Subie EJ wiring

[asra]

I attempted to start an EJ20 in my 2 seater today without success. The wiring up front was damaged when crashed a few years ago. I need to know if a black wire with a green trace coming from the loom is used to trigger the injectors and does it need power or should it be earthed. I don't want to gamble on it as it may damage the computer if I get it wrong. It is the last of the wires I can't work out yet. I have sorted out the ignition and got it sparking and the fuel pump is pumping but the motor is not yet firing. Any help would be appreciated.PetePete

[Tim]

Pete, Is the black wire with a green trace an original Subaru wire?normally one wire from each of the injectors are all wired together and are live (some ignition switched and some not) and the computer earths the other 4 individual injector wires as programmedTim McClure

[asra]

Thanks Tim. Yes the wire is part of the original loom. I take it you then believe it would be correct to run power to it and the computer will provide the earth.Pete

[NiqueNaque]

Pete,As a general rule in electronics, they are good at 'sinking' voltage rather than 'sourcing' voltage. This means the device that does the switching is at the end of the line as opposed to the start of it, relative to the positive terminal.Hope this helps,Cheers,Nick.

[Tim]

If that is the power wire to the injectors you can tell by simply unplugging all the injectors and probing the connectors in the plug for continuity with the Bl/g wire. If one connecter from each of the injector plugs has continuity then it is the main power feed to the injectors. It can be connected directly to the battery or relay switched through the ignition.Tim McClure

[asra]

Thanks very much Tim. I will do just that.Pete

[asra]

Hi Tim and Nick,I got hold of an ej20 wiring diagram yesterday and established the black wire/green trace goes from a water temp gauge to the computer. My feeling is that without any voltage input through the gauge down the wire to the computer, the computer would sense the engine is cooked,as the voltage drops as temperature increases, and turns off something, maybe the injectors. Does this sound feasible or am I clutching at straws? Also would any subie water temp gauge be suitable?Pete

[Tim]

Pete, I think the only sensors that will stop a standard Subaru are the crank and cam angle sensors. If others are detected as faulty by the computer then the settings revert to a mean setting and the engine runs OK.Tim McClure

[NiqueNaque]

Pete,Let me ask some stupid questions, 'cause I'm good at it....Tie your machine down first!Does it spark when you turn it over? [pull the plugs out and leave them in the leads, earth them and see if the sparks happen when you turn it over - easiest done in the dark]Are your spark plugs ok?Are the spark plug leads in the right firing order?Are the leads ok?Do you have compression?Is the timing belt ok?Have you checked the valve clearances?Are there any bugs living in any of the ports?Did you pull one of the injectors out and run it to see if it squirts? Danger - never put any part of your body in front of them, put it in a jar and see if it squirts.Are the timing cogs ok?Are the timing cogs on the right way, on the right shafts?Is the valve timing correct?Is there oil in the engine?Is the oil pressure switch ok?Is there oil pressure when you crank it over?Is there a rotor in the dizzy? [yep, I did it too..]Is the rotor cap ok?Is the centre electrode in the rotor cap ok?Is the rotor cap on the right way around?Is there enough pressure from the fuel pump to run the injectors? [?30 PSI]Is the fuel flow to the inectors ok?Does the exhaust smell like petrol when you turn it over?Did you try this nasty trick?? [Nick does this with his lawn mower when he runs out of petrol...]!!!!!!!!!!!!! MUST BE DONE OUTSIDE !!!!!!!!!!!!!!Nasty Nick trick - if you have an LPG bottle and most of us do - pull the bottle, hose and reg off the barbeque and put the end of the hose down the inlet manifold !from a safe place away from the prop and where you wont trip over it!...crank the engine over with an eigth through to a quarter throttle and gradually open the valve on the LPG bottle, you must keep cranking while you do this and shut the gas off immediately if you stop. IF there is compression, spark and timing, sooner or later it will cough and may run very nicely without the computer on at all, a squeeze bottle with petrol may work too but is much more dangerous if you drop it.What does this prove? - your injectors are not working, properly if at all. They may be gummed up with additives from the fuel, get them cleaned.Thats all I can think of for the moment.Please, if you are going to 'fiddle' like I do, be vewy, vewy, vewy, carefull.Hope it worksCheers,Nick.

[asra]

Thanks Nick and Tim for your help. Established that the injectors were not getting power via a connection at the alternator. Fixed that and then found the injectors were indeed gummed up. Cleaned them and runs like a dream. Just a few more things to do on the gyro then can consider flight testing in the near future. Nick after establishing there was power to the injectors and spark at the plugs I used your last nasty trick but simplified by just poaring fuel in via the air cleaner. She ran on all four proving to me that it was problem with the injectors. Thanks again.PeteBairnsdale,Vic.

[NiqueNaque]

Nothing more articulate than the human carburettor...Glad it worked for you pete.CheersNicholas TomlinAlarmist - www.alarmist.com.au - we scare for you