Ok before I start I'll give a list of what's done to my motor before I start explaining.

KA24DES15 T28 on 9 PSI.
370cc injectors.
N60 MAF (pull through)
BKR7E gapped to .26 or .28 iirc.
Walbro 255
Z32 fuel filter
4.36 diff with s15 hlsd.
Stock ignition wires
Stock FPR
Stock block
Stock head
So I'm curious about my enthalpy tune. Main concern is with my AFR's. Cruising at pretty much any speed from 15-50mph the afrs bounce between 10.3-14.5 it'll be in the 14s for like 3 seconds, drop down to the 10s and just keep bouncing to 13s and back to 10s for awhile then go back to the 14s for a few seconds, then back down to the 10s and so on. Meanwhile my foot is completely still holding the gas pedal in the same place. This just doesn't seem normal to me.

Then on the highway, from 50-85mph again just cruising hold my foot as still as possible, the AFR's will be bouncing from 10.2-12.3~ then again for a few seconds it jump to higher 13s and 14s then jump down again.

Then always at WOT at full boost the afrs are exactly at 10.0 any speed any gear.

Sooo is all of this normal with the bouncing AFR's or no? To me it should be steadier than what I'm reading.

Also some things I've replaced from what I have researched that may be the culprits but have not helped:

Coolant temp sensor
Plugs. Switched from bkr7eix to bkr7e
Fuel filter
All of the injector o rings.

 

Boost leaks maybe. How old is the o2 sensor?

 

No boost leaks. Did a boost leak test. and the 02 sensor. The one on the elbow.. Is factory aaand the motor has 185k

 

Who tuned it, how long ago and when did the problems start to occur?

Edit: is there any hesitation or significant problems?

 

Why don't you have Martin throw it on the dyno and clean it up for you? Hell you're close enough that I'd be down there to get it straightened out.

 

Re-calibrate your TPS voltage. My car used to do weird things in extreme temperature changes.

 

Or at least check it, so 10 points to griffendor Kevin!

RS-E tunes are 99% right, and if you're reading like you are with your AFR's, is most likely a mechanical failure somewhere.

+1 on having him run it on the dyno, at least a few pulls to see where it's at, and mybe help diagnose the problem in a controlled environment.

 

i'm sure factory o2 sensor with 185K on it isn't helping either.

 

If it works it works. I was referring to the wideband. They go out a lot faster.

 

I would check my wideband sensors are notorious for going bad. LC1's need to recalibrated more so than other brands.. Check your TPS voltage. Bad o2 or one that is going out could also cause this esp. seeing as it has such high mileage.