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Fuel level sensor signal
Fuel level sensor signal Under acceleration my fuel level goes to empty. After acceleration the guage levels back to 3/4
Why would the ECM need to see the fuel level. My ECM (E38) looks at a primary and secondary level sensor.
Both sensors are wired into the ECM as they should be. Wondering if this is the problem.
2008 Cadillac CTS with L76/6L80 from Pontiac G8 GT
Why would the ECM need to see the fuel level. My ECM (E38) looks at a primary and secondary level sensor.
Both sensors are wired into the ECM as they should be. Wondering if this is the problem.
2008 Cadillac CTS with L76/6L80 from Pontiac G8 GT
i think maybe the ecm takes the sensor info and feeds it to the bcm via the canbus and then the bcm sends it to the instrument cluster to drive the gauge (or the gauge gets the info strait from the ecm, not sure)
there should be a calibration curve for the fuel level sensor/gauge in the tune...might take a look and compare the cts vs the g8 values and see if there's any difference. i'd probably start there and if that doesn't clear it up need to compare the wiring diagrams and see if any differences there.
there should be a calibration curve for the fuel level sensor/gauge in the tune...might take a look and compare the cts vs the g8 values and see if there's any difference. i'd probably start there and if that doesn't clear it up need to compare the wiring diagrams and see if any differences there.
i think maybe the ecm takes the sensor info and feeds it to the bcm via the canbus and then the bcm sends it to the instrument cluster to drive the gauge (or the gauge gets the info strait from the ecm, not sure)
there should be a calibration curve for the fuel level sensor/gauge in the tune...might take a look and compare the cts vs the g8 values and see if there's any difference. i'd probably start there and if that doesn't clear it up need to compare the wiring diagrams and see if any differences there.
there should be a calibration curve for the fuel level sensor/gauge in the tune...might take a look and compare the cts vs the g8 values and see if there's any difference. i'd probably start there and if that doesn't clear it up need to compare the wiring diagrams and see if any differences there.
i was curious so i took a look at the schematics and it looks like the ecm sends the signal to the instrument cluster itself so at least the bcm shouldn't be affecting things.
looking at the diagnostic information for the fuel level gauge, they (cts and g8) seem to have the same upper and lower limit values for resistance on the fuel level sender (i think it was 40-150 ohms) though the calibration curves might not be the same like mentioned previously.
just thought i'd add that info as an fyi
i might be pulling this outta my *** but i seem to recall someone with a similar issue adding a capacitor in this type of circuit to slow down their fuel gauge jumping around. although this may have been on the side between the ecm and gauge where the ecm still sent a discrete signal to the gauge rather than the instrument cluster module itself controlling the gauge...not sure if you could accomplish the same thing on the ecm-fuel level sender side of things.
looking at the diagnostic information for the fuel level gauge, they (cts and g8) seem to have the same upper and lower limit values for resistance on the fuel level sender (i think it was 40-150 ohms) though the calibration curves might not be the same like mentioned previously.
just thought i'd add that info as an fyi
i might be pulling this outta my *** but i seem to recall someone with a similar issue adding a capacitor in this type of circuit to slow down their fuel gauge jumping around. although this may have been on the side between the ecm and gauge where the ecm still sent a discrete signal to the gauge rather than the instrument cluster module itself controlling the gauge...not sure if you could accomplish the same thing on the ecm-fuel level sender side of things.
Good information. Thank you
on a side note, when I fill the tank on my SAAB with the engine running the guage takes its time to get to full. With the engine off it shows full right away. It probably has a capacitor in the system.
on a side note, when I fill the tank on my SAAB with the engine running the guage takes its time to get to full. With the engine off it shows full right away. It probably has a capacitor in the system.
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TECH Senior Member
Joined: Jun 2016
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From: Central Cal.
Not a good idea to fill gas with engine running anyway.
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