Code P0125 but acts like a vacuum leak?? - Solved
05-23-16, 06:00 AM
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Code P0125 but acts like a vacuum leak?? - Solved
1995 LS400, 254K miles. Yesterday, after about 40-50 miles of mixed city/country driving, it started hesitating, giving me a hard time, not wanting to accelerate and running like a cheap lawnmower. It was like this when I bought it, so I said, I know what that is, that's a vacuum leak! No codes as it's doing this, by the way. I had recently done some work that made me think I might have jerked one of the ACV lines loose from the PS pump, and this, coupled with some white smoke from the engine compartment and a smell I thought might be PS fluid burning, led me to jack up one side of the car and start taking off the plastic cover to get at the PS pump. While I was under there, I noticed that the driver's side catalytic converter was discolored and appeared to have burned up the high-temp sealant I put on there to seal any possible leaks. Based on where the white smoke was coming from, I figured it wasn't fluid at all, but rather the sealant burning away.
All fluids, including PS, were normal and I couldn't find any vacuum leaks. Still no codes. So I drove it home--if I ruin both cats, it's still cheaper than a tow from where I was, and one of them is obviously toast, anyway. It would accelerate (slowly) and hold speed, but that's all I can say for it. After about 15-20 minutes of driving like this, the CEL came on. When I checked that, it was throwing P0125, which is for the ECT preventing the fuel system from entering closed loop status. On one level, that would explain why the cat got cooked, if there was too much fuel dumping. But it's still confusing to me...because the last time it acted like this, I got P0420 and P0430.
I replaced the ECT sensor probably two thousand miles ago. Both cats are new (cheap Chinese but new), as are the oxygen sensors and fuel ratio sensors. When I installed the driver's side cat, I didn't break it in as per the manufacturer's instructions, because that part of the instructions were missing--which I discovered when I replaced the second cat. Before any of this crap happened, I heard a rattling that made me think the substrate had separated from the metal. This weekend, I replaced the transmission mount--which was broken--and jacked the motor up a little bit to see if I could get a better sense of the engine mounts. Although I disconnected the coolant hoses, PS hoses so they didn't rip when I jacked the motor up, I didn't do anything with any of the wiring harness connectors. The rattling disappeared after I replaced the tranny mount, so I thought I was in the clear with that. Also, when I started it up after taking it off the stands, it ran fine. Ran me up and down the road without an issue...until this.
I'm pretty sure I'm going to have to replace the cat, and probably the O2 sensor on that side (this is the fun one, where you have to remove the daggum accelerator) but I wanted your opinion on what else I should be looking at. If this dead cat is more a symptom than the real problem, I want to treat the real problem. Any advice?
All fluids, including PS, were normal and I couldn't find any vacuum leaks. Still no codes. So I drove it home--if I ruin both cats, it's still cheaper than a tow from where I was, and one of them is obviously toast, anyway. It would accelerate (slowly) and hold speed, but that's all I can say for it. After about 15-20 minutes of driving like this, the CEL came on. When I checked that, it was throwing P0125, which is for the ECT preventing the fuel system from entering closed loop status. On one level, that would explain why the cat got cooked, if there was too much fuel dumping. But it's still confusing to me...because the last time it acted like this, I got P0420 and P0430.
I replaced the ECT sensor probably two thousand miles ago. Both cats are new (cheap Chinese but new), as are the oxygen sensors and fuel ratio sensors. When I installed the driver's side cat, I didn't break it in as per the manufacturer's instructions, because that part of the instructions were missing--which I discovered when I replaced the second cat. Before any of this crap happened, I heard a rattling that made me think the substrate had separated from the metal. This weekend, I replaced the transmission mount--which was broken--and jacked the motor up a little bit to see if I could get a better sense of the engine mounts. Although I disconnected the coolant hoses, PS hoses so they didn't rip when I jacked the motor up, I didn't do anything with any of the wiring harness connectors. The rattling disappeared after I replaced the tranny mount, so I thought I was in the clear with that. Also, when I started it up after taking it off the stands, it ran fine. Ran me up and down the road without an issue...until this.
I'm pretty sure I'm going to have to replace the cat, and probably the O2 sensor on that side (this is the fun one, where you have to remove the daggum accelerator) but I wanted your opinion on what else I should be looking at. If this dead cat is more a symptom than the real problem, I want to treat the real problem. Any advice?
Last edited by RA40; 06-04-16 at 10:53 AM. Reason: Additional
06-04-16, 06:27 AM
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1995 LS400, 254K miles. Yesterday, after about 40-50 miles of mixed city/country driving, it started hesitating, giving me a hard time, not wanting to accelerate and running like a cheap lawnmower. It was like this when I bought it, so I said, I know what that is, that's a vacuum leak! No codes as it's doing this, by the way. I had recently done some work that made me think I might have jerked one of the ACV lines loose from the PS pump, and this, coupled with some white smoke from the engine compartment and a smell I thought might be PS fluid burning, led me to jack up one side of the car and start taking off the plastic cover to get at the PS pump. While I was under there, I noticed that the driver's side catalytic converter was discolored and appeared to have burned up the high-temp sealant I put on there to seal any possible leaks. Based on where the white smoke was coming from, I figured it wasn't fluid at all, but rather the sealant burning away.
All fluids, including PS, were normal and I couldn't find any vacuum leaks. Still no codes. So I drove it home--if I ruin both cats, it's still cheaper than a tow from where I was, and one of them is obviously toast, anyway. It would accelerate (slowly) and hold speed, but that's all I can say for it. After about 15-20 minutes of driving like this, the CEL came on. When I checked that, it was throwing P0125, which is for the ECT preventing the fuel system from entering closed loop status. On one level, that would explain why the cat got cooked, if there was too much fuel dumping. But it's still confusing to me...because the last time it acted like this, I got P0420 and P0430.
I replaced the ECT sensor probably two thousand miles ago. Both cats are new (cheap Chinese but new), as are the oxygen sensors and fuel ratio sensors. When I installed the driver's side cat, I didn't break it in as per the manufacturer's instructions, because that part of the instructions were missing--which I discovered when I replaced the second cat. Before any of this crap happened, I heard a rattling that made me think the substrate had separated from the metal. This weekend, I replaced the transmission mount--which was broken--and jacked the motor up a little bit to see if I could get a better sense of the engine mounts. Although I disconnected the coolant hoses, PS hoses so they didn't rip when I jacked the motor up, I didn't do anything with any of the wiring harness connectors. The rattling disappeared after I replaced the tranny mount, so I thought I was in the clear with that. Also, when I started it up after taking it off the stands, it ran fine. Ran me up and down the road without an issue...until this.
I'm pretty sure I'm going to have to replace the cat, and probably the O2 sensor on that side (this is the fun one, where you have to remove the daggum accelerator) but I wanted your opinion on what else I should be looking at. If this dead cat is more a symptom than the real problem, I want to treat the real problem. Any advice?
All fluids, including PS, were normal and I couldn't find any vacuum leaks. Still no codes. So I drove it home--if I ruin both cats, it's still cheaper than a tow from where I was, and one of them is obviously toast, anyway. It would accelerate (slowly) and hold speed, but that's all I can say for it. After about 15-20 minutes of driving like this, the CEL came on. When I checked that, it was throwing P0125, which is for the ECT preventing the fuel system from entering closed loop status. On one level, that would explain why the cat got cooked, if there was too much fuel dumping. But it's still confusing to me...because the last time it acted like this, I got P0420 and P0430.
I replaced the ECT sensor probably two thousand miles ago. Both cats are new (cheap Chinese but new), as are the oxygen sensors and fuel ratio sensors. When I installed the driver's side cat, I didn't break it in as per the manufacturer's instructions, because that part of the instructions were missing--which I discovered when I replaced the second cat. Before any of this crap happened, I heard a rattling that made me think the substrate had separated from the metal. This weekend, I replaced the transmission mount--which was broken--and jacked the motor up a little bit to see if I could get a better sense of the engine mounts. Although I disconnected the coolant hoses, PS hoses so they didn't rip when I jacked the motor up, I didn't do anything with any of the wiring harness connectors. The rattling disappeared after I replaced the tranny mount, so I thought I was in the clear with that. Also, when I started it up after taking it off the stands, it ran fine. Ran me up and down the road without an issue...until this.
I'm pretty sure I'm going to have to replace the cat, and probably the O2 sensor on that side (this is the fun one, where you have to remove the daggum accelerator) but I wanted your opinion on what else I should be looking at. If this dead cat is more a symptom than the real problem, I want to treat the real problem. Any advice?
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