s13vette

iTrader: (1)

Ok so Let me start by sayin, I have read and googled everything about this but i have yet to find something that relates to my issue.

Now I have a STOCK 2000 LS1 A4 with ls6 manifold, truck coils, and ported throttle and tuned on HP Tuners on my 240sx. The issue im having and it started over night is this.

When i go WOT or just rev the motor passed 5000rpms it goes SUPER SUPER RICH from 11.5 to the 10.5 AFR. Now i dont hit a wall when this happends BUT it does break up all the way through the rest of the revs to 6500rpms.

What i have done so far. I have changed wires and plugs.
I have a log of the car on a WOT throttle i will post tomorrow.
I also opened the valve covers and the springs/retainers are not broken, and pushrods are good. But it does not feel like valve float but i could be wrong.

Car has no DTC's what so ever. But i have lost over 25 WHP when i put it on the dyno a week ago. Which is is really pissing me off.

If anyone can please shine a light or point me to an idea i can look into. Thanks I just want to take my car to the track and race the damn thing...

wait4me

iTrader: (10)

Is it throwing codes? or Is it flashing any lights? Did you try putting in the stock coils?

Unplug the mass air meter and try it again and see if it does better..

s13vette

iTrader: (1)

Mass is unpluged and same ****, no is not throwing no codes what so ever.

BLK02WS6

iTrader: (2)

Naturaly aspirated? Stock valve springs? How long has it been fine before this started?

Brennen's01SS

iTrader: (1)

Sounds like upstream 02 sensors. Mine did something similar. I could be wrong though....

s13vette

iTrader: (1)

Yes stock everything but it does it weather I'am at wot or just revving to does rpms


I was thinking that but the log shows them fine imma post the log now give me 10 min

s13vette

iTrader: (1)

this is the log of 1st gear trough second gear... if u find ANYTHING please let me know thanks

i will take another log today on te way home

s13vette

iTrader: (1)

here is another log i just did on the way home and i noticed something... Take a good look at the LTFT B1 and LTFT B2 see the difference???

The first one is a WOT pull and look at the LTFT B1 compared to LTFT B2

and the second one is Just driving and reving up to the 5000rpms

s13vette

iTrader: (1)

And also i get this

sho-me speed

iTrader: (55)

You are carrying an extra 12% fuel into WOT from you LTFTs. Based off the o2 switch points you are not going that rich. I realize they are not real accurate for WOT stuff but they can give an indication of an extreme over rich condition as you are describing and it doesn't reflect that.

I would look at ignition problems or voltage issues.

Ed Wright

iTrader: (1)

If this is normally aspirated, why in the world would you have it at 11.5-1 before it went tilt?
Not going into COT mode, is it?

s13vette

iTrader: (1)

huh??? im sorry i have no idea what u mean?

s13vette

iTrader: (1)

well in the does logs the A/F was at 11.5-12.0 rigth at 5000rpms like it shows on the log... I dont know ill test the charging system but im almost 100% sure that its good. Coils im using the truck coils ill see if i swap them for some from a yukon at the shop tomorrow

Thanks for the help everyone please keep thinking lol im still running around in circles

edcmat-l1

iTrader: (10)

He means, if it's normally asperated, why would you command 11.5:1 A/F in the first place? Should be high 12s, or 13:1 A/F.

s13vette

iTrader: (1)

I haven't commanded that a/f at all the car was tuned at a constanct 12.8-9 afr
And now is when it has changed out of no where. Like I said

Ed Wright

iTrader: (1)

COT mode is Converter Over Temp Mode: the PCM commands very rich A/F to lower EGTs, thus cool the cats.

s13vette

iTrader: (1)

Oh I haven't touched anything from the tune at all like I said I just started out of no where

Ed Wright

iTrader: (1)

Any decent scan tool will tell you if/when it goes into COT mode. It's nothing to see one go into COT during a dyno pull. Usually by 5000. 10.5-1 is black smoke.

s13vette

iTrader: (1)

It is black smoke but I don't have a decent scan tool

sho-me speed

iTrader: (55)

Unless your COT is coming into play, then someone raped on your PE tables to get it tuned which is why the 11.5:1 commanded.