Injectors not firing problem.....

[Ant GTR]

Hi guys,

I have R33 GTR

Is there a supply to the ECU that would cause the injectors not to fire at all?

I have an Apexi PFC (have also tried std Nissan ECU to test) Engine cranks over, have good fuel pressure at the rail, but no fuel being delivered to the pots. I have checked resistance at injectors, resistor pack power supply, and continuity wiring from injectors back to ECU - all ok.

I have manually tested the injectors and they are working.

When cranking over the engine the injectors are not 'clicking' like they normally do when firing.

Appears like the ECU is not outputting any firing signal. Just wanted to know if there is a fuse or input to the ECU I should be checking first....

Cheers,
Ant

[Cornhoolio]

CAS?

[Ant GTR]

I'm getting an RPM reading from the Apexi so the CAS must be working.

[GarethK]

Do you have the Apexi boost control kit with the PFC? If you have it selected but not fitted the injectors will not fire.

EDIT:-Just realised you said you had tried std ECU with no luck.

[Ant GTR]

Yeah that's right, I don't have a boost kit connected to it, but kinda rulled out anything Apexi by giving a std ECU a try.

[GarethK]

Did it work before you fitted the PFC?

[Ant GTR]

It's been running with the PFC previously, it's not new. The car has been off the road for a while, and has has a lot of engine parts replaced/cleaned/upgraded. It's all back together and can't get the injectors to run.
They are replacment injectors, but have been tested.
Measured resistance of the injectors is 2.7 ohm and the resistor pack is 6 ohm, which i think is correct.

[Cornhoolio]

Resistor pack earth, this is the only thing I can see common to all 6 injectors (R32 GT-R wiring diagram anyway) worth a try

[Ant GTR]

I know for a fact that the resistor pack is not earthed where it's currently mounted (the metal shield anyway)

Are you sure this is part of the circuit? I was pretty sure the 12v supply and the 6 injector connections were isolated from the metal cover...

[hpt_simon]

i would still go for cas

coul de getting the 120º signal but not the 1º,
try chequing see if spark plugs fire

if they dont, defo cas

hope this helps

[Cornhoolio]

I have being trying to attach the PDF of the circuit but to no avail........

It deffo shows the connection of the back side of the resistors to an earth

Someone else may be able to send you a schematic to confirm this as I may also be speaking sh1te......

[Cornhoolio]

According to circuit, connection no. 3 in multi-plug on resistor pack is the earth, it is not earthed through its casing (R32 circuit I am looking at though remember)

Could be a busted wire, you know how brittle some of these looms get

[Ant GTR]

My multiplug on the resistor pack only had 7 wires (I to each injector and +12volts)

Mine does not have the earth connection and the metal shield is not attached electrically. If you could send me the diargrams you have of it that would be helpful please. My email is ant@fast-r.com

I hav bought a second hand CAS to try and it's just the same.

[Ian C]

if you put 12v across an injector does it click?

[Cornhoolio]

I am over working in Thailand just now and all my GT-R sh1t is on my own laptop, I only have the works one with me...................

As soon as I get back I will fire it across to you, may be a few weeks yet though