dewmanshu

iTrader: (4)

Hey DP(hehehe DP)...I am in no position to question the instruction of an ASE guy, but I thought when the maf fails (unplugging it) the pcm will resort to the open loop table. Most people's table reference 1 (14.68) in the normal temp range...then rest is up to the pe table being right. What references exactly richen the tune up for safety? Most people (disclaimer:I have never seen the radix stock tune in hpt) have the pe set to enable at 90% TPS. Cause that's what is stock. Definitely a bad scenario for testing purposes...if that's the case. Just curious...no smart assness here...just thought something different.

Oil on the maf will definitely do some skewing...my air filter oil has caused problems more than once.

Again...why I say if you are gonna join the modding crowd and get a blower or turbo...just make a widebband part of your budget. It will save you hours...errr days of troubleshooting.

Danville Performance

Dewmanshu, you are all right. It is always better to be a smart *** than a dumb ***. LOL Anyway, this is true on stock tunes PE is 90%, The performance tuners like crane and superchips change it to 71.99% and the stock radix tune is a little tricky. 0-800 rpm it takes 80% throttle but everything above that it only takes 40% it enable PE Modifier. I will have too apologize as I did explain what I meant about it making it richer when MAF is disabled. Yes it goes into open loop mode but when it is a critical sensor failure like map or maf(has to be an elctrically shorted issue like no voltage so it is pegged one way or the other or it really can't tell when the sensor is malfunctioning) it goes in to engine protection mode. B5912 is the file in the EFILIVE software for the timing that is used when the computer determines it needs to go into engine protection mode. It is a very retarded timing map to keep you from doing something to the motor when there is a sensor failure. I have noticed in my years of driveabilty work that when the computer goes into engine protection mode the O2 sensors goes rich and stay there. I am trying to find the table to support this for you so when I find it I WILL post it but it might be in the diagnostics software. Hope this was the explanation that you were looking for. I was just giving an alternate way to find out what the problem is. I have been using this method to find out fueling issues on MAF cars for about eight years and it works very well. Just my 2 cents worth.

Danville Performance

Today's cars have computers that process calibrated data points, called "tables", to control the operation of the engine. Different sensors provide real-time data, used by the PCM to decide which table to use and when. The reason for this computer-controlled system is first to decrease exhaust emissions, second to increase fuel economy and finally to increase performance and make servicing the engine simpler, in that order. Turning the key “wakes up” the PCM and cranks the starter. After ignition and idle stabilization, the engine management system is in a state called open loop. It is called open loop because the primary sensors in this system, the oxygen sensors, are not hot enough and will not be used by the PCM until they are. In addition, but unrelated to open loop, the catalytic converters (cats) need to be very hot to perform their exhaust cleaning function. Open loop uses pre-programmed information, based on the specific engine application and provides adequate performance, economy and emissions while the engine warms up. The mixture is usually much richer (like the choke in the "old days"), both to keep the engine running better and to get the cats hot. Most OBD II cars use heated oxygen sensors that have filaments (like a light bulb) to get them hot as fast as possible, and an AIR pump to blow extra air in the manifold to burn the extra gasoline to heat the cats quickly. Therefore, open loop rarely exceeds a few minutes of operation. In open loop, the PCM also uses the MAF, ECT and IAT sensors to determine how much fuel enrichment is needed to keep the engine running prior to reaching operating temperature. Once the PCM determines that the oxygen sensors are within their operating temperature and other conditions have stabilized, it changes mode from open loop (ignoring the oxygen sensors) to closed loop (using the oxygen sensors). To keep a warm gasoline engine running, requires about 15 parts air to 1 part gasoline. The optimum ratio is 14.7 to 1, but this may vary under different operating conditions and the desired performance demands of the engine. Restricting fuel creates a LEAN mixture and adding fuel creates a RICH mixture.
This is right out of the EFILIVE Scan tool manual. Supports what I was telling you about it running it richer in open loop also along with the engine protection mode.

Danville Performance

Was just wondering if you got to the root of your problem yet? I'm really curious to see what you find wrong. I have a few customers with this setup and haven't had a single problem yet with them. One customer has a 03 Sub with 6.0l 4l80e 4x4 9" lift and 35" tires and he has already put over 20,000 miles on it with no trouble at all. Hope you get it figured out soon.

BLASTER

iTrader: (4)

UPDATE:

Labor Day:
Well, I replaced the knock sensors during the labor day weekend. While I was
in there, I checked the gaskets and made sure everything looked alright. Put
the blower back on and torue the bolts in a criss cross pattern to spec.

Also added the LS6 valley cover and PCV setup.

Unfortuntely, that didn't help as I was still seeing knock, so that left me the only option of getting it dynoed and see what it would do.


JUNE WEEKEND:

Performed a compression test with the motor warm, all plugs out, TB blocked wide open and results seemed acceptable so I figured that I don't have any stick valves or bad rings.

1 - 165, 170
3 - 160, 160
5 - 165, 170
7 - 163, 160
2 - 165, 165
4 - 155, 160
6 - 163, 163
8 - 160, 160

At this time I also replaced the plugs with TR-6s to see if that took away the knock. It didn't so on to the next step.


JULY 4TH WEEKEND:
Went up TTP were I get my car dynoed and had them dyno and check out the tune.

Pre-blower the truck did 232HP & 275FT-LBS. This was with an filter intake
and exhaust mufflers. I realize this is low for a 6.0L but oh well, at least
this is my baseline.

First, seeing as we didn't here any knock coming from the engine bay on the dyno, we verified the knock we were reading via the PCM was false.

As such, we desensitized the sensors slightly and were able to get rid of all the WOT knock.

With the blower, the truck only did a best of 285 HP & 350 FT-LBS

With the widband, we noticed that I was still lean for FI (13.0), even with the magnacharger tune, so Matt richened it up for me for saftey to around 12.0

This resulted in 307 HP & 353 FT-LBS. We then tried to bump the timing up to 18* but the truck didn't like that so, Matt left left timing at the 16* per the Magnacharger tune.

We saw close to 7 lbs on the dyno and I thought the good rule of thumb was 20HP/TQ per LBS of boost, but with my numbers, it seems like I am only getting 10Hp/10Ft-Lbs per LB

Now, I realize it's hard to get exactly 140HP 140FT-LBS, but only 55HP, 70
FT-LBS? and then That's extremely low? I know other factors would reduce my gains, like the heat and my slightly larger tires (295s versus 265s) but I would have expected closer to 100 to 110 HP/TQ gains then.

Obviously I have to say that I am very dissapointed with the results.

So what next?

I am reading good boost but could I be leaking at a place afterwards?

Any help would be appreciated.
Any help would be appreciated.

BlownChevy

iTrader: (20)

If it is that lean with the stock magnuson calibration then you have a mecnahical issue. There is no way that the Magnuson calibration is going to let your truck run 13.0.