After managing to get the engine up and running last time, we had a small issue – any touch of the throttle would cause the engine to stall.
We didn’t run the engine much past what was shown in the previous video, as we had no way to cool the engine. So, we spent some time putting together a cooling system, which would allow us to run the engine for longer than a couple of minutes, and perform some troubleshooting.
With some pipework made from some large bore pipe, and a loop of pipe on the heater circuit, we hooked up an old Mini radiator we had sitting around, to be able to get some coolant into it.
We refilled the “petrol tank” with petrol, hooked up the battery again, and I hooked up my laptop to the engine ECU to run EvoScan, and to the MAP-ECU to run the MAP-CAL software.
Upon starting the car, we could see that the RPM within EvoScan was around 700rpm, but it was showing at just 200rpm in MAP-CAL. The MAP-ECU was previously attached to a 6A13TT engine, and in the configuration it had been set to “6 cylinder”. The RPM wiring had obviously been on the signal to the tacho in the dash, rather than how we’ve now wired it – direct into the signal from the ECU to one of the coils. Changing the MAP-ECU configuration to “2 cylinder” then showed the correct RPM – and instantly we were able to rev the car properly.
The MAP-ECU “mimicks” the Kármán Vortex Frequency given out by the standard MAF by utilising RPM, manifold absolute pressure and intake air temperature – with the RPM incorrectly set, it wasn’t moving out of the correct RPM/pressure cell and adjusting the VKF frequency output correctly – this was then not telling the standard ECU that the amount of air had changed (increased), so was not adjusting the fuelling correctly – hence the immediate stalling.