading ZERO there? I think some how the gauge got a offset of about 1 kg/cm2, so now all the readings are that much higher then they should be. I don't know how I could reset the zero point thought. Any ideas?
 

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tis was at the car wash right? You probably got some water in the sender unit pull it off and low it out with compressed air dry the contacts and rewire.
 

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D u a l s t a r
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Discussion Starter #9
dzeiler said:
tis was at the car wash right? You probably got some water in the sender unit pull it off and low it out with compressed air dry the contacts and rewire.
I wish it was that easy. The problem deffently started before I washed the car. I had the motor off while I was waiting for the cars to finish infront of me. When I drove into the wash bay the gauge was reading wrong, so i'm 99% certain water isn't the problem.
 
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