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Well, I put this up on G35 driver but haven't got anything very useful back. Please help me with troubleshooting ideas or advice, or if you can read the datalog and see something PLEASE tell me!
My G started running rough, throwing check engine light due to running too rich? lean? on Bank 2 (passenger side). Power down 10%-15%, exhaust droning more than normal (I'm almost positive that this is not caused by any exhaust system issue.) I'm trying to sequence the trouble shooting from easiest to hardest, while also considering probability.
The exhaust smells rich, but data logging indicates otherwise.
I'm thinking possibly:
1. Bad Coil -
-I plan to swap all from Bank 1 to Bank 2 to see if problem moves. This would rule in/out coils.
2. Faulty Bank 2 #1 02 sensor (narrowband on my early '04)
-I plan to swap from bank 1 to bank 2 to rule in/out o2 sensor.
3. Compression problem
-I plan to run compression test
4. Faulty injector - Sticking open/rich? clogged/lean?
- Any troubleshooting on this requires puling intake manifold for access so I'm reluctant to go here.
I have Uprev Cipher and can read ECU parameters and log engine performance. I've attached a short log.
This problem occurred about 6 months ago. I thought it was a problem with my exhaust. I replaced my rear muffler thinking there may have been a problem with it. It did nothing. I used Cipher to selectively turn on/off each cylinder (shuts off injector and spark) to try to identify which one was not performing correctly. (The problem was on Bank 2, I don't remember which cylinder. During the cylinder shutdown testing, the problem suddenly cleared and the engine has run perfectly since then until now.
Using the cylinder shut down test I am currently unable to isolate any cylinder causing the problem. The problem IS clearly Bank 2 specific making me think that I should perhaps look at the o2 sensor first. (I think a coil, injector or compression problem would be cylinder specific) If the 02 sensor is faulty, perhaps reading leaner than actual, then it may be causing the ECU to flood that bank. That could explain logs that say lean while the exhaust actually smells rich. Having said that, if that were the case, why would the injector bandwidth be lower on average for Bank 2???
I have attached a pdf of an operating log from cipher. I observe in it that:
The A/F correction generally reads lower on Bank 2
The difference between B1 and B2 AFR readings oscillate but average slightly higher on bank 2 (leaner)
The injector pulse width is generally reading a little higher on Bank 1
Bank 2 o2 Sensor 2 readings are wild because my high flow cat is below efficiency and I have an anti-fouler installed on B2.
Engine has 70,000 miles on it.
Please respond: Anyone who has experienced anything like this or who can share useful advice on my troubleshooting process.
My brain hurts trying to figure this out and I have little experience with tuning or this sort of diagnostic work.
what cel code? have you replaced your plugs? post the code, put new plugs, clean your air filter, change your oil, disconnect your battery overnight and report back.
need a clean slate to start with before chasing gremlins.
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VQ38DETT with SFR Twin 6262 on ProEFI128 Corn Fed
what cel code? have you replaced your plugs? post the code, put new plugs, clean your air filter, change your oil, disconnect your battery overnight and report back.
need a clean slate to start with before chasing gremlins.
You're in Raleigh too! I wouldn't mind checking out your Vortech system!
Code: P0430 Catalyst System Efficiency Below Threshold (Bank 2)
Plugs are NGK Iridium <1 year old, I just inspected them, they all look good and look the same.
I recently cleaned air filter and changed oil <3000 miles ago, but I will go ahead and change the oil and disconnect the battery tonight.
OK, driving this morning, the problem decided to pretty much fix itself!
One minute a loud droning exhaust, then over a period of a couple seconds, the deep drone faded and my normal exhaust sound returned! I had been driving about 15 minutes on back country roads, getting on it mildly so things were getting warmed up.
Power is now much better, though still seems not quite spot on.
I ran a data logging session afterward and found little change, although there are a few things maybe worth noting: Excluding the lean out periods with AFR readings of 30 (narrow band AF sensor in early 04 cars), the average AFR was 14.77 and is 14.76.
The average difference between B2 and B1 AFR was +.05 before and is now +.25 (leaner on Bank 2)
The avg AF Corr was: 101.7 B1 and 101.11 B2
The avg AF Corr IS now: 100.0768 B1, 100.6365 B2
I don't know if this means anything. I'm very happy my car is now running much better, but frustrated to not know why, what was wrong, whether it is actually fine now or just less bad, or what to do next time it happens.
Does anyone know if loud droning as an intermittent condition can be caused by anything other than the exhaust? Maybe I should be looking for a bad baffle in the center pipe resonator or something like that.
Trouble shooting rough running 04
