Kawabuggy

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History... 2006 Chevy Silverado, 5.3, 2 wheel drive, 31" tall tires, 3:23 gears, CAI, LT headers, cat delete. Truck has just had a new engine put in. Supposed to be fully rebuilt. BIG cam.. unknown specs. 4L80E trans, 2600 stall. Operating system had to be changed because his original OS could not be segment swapped for the 80E. Regardless, it had this problem with the original OS as well. When the truck was picked up from the engine builder, they supposedly put a tune on it to get it running. They said that the fuel pump was going out and that is why the engine would not pull. Just put a brand new fuel pump in the truck. Something else is WRONG.. Engine will not rev past 2400, and makes ZERO power anywhere. It is sluggish from the moment you begin pressing the gas pedal, and just gets worse the further you press it. No shuddering. No popping/knocking/rattling/engine noises. There are NO CODES. I've been tuning the MAF, and VE table just driving it slowly, and cruising, which it seems to do quite nicely. Idle is good. Just NO POWER under throttle at all! MAF & VE are extremely good % wise, and smooth.

For those of you more skilled than myself, can you look at this tune, and log, and tell me your thoughts?
Peronally, I'm thinking the cam was installed either too far advanced, or a tooth off. That's all I've got so far. From my engine building experience, this seems to me to be the most likely culprit-unless something is drastically wrong in the tune.. That's where you guys come in. Before I send it back to the engine shop I'd like to at least have some confirmation that I'm on the right track. I'm typing this on my desktop, so I will post the tune and log in the next response. Happy Memorial Day!

Kawabuggy

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Attached in order-the current tune file that is in the truck. Then the log file from the road test. At 10:18 of that log you can see where I went full throttle leaving a red light.. and essentially NOTHING happens.. The truck just kept on accelerating at it's STUPID slow pace. No bucking, no jerking, no knocking... Really really odd. The last tune file is the tune that was on the truck when it came to me.

mrvedit

Around 7:17 I see that you MAP stays over 90, indicating your throttle is open enough for near full torque. Yet your car barely accelerates, exactly as you explained.
I don't know how much a mis-timed cam would affect performance, but even one gear off probably wouldn't kill the engine like that.
I would consider a seriously clogged exhaust.
First I wondered if this was a DBW limp/safe mode, but the near-WOT MAP values are not consistent with that.
Not a lack of fuel either - you start off a bit lean, but the STFT seem to adjust for that and around the 7:17 time your injector voltages are fine.

G Atsma

Muffler baffles blocking flow, since no converters and no other back pressure cause.

Kawabuggy

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Thanks for the insight fellas. Thinking that the fuel pump might still be an issue, I put a fuel pressure gauge on it this morning.. It was holding 48 lbs pretty steadily at idle, but does drop down to about 43-44 when I pegged the throttle momentarily, while in Park. My guess would be that driving it under a load, it might drop even more than that. Have not road tested it with the gauge hooked up yet. Doing a gear swap in it this morning, and then back after this "other" issue. Would the fuel injector pulse width indicate a fuel pressure, or supply, problem?

Truck has true dual exhaust with 2.5" pipes running back to 2 flowmasters (no x-pipe, no Y-pipe-both exhaust banks completely separate) to twin pipe exits right in front of the passenger rear tire. I don't think the exhaust is the problem. The LT headers are welded to the head pipes.. No clamps, or any connection points that might be an obstruction.

Is it possible that this is something off in the tune? I did notice that the tables for ETC effective area are different between this tune file, and another '06 Chevy tune file that I compared it to.. I'm grasping for straws right now.. Putting gears in it right now, then back to trying to figure this BS out..

Kawabuggy

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Getting more information this morning... Cust states the engine was purchased from O'Reillys Auto parts as a remanufactured long block. He states that his "buddy" then took that motor and installed the cam.... The cust is not sure if the oil pan, and timing pump were removed to install the cam.. Just that a bigger cam was put in before the engine was installed. This, now, again, leads me to think cam timing issue. Is it possible for the engine to run with the cam 180 degrees out? Or, maybe he has it 1 tooth off? I think this morning I will go and put the original tune back in it just to see if the truck will make any power that way.. The original tune was for a 4L60E trans. Once I flash the tune back into it that was in it when it arrived here, it will still move forward but will be in failsafe, and setting a bunch of codes. That is my next test. If it still does it with the original tune, I will feel fairly confident that this is not a tune issue.

Kawabuggy

iTrader: (1)

Going out on a limb here.. This is a '06 Truck.. But it still has the OLD style intake manifold on it... Would a 24X or 58X reluctor ring mis-match cause a condition like this? Would it even run if the wrong reluctor ring was on the crank? Again, I'm grasping at straws here trying to get lucky and hit on the problem.

G Atsma

It won't run with the wrong reluctor.
It won't run with the cam 180 out.
It WILL run with the cam a tooth or 2 off, but really crappy. I bet it's a couple teeth advanced.

Kawabuggy

iTrader: (1)

Gatsma.. I think that you are RIGHT.. It's what I've been thinking since the beginning. Especially since his "buddy" was the one that did the cam install. I'm putting a NEW GM/AC Delco fuel pump in it in the morning to see if that fixes it. If not, I'm pulling the timing cover off to check gear installation. Either way, I will post back with what fixes it.. I HATE searching problems like these, and finding similar posts, and then NO CONCLUSION... WTF???????? :-( I will post back what actually fixes it so that anyone searching for this problem, can see what fixed it for me.. If you search "LS engine won't rev" in Google.. You will be amazed by how many posts come up.... and NO ANSWERS TO ANY OF THEM!

dixiebandit69

I was of the understanding that these engines will run just fine if the cam is installed "upside down," because there is no distributor, and spark/ injection timing is determined by the cam position sensor.

I've never tried it myself, but that's what I've heard.

Kawabuggy: Do you have any compression test numbers? That could tell us a lot.

Kawabuggy

iTrader: (1)

After the fuel pump install in the morning, if that does not make it run right, I will gladly do a compression test and then post the #'s here. Do you think I could diagnose a mis-timed cam with a compression test? If so, I'll gladly do it. I have a compression tester and it would not take more than about 15 minutes to test 1 cylinder.... Good call on drilling down on the problem. Maybe I should do that FIRST.. If it identifies the cam being mis-timed, it will save purchasing and installing the fuel pump..

One other thing I forgot to mention... The engine is hard to start.. When you hit the key to the "start" position, it will turn over for a few seconds... But does not fire. Then after a few seconds the starter stops turning the motor over (some type of auto start as it keeps spinning the motor over even after you release the key). Then, on the second time you hit the key, it usually starts... Also, with the fuel pressure gauge hooked up this morning. When I turned the key to the "RUN" position, it took almost 3 full seconds for the fuel pressure to reach 48.. You could watch the gauge slowly climbing.. In my mind, that pressure should have spiked INSTANTLY... maybe that is the delay in starting, slow fuel pressure rise. We shall see tomorrow in the morning.

mrvedit

Yes, a significantly mistimed cam will give very low compression numbers because a valve will be open at TDC.
It is a problem that your fuel pressure rises so slowly, but I did not see significant lean conditions in your log file.

Kawabuggy

iTrader: (1)

Got a late start today. Just got the tank down. Going to install an AC Delco pump in the am and PRAY that it fixes it.

Kawabuggy

iTrader: (1)

Update: SCREWED. Like every project that involves HP Tuners.. FUBARRED..
Put the new fuel pump in. Truck is now starting on the first try. Fuel pressure holding at 58PSI as soon as you turn the key on, it spikes right up there and holds even when you rev the motor. Still did not fix the problem with the engine not wanting to rev past 2500.

At this point I went back and looked at the original tune with the original OS. I noticed that the ORIGINAL OS uses a different DESIRED THROTTLE AREA (HPT>ENGINE>AIRFLOW>ELECTONIC THROTTLE>Desired throttle area) area than the OS that I copied over. When I burned the NEW OS, along with SEGMENT SWAP for the 4L80E, I copied over the customers DESIRED THROTTLE AREA from his original tune, into the new tune with the new OS. That, apparently was the reason that the truck just fell flat on it's face at 2500.. Those fields were different between the NEW OS, and the ORIGINAL OS. Apparently those fields change with different OS's and CAN'T JUST BE CHANGED AT RANDOM... I did not know this.. Maybe you guys did? How do you know WHICH Desired throttle tables will work with which OS's?

So... I went back and put in those fields that were originally paired with the new OS... and it now works! It has pedal, and will accelerate past 2500RPM! YEA! YES! YES! But... HP Tuners was NOT done with me yet... Because I had tuned the VE table, and MAF table, with the bad fuel pump, I had to go back and and re-do those tables.. I figured it was easy enough.. I went back in, did a short log, and saw that I was about 8% off the entire range.. I high-lighted the ENTIRE MAF table, and decreased it by 8%. Scanned, logged it again, and it was very close. Did a Copy/Paste 1/2% and MAF was DONE.. Then I went into the VE table and did the same. Got both tables sorted out.. Went back and turned on LTFT, and CLOSED LOOP, and DFCO, and got the MAF back on-line, and all the other things that you turn off to tune the tables.. Burned that tune turning everything back on thinking I was finished.. Started the truck and was letting it idle while I got the scanner back on-line so I could double check my work on the way back to the shop.. Yes, I was AWAY from the shop.. The truck idled for about 30 seconds, and then slowly died. I could hear it starting to chug, and then the rpm's dropped lower, and lower, until the engine finally stalled. Tried to restart it.. It will fire, run for 2-3 seconds, and then die again. Tried burning a different tune.. Tried putting the original tune.. Tired turning off the MAF-no love. Tried putting it into speed density-no love. All do the same thing-starts, runs for 2-3 seconds and dies. The PCM is dead. It will accept programming, without error, but it will not run the truck. I re-tested the fuel pump thinking the new pump took a dump-nope.. Good fuel pressure across the board. Thought maybe it was VATS causing the problem so I deleted VATS, burned the tune, and tried to start it again.. Same thing runs 2-3 seconds, then stalls. Fuel tank is 1/2 full, and it has fuel pressure. So.... I have to pick up a P59 PCM and begin ALL OVER!!!! Lucky me! Does anyone else have the same luck that I do? If you guys knew how many computers I've had to buy messing with "tuning". I tell you.. No one tells you just how expensive it is using HP Tuners... And few rarely have the experience to help get you through dilemmas such as this one. Anybody got a spare P59 for sale? I'm in need of one ASAP!