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BeerMoneyMotorsports / 01-05-Miata-Poly-Issues

01-05 Miata Poly Issues
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Adding Fuel Level #1

Open DykstraSound opened 1 week ago

DykstraSound commented 1 week ago

First attempt at adding fuel level to BMM NB2, jumper wire installed from P17 to AV10. Fuel level does not read. Simultaneous issue with flex fuel sensor.

DykstraSound commented 1 week ago

Steps to take:

  1. Verify AV10 has 5v when ECU is powered on
  2. Confirm pullup for fuel gauge is sourced from the cluster and not the ECU

Questions If pullup is sourced from cluster, would ECU read correctly if cluster pullup was disconnected? One wiring diagram shows that 4AD (fuel level in) on the ECU harness connects at some point with the pullup wire from the cluster, prior to the fuel level sender, and the other shows a direct connection between pcm and fuel level sender. If they connect, is the pullup from the cluster back feeding voltage into the ECU?

DykstraSound commented 6 days ago

AV10 Does not have 5V when bench tested out of car. Pullup is sourced in cluster. Pin 4AD currently measures 2.5V at the harness with key on and ECU removed.

Seems like this might work if configured as a pulldown?

DykstraSound commented 6 days ago

Jumper from P17 to AV10 does not show voltage in TS when using fuel level, but measures ~2.5v with multimeter. Followed up with changing the AV10 input to Fuel Pressure Low and showed correct voltage in TS.

DykstraSound commented 2 days ago

Snapshot update has corrected the incorrect reading of AV10. Reading correctly. Now working on why Fuel Level Gauge is not changing readout to match voltage reading.