1996 Del Sol with a H23A swap boosted. S300v1.

Smooth idle only with the fuel table reduced (leaned) by 85-90%+. Otherwise - it's a total fuel dump cylinder wash.

Clearly, something is wrong but there isn't anything obvious (to me or tuners who have looked at it). I have included data captures and the base tune. I haven't swapped the dizzy yet. It seems like something is triggering the injector signal more frequently than each TDC pulse.

 

what injectors?
resistor box?

 

The injectors are RC 750 hi Z (attached) and no resistor box is installed.

 

Oh well, sometimes HondaTech folks are here for you and other times not so much. Not that anyone is interested, but I figured I'd close this out. The culprit - the map sensor power supply wiring was backward. Stupid me knew something was up because the SManager was showing ridiculous numbers like 39. Do a vacuum test!!! See below.

The reason it ran with the fuel table reduced and an OE map sensor installed is that "it" wired backward puts out 2.75 VDC and it's close enough for the ECU. And looks right when testing voltages without a vacuum pump.

Lesson, don't believe the tech when they tell you the map sensor is bad without ever testing it. They did the same thing by swapping out the 4 BAR with an OE.

If you suspect a MAP, connect a vacuum pump and check for a voltage drop between the sensor ground and the sensor send. OE will be looking for 3 Vdc and will drop when the vacuum is applied. A 4 BAR will be approximately 1.4 Vdc and drop from there.

On an OBD1 - three-pin plug for the MAP looking at the end that plugs into the sensor with the snap clip tab up, the supply voltage (5Vdc) is the far right, center is GND, and left is the sensor send. Before you say "duh" remember this is another person's build with a H23A JDM swap w/harness splicing adaptations. Wire color codes just don't matter. Ringing it out doesn't matter if you don't know the plug structure either.

Off to the tuner........... pirrello out!