I am wondering whether the SMC-500 is at fault here. Civic Si (B16A2, JRSC @ 10lbs) is hesitating and misfiring as soon as I hit boost. It directly coincides with when my Boost/VAC gauge shows anything > 0 PSI. I had originally thought ignition, and have replaced most everything except ignition coil. Fuel is 40 PSI at the rail at idle.

I logged MAP voltage while at idle: red line is voltage input to the SMC, green line is voltage output from the SMC. See below (and attached). Does this look odd? I wouldn't expect to see the voltage spikes like that every ~5 seconds.



Any ideas what the MAP voltage output should look like?

Thanks -Aaron

 

Holy wow.....

Your input voltage looks fine. ~.95v @ 19-21" vacuum is common. Atomspheric (just turn the car off) should be around 2.95v.

Your output voltage will reflect whatever addition/subtraction per rpm band you have dialed in on the SMC. However, it shouldn't look like that. Did you just install this device or was it working before and now took a crap?

 

Just recently took a crap. I'm actually awaiting a reply from zip to see what his reaction is (since it's his product), but wanted reaction from h-t.

So what you're saying is, if I have idle trim set at 33%, then the output voltage from the SMC should reflect a steady voltage of .95 - (.95 x .33) = .64?

Now, I also have a JR BTC installed. I assume that wouldn't have any affect on this graph, as it's not in the path of the ICM signal to the SMC?

 

Assuming that 33% really correalates to 33% of the input voltage, then yes, that would be the output voltage.

JR BTC should have no effect on this signal.

 

Thanks. FYI - it appears it was the SMC crapping out. Getting a replacement shipped to me from Zip.