Rx2jz Posted November 20, 2023 Report Share Posted November 20, 2023 Went to perform a injector test which failed on my new build. Link fury + 2200cc Bosch injectors. And after further investigation found 12v on both injector plug pins. Also found the injector setup was set to peak and hold... not situation which I would have expected it to be.... Didn't wanna change this setting until I got further advice. I've pinned injector pins back to ECU and all is good. Can't see how the ECU would be putting 12v down the negative side of the injectors ... Hopefully a simple fix that I've missed .... Just some further info. The loom and ECU was from another built 2jz which I'm now using on my built 2jz. Loom was done by Mr 12v Quote Link to comment Share on other sites More sharing options...
Vaughan Posted November 20, 2023 Report Share Posted November 20, 2023 both injector pins should be showing 12v while the injector is plugged in but not being activated. If the injector is not plugged in one pin should be 12v and the other floating. Quote Link to comment Share on other sites More sharing options...
Rx2jz Posted November 20, 2023 Author Report Share Posted November 20, 2023 Thanks mate. Yeah it's showing 12v with plug off on both plug pins. Injectors were cleaned and tested few weeks back just to add some more info. Also no other sensors etc are plugged into the engine. I was just starting to work my way through testing stuff. Starting with fuel pumps etc but have stumbled at this injector issue .. Starting to wonder if it would make a difference having everything plugged in ?? Like crank and cam sensors etc .. can't see how this would make a difference when performing a simple injector test. All earths are connected. ... Quote Link to comment Share on other sites More sharing options...
Vaughan Posted November 20, 2023 Report Share Posted November 20, 2023 27 minutes ago, Rx2jz said: Starting to wonder if it would make a difference having everything plugged in ?? Like crank and cam sensors etc .. can't see how this would make a difference when performing a simple injector test. All earths are connected. ... Won't make a difference, only important thing for doing an injector test using the Fuel -> Fuel Setup -> Injector Test testing stuff is that the Injection Mode and Auxiliary Outputs - Fuel -> Injector Drive functions are set correctly Quote Link to comment Share on other sites More sharing options...
Rx2jz Posted November 20, 2023 Author Report Share Posted November 20, 2023 Ok. Any idea why 12v would be showing on both sides ? I'm hoping it's not an ECU issue Quote Link to comment Share on other sites More sharing options...
Vaughan Posted November 20, 2023 Report Share Posted November 20, 2023 if you remove Inj1-6 pins from the ECU A and B plugs does the 12V disappear from one pin? and then does grounding of any of these wires cause the appropriate injector to click? Quote Link to comment Share on other sites More sharing options...
Adamw Posted November 20, 2023 Report Share Posted November 20, 2023 ECU's with P&H drivers have the injector outputs connected to a flyback rail so it is normal to see bat voltage on the injector output when it is "off". Note in test mode the injector output only pulses to ground for 2ms, so a multimeter or normal test light wont see it. You need an LED test light or "noid light" to check the injector pulse is there. Those 2200cc injectors will seize up with the slightest hint of moisture anywhere near them so perhaps touch one on a battery with some jumper wires to make sure it does actually click. The drivers should be set to saturated also. Vaughan 1 Quote Link to comment Share on other sites More sharing options...
Rx2jz Posted November 20, 2023 Author Report Share Posted November 20, 2023 Thanks Adam. Great to hear that it's normal. Maybe I am making the mistake of assuming the injector test isn't working as Im not hearing the injectors "click"... I'll borrow my mates noid light today and confirm what's happening. Quote Link to comment Share on other sites More sharing options...
Rx2jz Posted November 20, 2023 Author Report Share Posted November 20, 2023 30 minutes ago, Vaughan said: if you remove Inj1-6 pins from the ECU A and B plugs does the 12V disappear from one pin? and then does grounding of any of these wires cause the appropriate injector to click? I'll let ya know mate. Cheers Quote Link to comment Share on other sites More sharing options...
Vaughan Posted November 20, 2023 Report Share Posted November 20, 2023 7 minutes ago, Rx2jz said: I'll let ya know mate. Cheers Adam has covered the reason for the 12v, the tap of one of the injectors to ground to make sure they click will confirm wire connectivity but as Adam said the injectors might not click properly so noid light might be more conclusive. Quote Link to comment Share on other sites More sharing options...
Rx2jz Posted November 21, 2023 Author Report Share Posted November 21, 2023 Just found out that this wiring loom uses Aux 1 to energize 3 relays.... COIL relay. FUEL PUMP 1 relay and INJECTOR relay...... I've never seen this before.... Quote Link to comment Share on other sites More sharing options...
Rx2jz Posted November 21, 2023 Author Report Share Posted November 21, 2023 ALL SORTED. !!! Appreciate Adam and Vaughan help. After discovering the above wiring I quickly worked out injectors will only fire when fuel pump is running ( as AUX 1 is set as " Fuel Pump ". ) As soon as I changed Aux 1 to. ( ON / test ) the injectors worked. So looks like its all gonna work when it comes time to fire it up. Happy days. Quote Link to comment Share on other sites More sharing options...
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