ls430 engine won't rev past 2k rpm + fuel smell
07-17-19, 04:32 PM
#1
ls430 engine won't rev past 2k rpm + fuel smell
Long story short, I bought this ls430 a few months ago and it ran fine up until recently.
I was on the highway and the car just lost power.(couldn't go any more than maybe 35mph even though rpms would go to 5-6k)
I ended up slowly getting it back home, and since then I have replaced the fuel pump (assumed to be main culprit for the loss of power)
However, there was also a vacuum leak from a valve (which was stuck open) on the throttle body. I ended up also replacing the entire throttle body with one from a parts LS430
Now that everything should be fixed... I'm still unable to get the car to run correctly.
I can't get past 2000 rpm, however there is a multiple cylinder misfire code.
Changed coils, spark plugs - nothing really changed - still has random cyl misfire and won't rev past 2k rpm
Swapped TPS w/ parts car, cleaned MAF and tons more.... car just will not run correctly.
When I had cleaned a downstream o2 sensor, the car did rev to around 4-5k however it eventually ended up back at 2k
Bought a brand new o2 sensor and that still hasn't changed anything - car still won't go past 2k rpm
Maybe one of you gurus out there might know better than myself what to do at this point
I was on the highway and the car just lost power.(couldn't go any more than maybe 35mph even though rpms would go to 5-6k)
I ended up slowly getting it back home, and since then I have replaced the fuel pump (assumed to be main culprit for the loss of power)
However, there was also a vacuum leak from a valve (which was stuck open) on the throttle body. I ended up also replacing the entire throttle body with one from a parts LS430
Now that everything should be fixed... I'm still unable to get the car to run correctly.
I can't get past 2000 rpm, however there is a multiple cylinder misfire code.
Changed coils, spark plugs - nothing really changed - still has random cyl misfire and won't rev past 2k rpm
Swapped TPS w/ parts car, cleaned MAF and tons more.... car just will not run correctly.
When I had cleaned a downstream o2 sensor, the car did rev to around 4-5k however it eventually ended up back at 2k
Bought a brand new o2 sensor and that still hasn't changed anything - car still won't go past 2k rpm
Maybe one of you gurus out there might know better than myself what to do at this point
Last edited by enycetony; 07-17-19 at 04:46 PM.
07-17-19, 05:42 PM
#2
Moderator
Not revving over 2K rpm simply means that your car going into "Limp home mode".
What is causing it could be many things and you need to find out the root cause of it. Since you already got a multiple cylinder misfire code, you need to find why it is caused. I worry that your car's cam timing is off more than the limit. This could be caused by the skipped timing belt, the malfunction of the OCV, failed ECU or some others. The best way to troubleshoot is to check the timing using an oscilloscope. Without it, it would take time to pinpoint the cause.
What is causing it could be many things and you need to find out the root cause of it. Since you already got a multiple cylinder misfire code, you need to find why it is caused. I worry that your car's cam timing is off more than the limit. This could be caused by the skipped timing belt, the malfunction of the OCV, failed ECU or some others. The best way to troubleshoot is to check the timing using an oscilloscope. Without it, it would take time to pinpoint the cause.
07-18-19, 04:03 AM
#4
Lexus Champion
Please don't take my comments the wrong way, but installing "used" parts to try to resolve your problem randomly can introduce new problems and make troubleshooting even more complicated.
In addition, everything in your engine bay has been "baked" in very high temperature for 16 years. Many plastic electrical connectors and rubber hoses are brittle and can be easily damaged while you try to work near them.
May I suggest to determine which Diagnostic Trouble Codes (DTC) you have currently, and go from there. If you don't have a OBDII reader, most of your local auto parts store should have one that they will retrieve the DTC for you for free. You will find a complete listing of DTC's on the link below...
https://www.clublexus.com/forums/ls-...for-ls430.html
In addition, everything in your engine bay has been "baked" in very high temperature for 16 years. Many plastic electrical connectors and rubber hoses are brittle and can be easily damaged while you try to work near them.
May I suggest to determine which Diagnostic Trouble Codes (DTC) you have currently, and go from there. If you don't have a OBDII reader, most of your local auto parts store should have one that they will retrieve the DTC for you for free. You will find a complete listing of DTC's on the link below...
https://www.clublexus.com/forums/ls-...for-ls430.html
07-18-19, 09:59 AM
#5
Instructor
I'm betting if you've replaced your plugs and coil packs and still having misfires then it's a wire on the coil plug. At this age it's super easy to pull one of those out or have the clip crack/break and not make a good connection. Have you had the ODBII codes read? It should tell you the cylinders that are misfiring. I would look really close at those coil pack clips.
That's assuming you replaced the coil pack and plugs with new ones. If those were used then that could be the culprit as well.
That's assuming you replaced the coil pack and plugs with new ones. If those were used then that could be the culprit as well.
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