Rogue_Ant

I'll look at my notes. Mind posting your idle fuel map?

Also, if the engine runs different with the NB connected, doesn't that suggest that the DME does something different with the NB disconnected?


-Rogue

Rogue_Ant

Yes, that could be the cause of the problem.
Without going into a lot of detail, the boost needs to be what the chip was mapped for. Along with the proper airflow sensor...


-Rogue

JohnKoaWood

With NB plugged in, it leans out (15.8:1) when cold, without NB plugged in it is at 14.7:1...

With the NB functioning and connected, the DME is adding or pulling fuel based on what it is seeing, without the NB it is up to the base maps.. and core programing of the DME, it runs smoother with the NB because it is taking up for any differences between what the engine needs and what it is getting, without the NB the DME has no feedback on what the AFR is... I tuned the PT and IDLE maps to give me 14.7:1 without the NB as a fail safe against my soldered NB failing (thread a long time ago..still works fine, solder and all, even some heat shrink)

schip43's car, he believes, has his Zietronix hooked to his DME NB input... this removes the stock NB input... so he disconnects the NB and sees no change at all, AND he is definitely running the wrong chips, even if he has the "right" chips in for AFM vs MAF... and he has no way to change the mixture himself...

Rogue_Ant

John, are those lambda values? Can you post the actual hex values instead?

JohnKoaWood

Sorry that was DME fuel values... here's the SW text representations



Hex is 5c, 5d, 5d, 5d, 5e for addresses starting at 0x053F (idle map starting location)

Rogue_Ant

Your values are very similar to your WOT table... Any thoughts on why, considering your idle is ~14.7:1 and your WOT is ~12:1?


-Rogue

Rogue_Ant

Like I said, I need to look at my notes - but if you disconnected the NB02, then the DME will add the maximum amount of fuel allowed by the O2/Lambda routine. So you tuning this way, assumes the DME is constantly adding this extra fuel.
Now when you plug back-in the O2, the DME runs lean until it adds fuel based off the NBO2. That would explain the cold-start enleanment w/ NBO2 hooked up.


-Rogue

JohnKoaWood

The lean on cold start I thought was driven by open vs closed loop off the fuel system temp sensor on the block.. it leans out to drive up temp faster, then drops down once the engine is warm... nothing to do with the NB...

A PT or idle map adjustment with the NB connected has little effect, the computer compensates for the adjustment, disconnected each point change results in idle and partial throttle AFR change immediately on writing the new maps...

My idle map is marginally different from my 6% throttle map and well below my WOT map given the amount of fuel flowing... I am sure my maps would be farther apart were I running smaller injectors, but I had these 55s on hand, new and flow matched... it just requires the maps to be tighter than with the smaller injectors... looking at my entire maps, there are only 8 hex points separating 800 RPM 6% and WOT 6200RPM... the difference in AFR can be accounted for by the 3BAR above manifold pressure fuel pressure (idle fuel is less than 2 bar, but 5000 RPM at 14PSI boost it is almost 4 BAR in the rail...)

Rogue_Ant

No - the DME should run rich on cold-start and warm-up, continuing to enlean to normal once the car is completely warm.

The computer will compensate, but has a limited range... one can most certainly alter the maps enough to go beyond the DME O2 feedback adjustment ability.

Fuel pressure is raised at the same rate as manifold pressure. This is to keep injector flow constant regardless of manifold pressure.
I.E. at 0psi of boost, FP is 43.5 (3bar regulator).
At 15psi of boost, FP is 58.5 (same regulator).
In both cases the pressure across the injector is the same (43.5).

The DME takes the airflow signal (AFM) and along with baro & AIT derives air mass. Once air mass is known, the DME calculates the necessary IDC in order to achieve a Lambda value of 1. From there your maps modify this value. There is no requirement for the maps to be tighter due to larger injectors - this scaling is already done by the DME before it even reads your maps.

The MaxTune SW appears to display in terms of %change from Lambda 1. If so, then it looks to me like your maps are quite lean.

Just occurred to me - how are you scaling for the 55lb injectors? If you are using the maps to account for the global change in fueling, then disregard my earlier point. Though if so, you should be using the FQS to do a 'global' adjustment, that way you could regain lost resolution on your maps.


-Rogue

333pg333

If a car is running lean on cold start but moves to a more normal read after a few minutes of warming up, is there any significant chance of problems?

Rogue_Ant

No. It will just be sluggish, and probably harder to start. Fuel doesn't stay is suspension as well on a cold engine, thus the need to be a little richer on a cold-start and cold running engine.

JohnKoaWood

She is lean on cold start, starts on first crank each time though.. not sure I would describe the car as sluggish, but the throttle response is definitely lower... but that just reminds me to let it warm up before getting into boost...

I scaled the maps for the injectors sizing, as I went from 36lb to 55lb, the FQS didn't offer enough subtraction to correct the AFR...

With the 36lb injectors the range on the maps was MUCH wider (15 or so points) where as with the change of the injectors and 3bar the maps got much tighter, but the performance difference is like night and day...

On a separate note, seals and such should be here tomorrow (to include turbo rebuild kit, I'm having a local shop balance the rotating assy for the turbo, but re-building it myself) as the replacement I have shows some signs of leakage (I pulled off the compressor housing, and it had oil in it).. I'm working from home right now, and will be pulling off the turbo on the car tomorrow.

Once I have the Turbo off the car, I will compare the pieces side by side, and build 1 turbo out of both using the rebuild kit.. balance the best of the two pieces internals, but have to wait until Monday to reassemble everything as my AOS seals and Venturi delete kit won't be here till Monday.. BUT this weekend will bring everything being removed, cleaned, and torn down for refurbishment..

Since I am going to all this trouble, I also ordered the LR turbo oil filter and optional adapter plate...

As long as all goes well, all the pieces should come in, I will get the turbo rebuilt, and have it back together early next week...

And be back to fine tuning the ignition maps...

Rogue_Ant

Ah, so the MaxTune SW doesn't allow you to adjust the FQS settings?

JohnKoaWood

FQS, TEMP Correction, Timing, Fuel, RPM limit... off the top of my head....

V2Rocket

you can alter FQS and rev limit?




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