I recorded the twenty km drive home. Kept it almost always off of boost. I'm curious what your thoughts are.
https://www.youtube.com/watch?v=-jUq_VJpbps
00:08 Starts right up. This has
never been a problem. Idles low at 550. Nice rumble but bothersome to a purist like me--I would prefer the to spec 800 +/- 50rpm.
00:30 Settles in at 14.2:1 Air to Fuel Ratio.
00:45
Immediately goes slightly lean (mid to high 15s) as I ease out of the parking garage.
01:20
Goes quite lean (higher than 16) as I get out onto the street, but settles down to the high 15s.
01:50: Settles to 14.6:1at a stop sign.
02:30: Hangs out slightly lean at 14.9:1 while cruising at low speed.
03:53: Oil Temp reaches 100 degrees F
04:15:
Lean as I merge into traffic and put a moderate load on. Varies from 15:1 with momentary spikes into 16s.
06:22: Coolant temp reaches 105 degrees F.
07:08:
Spike to 17:1 while under light load, then drops to 14.8:1 as I let off the gas and stays there as I continue to gain speed.
08:20:
Momentary (8 second) spike to high 15s, but settles back down to 14.8:1
08:37: Lean as I increase speed from 95km/h to 115km/h
09:30: Settles in at 14.8:1 as I accelerate from 115km/h to 125km/h
10:16:
Lean as I accelerate in 2nd gear through a curve, reaching 16s momentarily but mostly 15s.
10:26: Good acceleration near boost load, 60 to 95km/h in ten seconds, near stoichiometric ideal. Oil temp reaches 150 degrees F.
11:14:
Lean as I apply light load in a curve, and merge onto the expressway--mid 15s to mid 16s.
12:33: Settles down to 14.8:1 as I cruise at 100km/h.
13:10:
Goes lean (15s) as I apply light load, accelerating from 100km/h to 120km/h in 12 seconds.
13:37:
Lean again (mid 15s to mid 16s) as I apply light load, accelerating from 110km/h to 125km/h.
13:45: Settles down to bouncing around 14.8:1 as I continue accelerating from 125km/h to 150km/h in 14 seconds.
14:42:
Stumbling as I merge onto surface streets.
16:00: Take off from stop light. Nominal AFR. Oil temp reaches 176 degrees F, Coolant reached 185 degrees F.
16:30: Pull up a hill.
Some stumbling, but it settles in to 14.7:1.
16:52: Coolant reaches max temp for this trip at ~200 degrees F.
17:45: Coasting clutch in downhill. Idling at 14.9:1.
18:00: Cruising at moderate load. 14.7 to 14.8:1.
19:13: Acceleration 75km/h to 100km/h in 16 seconds. Bouncing around 14.7:1.
19:52: Take off from stop light. Nominal AFR.
20:58: Oil reaches max temp of 195 degrees F.
21:50: Destination reached. Idling at 14.9:1.
25:10: Started back up. Idling at 14.8:1 and 14.9:1.
As I listen, I'm struck by a couple of things.
One, wow, that suspension is rough. Really looking forward to the Feal 441s, which I hope will tone that down.
Two, it doesn't sound clean. I can definitely tell it's microstuttering, just from the engine tone.
I am considering these possibilities:
1. Bad distro? I have a cap and rotor on hand.
2. Bad O2 sensor? Could be feeding bad data to the ECU.
3. Bad fuel pump? I have a Denso unit on hand now.
4. Failing ECU. This was mentioned earlier as a possibility.
5. Failing AFM. Perhaps. I could do continuity tests and crack it open and inspect.
6. Clogged Fuel Injectors. Perhaps. I ran a can of fuel injector cleaner through it at the end of October/beginning of November. I could run
another can of fuel injector cleaner through it.
I checked for air leaks with throttle body cleaner. No leaks.
No Check Engine Lights.
I made certain sure the gas cap was on tight.
I put the fuel pump on the GT-Four. In the spirit of mechanics everywhere I charged 2 hours labor.