Status: V3.3 Serial #1973 up and running, but with many issues.

Initial Issues:

1) P259 Ch5 used for Fuel pump Relay trigger, this would work when priming. But with the engine cranking, the relay would not activate. I later changed the output to Inj 5 (Ch. 4) and it worked OK.

2) Tach output (500 ohm pullup from Webshop) works, but the Tach will sporadically jump up very high, example jump to 4000 rpm at idle instead of 1000. I changed the Pull-up to 100 Ohms, but did not fix.

3) LCD screen will display normally after start-up. But after a few minutes the LCD data will get scrambled (? marks, data numbers and letters all over the place)

4) Car was running and driving, for about 6 hours of total run time. Several runs were made to 240 kpa(absolute) boost.

Then injector #1 (Ch.0) stuck on during a 1-2 gear power run. Output dead short to Ground. This is most often caused by a flyback connection problem. The FETs can service 2A all day long. But they die above 60V. Can cause other serious problems.

  • flyback checked out with ohm-meter before and after install.
  • curcuit is thru wiring harness (O2 sensor plug two wires joined) - fuel pump relay (two terminal 87 circuits) - to ECU

Took box apart to replace FET, decided instead to change wire to another injector output (Inj 6, Ch. 5).

Engine started and ran fine. Made a couple boost runs to 200 to 210 kpa.

But when making more runs at 220-240 kpa, the ECU "cuts out" and engine stumbles badly. (ecu loses communication, and you can see this in Megalogviewer when you graph the "time" and "seconds".


Is it possible that somehow ECU is powered down while injectors are still powered ? Or flyback wire does not go to injector common directly but via some relay or other indirect method ? (measures low ohm, but disconnects for short time in certain cases like powerdown, that can damage injoutputs to fail later).

  • Yes - Possible. ECU controls Fuel Pump Relay via Inj Ch4.
  • Relay may have possible Diode-shutdown delay?
  • Fuel Pump Relay's other 87 circuit supplies injector power
  • note OEM wiring .pdf below, flyback circuit is on pages 3of9, and 7of9

In any case, we recommend that you fire a warranty replacement order with same specs (or slightly more generic one). But best to investigate carefully before swapping. It seems you've measured carefully though.

  • If Rinj >= 5.5 Ohm, can we purchase these injectors (new ones. 100 .. up to a few hundred) ?
  • Yes - will email the contact information to webshop.



Factory Wiring .pdf