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So we are getting close to a year that my car has been sitting amd im ready to push it off a cliff lol
Car wont accelerate or hardly idle.
Tested and replaced items
ECU
MAF
Fuel pump
Fuel regulator
Efi Relay
Main Relay
Injectors
Fuel damper
IACV
APPS
TPS
Good spark
Im running very lean but noticed my o2 sensors wont even show .1 All four are flat out 0 nothing happening at all. How would one go about testing why? Ive dug around all over the internet trying to figure out how to diagnose something like this but I have no clue at all. Am I testing continuity or what? These wires go to like 3 different harness locations so its gonna be a hell of a job but is there something else I should check before I start doing crazy stuff? Thanks!
My fuel trim level is with MAF unplugged so disregard.
I assume your engine is running while you are taking this test?
Do you have access to something that will show the O2 voltages over time? I have the autoenginuity scan software. The O2 voltage looks like a sine wave so you really won't ever see a static voltage out of them.
I assume your engine is running while you are taking this test?
Do you have access to something that will show the O2 voltages over time? I have the autoenginuity scan software. The O2 voltage looks like a sine wave so you really won't ever see a static voltage out of them.
Thanks bruce! Yes this is very rough idling with MAF unplugged. Its so lean my manifold glows red after 5-10 minutes. I am running a new Pacesetter manifold as of a year ago but I have ran 3 different Mafs so I know its good plus its reading a good 4-7 g/s. Ill look into that software and see whats up. You would figure it would at least show .1 though for the 15 minutes I had it idle.
Is it still fair to say you still probably wont see voltage? from what i read it will read .1 if running lean but this car is running very very lean. I am also using the Torque Pro Bluetooth app
Last edited by Hypnotyk; 03-20-17 at 04:11 AM.
Reason: Add on
Update I seen stuff happening breifly also tested continuity to ecu and everything was good. This is bank 2 sensor 2. Does that sensor helpy with AFR or no? I noticed it was getting very hot when I pulled it and started the car as well. I feel like im back at square one now if this o2 isnt the problem. Any ideas would be awesome! I can do pretty much anything and if i need to invest in software i will but dont want to jump into things I dont need to since money is limited right now. I only have about 800$ to work with at this moment and this car is my lifeline now to get to work. Im gonna try and check for vacuum leaks since I noticed back firing in my throttle body but from previous experience a vacuum leak shouldnt keep me from accelerating. I noticed awhile back when i pulled intake.manifold off it was wet 2ith i believe fuel in there. Idk if that helps with anything but im throwing every idea out there since this car is basically a lemon to everyone lol.
Your oxygen sensors all reading 0V indicates a lean system. To verify o2 sensors being faulty, you could spray some liquid fuel into the intake while idling. This will give additional fuel, making it richer. While spraying, check to see if the o2 sensors respond (they should go up to around 0.8 - 0.9V). If they don't, then you would need to change your o2 sensors. If they do, then you will have to go back and check what is making your system lean.
For the test I described above, it is good to take the car for a drive and get it up to operating temp if you can and then use a voltmeter or scope directly on the sensor wires while spraying the liquid fuel.
The other problem why the o2 sensors aren't working as they should, could be the heater circuit positive side. Basically there are 4 wires, one 0V wire, signal wire, 12V wire and a heater triggering wire. Usually the heater section is two wires that are the same colour. And you can measure their resistance with an ohms meter, it should be less than 30 ohms if I remember correctly.
I had it disconnected because it would not idle at all i had to floor it. However recently i found a few vacuum leaks which allowed me to start the car with MAF plugged in and it actually idled at 750 rpm give or take. On top of that I also did the 12v fuel mod which helped it seems but i blew a fuse shutting it off so I probably wong keep it that way. it was not smooth idle though it feels like its cammed and still pretty rough feeling.
As far as acceleratung right now. When i press the gas she shoots up to 2k rpms for half a second then falls back down but it has good torque in that half a second. it wants to spin the tires i the dirt but it just falls back down. On the plus side I got it up to 10 MPH today! haha Ill try that method with the carb cleaner and see what i can come up with on the o2 sensor. I know.continuity is good to my ecu but ill check the resistance to those two wires you told me about. I may try and find a way to put a video up so yall can see whats up. I also noticed i have a pretty heavy valve cover leak but with that being said, shouldnt it still accelerate with vacuum leak?
Is there any codes?
The MAF sensor that you changed, was it brand new and the correct type? Because the 2jzgte maf also fits the plug too I think. Unplugging the MAF sensor would put the car into a type of safe mode because it cant read the amount of air coming accurately anymore.
Yip a vacuum leak would definitely cause problems especially under load depending how bad it is. If the leak is before the maf, then it doesn't matter too much just getting a little unfiltered air coming in. But if the leak is after the maf, then your getting un-metered air coming into the engine which is why its running lean.
You could try spray your carb cleaner around vacuum hoses and joins to see whether it idles higher. If it does, then you found the leak.
This is what the signal from a maf sensor should look like when you do a quick blip of the throttle with a scope. You can use a multimeter but its harder to get the voltage unless you have a "max" button on your device. If using a multimeter, your looking for a peak dc volts of around 4V when blipping the throttle.
Check for broken or open grounds, they are usually black and white wires. You may have some mounted on the back of the engine somewhere that may be disconnected or broken.
Has this vehicle ever run correctly since you have owned it? You really don't give us much information.
Pacesetter manifold? Did it run right before you replaced it? Did you change the O2 sensors when you replaced it? What type of anti-seize did you use on the O2 sensors if any?
03-19-17, 10:24 PM
All o2 Sensors showing 0 Volts?
