I've got a bit of a problem. I started my car for the first time in over 3 months (it was away getting painted), anyway when I first started it the idle was very high (about 2500rpm) and it had a miss so I let it run for few minutes. I then shut it down and restarted it, same problem high idle so i unplugged the ISCV and the idle came down but the miss was worse. After checking all the sensors I started the car and unplugging one injector at a time and discovered that 2 and 3 were not firing. I did a few more checks and everything else seems ok so I then swapped the injector wires around (1 to 2 and 4 to 3) so now 2/3 work and 1/4 does not. Could it be the loom that cause only two injectors to fire or is my ECU fooked?

In addition to checking everything else I also replaced the ignition amp, coil, phase sensor, I also adjusted the TPS and crank sensor. All cylinders have good spark too.

HEEELLLLLLLLLPPPPPPPPPPPPPPPP!!!!!!!!!!!!!!!!!!

Almost forgot it's an L8 ECU with the two piece loom.
Wes

 

Do continuity testing, if thats all fine then it must be the ECU

 

Thanks mate, I'll do that now.

A few minutes ago I switched the injector wires around and regardless of which of the four plugs I use injectors 2 and 3 will not fire. Also there is 12V to all the injectors.

 

Are the injectors sticking then?

 

I thought so but yesterday I switched all the injectors around so the ones that were at number 2 and 3 cylinders are now at 1 and 4...

Update... I unplugged the non working injector connectors and plug those into two stock injectors i had laying around and what do know they work just fine, I can feel them clicking. Seems like I have two dead injectors, how strange.

Thanks mate...

 

If you have access to an occiliscope you can check the signal from the ECU at the injector plugs and also direct from the ECU.

In theory you could also do this with a test lamp (a proper bulb test lamp, not one of those shit LED test lamps that MAC Tools make!! Usless peices of shit).

Connect the croc clip to the positive battery terminal and probe the negative connection on the injector plug. If it pulses on and off when the car is running, it is getting a signal from the ECU. If not, you can do this at the ECU end of the wiring loom and see if it work there.

If it works at the ECU plug but not at the injector plug, then there is a wiring fault.

Assuming it's a Cossie, wiring pin numbers and colours for the injectors are as follows...

Cylinder 1 - Pin 18 Brown/yellow trace
Cylinder 2 - Pin 32 Brown/green trace
Cylinder 3 - Pin 33 Brown/black trace
Cylinder 4 - Pin 35 Brown/white trace

 

Doh!! Too late!!

 

Thanks mate. How the the hell does two injectors side by side go bad like that? And after the car has been sitting for awhile. So hopefully with a new set of injectors I should be ready to rock and roll

On a related note would this cause high idle issues?

 

I wouldn't have thought so directly. It would cause low idle so that the ECU will increase RPM via the idle spped control valve but I wouldn't have thought it would rev it up to 2.5k rpm...

 

are you getting 12v through the injector from pin to pin, or pin to earth as the injectors have a negative switch from the ecu?