Injector flow rate maxxed out fuel gauge error

[hymey]

I have done some research into injector flow rate and trip meter/fuel gauge error. Everyone is aware the maximum hard limit is 63 pounds per hour in the injector flow rate table. So my siemens 63 pound injectors at 58 psi actually flow more like 73lb/hr. So my fuel calcs are 15% out. If I am reading 8L/100kms I am actually well into the 9s.

Another problem we face is that if IFR is low from bigger injectors and we cant raise the IFR number high enough. VE is then low and then g/cyl calculations is also low.Higher IFR is leaner mixture hence higher VE. If we could increase IFR to 73 or more we would have to increase VE which fixes the 15% error and our fuel gauge calcs are correct.

Now the e38 has a lot of untouchable hard limits. IFR tables being one of them, there have been suggestions of increasing the voltage multiplier and IAT multipliers, but this DOES NOT WORK. I have changed all of them to 1.1, 1.5, 3! and still no change so the hard limit is there!.

There is a way though. Tables B0179 and B0180. B0180 we don't have to touch it is only a multiplier and if you are SD anything over 0 is ignored anyway,But I recommend you change this table to 0.1. Now B0179 is very important. I ALWAYS tune cars with this at a constant value. Because as speed increases the mixture richens by a fair bit which is why i had issues with afrs richer in higher gears at speeds over 130km/h. This is a charge temp table, based on the fact that as speed increases VE is more efficient so more fuel is added. Now this has caused me nothing but issues and if anything the mixture needs to be leaned if load increases, which is what I have done with my own car...and numerous other e38s. The table does work. Higher numbers leaner, lower numbers are richer.

Now what I have done with my own vehicle is work out the fuel gauge error of 15%, I initially tuned my car with the whole B0179 table at .50 and B0180 at 0.100. I increased the B0179 table 15% which decreased my VE by 15% which was noticed by both w/b and STFT. I then increased the whole VE table by 15% to correct VE and AFR's. Now my g/cyl is 15% higher and where it should be and I am looking forward to checking the trip meter next tank to see how close it is. I am hoping within two percent if it's still too low I will increase B0179 and the VE. If error is high I will decrease the B0179 table and VE by the correct amount. Atleast I now know and am confident that my g/cyl calculation is correct.

I wanted to share this info in hoping some other guys can try it just to ensure it works across the board. Very promising.

cheers

Joel

[GMPX]

Thanks for your post Joel, the injector limit is annoying (though GM sorted it in the 2009+ OS's), we looked at modifying the earlier OS's but it's just too massive!
I had also said in the other thread the IFR multipliers would not work, you can't make a 16bit number bigger than 65535 no matter how much you multiply it.

Cheers,
Ross

[oztracktuning]

Its unfixable, an old issue Joel. You can either use the FAST 65lb at 4bar injectors and be close or change the cars entire system to a E67!

[hymey]

Hi steve, it definately works, from ur reply it appears u have not checked this, once the injector tables are maxxed to 8 i just altered the charge temps tables and all fixed.

[oztracktuning]

Hey Joel,
Ross has just stated that it doesn't work. This was an old issue.

What i meant doesnt work is the fuel usage is unchanged. You may get the g/cylinder to report right though.

[hymey]

ok, as u said though it corrects the g/cyl which gets the ve right. I have my fuel gauge working accurately with the 63 pounders.

[oztracktuning]

Its the fuel usage data and L/100km values. Tripmeter etc that is the problem, if that is fixable it is good news.

[hymey]

Yeah I checked the trip meter, its spot on against the factory gps.

[ringram]

Ross can we flash to an 09 OS? Or does that kill ECU's?

Also guys I use voltage mod with a factor of 2.2 and while the trip meter is probably bad as well as the g/cyl fueling seems spot on.

Hymey your plan sounds interesting. I too have the siemens injectors.

[The Alchemist]

Hi Hymey, I'm tring to do the VVT in this VE ute and am having issues with a weird 0.3ms jump in IPW at a calc load of 32g/s. At 2700rpm this becomes 0.2ms at the same load 0f 32g/s. screen shot and log attached. I have B0179 and B0180 standard at the moment. Could this be my problem? I turned off dynamics and all pulse adders made no difference. I have 65lbs Fast injectors with my IFR table fudged at 8g/s at 512 delta map
I have been creeping up on the problem with the slightest of throttle movements on the dyno and me VVE table is smooth around the problem area.

Cheers,
Mike