Microsquirt issue. Car won't start with SPOUT in


New Member
Mar 13, 2020
Latrobe, PA
Got a Microsquirt and PNP harness from EFI Source for my foxbody. It will start and run with the SPOUT out but as soon as I plug it in the car shuts off and will not start. Had a few problems at first due to the resistor in the harness touching multiple pins and ruined my TFI and PIP. Replaced distributor and now all that stuff tests good. I tested the resistor that is in the harness and it is reading 331 ohms but in the microsquirt manual it calls for a 1000 ohm resistor. Not sure if this would be causing the issue or not.

Just looking if anyone has any ideas of what else could be causing this issue. Car started and ran fine prior to installing the microsquirt and harness.
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I'm not well versed with microsquirt or the pnp harness. I run mspnp2. Make sure all the wiring pins are going where they are supposed to. Im sure you've already checked all that. It seems like with the spout out it would be running on mechanical timing. Plugging it in seems like it would allow the microsquirt to take over. Did you set up the timing properly in TS. Offset should be 10°. Can you post a tune file and a datalog ?

I had serious issues getting my car started a couple years ago. A91what was a huge help. He's gotten busier but is always willing to help. If I were in your boat I'd call or message him and give him a little scratch to get it started and the first tune. Actually, I pay him and watch the magic happen on my lap top.
Here is a datalog of trying to start with spout in and starting with spout out. I hooked up the stock ecu, unplugged the map sensor and kept the spout plugged in and it started with the stock ecu.


  • Spout in 2020-03-14_08.42.53.mlg
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  • Spout out start 2020-03-14_08.42.53.mlg
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The first thing i see is the MAP signal and the sensors freak out during cranking... This is the same behavior that kills the a9l stock ecu, I believe when you are cranking the NSS circuit is feeding 12v onto the signal ground. this is a major issue. This needs to be found and addressed as soon as possible. do you still have the stock O2 sensor harness installed? if so unplug it

I see rpm in the log file on the no start condition so it is the TFI that is not firing. try and remove the pullup resistor first as a test.