23 Nov 2012

So, the day went something like this:

1. Remove plugs to spin up engine in order to build oil pressure.
2. Try to start car. Car starts but runs really bad, won’t idle, tons of black smoke, like it’s really rich.
3. Check that all sensors are connected – they are – then stare at car for about an hour, waiting for it to tell me what’s wrong.
4. No answer, so I pulled out the laptop, figuring the Hondata ECU would certainly flag a obvious problem.
5. Nothing, not one single error or warning. Engine runs but crazy-rich.
6. After watching it run so rich, I tried an experiment: turned off the ignition, unplugged all the fuel injectors, then tried starting it. Not only did it start, it idled smoothly for a couple seconds… huh?
7. Checked that fuel pressure regulator was working and set to ~40lbs – it was.
8. Figuring, “what do I have to lose” I cranked the fuel pressure down to 10 lbs and tried starting the engine. It idled much better…
9. Looking through the parameters (having saved off the original set) I figured there was nothing to lose by messing with things.
10. I’m running 1000 cc injectors, which the Hondata ECU confirmed. However, just for fun I tried changing it to “2000 cc”, meaning that the ECU would then inject half the fuel. It idled better…
11. Injector size was then increased to “4000 cc” and it idled better still…
12. Further messing with idle settings improved things to the point that it idled just fine, nice and smooth. However, anything above idle speed was once again met with a big cloud of black smoke (unburned fuel.) There would be no drive down the block.

I’m completely stumped – it ran fine before. The fact that I could juggle variables and get it to idle – without sensor errors – seems to indicate that everything is working. It’s almost as though the ECU completely lost its mapping, but that doesn’t make sense because there’s obviously some kind of map in there. And, the PC-based interface confirmed that the important parameters (MAP sensor scaling and injector size) are correct. Because it was running rich instead of lean means there’s no vacuum leak on the inlet side.

I had planned to eventually take the car back up to Church Automotive for final tuning but it now looks like that schedule has been moved up a bit. Hopefully they can make sense of whatever is going on.

With no drive around the block happening I decided to eat my pride and remove the fuel tank, so that was done. Tomorrow I’ll try repairing the leak. If there’s an update tomorrow it means that I didn’t blow myself up…