Silverado going into Reduced Engine Power at 5600 RPM - Can't figure out why

[hirdlej]

Ok gang, I just swapped a 6.0L into a '04 2wd Silverado with a 5 speed manual. Mods on the engine are 10.6:1 comp, ported 243 heads, comp 218/224 cam, long tube headers with no cats. Attached to this post is a copy of my latest tune. I was doing some STFT tuning adjustments tonight (I'm going to be running SD) and discovered in a hell of a hurry that my truck continues to go into Reduced Engine Power when I hit 5600 RPM's. When this happens I push the clutch in and the tach will drop and stay steady at 3,000 RPM's even and no inputs from the gas pedal makes any difference. I have to clear the code, shut the truck off. Wait and restart then all is fine again. The truckload of codes that are being thrown is in the screen shot below. By looking at this, can someone tell me if it looks like I may not have all my grounds hooked up properly (late and don't feel like crawling around in the dark tonight) or is this problem I'm having found in the tune somewhere? Please have a look at my tune and see where my problem is and why I'm hitting REP. If I can get past this bug I can handle the rest of the tuning myself

[hirdlej]

Oh and one more thing I forgot to add, when my dad was driving the truck tonight and he hit REP, at the time time that happened or close to it, the VCM scanner temporarily lost connection with the PCM and had the "retry countdown" thingy going on.

[RWTD]

Not really sure why you want to run SD, when the factory 85mm MAF is perfectly capable of being tuned properly with this setup, and ultimately allow for much more stability and precision. To each his own, tho.

A few things:

1: You have your MAF Fail High set to 0. That's all fine and dandy, but you also need to set your DTCs P0101, P0102, and P0103 to "2 - No MIL Light" (go ahead and uncheck "SES Enable" on all 3, too).

2: Try maxing your "TPS Sensor - Calc Airflow - P1514/P0068 Error" table out. Set it to all 4.10 and see if you have the same issue.

3: To be safe, double or triple your "Maximum Delta Airflow - P0101 Error" table, as well.


A few questions:

1: Are you ever going to re-enable PE mode?
2: What type of octane are you using to justify the insane amount of spark you're running?

Let us know!

[hirdlej]

Not really sure why you want to run SD, when the factory 85mm MAF is perfectly capable of being tuned properly with this setup, and ultimately allow for much more stability and precision. To each his own, tho.

A few things:

1: You have your MAF Fail High set to 0. That's all fine and dandy, but you also need to set your DTCs P0101, P0102, and P0103 to "2 - No MIL Light" (go ahead and uncheck "SES Enable" on all 3, too).

2: Try maxing your "TPS Sensor - Calc Airflow - P1514/P0068 Error" table out. Set it to all 4.10 and see if you have the same issue.

3: To be safe, double or triple your "Maximum Delta Airflow - P0101 Error" table, as well.


A few questions:

1: Are you ever going to re-enable PE mode?
2: What type of octane are you using to justify the insane amount of spark you're running?

Let us know!

Thanks, I'll try that on my way to work this morning. The answer to your few questions

1: Yes, I will re-enable PE AFTER I get the STFT's dialed in perfectly. I usually save this for the end. For me anyways I usually get my best results this way.

2. I'm running 92 non-oxygenated gasoline. I don't think the spark really is that insane. I'm not getting KR and it keeps the "go pedal" more senstive. I like a touchy gas pedal and this works out fine for me.

3. Last but not least I never liked running the MAF on my setups. Enabling the MAF never quite yielded the results I wanted. The throttle transitions always seem to be "mushy" and not sharp like I like 'em.

[RWTD]

Let us know if that worked out, when you can.

As for spark, I'd reckon to wager that a super majority would open their mouths and raise their eyebrows if they saw a minimum of 30 degrees to a max of 34 degrees at WOT, all while using pump 92 octane. Whether you're getting KR "readings" or not doesn't mean that the timing you're using is proper for the vehicle, nor does it mean that you're not getting inaudiable KR. I've seen vehicles that do not make any more power between 23 deg and 28 deg. Also, the engine you have in the vehicle is completely different. Keep in mind, the knock sensor calibration was built for the harmonics of your original factory setup, not what you have in there now. Knock sensors are calibrated in labs specifically for a certain setup. Once you get most all of your issues sorted out, you are going to need to put the beast on a dyno to determine proper spark.

[hirdlej]

I'm going to head out for lunch and do some tuning. I'll let you guys know how it turns out. I'll post up in a couple of hours

[EC_Tune]

Generally the issue with P0103 (unless you are tuning SD) is that the difference between MAF Airflow and VE airflow have too much differential airflow. That's how it is supposed to work in stock form anyway. If you are running MAF you need to have the VE relatively close.