Sporadic Voltage Spike Flex Fuel input

[pgranberg11]

Posted this in a Facebook group, but figured I'd post something here too since not everyone's on Facebook. Just trying to get an idea of what the problem may be. I have an idea but I'd like to gain input from others.

I have a moto-east flex fuel kit that uses the passenger side evap ecu harness. My tuner is telling me and the log shows that there are random spikes in voltage. We're both thinking that it's running next to a high current wire and is causing induction. Im talking about the big jumps/spikes. Anyone run into this before? Any input would be helpful!

As of right now I'm planning to take a look at the wiring making sure it's not slightly bare and making contact. The tuner suggested that I get a ferrite core to put around the wire which I have already ordered. Let me know your thoughts!

Thank you!

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[steve99]

The evap input to ecu is pulled to 5v internally in ecu. So if your connection goes open circuit then the evap will go to 5v.

This might also happen in your eca module looses 12v power or ground

Id check connecrions

[Kodename47]

As above, you pull the voltage down to earth on that input so a rubbed wire causing an earth would cause downward spikes towards 0v.

[pgranberg11]

i put on a ferrite core just as the tuner suggested; looks like the problem went away. I did inspect the cabling though and I did notice that the signal wire was basically on top of a high current wire zip tied tightly together.. (my fault being lazy upon initial installl; never really thought that would end up being a problem). Thanks for the replies!

[Yoshoobaroo]

Originally Posted by pgranberg11

i put on a ferrite core just as the tuner suggested; looks like the problem went away. I did inspect the cabling though and I did notice that the signal wire was basically on top of a high current wire zip tied tightly together.. (my fault being lazy upon initial installl; never really thought that would end up being a problem). Thanks for the replies!

Where on the wire did your put the ferrite core? Going flexfuel soon and might as well do this as cheap insurance.

[pgranberg11]

ferrite cores are placed closest to the input signal. To be honest, I used two since I ordered a box of them since that's just how they came. I put one on each end of the cable. and if there are ANY wires that are transferring a current to power up accessories (in my case gauges/displays) keep them away from it just to be safe. My ground was perfect and the nothing was wrong with the cable itself; so it was definitely just induction.