1991 Acura NSX: That Didn't Take Long
October 14, 2011
Ed Hellwig is right about the way our new/old 1991 Acura NSX sounds. It's got quite the stirring intake note when you give it the pedal. It also boasts one of the best shifters I've used in... well, a long freakin' time. There are shifters that are light and positive like this one's, but few also manage to feel like a mechanism. The NSX's gearchange retains that satisfying mechanical feel. Can't get enough of it. Shift just for the hell of it. The clutch is on its last legs, for sure, though.
Anyway, I was exploring the reaches of the throttle when the above light flicked on. It's a check engine light. No change in the way it's running, all gauges normal, and I'm just around the corner from my destination at this point. Stopped, I snap the photo and cycle the ignition just to see if it sticks. The CEL doesn't return. Hmm.
Now, this is a '91, so it's OBD-I, meaning it doesn't have anything near the diagnostic capability of today's OBD-II cars. No quick hookup of our DashDaq to see if it stored a code, then; this is a count-the-blinks deal.
First, dive under here (weird, in this photo it looks like there are those fake Halloween cobwebs stuck all over the place. Optical delusion.)
Then, find the blue two-pin connector that's not connected to anything:
Jumper the pins in this diagnostic connector with a paperclip (how quaint!) and count the CEL flashes. Our registered two codes: 2 and 36. These are, respectively, Rear Primary HO2S Circuit Hi/Low Voltage and TCFC Signal.
Translation: the oxygen sensor in the rear cylinder bank saw or thought it saw an unusually rich or lean condition momentarily, and at some point the Traction Control Fuel Cut was triggered. I'd guess that a TCFC code doesn't light the CEL, and that it only shows up when you check for stored codes.
O2 sensor codes can be triggered for a number of reasons, so we may have a problem and we may not. For now, I'm inclined to stay the course and see if it returns before getting too excited.
Also, aftermarket stereo installers are a bunch of hacks. All of them.
--Jason Kavanagh, Engineering Editor