VCM Scanner Interpretation

[Hendonjt81]

New to tuning. I'm Idle tuning on a Gen IV E38. I've adjusted idle air/RPM and spark.

When interpreting the log file...

1. How do you know idle air is correct? I'm seeing .26-.30g Cyl Air mass.
2. How do you adjust spark advance? Simply add the amount to the tune that is being advanced in the graph log?
3. I'm seeing LTFT climb. If I disable OL or reset LTFT the idle is good. Can I simply adjust fueling table by percent show on log graph?

Any feedback is greatly appreciated.

2010 Silverado E38 Tune1.hpt
Idle Tune 2 2020.hpl

[5FDP]

Look at your check engine codes, that should tell you something.

There are codes for both rear o2 sensors and both front o2 sensors are doing nothing. You have a major issue if both front o2 sensors are not responding. That is why your fuel trims are going nuts and the reason the log files shows OL-Fault for the o2 sensor status. You need to figure out why the o2 sensors are not working.


This is a MAP sensor code and several other codes with no listings and 3 more EVAP codes.

There should be no changes made to the tune until the o2 sensor and MAP codes are fixed. Some of your issues will likely be fixed once that stuff is figured out.



You also didn't say if this vehicle is stock or what is done to this engine.

[Hendonjt81]

5FDP, I was tracing down an idle problem and missed a few SES deactivations when starting over.

I currently have MAF off, no rear o2's, all EVAP deleted, the 340x codes needed to be deactivated...The scanner is reporting MAF/o2 data. The truck has not been driven nor started enough to clear pending/stored codes. I had a pedal issue that caused the P2138. The P0650 I'll have to look into tomorrow.

This is a 5.3L/6L80 with a BTR4 truck cam, no DOD, no VVT, and in an 85C10. Otherwise, engine is "stock"

Can you provide any feedback on my initial questions regarding spark advance adjustments/VE adjustments? It appears all VE is adjusted through virtual VE?

[5FDP]

That log is not reporting any o2 sensor data, just look at your bank 1 and bank 2 sensor readings, they are both at 0mv like the whole time. That is a problem.


The MAF isn't off in that tune, it's still working as normal per the tune file.


Unless you understand VVE tuning I suggest you skip it for now. Focus on MAF tuning just to make it run.

The tune still has the VVT enabled. You need to set the variable camshaft under the airflow tab from "one" to none in the top left corner where it says camshafts.

You didn't disable the AFM/DoD either, the master switch needs to be set to disable under the Lean/Fuel savings tab.






That's a huge camshaft for a stock converter, it will be lazy down low. And make sure fuel pressure is at 58psi too with no vacuum leaks or exhaust leak. The exhaust must be complete as well, no open headers. You'll need a wideband too.

[Hendonjt81]

Thanks again, I?m following a ?Tuning Guide? that doesn?t go into depth. I noticed the VVT/DOD after last post.

With respect to Fuel pressure, if it?s lower than 58psi do I need to rescale injectors and replace 58psi with new value?

I?ll adjust, reflash, and log today.

The truck has a 3200 stall and full exhaust. I?ve verified vac/exhaust leaks. Previous logs showed good Fuel trims and o2 readings. I have a wideband for WOT/part throttle as well.

[Hendonjt81]

5FDP,

Adjusted tune last night and addressed LTFT at idle via Virtual VE (among other issues previously discussed). The permanent codes will require drive time to clear (specifically P2138). I'm unsure if the EVAP codes will disappear, but they are turned off in the tune under DTC's. Should I Write Entire or should Write Calibration suffice?

If I'm looking at o2 data correctly, B1 is running rich and B2 is running lean? No abnormal sounds/leaks from exhaust. LTFT seems to be inline at idle. I'm running LS swap manifolds, mid-pipes into X-pipe. Any feedback on this?

Also, with respect to idle air for that cam...how do you know the table is correct?

Attached is updated tune/log.

Idle Tune 3 2020.hpl
2010 Silverado E38 Tune1.hpt

[RobZL1]

This might be a good read for you regarding idle tuning, once you have your fueling dialed in:

https://forum.hptuners.com/showthrea...e-tuning-guide

[Hendonjt81]

This might be a good read for you regarding idle tuning, once you have your fueling dialed in:

https://forum.hptuners.com/showthrea...e-tuning-guide

Thanks RobZL1. I'll read the post. I have the tune dialed in until I hit 133*. Upon restart, the engine revs.

[5FDP]

Adjustments can't be made to the VVE if the MAF sensor is still being used. The tune must have the MAF failed first, then VVE tuning can be done. Otherwise all the data you get is wrong if it's taking in both MAF and VVE readings.

The most current tune has it setup with the dynamic airflow high rpm disable set to 200rpm meaning it's only running off the MAF and the MAF is not set to be failed with a few given changes.

The truck needs 58psi of fuel pressure, if you do not have that much it could not have enough injector to make the power this engine can make.


The bank 2 sensor is dropping out still, it falls all the way to 0mv and pegs the fuel trims. Make sure the o2 sensor harnesses are in the correct banks, it's possible to get them mismatched on swap vehicles.

I'd start over with the stock timing tables as they tend to work better for starting off. I'd also cut the under/over speed spark corrections for park and in gear. Instead of +/- 17 degrees, try something like 8-10 degrees with that size camshaft.

[Hendonjt81]

Adjustments can't be made to the VVE if the MAF sensor is still being used. The tune must have the MAF failed first, then VVE tuning can be done. Otherwise all the data you get is wrong if it's taking in both MAF and VVE readings.

The most current tune has it setup with the dynamic airflow high rpm disable set to 200rpm meaning it's only running off the MAF and the MAF is not set to be failed with a few given changes.

The truck needs 58psi of fuel pressure, if you do not have that much it could not have enough injector to make the power this engine can make.


The bank 2 sensor is dropping out still, it falls all the way to 0mv and pegs the fuel trims. Make sure the o2 sensor harnesses are in the correct banks, it's possible to get them mismatched on swap vehicles.

I'd start over with the stock timing tables as they tend to work better for starting off. I'd also cut the under/over speed spark corrections for park and in gear. Instead of +/- 17 degrees, try something like 8-10 degrees with that size camshaft.

Thanks! I made a minor adjustment to the VVE table to assist with idle. The tuning guide I'm using instructs to enable MAF only mode while idle tuning. I'm running 340lph pumps in each tank. Key on no start I'm at 45psi, not sure what it's at under load (I will change the regulator out). The psi started out 55-56psi and has dropped over several months. I assume the pump is pushing past the regulator (Delco). I'll swap 02 harness banks momentarily.

I played with over/underspeed yesterday and the cam sounded worse when I got in the 8-10 degree range?

In the recent log, my MAP sensor reads correct but the Throttle Body reads 14-24% at idle. I checked MAP this morning and cleaning TB. I'm now doing a relearn on it.

Aside from intermittent P0106 and o2 data being off, the truck idles at 850-875rpm. I chased a random issue though. The truck would start and idle to temp. If I turned truck off and restarted anywhere above 130* the truck would rev to 3k. I brought the BRAF table back down which solved the issue.

I'll post up my findings.

[Hendonjt81]

Ok,

Fuel Pressure Key on - 45psi
Fuel Pressure Started - 56-58psi

O2 Harness cannot be swapped since Bank 2 runs along side trans harness.

I pulled/cleaned MAP, TB, and did a relearn.

Still intermittent P0106, but I assume it's due to TB% open.

Bank2 o2 is still dropping to zero.

O2's are new - I'll swap sides and see if problem follows......will report back tonight.

Idle Tune 8 o2 issue.hpl

[Hendonjt81]

Adjustments can't be made to the VVE if the MAF sensor is still being used. The tune must have the MAF failed first, then VVE tuning can be done. Otherwise all the data you get is wrong if it's taking in both MAF and VVE readings.

The most current tune has it setup with the dynamic airflow high rpm disable set to 200rpm meaning it's only running off the MAF and the MAF is not set to be failed with a few given changes.

The truck needs 58psi of fuel pressure, if you do not have that much it could not have enough injector to make the power this engine can make.


The bank 2 sensor is dropping out still, it falls all the way to 0mv and pegs the fuel trims. Make sure the o2 sensor harnesses are in the correct banks, it's possible to get them mismatched on swap vehicles.

I'd start over with the stock timing tables as they tend to work better for starting off. I'd also cut the under/over speed spark corrections for park and in gear. Instead of +/- 17 degrees, try something like 8-10 degrees with that size camshaft.

5FDP....injectors!

I had an issue on initial startup where several injectors were frozen...