Need some hp tuner help

[nobox351y]

Stock computer, stock harness modified
At the 13:08.50 mark on the log I put it into closed loop and things look better.
Wont rev above 2k in open loop.
Wont rev above 3500 in closed loop.
Random misfire code, sometimes
Got a knock sensor code today

Ill post or email logs and tunes to anyone that is willing to take a look.
Not sure how to post the hpt files. Comes up with an error.

[BR3W CITY]

How bout information like;
Motor and year / trans and year
stock or not?
Who did the harness?


Have you tried to fix any of this? (checking usual culprits like; fuel pressure, mechanical condition of ign components, good fuel, grounds and good power sources on all added wiring, matching DBW components etc).

Going through someones logs is pointless if there is a mechanical issue. All the logs tell us is what the sensors saw, not always what actually happened. (and can also be a large investment of our time)

If you had a tuner involved, he should be the one going back and troubleshooting the tune related issues. Don't be afraid to request changes from a tuner if it never worked right.

Give us a starting point.

[nobox351y]

01 silverado 4.8 in an 87 burb
T400
Headers and converter only changes from stock
no a/c, egr, evap, trans wiring
Stock Harness modified by myself using lt1swap guide
Used hptuners to modify the tune myself
Aeromotive stealth pump in the 87 tank
Stock 87 fuel lines

Grounds and added wiring have been ohmed and have continuity

Fuel pressure has not been checked. Dont have a gauge to check pressure, yet.

Bank 1 shows lean condition until it goes into closed loop and stft get it switching. Started looking for a vacuum leak with the carb cleaner method. Pretty certain I have a leaky intake gasket causing this issue. Will fix tomorrow.

New issue today: tps was not reading on the updated software of hp tuners. Worked last week, today not so much.

Questions: What allows the computer to go into closed loop? What would prevent it?

What are normal readings for map, maf, how much do o2 sensors moving when operating correctly?

I believe I am close and there could be wiring/mechanical issues to sort out, but thought an experienced eye might notice something on the log.

Thank you for the suggestions. Apologize for the poor first post.

[BR3W CITY]

**because you said you had a misfire and a knock code, I want to preface this by saying use good judgement and take all this advice with that warning. If things seam like they are failing, stop before more damage occurs. This post is long, and its late. Its only meant as a way to get you started. When we start on a self-wired-self-tuned project, there are things we will never know.**

If you suspect a leaky intake, check those gaskets as well as the gasket on the TB and any of the ports where the vacuum/emissions stuff plugs in on the top/rear of the intake. Also check the electrical connectors on the wiring harness to the coil pack branch of harnesses. They can cause multiple coils on the same bank to misfire.

Cold engine, WOT, will ignore 02 sensor feedback, so don't worry as much about the 02 sensor readings at that time (unless you have a wideband, log that separately!). DO log them, but don't worry about them till your reviewing the log. Properly working 02's WILL fluctuate a bunch, with the pulses of the engine. Those fluctuations are the pulses and drawbacks of the exhaust pressure, which will create the peaks and valleys on your 02 sensor mV log.

Off the top of my head, the 02's read around 650mV, moving a few hundred either way potentially. High lift cams on low LSA's have a more gapped pulse, and so this fluctuation is more pronounced. If you'd like I can screenshot mine and show you have drastic it can be. @640+ lift on a 111.

Clear all the codes. Run another short log (call it Cold Start) and make sure you have the PID's for injector cycle being logged. Sticky injectors or leaky injector seals are notorious on pullout swaps. Also make sure the IAT is being logged along with the MAF functions, as well as Kr* and the misfire counter. Just run it for a few minutes of warmup, let it get up to temp but you don't have to log much past that then:

• See if the IATs are reasonable for the ambient temp outside. The IAT sensor is in the MAF wiring and can be damaged or wired improperly when extended or repinned. Incorrect IATs will drastically throw of the cylinder volume calcs. Also, if at any time it reads a drastic # like -32c, -264, then the IAT has failed and is defaulting to its lowest value.
  
• Go back and glance at the 02 sensor mV, and your stFT LtFT values. Look at the trend line and see if there are any freak spots. See if you can identify the point on the log when it switches.

Save all that, and start another log (call it Warm Start). When you start it warm, it should ignore the cold start stuff, but still use After Start Enrichment. You should be able to see a point at the beginning when the truck goes very rich to help catch the idle, this is fine.
Again, log all that same stuff.

This time, rev it up smoothly from idle to that 2-3500 limit.
Then rev it again, this time sharply to full throttle then lift off.
Now unplug the MAF (iat will default cold). Is there a noticeable change right away?
Repeat the smooth rev and the stab as mentioned above.

Save the log and review it. When you rev, watch the replay on the log for sharp anomalies, and ANY sign of Kr*. Compare your smooth rev to the stab. Then look at the same areas after the MAF unplug. Do you see any crazy differences in the data trends?


Use that to give yourself some basic parameters and things to look at. Save incremental changes to your tune if you decide to update it. Things like knock, spikes in timing, random 02 readings, or unreported errors will stand out right away and give you something to investigate. You CAN do this all as one log, but clearing the codes in between the sessions prevents getting old info mixed in with what your looking for.

[nobox351y]

Thanks for all of the info. I will read through it again in the morning and try to replicate.

Off the top of my head, the engine will not show any stft until I put it into closed loop with hp tuners. At this point stft moves with throttle position as I am guessing it should. This is also when the lean back starts switching. The other bank does its best to stay between 400-500 Mv all of the time. Going to check continuity on both of these.

LTFT show adding 25% all of the time when the engine is running, to both banks.

I have not touched anything in the tune other than to raise the idle.

Going to check a couple of wiring things out, change the intake gaskets, and check fuel pressure.
Really appreciate the time you spent helping me out.

[BR3W CITY]

Wait....are you running rear 02?

[nobox351y]

no. Rear o2 are set to not throw a code.

Changed the intake gaskets. Sure seems to run better. Laptop died so no data. Going back out in a bit to scan it.

[nobox351y]

Intake gaskets did not affect o2 readings.

Random misfire is gone in closed loop, still there in open loop.

Knock sensor hasnt showed back up.

STFT are not being activated until put into closed loop.

Going to tackle tps and o2 sensor wiring, maybe that will help.

[nobox351y]

br3w: another issue im tracking down is why the engine will not go into closed loop. Read on ls1tech about the mil indicator error will prevent this change. Got any thoughts on that?

Going to get one hooked up to see if it makes a difference.

[BR3W CITY]

If the 02 heater circuit is bad, or if something in the 02 wiring or setup in general is off, it won't allow closed loop. Coolant temp needs to be high enough, so make sure the car is actually warmed up and cycling coolant. A cold engine won't go into closed loop, but a warm engine with a bad coolant sensor won't either.

[nobox351y]

Thanks, more things to check out.

[nobox351y]

Update: Got a mil installed. Checked some continuity on the o2 sensors. Continuity is good. I checked to make sure I was working with sensor 1 and not sensor 2.

At this point I still have one 02 sensor reading .44 volts, which Ive read is an indication its not working properly and the other is reading .20ish volts in open loop, in closed loo it switches, but the stft and ltft are both adding a sinificant amount.

Only code being thrown is a tcc code. 1860

[nobox351y]

Brew: thanks for all the suggestions. Getting things cleared up.

Fuel pressure was low. 40 psi is all it would muster. The hose from the pump to the sender had some leakage. Fixed that up tonight.

Hoping that clears up the lean issue I was having. Fix up 1 02 sensor and we should be rolling. Will have only taken me 5 more weeks than I expected it to.

Feeling like an amateur in all facets of swapping an ls.

[nobox351y]

Fuel pressure is good. Swapped out a brand new denso o2 sensor that was not functioning properly. New one works great. Truck is running good.

Got a misfire on cylinder 5. Changed the plug, swapped coils with another cylinder. Still there.

Thoughts? my best guess is that its the injector.