02 Sensor Problem! [Archive] - GrandAmGT.com Forum

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harvester45
02-06-2007, 10:01 PM
Ok, so I just got my car back from the shop, and after working out a few kinks from the LIM repair work, I am having some problems with my upstream (before the cat) O2 sensor. Since I didn't have the problem before I had the work done, I'll list the problems which I've had since then.

When I got my car back, it was hesitating and bogging down on the drive home, so I immediately scanned it and added a little more fuel (in the MAF section of the PT), which fixed that problem.

Driving it later, the car stalled, and upon attempting to restart it, I realized that the mechanic had routed the MAF wires incorrectly, and they had fallen onto the exhaust plumbing, causing a short and blowing the PCM ingition fuse (bear in mind that this is not a stock setup, so I had to lengthen the MAF and IAT wires). I replaced that fuse, and fixed the wire problem.

I noticed that the car wasn't maintaining boost when I went WOT, in fact the MAP was dropping down to 1 BAR, and the O2s were dropping off, from rich down to stoic, and even to lean! I checked the IPWs, and they were fine (consistent with the MAF readings), so I decided to check out the intake plumbing. Sure enough, the silicone connector at the TB wasn't on right. I fixed that and can stay at max boost now, with little to no KR, so I imagine it's getting enough fuel and air, but the O2 sensor still falls off till it reads almost 0.

My question is whether the O2 might be defective only under sustained rich conditions? It's got me puzzled, and on the verge of buying a WBO2 with a narrow band sim, but I'm really not wanting to cough up the money for that right now, especially if the O2 isn't my problem. I've even reflashed the PCM to an earlier calibration, to no avail. Any input would be great!

Thanks,

AaronGTR
02-06-2007, 10:47 PM
A wideband O2 is always a good idea, but you shouldn't have to completely replace the stock O2 sensor. If everything's working like it should the O2 sensor should work fine too, so there is obviously a problem. Beyond that it's hard to tell what the problem could be without seeing more specific scan data. First thing I'd do is get a new O2 sensor and try that out. That way you can rule out that possibility, and if it's not the O2 sensor then at least you'll have an extra good one. You'll need it eventually anyway.

harvester45
02-06-2007, 11:27 PM
I'll post up a scan, but with the expenses of school, etc. I don't want to spend unnecessary money. So if I need a new O2 sensor, I may as well get a wideband. I'll include one of the scans I've done since then:

24433

It was too big to upload as a CSV, so just rename it to .csv

Sprucegagt
02-07-2007, 12:21 AM
Few questions.

1. Do you know that the current MAP on your car is 1 bar and cannot read boost pressure? I ask because you said you noticed boost was dropping to 1 bar, yet your scan shows a max MAP value of 30.7 Hg or 103 kPa. That's not even 1 PSI of boost.
2. What do you call little to no KR? 6*+ of KR is not little.
3. What tuning software are you using?

As for your problem. It looks like your not getting full fuel pressure. Also it doesn't help that your not locking in at 0 LTFT when in PE mode.

harvester45
02-07-2007, 01:26 AM
Few questions.

1. Do you know that the current MAP on your car is 1 bar and cannot read boost pressure? I ask because you said you noticed boost was dropping to 1 bar, yet your scan shows a max MAP value of 30.7 Hg or 103 kPa. That's not even 1 PSI of boost.
2. What do you call little to no KR? 6*+ of KR is not little.
3. What tuning software are you using?

As for your problem. It looks like your not getting full fuel pressure. Also it doesn't help that your not locking in at 0 LTFT when in PE mode.

1.) Yeah, I know, that I've only got the 1 BAR sensor, but I have a mechanical boost gauge, and it was falling from 7PSI to 0 (or 1 BAR).

2.) Yeah, that is a lot, but that was the most recent scan that I could post, since something went wrong with saving the scan I took today. Also, these scans were taken with autotap (since I'm having troble saving scans with my PT), so the fuel trim cell data will be off (by 1, I think?). That scan was taken before I fixed the problem with the intake coupler, so it won't be entirely accurate, but it shows the IPWs as related to the MAF, KR (to a degree), and O2 sensor.

3.) I'm using the Powrtuner for the tuning, but, as I said in #2, it isn't working for my scans. I've actually had a lot of trouble saving scans with the PT, but I'm working on that. I'm just really lazy right now, and the autotap is real-time recording, so I don't have to wait till the end of the scan, or try the PT beta version 2.2.3

Sprucegagt
02-07-2007, 07:43 AM
OT: Try saving with the new software 1.2.3e. It is real time recording and works great. But be sure to use these settings.

http://www.gmv6pcm.com/index.php?showtopic=5345
/OT

I still think you should check your fuel pressure and if your fuel filter is old, change it.

harvester45
02-07-2007, 11:31 AM
Fuel filter is fairly new (seven months), and I don't have a fp gauge. I just can't see what's going on as far as that, but since this is a recent occurance, and I don't get detonation under WOT even when the O2s drop to .200 and below at 7 PSI, it leads me to believe that the O2 is bad.

I think the last time I tried the 1.2.3e, I had more problems than it fixed, but I'll give it another shot. (I accidentally refered to it as 2.2.3 above lol )

Sprucegagt
02-07-2007, 12:14 PM
In order to verify that I would need a recent scan showing your current symptons.

harvester45
02-07-2007, 08:22 PM
24438

Here ya go, I took this one today with the version of PT you reccommended. The software worked great!

Same deal as above, rename it to .csv to read

Sprucegagt
02-08-2007, 08:14 AM
I agree your O2 is going dead on you. It looks like it's overheating and losing calibration. Where is your O2 in your downpipe from the turbo? You could have it to close which is causing this problem. Another problem is your commanding to much fuel vs. time in PE. I don't think you want to be dropping a full AFR point in less than 2.5 seconds. This could be another reason why the O2 is going bad because your commanding a very rich AFR with I'm guessing premium fuel. But get a wideband O2 and scan with it before making changes.

OT: Check out lines 1624-1629. Has your commanded AFR always been doing that?

harvester45
02-08-2007, 01:21 PM
I agree your O2 is going dead on you. It looks like it's overheating and losing calibration. Where is your O2 in your downpipe from the turbo? You could have it to close which is causing this problem. Another problem is your commanding to much fuel vs. time in PE. I don't think you want to be dropping a full AFR point in less than 2.5 seconds. This could be another reason why the O2 is going bad because your commanding a very rich AFR with I'm guessing premium fuel. But get a wideband O2 and scan with it before making changes.

OT: Check out lines 1624-1629. Has your commanded AFR always been doing that?

I was afraid of that. Looks like I'm gonna be getting a WBO2. Does anybody know where to get this PLX setup for the same price or cheaper:

site (http://www.plxdevices.com/cgi-bin/shopper.cgi?preadd=action&key=00WBSMAFR-DM5-CMB&reference=/cgi-bin/shopper.cgi%3Fsearch%3Daction%26keywords%3Dall%26s earchstart%3D0%26template%3DPDGTemplates/Header_Footer/SearchResult.html%26category%3D00WB)

The O2 is actually pretty far down the DP, which I think is why I was getting lazy readings from the time it was new. It could also be the fact that it carboned up pretty quickly. The only real variation from stock values in the PE table are in the Base PE A/F table. In some places I dropped it to 11.8 where stock was 13, is that enough to do it?

I noticed when I was scanning that the command AFR was a lower than what I've ever noticed before. Could that have something to do with the colder temperatures?

Sprucegagt
02-08-2007, 02:11 PM
Your lower commanded AFR is from you using the stock PE vs. time table. It is setup to drop your AFR pretty quick. Add that with you already lowering the Base PE table and it will make your commanded AFR real low. You need to work on your PE vs. time table. But I wouldn't do it until you get the Wideband O2 setup first.

I just installed an Innovate Motorsports LC-1 in my car and I'll tell you, it can be a pain to install. But when you pop the hood, you can't tell its there.

harvester45
02-08-2007, 04:44 PM
Do any of the Innovative products offer narrowband output? I'm leaning toward the PLX right now just for that reason. I do like the gauge options offered by Innovative, they look like they'd match my C2s better than the PLX, but without the narrowband sim, I don't know if I can justify the added expense.

Sprucegagt
02-09-2007, 01:14 AM
Both the LC-1 and LM-1 come with narrowband outputs.

harvester45
02-13-2007, 09:19 PM
Well, I cheaped out and went with the PLX setup, it looks like it should be good for my needs. I kinda wish that these other slick looking packages with gauges were more basic, it seems you pay a lot for the data logging that they do, but since I've got the Powrtuner, I didn't need all that. I'm excited to get this in so I'm not reading mvs all the time trying to guess what that corresponds to in A/F Ratio. lol

Sprucegagt
02-13-2007, 11:33 PM
Just be sure to setup the wideband right. Ground offsets will throw off the wideband reading. I'm sure the PLX unit has a forum to help new customers with this. I'm currently dealing with this with my LC-1.