Joined the VR4 Fire cru this AM...
I was messing around tuning in ECMlink this AM and a bit of smoke starts coming out of dash. Pull battery! poke around and find the MPI relay is melted.
- Pin 10 (black w/red stripe) appears to be source
- MPI relay internals look sound
- ECU looks fine at a glance
I tested pin 10 in MPI harness and it's grounded, shows continuity intermittently with cig lighter frame and ECU ground.
ECU looks fine, IC110 looks fine, for what I can tell.
I figured to just run a new fused +12V to pin 10 and new MPI relay to get it home, BUT on testing other pins on harness I have ground continuity on 2/3/4/5/6/9 (key off) too? That seems wrong so am nervous to proceed.
Here's a schematic and MPI testing steps.
Applying +12v to pin 10 and the ground (-battery) connection to pin 8 should make 12v show up at pins 4 and 5. Same deal for pin 3 and 7 causing 12v to show at pin 2.
Applying 12v across pins 9 and 6 will cause continuity between pins 3 and 2.
I was messing around tuning in ECMlink this AM and a bit of smoke starts coming out of dash. Pull battery! poke around and find the MPI relay is melted.
- Pin 10 (black w/red stripe) appears to be source
- MPI relay internals look sound
- ECU looks fine at a glance
I tested pin 10 in MPI harness and it's grounded, shows continuity intermittently with cig lighter frame and ECU ground.
ECU looks fine, IC110 looks fine, for what I can tell.
I figured to just run a new fused +12V to pin 10 and new MPI relay to get it home, BUT on testing other pins on harness I have ground continuity on 2/3/4/5/6/9 (key off) too? That seems wrong so am nervous to proceed.
Here's a schematic and MPI testing steps.
Applying +12v to pin 10 and the ground (-battery) connection to pin 8 should make 12v show up at pins 4 and 5. Same deal for pin 3 and 7 causing 12v to show at pin 2.
Applying 12v across pins 9 and 6 will cause continuity between pins 3 and 2.
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