iluvdrt Posted May 29, 2010 Share Posted May 29, 2010 My car (98 Legacy GT 2.5 with MT conversion) started running like crap today then died. It threw a P1100 ign switch circut fault. It cranks fine. Sometimes it fires up and runs for a minute but then it dies. I have checked to see if the coil is getting 12V and it is. The fuel pressure is also good. I removed the factory alarm and it is still doing the same thing. Someone please help because this one is really whipping me. Thanks. Link to comment Share on other sites More sharing options...
Cougar Posted May 29, 2010 Share Posted May 29, 2010 (edited) The trouble may be with the power to the ECU. It could be a faulty ignition relay or main relay if you have one. After looking at some data it shows the main relay is located in the upper far left side of the dash. The relay may be mounted in a brown socket. Edited May 29, 2010 by Cougar Link to comment Share on other sites More sharing options...
iluvdrt Posted May 29, 2010 Author Share Posted May 29, 2010 Yes I just changed it. It was a PITA. I also bought and replaced a new crank sensor and cam sensor. Nothing has worked. I am thinking the ignitor might be bad. I think the main relay and the ign relay are the same. I only saw two relays up there, the brown one and the green one (Fuel) It did this about 3 months ago, but after towing it home it fired right up and there was no more problems. Link to comment Share on other sites More sharing options...
iluvdrt Posted May 29, 2010 Author Share Posted May 29, 2010 Well I unplugged the new O2 sensor and it fired right up, running perfect. Wierd. Any thoughts?? Link to comment Share on other sites More sharing options...
Fairtax4me Posted May 30, 2010 Share Posted May 30, 2010 (edited) Might be in limp mode with the O2 sensor unplugged. I suppose you could replace it but I'd recommend testing it first. There is a wire for the ECU that breaks off somewhere along the line from the starter solenoid wire that comes from the inhibitor switch (the small wire that trips the solenoid). I would assume that it uses this wire to determine when the starter motor is engaged, and changes something... Maybe somebody who knows what it's supposed to do for sure will splain it fer us. I worked on a BMW once that had a bad starter, I roll started it and it ran like crap. I thought a fuel injector was stuck wide open. But with the new starter on it, it ran perfect. Figured out later on that it had a similar type of circuit. Try to dig up an FSM for your year and find out exactly which pin and what color wire it is so you can check it for 12v when the ignition switch is turned to start. It may even come right from the connector on the starter solenoid. edit: good lord, I must be tired... Edited May 30, 2010 by Fairtax4me Link to comment Share on other sites More sharing options...
Cougar Posted May 30, 2010 Share Posted May 30, 2010 The O2 sensor along with other sensors are tied to power through the main relay so my guess is the sensor is causing a problem to the power for the ECU which uses the same relay. Link to comment Share on other sites More sharing options...
hankosolder2 Posted May 30, 2010 Share Posted May 30, 2010 That's an interesting theory, Cougar. So you're thinking that the heating element in the O2 sensor is causing a voltage drop somewhere? Makes sense, the heater does draw a bit of current. I suppose you could test that by disconnecting the wires to the heater portion of the 02 sensor and see if the problem went away. It would eventually get up to temp and function normally... Nathan Link to comment Share on other sites More sharing options...
Cougar Posted May 30, 2010 Share Posted May 30, 2010 (edited) Since disconnecting the O2 sensor cleared the trouble it seems the sensor is causing a problem somehow at least and it very well may be the load for the O2 heater. The main relay has two contact sections and one is used to provide power to the ECU while the other goes to the O2 sensor and other areas. The power lead for both relay sections is commoned to fuse SBF-2. Perhaps the trouble is with the common power to the relay since that is the only link to the seperate areas. There looks to be an easy way to check the power from fuse SBF-2. Pin 1 of the OBD2 plug is also tied to that fuse so checking the voltage on that pin should be a good easy to get to monitor point. Going over the drawing again I found out there is another power connection to the ECU using the same fuse but it doesn't go through the relay so that may be the memory power to the ECU. Edited May 30, 2010 by Cougar Link to comment Share on other sites More sharing options...
iluvdrt Posted May 31, 2010 Author Share Posted May 31, 2010 Well I was able to confirm the O2 had a direct short to ground (The heater was bad) causing the car to not run. When I changed the main relay out I also added some new battery grounds as well. Car starts like a champ now....except I keep getting a P0130 O2 malfunction code. I am going to clean the connectors today (since I applied dielectric grease to it) and see if that helps it. Maybe the sensor doesnt like the grease on the connector. Link to comment Share on other sites More sharing options...
johnceggleston Posted May 31, 2010 Share Posted May 31, 2010 Well I was able to confirm the O2 had a direct short to ground (The heater was bad) causing the car to not run. When I changed the main relay out I also added some new battery grounds as well. Car starts like a champ now....except I keep getting a P0130 O2 malfunction code. I am going to clean the connectors today (since I applied dielectric grease to it) and see if that helps it. Maybe the sensor doesnt like the grease on the connector. did you replace the o2 sensor? Link to comment Share on other sites More sharing options...
Cougar Posted May 31, 2010 Share Posted May 31, 2010 Glad you found the heater trouble but it sounds you now may have trouble with the replacement unit. Link to comment Share on other sites More sharing options...
iluvdrt Posted May 31, 2010 Author Share Posted May 31, 2010 did you replace the o2 sensor? Glad you found the heater trouble but it sounds you now may have trouble with the replacement unit. Yes I changed the sensor out for another new one. I am going to clean out the connection with some good cleaner and check it to ensure it is secure. I'll clear the code and report back in a few days. I have a hard time thinking I got 2 bad sensors back to back. Link to comment Share on other sites More sharing options...
Cougar Posted May 31, 2010 Share Posted May 31, 2010 If you did get 2 bad ones you better find a different parts supplier. Link to comment Share on other sites More sharing options...
iluvdrt Posted June 1, 2010 Author Share Posted June 1, 2010 (edited) LOL no doubt. Usually (90%) I buy all my stuff at NAPA. This O2 came from the Zone. I cleaned the connector with elec con cleaner today and had a much more audible "click" as I reconnected it. Maybe it will be better now. I also cleaned the MAF and its connector. Next I think it cleaning out the IACV. Dispite having the ECU grounded so it knows my car is now a 5 spd, I have been getting quite a few engine elec probs not related to the conversion. Like the O2 sensor, IAC valve...mostly. Edited June 1, 2010 by iluvdrt Link to comment Share on other sites More sharing options...
iluvdrt Posted June 1, 2010 Author Share Posted June 1, 2010 Well the code is back. I cant shake it. SHould change out the sensor again or what?? Link to comment Share on other sites More sharing options...
Fairtax4me Posted June 2, 2010 Share Posted June 2, 2010 Which code is returning? P0130? The ECU must not be seeing the signal it wants to see from the sensor. Is this the second replacement sensor? What brand is it? Link to comment Share on other sites More sharing options...
Cougar Posted June 2, 2010 Share Posted June 2, 2010 Before you install another sensor I suggest you check the voltage on the sensor and the heater leads that tie to the sensor. Just to make sure that the sensor isn't being damaged by something wrong with the circuit to it. The heater leads should have 12 volts going to them. As for the sensor leads I am not sure what you will see with an open circuit. I don't think you should have 12 volts on them though. The sensor is supposed to generate its own voltage which the ECU monitors and should be between +1 and 0 volts when things are tied together and running normal. Here is a link for your reference that may help you out with this issue. http://mr2.com/TEXT/O2_Sensor.html Link to comment Share on other sites More sharing options...
iluvdrt Posted June 2, 2010 Author Share Posted June 2, 2010 Which code is returning? P0130? The ECU must not be seeing the signal it wants to see from the sensor. Is this the second replacement sensor? What brand is it? Yes, it is a Bosche Before you install another sensor I suggest you check the voltage on the sensor and the heater leads that tie to the sensor. Just to make sure that the sensor isn't being damaged by something wrong with the circuit to it. The heater leads should have 12 volts going to them. As for the sensor leads I am not sure what you will see with an open circuit. I don't think you should have 12 volts on them though. The sensor is supposed to generate its own voltage which the ECU monitors and should be between +1 and 0 volts when things are tied together and running normal. Here is a link for your reference that may help you out with this issue. http://mr2.com/TEXT/O2_Sensor.html Cool, Thanks Cougar. I'll check it out today. I have a fluke and some back probes so I should be able to get the readings with that. Link to comment Share on other sites More sharing options...
iluvdrt Posted June 2, 2010 Author Share Posted June 2, 2010 Here is the data log from the freeze frame data when the latest code hit: Fuel sys- OL Fuel sys 2-NA calc load-17% ECT-183.4 STFT-0.00 LTFT-0.00 MAP-(KPA) 43 RPM-2562 Veh spd-33MPH Link to comment Share on other sites More sharing options...
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