TXjeepTJ

iTrader: (8)

This almost looks unreal to me, the engine acts very strange when you either drive it, or rev it up past 1k RPM in park/neutral. It sounds like it revs high, then low, then high, then low repeatedly by about 100 RPM very fast

**it runs fine in open loop, but once it goes to closed loop all hell breaks loose**



This is from a 5.3L that was installed in a jeep wrangler. It is ran by a 1998 pcm/harness of a Camaro that was/looks like tuned correctly. I cannot confirm if the front oxygen sensors are from a 98-02 F-body. LS1 injectors were installed on it to work with the harness, I cannot confirm if the tune was set up for them or not though.

SupraNatural

iTrader: (2)

Maybe you have the right and left bank O2's crossed up? Unplug one and see if you have correct.

TXjeepTJ

iTrader: (8)

Already tried it, still nothing!

TKR88GTA

What all have you checked so far? With the way the fuel trim looks, it shows that bank 1 is reading rich and bank 2 is reading lean. I never seen data like that before but just saying by the way it looks one side is seeing the complete opposite of the other side. If I'm correct shouldn't the tps be more than 6% over 1200rpm? From what I have messed with before it should be about 6% at idle.

Correct me if I'm wrong I'm jus throwing out some idea but I havent messed with a swapped engine in other vehicle yet. Idk if that should matter in this case or not.

TXjeepTJ

iTrader: (8)

I've checked everything as far as vacuum leaks, fuel pressure, running scans on it- posting about 5 other threads asking about stuff

It doesn't have an electronic throttle body, so the TPS % is 0 at idle

I'm about to take the intake off, check over it. I'm also swapping in a 99+ LS1 wiring harness w/ 5.3L injectors and newer PCM

Mez

iTrader: (1)

Because the wave pattern is very square and sharp, my guess is something is wired incorrectly. Normally, the O2 sensors will have a sharp zig-zag up and down with no plateaus at the top or bottom. Yours graphs have square wave which is not possible with gases that flow across your O2 sensors. That suggests to me you have a wiring problem.

TKR88GTA

What if you took the oxygen sensors out of the picture? Disconnect it see what your computer does. I know that's how I knew I had a oxygen problem with mine, it did the same thing but I didn't have a scan tool or dso to look so I just replaced the sensor and got lucky. Does the computer go into open loop again at a certain rpm? I know some do, I know all should go open loop with WOT.

2xLS1

iTrader: (25)

Unplug the drivers side O2 and post a pic of the chart display with it unplugged.

TXjeepTJ

iTrader: (8)

I did this, but didn't record the scan. I think you told me to do it in another thread in another section I posted about this haha. It showed drivers side o2 at a constant mV and the passenger side o2 still reading

Oxygen sensors unplugged it goes to open loop right away and runs good. So it is something to do with the oxygen sensor wiring I am guessing




right now I am in the process of taking off the 1998 pcm/harness and swapping in a 99+ LS1 harness and 99+ style PCM. I will keep everyone updated at to if this solves the problem

edcmat-l1

iTrader: (10)

O2s are crossed. Look at your fuel tirms. They match the opposite O2 sensor. Classic O2 swapped pattern.

TXjeepTJ

iTrader: (8)

I swapped the o2 plugs though and it shows the same pattern but just a little more wackier and it revs really bad, where as how it is now it revs, but it's just not a stready rev

Unless something is messed up in the internal wiring of the 1998 harness. Such as 1 wire was switch from the main PCM connector. The harness was made by some random person that they tried to sell as a professionally made harness

edcmat-l1

iTrader: (10)

Swapped O2s are the only thing that makes sense. Fuel trims on one side go rich, forcing the opposite O2 rich, and vice versa. I've seen it many times. I've never seen that pattern and it not be swapped O2s.

Even if it's screwed up wiring in the harness, O2s only report what they see, and it's obvious they are reporting.

2xLS1

iTrader: (25)

It's hard to continue to help with your problem when you refuse to do what is asked. That is why I didn't reply to your PM. Good luck.

TXjeepTJ

iTrader: (8)

I did do what you asked, I just didn't record the data as I thought it was just to see if the computer recognized bank 1 sensor as bank 1, which it did

I really appreciate the help, I just wished I would have recorded that scan so you could see it (now the wiring is off..)

I forgot that I did get a scan of swapping the oxygen sensor wiring (bank 1 to bank 2, bank2 to bank 1) so everyone can see that crazy data lol