Bad news with MAF - need some help
Thread Starter
Junior Member
Joined: Oct 2017
Posts: 66
Bad news with MAF - need some help
So I REALLY need some good advice here(scrap and sell is not advice). I bought a 2000 Maxima and have done all the work on it myself. All 4 engine mounts, neutral position sensor, cooling fan assembly, two new tires. I am now getting an intermittent issue with idle. The RPMs oscillate between 0 and 1000 constantly and it is throwing an engine code related to the MAF. Shop looked into it and found that someone had tried to rewire the MAF to a "switch" inside the car that would supposedly provide more voltage to the MAF to give the car more "power".
Does anyone know anything about doing this? Simply because, I need to undo it and I have NO idea how to do this. I am not an electronics guy, I can fix things, but wiring and volts and ohms just aren't my thing. Car is for my student son and I can't afford to pay someone else to do it, I've got to do it myself. ANY help on this would be really great. I'll try and add the engine codes that come up on the scanner if that will help.
Does anyone know anything about doing this? Simply because, I need to undo it and I have NO idea how to do this. I am not an electronics guy, I can fix things, but wiring and volts and ohms just aren't my thing. Car is for my student son and I can't afford to pay someone else to do it, I've got to do it myself. ANY help on this would be really great. I'll try and add the engine codes that come up on the scanner if that will help.
Thread Starter
Junior Member
Joined: Oct 2017
Posts: 66
Member
Joined: May 2017
Posts: 222
From: Hudson, NH
I would worry the car has been beat on when I see things like this. Whatever that is, its completely useless, a performance downgrade. Its not a CAI, its sucking air from the engine compartment. Design engineers found out 20 years ago that sucking hot contaminated air from the engine compartment degrades HP because warm air is less dense, so it carries less oxygen. Its not ram air either. There's no air pressure from the nose like there would be with a snorkel. Why they use snorkels to this day. "short ram" maybe. But thats just a word that sounds powerful. I suggest you buy a used factory air box from ebay, remove and toss that stupid thing in the dumpster. I'm thinking you can cut that jumper wire out and reconnect the 2 same colored wires together and see what happens. Also your symptoms suggest it could be the TPS sensor which is the brown connector at the TB. Have a look down there.
Thread Starter
Junior Member
Joined: Oct 2017
Posts: 66
I would worry the car has been beat on when I see things like this. Whatever that is, its completely useless, a performance downgrade. Its not a CAI, its sucking air from the engine compartment. Design engineers found out 20 years ago that sucking hot contaminated air from the engine compartment degrades HP because warm air is less dense, so it carries less oxygen. Its not ram air either. There's no air pressure from the nose like there would be with a snorkel. Why they use snorkels to this day. "short ram" maybe. But thats just a word that sounds powerful. I suggest you buy a used factory air box from ebay, remove and toss that stupid thing in the dumpster. I'm thinking you can cut that jumper wire out and reconnect the 2 same colored wires together and see what happens. Also your symptoms suggest it could be the TPS sensor which is the brown connector at the TB. Have a look down there.
Can the TPS be cleaned or does it just need to be R&R?
Member
Joined: May 2017
Posts: 222
From: Hudson, NH
Its definitely a TPS symptom. But its not a factory setup, so who really knows. Its quite common to experience odd MAF problems after installing one of these. Internet is jammed with posts. Location of sensor is critical. Otherwise you won't get the right fuel air mix, hard to start, misfires, etc. The answer is always the same. Get rid of it. But before you do, cut that jumper wire out of the loop and splice the 2 wires together again. Pray thats all thats wrong.
Thread Starter
Junior Member
Joined: Oct 2017
Posts: 66
Its definitely a TPS symptom. But its not a factory setup, so who really knows. Its quite common to experience odd MAF problems after installing one of these. Internet is jammed with posts. Location of sensor is critical. Otherwise you won't get the right fuel air mix, hard to start, misfires, etc. The answer is always the same. Get rid of it. But before you do, cut that jumper wire out of the loop and splice the 2 wires together again. Pray thats all thats wrong.
They may have tried to wire in an air/fuel controller but it doesn't look right for that. You don't just T a line from the MAF to the ECU plug. It's horrible wiring even if it was hooked up correctly.
They could have also been trying to bypass some damage in the wiring harness by going straight to the ECU with that long black line. If they weren't getting good continuity they could have tried to jump around the harness to the same line.
A new wiring harness will be pretty expensive. I don't think it's necessary.
There are people who could put that back together. I could do it if I had the car but I don't know if I could walk you through it. If you find a sharp mechanic that knows wiring he could figure it out.
The first step is to figure out what they were doing.
IF they were trying to mod I would start my disconnecting the extra wires that go to the ECU and other harness. Tape them off but leave them hanging for now. Open up the harness that goes from the MAF till you get to four unmolested wires that match the four coming from the MAF plug. Get rid of the married sections and splice the four wires back together. That should get the MAF talking to the ECU again.
If they weren't modding, I would diagnose the wiring issue starting with checking continuity and going from there.
Look at a pin out and see what wire they Td into at the ECU. Let us know that.
They could have also been trying to bypass some damage in the wiring harness by going straight to the ECU with that long black line. If they weren't getting good continuity they could have tried to jump around the harness to the same line.
A new wiring harness will be pretty expensive. I don't think it's necessary.
There are people who could put that back together. I could do it if I had the car but I don't know if I could walk you through it. If you find a sharp mechanic that knows wiring he could figure it out.
The first step is to figure out what they were doing.
IF they were trying to mod I would start my disconnecting the extra wires that go to the ECU and other harness. Tape them off but leave them hanging for now. Open up the harness that goes from the MAF till you get to four unmolested wires that match the four coming from the MAF plug. Get rid of the married sections and splice the four wires back together. That should get the MAF talking to the ECU again.
If they weren't modding, I would diagnose the wiring issue starting with checking continuity and going from there.
Look at a pin out and see what wire they Td into at the ECU. Let us know that.
Thread Starter
Junior Member
Joined: Oct 2017
Posts: 66
They may have tried to wire in an air/fuel controller but it doesn't look right for that. You don't just T a line from the MAF to the ECU plug. It's horrible wiring even if it was hooked up correctly.
They could have also been trying to bypass some damage in the wiring harness by going straight to the ECU with that long black line. If they weren't getting good continuity they could have tried to jump around the harness to the same line.
A new wiring harness will be pretty expensive. I don't think it's necessary.
There are people who could put that back together. I could do it if I had the car but I don't know if I could walk you through it. If you find a sharp mechanic that knows wiring he could figure it out.
The first step is to figure out what they were doing.
IF they were trying to mod I would start my disconnecting the extra wires that go to the ECU and other harness. Tape them off but leave them hanging for now. Open up the harness that goes from the MAF till you get to four unmolested wires that match the four coming from the MAF plug. Get rid of the married sections and splice the four wires back together. That should get the MAF talking to the ECU again.
If they weren't modding, I would diagnose the wiring issue starting with checking continuity and going from there.
Look at a pin out and see what wire they Td into at the ECU. Let us know that.
They could have also been trying to bypass some damage in the wiring harness by going straight to the ECU with that long black line. If they weren't getting good continuity they could have tried to jump around the harness to the same line.
A new wiring harness will be pretty expensive. I don't think it's necessary.
There are people who could put that back together. I could do it if I had the car but I don't know if I could walk you through it. If you find a sharp mechanic that knows wiring he could figure it out.
The first step is to figure out what they were doing.
IF they were trying to mod I would start my disconnecting the extra wires that go to the ECU and other harness. Tape them off but leave them hanging for now. Open up the harness that goes from the MAF till you get to four unmolested wires that match the four coming from the MAF plug. Get rid of the married sections and splice the four wires back together. That should get the MAF talking to the ECU again.
If they weren't modding, I would diagnose the wiring issue starting with checking continuity and going from there.
Look at a pin out and see what wire they Td into at the ECU. Let us know that.
Extended crank - this is always producible after the car has sat for a while. If you start it, shut it off, and then restart it, it will sometimes crank long, sometimes not
Intermittent RPM oscillation after start - This may be warm and cold start, but seems most common on cold start. The RPMs will oscillate between 6-700 RPMs until the car gets warm(er)
Herky-Jerky - Only when cold. Any gas pedal release is exaggerated and jerks you everywhere. Any light movement with the gas pedal while engine very cold causes this herky-jerky movement of the vehicle. Doesn't do it at all after warm.
Thread Starter
Junior Member
Joined: Oct 2017
Posts: 66
Its definitely a TPS symptom. But its not a factory setup, so who really knows. Its quite common to experience odd MAF problems after installing one of these. Internet is jammed with posts. Location of sensor is critical. Otherwise you won't get the right fuel air mix, hard to start, misfires, etc. The answer is always the same. Get rid of it. But before you do, cut that jumper wire out of the loop and splice the 2 wires together again. Pray thats all thats wrong.