E38 and Power enrichment

[markemac]

I have a 2008 5.3L E38 Silverado that was brought into me to tune, it has a homemade turbo install. Stock MAF, Injectors (i am sure they will be too small) the problem I am having is when I get the throttle to a point where I am getting into a few psi of boost I want the PE to kick in, I have lowered the TPS for PE and made sure there is no delay for Pe, yet the enrichment will still not come in until a much heavier throttle? Any help would be appreciated, it is a mild truck so the stock MAF should be ok?

[swingtan]

check this thread....

http://forum.efilive.com/showthread.php?t=6461

in some ( if not all ) E38 tunes, the PE TPS figures are not the same as the logged ETCTP PID. There can be a logarithmic relationsip that makes setting the PE via TP% a little more difficult. At post 7 in the above thread, I give a quick table for the corrections. This may be your issue.

Simon

[markemac]

Thanks, that make sense I'll try it

[markemac]

Ok it worked great, one question about VVE and the differant ones, there are open intake valve closed intake valve.
the truck has no intake valve
one bar two bar three bar
one and two bar make changes to the fueling but how do you know which it is in when? and should the higher vacuum area of the two bar be similar or the same in numbers as the one bar? what is the whole thing with the calculate co eficients or what ever it is called?
should the vve look like a normal ve table?
sorry about all the questions I have been reading as much as I can find in the forum.

[GAMEOVER]

Have you read Swingtan's tutorial on VVE adjustment:http://download.efilive.com/Tutorials/PDF/Virtual%20VE%20Adjustment%20Tutorial.pdf

[markemac]

Yes a couple of times and it is great, I didn't see those answers in there I'll look again?

[markemac]

It does answer what it should look like, and slightly about what generating coefic are, still not clear totaly why it is in there and not just a ve table? what about the diff vve tables how do you know which it is using since they all have high vac areas, and should the high vac areas be sam or similar to each other?

[joecar]

It does answer what it should look like, and slightly about what generating coefic are, still not clear totaly why it is in there and not just a ve table? what about the diff vve tables how do you know which it is using since they all have high vac areas, and should the high vac areas be sam or similar to each other?The E38 and E67 calibrations contain all those tables of polynomial coefficients, this is how the GM engineers designed the E38 and E67 to function...

since humans can't visualize what the 3D VE graph looks like from a set of coefficients, the EFILive tunetool provides a tool which maps the coefficients to a 3D virtual graph... the tool lets you edit the graph from which it recalculates/regenerates the coefficients.

Look at the name of the tables... the various tables apply for those situations... look at the descriptions of each of those tables... somewhere in the calibration are entry/exit parameters for the various modes.

:)

[swingtan]

The way I "think" it works is....


Adjusting the 1Bar ( up to 105kPa ) VVE should suffice for non FI appliactions.
If going FI, then the 2Bar VVE will need to be adjusted. The lower pressure areas ( higher vacuum ) should take the shape of the 1Bar tune and you should only need to adjust the upper areas.
The Intake Valve / open tables only need to be changed if your vehicle has the vale fitted. I don;t have one so I just copy the 1Bar table for both open and closed.


The reasoning behind this is that in reality, there is not multiple "tables" in the tune at all, just one set of coefficients. The tables were generated to help us visualise the shape of the graphs. So the 2Bar VVE is actually the 1Bar VVE with a set of higher pressure values stuck on the end.

Of course, you could avoid a lot of this if you plan to keep the MAF and just set the high speed air flow setting to just off idle........

Simon.

[markemac]

"]Of course, you could avoid a lot of this if you plan to keep the MAF and just set the high speed air flow setting to just off idle[/COLOR]

This would disable the VVE and run only with MAF? correct?

In reading all the forum it seemed that the vve should be set up close and then set the MAF?

It is turbo'd

seems like there is the age old contraversy about never change the maf table or the other side, do it because it is the best choice. I have no problem changing it as nesc. thought I would set up vve first?? the MAF may max out not sure yet?

[swingtan]

With FI, you may run out of MAF calibration, so it might be better to keep the VVE accurate.

When using the MAF, the only thing the VVE is used for, is to provide a "sanity check" and correction for the MAF signal. This only occurs when the engine RPM is below the "Fast Speed" threshold, above that value the ECM only uses the MAF anyway.

Basically though, if you plan to use the VVE, then dial it in.

As for the old MAF vs MAFless debate, the E38 has changed the battle field a bit.....

[hymey]

Hi , leaving a 1 bar sensor will work fine with the e38 (MAF tuned), you may have to raise the max threshold limit though of the map sensor to avoid codes. I have done this scenario it works well. as if the 1 bar vve is already correct it helps with low speed fueling and then all you need to do is scale the maf. If you change to 2 bar you have to change the MAP settings to 188 and -10 from memory, when I go home I will check for you, This will allow the 2 bar vve to function. It will also allow you to log boost pressure rather then reading a gauge, but remember you are tuning via the MAF table ie flow not boost, timing is also done by flow not pressure.

I would bet the engine is coming onto PE that its actually commanding PE when you want it to. The extra boost pressure is reducing the effects of fuel dynamics so it is lean on rapid throttle movement.

This can be repaired by altering the dynamics table so at the higher end of the table the multiplier is increased from 0.8 upwards to 1.5 to 2.0 since the engine is on boost when this table is maxxed out the last cell is most important.

The 2 bar vve works very well with a boosted e38 in SD, but my trap speeds in quarter mile time did not alter with the MAF on and I think the MAF gave me more flexability, responce with the MAF was awesome, the e38 responded well to it and dynamics allows awesome flexability to low and high flow fuelling.

[markemac]

I have logging question when running scanning and looking at logs the trace that shows up in the tuning software, on the Na and 2 bar vve it stays all the way on the left (high vacuum area) on the three bar table it moves around as normal, on the NA and 2 bar vve I cannot change from kpa to psi in display units? I must be missing something?

[The Alchemist]

I really liked the bit on IAT adjustment correction, (havn't done this on a E38 yet) well done for taking the time to put this all down for others to benefit from mate. Bloody impressed !!!
I'm doing a brand new E2 wagon R8 next week so I'll be giving that a go.
:coool:



Have you read Swingtan's tutorial on VVE adjustment:http://download.efilive.com/Tutorials/PDF/Virtual%20VE%20Adjustment%20Tutorial.pdf

[hymey]

I have logging question when running scanning and looking at logs the trace that shows up in the tuning software, on the Na and 2 bar vve it stays all the way on the left (high vacuum area) on the three bar table it moves around as normal, on the NA and 2 bar vve I cannot change from kpa to psi in display units? I must be missing something?

Best to stick with kpa, its easy to learn and more resolution.

It shouldn't trace on the three bar table.

B8034 try 201 kpa

B2101 188

B2103 10

Tune with

B8103

once your done go back to MAF tune with a M6 its even harder to get dynamics right with boosted engine from the pressure in the manifold and port opposing pressure back to the injector and blowing fuel off the port creating lean conditions. Some tuners say its fuel pressure and it isn't its the dynamics.