Riviera from hell

Everything's brand spanking new Vapor can, Lower intake , plenum gask, thermostat, maf sensor, coolant elbows,egr gasket ,injection orings vacuum lines

AA wrote:

Should be able to reset fuel trims with the Aeroforce gauge.

I reset the fuel trims they go err right back up and now im getting a p0420 code that just came on lastnight

Absolutely. You removed the Cat right? The P0420 is Catalyst System Low Efficiency. Without having the codes tuned out with a DHP or a Cat Simulator in place, that P0420 will never go away. That code is a direct result of what the rear O2 sensor is reading. It won't affect engine performance at all. It's just an annoying SES light.
I'm curious. What exactly is your Intake made out of? What kind of filter? Pics? We have a kid (friend of one of the Service Advisors) with a Grand Prix. He brings it in all the time. He installed some aftermarket intake on the car, and it kept throwing a MAF code. We told him that the Intake was crap and needed to be taken off the car. He didn't listen the first 3 times.....It was one of those Weapon R intakes. It had a smaller tube mounted inside of the big tube with fins in it. I think that what it was doing was accelerating the air coming in somehow and causing a false MAF reading at idle and cruising. As soon as we took the Intake off, even with an open TB, the engine stabilized. But, that wouldn't explain why the trims level out when you unplug the MAF sensor. The O2 would still be reading the overabundance of air if that were the case.....

Pvc with a spectre cone filter 3in in the fwi

I gave Abaddon a + cuz he deserves them all too! Sometimes it's just repeating the same tips until it all sinks in.

Johhny do you still have the stock intake around? Any chance you could put it back on for a bit as a test?

Nope cut that up years ago trying to make a gutted airbox

I have a thought, and Abaddon will be more experienced than me to say if this is correct. If he monitors both O2 sensors, Sensor 1 bank 1, and sensor 2 bank 1, shouldn't sensor 2 mimic sensor 1,so we can atleast rule out his O2 sensor? Without a cat they should read almost identical, shouldn't they? If he is sure that he has no vacuum leaks and his MAF is new, is it possible his pre-cat O2 sensor is malfunctioning? If nothing else, this should atleast confirm that the O2 sensor is ok.

Thats what I was thinking too dave that was my concern while monitoring .. my o2 sensor fluctuate too much for it say its steady flow so im going to post some footage

Stft with the MAF freq. While trying to drive

I thought this was weird im doing about 65 cruise control is on and these are my readings for the o2 sensor it only lets me see one sensor so the numbers should mirror each other but they are not

Ltft and s1b1

this me sitting at the red light.

You have to excuse my shocks and the road mouse's.

O2 readings will not mirror exactly because the O2 sensor is updating rapidly, and the Aeroforce gauge updates each display independently, at a set refresh rate. You could increase the refresh rate to get them closer, but it's pretty pointless to do.

It's not that weird. It's like trying to take two identical pictures using the same camera.

I can't tell what you are showing in the other pics. Need to move the camera back and focus.

My point wasn't so much that they give identical numbers, but more so that sensor one may show a lean reading (below 450 mv) and sensor two may report a rich reading (above 450 mv).

Well im saying is that since its two o2 sensors but im only able to see what the one inside the manifold is doing

And Goodmorning AA & BigDave

I'm not familiar with what the Aeroforce gauge is capable of, so maybe someone else can chime in. I know with my Actron scan tool I can monitor both sensors. I would think that the Aeroforce could do the same.

You can monitor sensor #2, but there's really no need to, because the engine only uses feedback from sensor #1 in closed loop mode. #2 is just there to monitor function of the cat.

He's not running a cat so in his case I would think that this test may be of some value. If his #1 sensor is reading lean and his#2 is reading rich then I would think sensor one is not reporting accurate data.

Good point. Do we know if the sensors are the same and read the same? I mean, in order to trust sensor #2, we would need to be sure that a healthy system has identical readings from both sensors without a cat installed.

The thing that really gets me is that when he unplugs his MAF, the O2 shoots up to rich (940mV), and the STFT goes negative to compensate. The MAF is still reading over 2000Hz at idle plugged in, and the O2 reads lean, as it should according to the MAF reading.
If there were an air leak present, the O2 would pick up the lean condition even with the MAF unplugged, but it doesn't appear that he has one, because it goes rich. This is strange.

I think the rear O2 is completely different than the front O2. It's much slower. Although I suppose we could run the same "test" to see if the front O2 is malfunctioning somehow. Although, that still wouldn't explain the high MAF frequencies at idle. Either way, see what both O2's are reading at idle. Then unplug the MAF, and see what the O2's level out too. I suppose the rear O2 should eventually go rich just like the front.

I don't understand how the O2s can tell you anything - a properly functioning O2 output should be rapidly oscillating from low to high at idle & cruise. I'd think the two could be reading completely different values and it would be normal.

Right. With a Cat in place, the rear O2 would be completely different. However, with the cat missing, in theory, it should read somewhere close to the front O2. IT just wouldn't cycle as fast. The P0420 appeared because it's reading outside of the predetermined values.  

Again, in theory though. We don't know. It just sounds like it would make sense. We're probably barking up the wrong tree either way lol. The P0420 is just a byproduct of the cat missing. It has nothing to do with his lean condition. But if the rear O2 is reading rich, and the front O2 is reading lean.....without a catalyst in place, the rear O2 is going to read whatever the engine is putting out.

In a shop environment this wouldn't be the way to approach this. That being said,Johnny has limited resources for testing. I'm just trying to make suggestions for things he can do himself for free. With his fuel trim history, I would think his O2 sensors might spend some time below 450 mv. If # 1 does and # 2 doesnt it might suggest the pre cat sensor is faulty.

My last option is out to put it on a system and have it scanned by a shop...that will determine if I have a leak but I know I changed out a load of parts just being safe and o2 sensor is not reading how I think it should read its .. im sorry the videos were a little blurry that was the best I could do with the factory tape still stuck to it...but I had it in the exhaust shop no leaks were in the exhaust how do I clean the injectors?