i have a legacy anyone have any ideas why have no spark , fuel pump , or check engine light ive replaced all relays fuses and ecu az the origanil one burnt out any ideas
intrade,
Apr 2, 8:50pm
yea you have to diagnose it correctly. not like a swaptron moron. first thing to do is to look what system you have on the car is it electronic ignition. where is the ignitor. how is the ignitor triggered . older systems usually have had a all in one unit also what does the engine crank like lumpy = uneaven = check cambelt is still moveing the valves methodical checking and ticking everything off that is ok . that is how you find a fault on this old car and this is the only way to even have remotely a chance of finding faults on modern fully electronic cars.
intrade,
Apr 2, 8:53pm
i would also like to look at the correct wiring diagram for the car before i would start getting my hands dirty , this means you will need to know how to read a wiring diagram and understand how electrical and electronics works , in the early 90s these jobs where done by auto electritions as swaptrons could not figure out and where not trained to diagnose just swap parts as per manufacturer flow charts. So you could take it to a auto electrition . or start learning on how its done correctly. these 2 options exist for you.
supernova2,
Apr 2, 9:00pm
Sounds like a power problem to me. Have you checked that the ignition switch is working? When you say "burn out" do you mean it caught fire? If so I think you might have a fault in the wiring loom.
Unless you know how to trace circuits and check for power etc its going to be a job for an auto electrician.
intrade,
Apr 2, 9:00pm
also 89 or 98 huge difference i would have said most 89 where still carburettors.
holdenpwr1,
Apr 2, 9:08pm
motor was running was driving when ecu went up in smoke caused by the oxy sensor wires melting etc . 89 legacy isnt carb factory ej20 turbo manual
holdenpwr1,
Apr 2, 9:14pm
yup ignition switch working
intrade,
Apr 2, 9:22pm
so do you have the wiring diagram? because you need that without it you might as well try and piss in to the wind . if you want to fix it your self . Somhow i cant see how a melted o2 sensor wiring would damage the ecu unless the wiring for heater of the o2 comes direct out of the ecu not a reley. The rest is just signal voltage for fuel trimming i also know that subarus of that age dont run when the mass airflow is dead as its the only way it mesures air going check if it has a map sensor. otherwise i be mesuring with a scope if the mass airflow is dead. if your sure there is no shorts now you could reset the ecu i had to do that on one of them subarus with no start who had just extreem dirty intake throttle and it has only had a map sensor no mass airflow on that on i had to do this to get it running again.
intrade,
Apr 2, 9:29pm
under the dash are the plugs to connect togather this makes the coolant fans blow in bursts on of on off this is telling that the ecu has fault codes cleared . also i assume it has got no anty-theft system in the ecu you fitted and that it is the exact same correct ecu replacment . your melted oxi wiring could have just been a coinsidence of another problem and not what melted your ecu if it even got melted at all. http://www.troublecodes.net/Subaru/
mechnificent,
Apr 2, 10:13pm
If you are sure you replaced the main relay, the one up at the top of the fuse board, the square brown one, with one that you absolutely know is a good one, then it sounds like a wiring problem to me. That main relay has two switching circuits and so aren't straight forwards to test. I'd check the fuses and that they had power getting to them, then disconnect the ecu, drop the fuse box and try another relay or test the one in there, then I'd check whether the power was getting to the main relay in all the right places. If it's not, then back to the fuse to check if it's getting power. The wiring diagrams are out there. Go to clubsub and look in their technical forum at the bottom of the page. It has links to manuals.
If there is power to the relay's pins, put it back in and listen to see if it clicks when you turn the key on. If it clicks then check the fuel pump relay which is only one switching circuit, and that it's getting power. The fuel pump relay is next to the main relay and is green I think. don't confuse it with the horn relay that's near there too. It won't be getting turned on by the ecu yet because the ecu is still disconnected.
Now plug the ecu in, check if things work. Check that the ecu has all it's power ins, there will be three at least. Check all it's earths are working/connected to earths.
If none of that fixes it, you have a wiring problem.
holdenpwr1,
Apr 2, 11:49pm
itz a brand new relay have pwr 2 main relay dont have check engine light ether im starting 2 fink its wiring as can ecu and relays in anuda subi and they work
phil1up,
Apr 3, 12:22am
Run Forest Run!
mechnificent,
Apr 3, 1:25am
If the main relay clicks when the key comes on, then there should be power to the ecu and the ignitor or coil. If the ecu has it's three(I think) power inputs, and it's earths, then the dash light should work. If it doesn't, then you have a crook ecu or a blown bulb.
holdenpwr1,
Apr 3, 4:41am
bulb all good ecu works in anudda subi
mechnificent,
Apr 3, 4:53am
Ok. And the main relay does click ? You have felt it with your fingers ?
Well it sounds like wiring. First place to check is connectors, multi-pin plugs. In the connectors, and at the back where the wires come out. You test them by doing a continuity test with an ohm meter set to it's beeper, or a self powered test light. You need to test the power wires and the earth wires for continuity. and you need a wiring diagram. Club sub have addresses where the manuals are.
aredwood,
Mar 29, 8:41pm
Check the 2 big green square fuses in the engine bay fuse box. 1 of these is all power to injectors, ECU ect except for ignition coils. And maybe fuel pump. The other one is for electric windows, sunroof, electric adjustable drivers seat. Interior fuse box has fuse for the coils. And fuel pump fuse will probably be here as well. Since the check engine light is not working. Almost guaranteed that your ECU is not getting power.
I actually had almost the exact same problem in my old 1990 GT wagon. Oxy sensor wires melted to exhaust mainfold. It was my fault because I didn't route them properly after an engine swap. Didn't damage the ECU, But after replacing the green fuse, and repairing oxy sensor wiring. The check engine light was on because the oxy sensor, wastegate solenoid, and idle control valve didn't have power anymore. I just ran new wires to those things.
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