Crazy PLX-250 wideband
12-02-2006, 08:09 AM
#1
Thread Starter
Crazy PLX-250 wideband
Hey Guys,
So in preparation for my FI build. I installed a PLX-250 with 52mm gauge. I used the Narrowband function of the PLX to my NB on the car. Originally i had found a ground on one of the screws next to the ecu with very long ground lines and ran the capacitors semi-near to the ECU... i knew it wasnt a great idea and when the gauge started going crazy... (for eg. it would go from ulta lean to ultra rich and everything inbetween 2-3 times a second... making the gauge all but impossible to read.)
I read you need to install the ground as near as possible to the ecu... so i found the ground on the ecu (the same ground that my vafc uses) and hooked both the gauge and the actual unit (the box) to that ground (which is on the ecu harness, but i used the harness extender used to run my vafc). i then put the narrow band wire from the PLX to the input on the ECU, putting the capicitor as near as possible to the ground...
It also says to put the capacitor as near to whatever your doing with the wideband... So would that mean i need to put the capacitor as near to the gauge as possible or to the plx box? its about 12 inches from the gauge now... Should i try and find a different ground for the gauge? compared to what the PLX box is using?
I need some help here guys, any input would greatly be appreciated!
Also, i left the narrowband plugged in, to keep the heating element of the plug happy (until i get some resistors). Could that have an influence on the sketchyness of my gauge?
So in preparation for my FI build. I installed a PLX-250 with 52mm gauge. I used the Narrowband function of the PLX to my NB on the car. Originally i had found a ground on one of the screws next to the ecu with very long ground lines and ran the capacitors semi-near to the ECU... i knew it wasnt a great idea and when the gauge started going crazy... (for eg. it would go from ulta lean to ultra rich and everything inbetween 2-3 times a second... making the gauge all but impossible to read.)
I read you need to install the ground as near as possible to the ecu... so i found the ground on the ecu (the same ground that my vafc uses) and hooked both the gauge and the actual unit (the box) to that ground (which is on the ecu harness, but i used the harness extender used to run my vafc). i then put the narrow band wire from the PLX to the input on the ECU, putting the capicitor as near as possible to the ground...
It also says to put the capacitor as near to whatever your doing with the wideband... So would that mean i need to put the capacitor as near to the gauge as possible or to the plx box? its about 12 inches from the gauge now... Should i try and find a different ground for the gauge? compared to what the PLX box is using?
I need some help here guys, any input would greatly be appreciated!
Also, i left the narrowband plugged in, to keep the heating element of the plug happy (until i get some resistors). Could that have an influence on the sketchyness of my gauge?
12-02-2006, 04:26 PM
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I am not an expert on this but what you describe sounds like normal A/F gauge behavior. Every one I have seen swings back and forth rapidly. Have you let it warm up good first and then take it for a ride?
12-02-2006, 06:15 PM
#4
Thread Starter
well it running from somewhere between 19 to all the way down to 10... i cut the wires and made them all shorter and it improved it a bit... but im still not sure if its giving me the true numbers...
12-02-2006, 06:38 PM
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Regular O2 sensors fluctuate. It will not give you one single reading unless it is pegged rich or lean which wouldn't be right. If you are looking for it to read 14.1 or something for a prolonged period of time while idling, it won't. You will always get a big sweep. Sounds like its performing exactly as designed.
12-02-2006, 10:50 PM
#6
Thread Starter
i know what your trying to say and but i understand the theory... just in my application it doesnt seem to be working right, at least compared to friends wideband's, it seems to be 'flickering' alot more... it just seems like the signal (ground) is getting messed up a bit...
i will do some more troubleshooting tomorrow
i will do some more troubleshooting tomorrow
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12-03-2006, 07:00 PM
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I've got an A/F guage (nothing fancy, just the guage) and it does the exact same thing.
If you push on the gas pedal it should move peg out at one point, let off and it'll slowly creep back to the other side.
At cruise it'll bounce around and at idle it'll either bounce around or fall straight off the bottom of the scale (my guage looks "off" sometimes).
So, yea, normal.
If you push on the gas pedal it should move peg out at one point, let off and it'll slowly creep back to the other side.
At cruise it'll bounce around and at idle it'll either bounce around or fall straight off the bottom of the scale (my guage looks "off" sometimes).
So, yea, normal.