Lift off?

Today I managed to complete the wiring and get the engine started. I’ll let you read further in the Done section to get the gist of my troubles.

I’m dissapointed that the car is not mobile, as I promised my son Hamish that he could drive it to a car event tomorrow.

As Malcolm Fraser once said “Life wasn’t meant to be easy”.


  • Completed all the sensor wiring and Mini electrics.
  • Tested Mini electrics, lights indicators etc.
  • Tested MegaSquirt connectivity to all sensors and peripherals e.g. fuel pump, radiator fan…
  • Adjusted VR sensor to get it to trigger properly. Discovered it was out of phase, so adjusted the “Ignition Input Capture” value from “Rising edge” to “Falling Edge”. I used the TunerStudio “Tooth Logger” which showed two long bars instead of one long bar when it passed the missing tooth. This indicated that the phase was out. I also adjusted the position, of the VR sensor a little further away from the trigger wheel.
  • Checked and tried to adjust the fuel pump pressure using the FP test O/P in TunerStudio and the Fuel regulator. Fuel pump was making a right racket, much louder than the original SPI pump, and the return hose in the boot (trunk) was banging back and forth. I haven’t fully come to a conclusion, but I think the pump (a MPI/SPI replacement from Mini Spares) is a 255L/Hr 3Bar whereas the original OEM SPI pump I replaced was a 1Bar unit, flow rate unknown, but obviously less.
    I ultimately adjusted the regulator to ~ 12PSI, the gauge in TS was jumping around a bit… maybe +- 0.75PSI or more. Never had this problem with the original pump! My theory is that setting it to 12PSI which is 30PSI or so less than the MPI setting, the flow rate is overpowering the FP regulator causing it to fluctuate.
    I wired up the Main and FP SSR’s using the DIYAutotune wiring diagram. This allows the FP to be used both as in a ON/OFF and PWM mode without any wiring changes. So I might try bypassing the FP regulator and use  the ‘T’ piece with the FP pressure sensor, I have nothing to loose, and this was my original intent to use PWM to effect a returnless fuel system.
    Any ideas folks?
  • Noticed the Knock Sensor gauge was running around 60% when car was idling (surging more like it). I will turn this off until I get a stable idle and tune. Good to know though that it’s sensing something!
  • Started engine and got it to run sort of. It was running lean and hunting, pretty badly.
    I’ve abandoned trying to get it to idle, until I get the FP sorted. One interesting thing I tried to get it to run better was to change the injector flow rate from 622cc/min @ 12PSI to 400cc/min which equates to running the injector @ 5PSI. This richened it up a bit, but still had hunting. I’m confused; the injector is a brand new one, but could they have supplied an incorrect or badly flowing one?

    My Air Fuel and Volumetric Efficiency tables are pretty much as per my original tune, so why the lean running?

Eddie my dog, in his usual repose!
Eddie my best mate, in his usual repose!

To Do

  • Find a solution for fuel pump pressure regulation (maybe PWM) and flow.
  • Test injector flow rate, and check P/No is correct.
  • Test and set-up PWM for radiator fan control
  • Check timing and adjust the index position using TunerStudio to give the base timing value.
  • Adjust VE table to get it running OK
  • Take it for a drive to dial in VE table using TunerStudio’s VEAL.
  • Use and enjoy it!

Nice to do, but not required!

  • Fit the new heater. (Not doing until I have car on the road and tuned in… it is summer after all!)
  • Get a wheel balance and alignment.

If you would like to leave a comment (please do) , click the Leave a Reply link below.