DirtyJohn

iTrader: (8)

Cliff Notes:

• OLSD tune for E85, was working fine for 92 Pump Gas
• Random lean spikes just recently showed up in logs after 1st tank of E85.
• Don't know if its fuel type related, air leak, tune or O2 sensor
• Of course I feel like I've tried everything

So I've recently attempted to move the car to E85 since I'm in the land of corn and we've got alot of it.

After the Lucas 42# injector install, things were progressing fine, even got the car to the track for a dozen runs or so and the problem in question was nowhere to be found.
Fueling wasn't perfect for an OLSD tune, as weather changes threw it off from day to day, bot for the most part it was just a matter of getting road time to get it in line.
I was satisfied the fueling was close enough to run the tank almost dry and begin on the first E85 tank.

Ever since this happened I have been registering random mildly severe %15-%20 lean spikes throughout the fuel map.
As far as I can tell, it happens everywhere. Its most easily seen in decel and idle, but it will show up at part throttle cruise as well.
I'm hesitant to go WOT on it for obvious reasons until I can get these to go away.

I have tried everything I can think of including adjusting:

• Offsets: Tried; stock, One I found on the forums, a hybrid of those, stock -10%,20%,30%..etc
• Min pulse widths: from 1.0 across the board to .75
• IFR: (I have two calc'd IFR tables, both are good symptoms follow each)

I resorted to the EXACT fueling settings I had for the track runs and previous where there were no symptoms and the spikes are still present.
I have tried checking for intake air leaks but have come up with nothing
I switched the WBO2 location from Bank 2 to Bank 1, to troubleshoot an exhaust leak and it remains.

If you look at the logs you will see the avg pulse widths never spike with the lean condition, and never come close to less than 2.0 ms, which AFIK should even make things a little rich with these injectors.

I can't find anything that is affected by the lean spikes either.
RPM's don't budge, Airflow doesn't budge, (and I don't know if this is even logical to infer), but I'm logging trans delivered TQ and it doesn't budge with the spikes either.
If my Narrowband O2's were not totally dead I'd see if they would register lean along with the WB.
(this may be my next step, or Running the E85 dry and filling back up with 92)

I recalc'd and re-calibrated the LC-1 and it still remains.


I'm officially at a loss and asking for input.
The only things I can think are..

Intake leak, I checked by spraying some gas around the intake and other areas and looked for RPM rise, but I don't know if thats proper.
I re torqued the FAST down, and when I reinstalled last time I put in new intake gaskets in, so I'm HOPING its not an air leak.

or..

The WBO2 sensor is going out, its been in for a couple years and seen allot of richness so it could be due for an $80 swap.

I humbly ask for a review of my tune/logs and any thoughts you might have.
I really wanted to figure this one out myself but its causing me alot of heartache.

Thank you for your time and consideration

Sorry for the long post

~T

Files attached
HP Tuners Tune
HP Tuners Log
HP Tuners Config
HP Tuners LC-1 and AFR Error parameters for user defined PID(in text)
HP Tuners AFR Histograms

Frost

iTrader: (45)

Bosch LSU based wideband setups (most popular controllers) can have a tendency to get some lean spots ont heir way out, but this doesn't necessarily look like what is going on here. You know a misfire here and there, just a single cylinder, can look like this.

DirtyJohn

iTrader: (8)

Thank you for your thoughts Frost.
Your very helpful in this section and I appreciate your efforts.

It may be wishful thinking but I am feeling like its coming down to the sensor or sparks for a couple reasons.
Mostly because they are known to have a limited lifespan which is known to be shortened by extensive rich conditions, which I'm ashamed to admit have been plenty in the last two years.

I might just pull a plug or two to take a look, couldn't hurt to swap the set since they're so cheap anyway. I've also got a friend with an LM-1 that I could "side by side" so do a reality check on the LC-1.

I've also never been able to successfully log any misfire data, I don't know what I'm doing wrong. Maybe ill just load the scanner with every misfire parameter in the system and see what happens.

The thought was put out there about it potentially being the fuel pump, which could make sense. That might be the last thing I check as my fuel pressure checker inventory is currently -1.

Thanks again Frost,
Keep up the good work.

Also, I did manage to track down an idle issue I was complaining about earlier.
Who woulda thunk GM knew more about idle over/underspeed spark controls than me? I had previously scaled them like -50%.. not good.

Frost

iTrader: (45)

No problem,

I just looked a little closer at the snippet of log you posted. The last lean spot that went past full-scale (20:1!), you were at 20% throttle. This is a significant level of pedal, and a real lean spot that clearly goes past 20:1 would cause a significant stumble. Looking at the RPMs, you can see that it doesn't.

Do you ever feel these lean spots? You should.

DirtyJohn

iTrader: (8)

Nope, everything always feels solid, I'm really thinking they're false readings.

I already ordered a new Bosch sensor, not JUST because you mentioned it, but because nothing else really sits as a likley of a cause.
Its been permanently in the car for about 3 years and has also been taking longer than usual to warm up recently.

$80 for a new one, and I have a free dyno pull this weekend at CarCraft.
Earliest I can test with a buddy's LM-1/fuel pressure gauge is Tuesday night which isn't enough to get WOT close for Saturday if I had to order a new one.
Best case, its a bad sensor and problem solved.
Worse case (as far as the weekend) is its not and I cancel the free dyno pull and have a spare sensor to use.

I have a Racetronix fuel pump waiting to go in if it turns out to be that too, just haven't had time to install it.

I tried logging total misfires, and misfires per cylinder and nothing shows up.
Idle is a solid flat line and nothing seems to be responding like I would think it would if they were real.

Sensor should be here by Wed/Thrs so we'll have at least one thing troubleshot by then. We'll see.

Thanks again man.
~T

PurplePiss

Is it possible the sampling rate is too slow and that your seeing inbetween engine pulses?

DirtyJohn

iTrader: (8)

I'm not thinking so, It's always been set to 1/12th second and has worked for a couple years that way. I thought it could have been that, but it doesn't explain why it just now showed up....although...It MIGHT have been set too fast..I'll have to check that.
Crap, I reset calibration on it, I wonder if it switched back to "instantaneous", that could have done it.
I can check that tonight.

Good thought.

DirtyJohn

iTrader: (8)

Turns out the sensor was the problem.
New sensor and AFR is flat lined.

You are the dude frost, thanks for your help.

~Mot

TLewis4095

iTrader: (10)

Have not tested E85 to see it it as prone as gasoline, but cavitation & turbulance in the fuel rails can cause bubbles and random issues with the injectors on very high flow builds...but it is rare. Just an idea......

DirtyJohn

iTrader: (8)

Thanks for the heads up.
I'll keep an eye on it.

~T