Speeddemon777

I need a little help with diagnosis. First off so I noticed under "OBD advance code diagnostics" I have a P2119H code. I cleared it took it for a spin came back reread the code and sure enough the code it back.

Heres the thing, if you look at the live diagnostics file I posted above you can clearly see that "long term fuel trim bank 2" is super lean and almost always negative while bank 1 is pretty stable. Compare this to O2 B1-S1 and O2 B2-S1 and you can see that O2 B2-S1 is much different then O2 B1-S1, which make me think that I have a bad B2-S1 sensor. After the CATS(B2-S2 and B1-S2) the O2 sensors read almost identical. Would a throttle body actuator code be responsible for one bank running lean? Logic tells me no, but I need someone to confirm I am on the right track.

Joe_G

The o2's aren't setting a code so I don't think there is anything wrong with them, they are often different from bank to bank.

The throttle body code is unusual - have you cleaned it lately with throttle body cleaner? If you don't have a catch can you might have some oil building up in there. Try cleaning it and then do the reset procedure here, that's very cheap to try, just a can of throttle body cleaner.

https://www.corvetteforum.com/forums...ese-codes.html

Speeddemon777

Yes I did clean it this weekend it had some tarnish or build up on the outside. I figure it could be preventing it from getting a good seal. Didnt make any difference cleaning it. I didnt do the reset though, I will try that as well thanks! The inside had some carbon build up, but not much. Any ideas why one bank(bank 2) would be trimmed very lean(negative fuel trim), while the other is normal to rich(0-postive fuel trim)?

Side note: With the ignition on and the car off I noticed that O2 B1-S1 would drop to zero relatively quickly, while B2-S1 would hold steady or drop slowly. Not sure if that is a valid test but I found that interesting. Also, B2-S2 and B1-S2 O2 sensors were immediately zero. Ideas? Thanks.

Joe_G

I don't think 6 seconds of data is enough to make any conclusions...if I'm reading your scan correctly it's only 6 seconds of data.

Did you mention that you have HP Tuners? If you could get a scan and make the car do the problem during the scan, that would be useful to see.

I don't really worry too much about closed loop 02 readings, the computer manages those very well in a stock tune. I suppose perhaps you might have a lazy 02 but there's a test for that in the tune and if it was really lazy you'd get a CEL and a code.

Plus as I understand your problem, your hesitation happens when you go WOT and your 02's are not in play at that point as you're in open loop, just your MAF and the prescribed WOT fueling table in your tune direct your fueling.

An HP Tuners scan would point out other things - I've seen loose exhaust hit the frame and cause a huge knock event which causes the car to pull a bunch of timing and you could feel that as a hesitation...just many things could be causing it but seeing what the computer is seeing and doing at the point of the concern would be very helpful.

If you had an aftermarket tune, I would direct you straight to the MAF table, if you've got an 06 you have two maf tables, a high one and low one (not sure when that changed back to one table) and if tuners don't make the break point between the two tables the same value then you get a hesitation and often a CEL when the MAF hits the HZ cell in both tables and there are two different values recorded. But stock tune doesn't have that problem.

Any chance your car has a tune?

Speeddemon777

The car doesnt have any tune other then stock. I replaced the computer so it has the most updated tune from the factory/dealer for this car. I dont here a knock of any kind at WOT just a hesitation and slow rpm build. If the computer is running the wrong maps for bank2 and then at WOT couldnt it be using those wrong maps causing the car to go even more lean on bank2? What I am trying to say is the Long term fuel trim is negative all the time not just at WOT while the other is rich and rarely goes negative. I maybe wrong but I feel like one side of the motor should be at least some what similar to the other not completely lean while the other is mostly rich?

Joe_G

If you have an exhaust leak or crack in your exhaust pipe it can cause one side to go very rich as the 02 reads the extra air as a super lean condition and it adds a lot of fuel, but you're showing lean so doesn't sound like you have a leak.

I don't know how long you scanned it but 6 seconds isn't long enough by a mile. Maybe you did it longer but only 6 seconds show on the little graph.

Anyway I don't think your 02's are causing this as when you go WOT your 02's don't matter.

Can you get a video of what the car is doing when it does it using your phone and a cheap suction mount like I did on the video below? Won't be as good as a HP Tuners scan but you never know maybe someone will have an idea for you.

I'm leaning on your throttle body since you did have a code there and throttle bodies are super sensitive. Try the reset and post up.

Speeddemon777

I did a throttle body reset and the code has yet to come back. Sorry it took me a while to figure out what you meant by "6 seconds". The code reader is misrepresenting time at the bottom of the graphs. It should be minutes I think?(The scan was over the course of 15min). Ignore the bottom, heres what is fact each dot is data taken at the same exact time for each graph and the time between each dot is 6 seconds. Sorry for the confusion I didnt make the graphs this stupid program they give you with the scanner did. The only thing keeping me from agreeing with the throttle body is why only one bank's fuel trim is twice as lean as the other all the time at all rpms and loads. I will try and get a video up tomorrow. thanks for your help!

Kent1999

I know you said you did the fuel injector cleaner, but as we all know, that stuff isn't a cure all.

Might you have a semi-clogged or semi-functional fuel injector? It might flow well enough at lower RPMs, but chokes out/doesn't cycle properly at higher RPMs?

schpenxel

Post a log.

Speeddemon777

Hey Guys,
Things got busy with the car. Kinda wore me out so I didnt have time to post an update. So I ended up caving and had a local speed shop that specializes in corvettes put it on a dyno. I added a KNN filter just for justification purposes. The car put down 328rwhp on the first pull . The tuner said it had massive timing issues causing lots of detonation. After 4.5hrs of waiting the best he got the car to do was 429rwhp(A/F 12:1 @ 91 octane). Dont get me wrong from what he start with to now is a huge difference, but I feel like this is pretty low number. He said it could have more if I changed the plugs from delco iridium to ngk tr6/477 and MSD wires. Additionally the car no longer hesitates but still sounds like marbles rattling around in the exhaust at 5k rpm. I am assuming this is still detonation as it sounds the same as before if not a little louder or more noticeable without the hesitation. The pull of the car feels close to the way it felt before all this mess started but not quite in my opinion(this is my daily so I feel that I am pretty accurate with that statement).

Anyway, Im not sure where to go from here as I dont feel as though it is fixed, correct me if I am wrong but I should of put down some where around 475rwhp. right? I wanna hear what yall think.


Side Note: I talked to the tuner about why bank 1 runs richer then bank 2. He said that the way the intake is laid out(spiral) the air reaches bank 1 before it reaches bank 2 so naturally the car wants to run bank 1 richer and bank 2 leaner in relation to fuel trim.

Speeddemon777

Is there any way to narrow down which injector it could be? Also would this still hold after having it on the dyno? I feel like the tuner would be able to see something like this. If not I will look into removing the injectors to take a look tomorrow. Thanks.

schpenxel

The way people say a bank runs "leaner" or "richer" when looking at fuel trims is oftentimes backwards, and I think this is one of those cases.

Bank 1 runs LEANER on LS engines, which means the fuel trim numbers are numerically HIGHER (i.e. computer has to add more fuel to bank 1 than bank 2 to get to stoich). A lot of times people see the higher fuel trims numbers for bank 1 and in their mind that means that bank is running richer, which is not the case.

If the numbers are drastically different from bank to bank then there is something wrong, though. Mine are within about 2% from bank 1 vs. bank 2. When I had some cheapo injectors they were more like 7-8% difference. I'd start there and see if there are any large differences in trims from bank to bank.

The sound you mentioned would really worry me though. Do you have a copy of the tune and a log or two?

Speeddemon777

Agreed, you are right. I misspoke...I had them confused in the beginning but I understand now how it all works...Forgive me I am still learning. I will do a scan tomorrow of the new tune to compare. I just put in the plugs and wires. Next week I will try to have it re-tuned as the tuner suggested I do. Only thing I am skeptical of is picking up 30-35rwhp from just wires and plugs alone. Thats what I was told would happen. As far as the sound I will try and get a clip of it up. Im all out of go pro stickies so I will have to macgyver something. thanks!

Also, I didnt mention rwtrq in my previous post. I ended up with 355rwtrq.

zali0104

Wah.....? 35 hp from sparkplugs and wires?
I've seen maybe a 5-8 hp increase on the dyno after new plugs and wires. That goes away really fast as those new plugs loose their shiny sharp edges that give a slightly hotter spark.
The tips of a spark plug are basically an anode and cathode that erode with every spark. Hotter spark, faster erosion.

Joe_G

Did the tuner tell you why it only put down 382? Something was wrong, that's just not right. Ask him what was wrong.

Only way you'll get 35 hp from plugs and wires is if you'd left at least one wire completely off and were running on 7 cylinders. That is BS that you'll get HP from new plugs and wires unless yours weren't working. Which they might have been if you got only 382 rwhp. But in that instance you would have set a blinking CEL as the computer can detect that complete misfire.

You should not hear rattling - the knock sensors cut timing to hear knock before you hear it, I hope he didn't turn off your knock sensors (reputable tuners won't). If you are hearing something like knock, turn on your knock detection in your scanner and scan it while you hear the sound.

Glad it seems to be getting sorted but I'd love to hear what the tuner did to get it there.

zali0104

After seeing plot of your timing my initial taught was possibly a loose or defective crank sensor as the timing was all over the place. The fact that you picked up 101 hp from a tune only makes me wonder if some information is missing. That being said, The car seem to be where it should be in terms of hp.
One possible explanation of your exhaust rattle can be catilitic converter damage. If your timing was severely retarded as your tuner indicated, this would make sense.
Another possible senerio that can possibly explain your initial timing issues can be a timing chain issue. A damaged timing chain tensioner would explain the timing jitter, and to some extent the retarded timing. possibly even the noise issue.
Just my opinion of somethings you may want to look at.

truckplay

when the car goes lean, is it one side or both? If is both, I would recheck that mass. If it is on one side, check your 02 sensors and make sure they are switching smoothly, compare the difference before and after the cats, a partial blockage can cause your miss. I would not be surprised if the orings that seal the intake to the heads have hardened and are leaking, especially on an older car with 20k on the clock.

best of luck and let me you if I can help

zali0104

Recommended a smoke test over a week ago. Assuming the pcm the OP installed was somehow not incorrectly programmed. I think this a a case of bandaging or masking a mechanical problem with a tune.
Not trying to cry wolf but an important piece of the puzzle is missing.

djbrun

+1 need to start with the basics first.

Speeddemon777

The car actually only put down 328rwhp(<- thats not a typo). He said the timing was so retard and advanced that it wasnt able to over come it causing the car to run super super rich. I was off the charts apparently. He said he dialed back the timing and reduced the retard sensitivity, but DID NOT turn of the knock sensors or another sensor for that matter. At the end of it all he was able to get 429rwhp @ 355rwtrq he said the car should be continuing after 4500rpm but starts to fall off again because of timing. He blames bad spark plugs and wires. I told them they were brand new delco iridium plugs and these are the wires link

The tuner said that if i replace the plugs and wires with ngk and msd and optional 180 stat I would make up my power losses and that the car wouldnt drop off at 4k.


Im going to attach the dyno sheet as well. Its a pretty **** sheet in my opinion. I have had other cars that have been on the dyno and the print outs are way better.