nintyfive
05-07-2014, 01:06 AM
I need help figuring out why my car wont start/run. It's a 1994 240sx vert with KA24DE-T. The car starts without problems until I replaced the headgasket almost two weeks ago. the car cranks up, but no spark or fuel. I double check everything and everything seems to be in place. I check the ECU for codes and realized the ecu is not turning on. It has no power when the ignition is "on" position. Check engine light not lighting up on dashboard but other indicator lights to the right side lights up, battery, open door etc.
I did touch/move the relay/fuse box near the battery, to tidy up a bit. Maybe I pulled something or crimp a wire or something. check for any loose/crimp wire. I haven't seen any.
After trouble shooting it for a few days now, I noticed that when I try to start/retart and remove the key, the ecu will power up for a few seconds while in accessory and turn off.
I found the ignition relay (brown relay) by the driver side kick panel (behind the fuse box) When I removed the relay, when "on" position, the ECU will light up but the orange lights to the dash will not light up. ECU seems to be fine as I can pull out codes.
the first code was 55 (Normal engine management system operation is indicated)
after cranking, the rest of the codes = 21 (Ignition signal in the primary circuit is not being entered to the ECU during cranking or tuning)
when starting/cranking. the ecu light will turn off and goes back on again once key is "on" position. Should the ecu be on all the time when starting/cranking the car?
I bought a new ignition relay hoping it will solve my problem. I am back to step one. Where the car cranks but no power to ecu.. The right side of dash will light up again. (battery, door light indicators)
Playing with the ignition, from time to time I can get power to the dash indicator lights and ecu while in accessory. Finally figured out that the EGI relay (by battery fuse) is getting stuck and applying power to the orange lights in dashboard and ECU. But when you put it "on" position and try to crank the car, the ecu will turn off. I tried switching the egi and fuel pump relay and I am back to step one again.
conclusion,
1. a wire loose or crimped? (there is too many wires to consider/check)
2. a short (I don't really think so as there's no blown fuse yet)
3. malfunction ecu? (maybe, but I can pull out codes if light is on...)
4. needs new relay? which one? EGI/fuel pump (I just switch them from each other)? maybe both? (how often relays fail?)
5. key ignition? (240sx are notorious)
Any suggestion is appreciated!
Ill try to get new egi and fuel relay first. might get it by Thursday.
is there a way to keep constant power to the ecu while cranking?
I did touch/move the relay/fuse box near the battery, to tidy up a bit. Maybe I pulled something or crimp a wire or something. check for any loose/crimp wire. I haven't seen any.
After trouble shooting it for a few days now, I noticed that when I try to start/retart and remove the key, the ecu will power up for a few seconds while in accessory and turn off.
I found the ignition relay (brown relay) by the driver side kick panel (behind the fuse box) When I removed the relay, when "on" position, the ECU will light up but the orange lights to the dash will not light up. ECU seems to be fine as I can pull out codes.
the first code was 55 (Normal engine management system operation is indicated)
after cranking, the rest of the codes = 21 (Ignition signal in the primary circuit is not being entered to the ECU during cranking or tuning)
when starting/cranking. the ecu light will turn off and goes back on again once key is "on" position. Should the ecu be on all the time when starting/cranking the car?
I bought a new ignition relay hoping it will solve my problem. I am back to step one. Where the car cranks but no power to ecu.. The right side of dash will light up again. (battery, door light indicators)
Playing with the ignition, from time to time I can get power to the dash indicator lights and ecu while in accessory. Finally figured out that the EGI relay (by battery fuse) is getting stuck and applying power to the orange lights in dashboard and ECU. But when you put it "on" position and try to crank the car, the ecu will turn off. I tried switching the egi and fuel pump relay and I am back to step one again.
conclusion,
1. a wire loose or crimped? (there is too many wires to consider/check)
2. a short (I don't really think so as there's no blown fuse yet)
3. malfunction ecu? (maybe, but I can pull out codes if light is on...)
4. needs new relay? which one? EGI/fuel pump (I just switch them from each other)? maybe both? (how often relays fail?)
5. key ignition? (240sx are notorious)
Any suggestion is appreciated!
Ill try to get new egi and fuel relay first. might get it by Thursday.
is there a way to keep constant power to the ecu while cranking?