I would like to stick with tephra but it keeps adding more issues then its curing. Takes two key starts to turn the car on every time. For what ever reason the car will not start on the first crank over, even after a min of cranking but if you stop cranking and turn key again it will start instantly. That and the random additional knock, the consistent "Rev Hang Issue" that i've seen nearly every run now and the major fact that it didn't help the initial issue.

I did not have any knock on the Lancer rom where this issue started. Once i switched back to tephra i continued to see the same issue in a more server fashion in addition to crazy amounts of knock. I believe the stumbling was a bit worse on tephra for what ever reason and that resulted in a lot of motor vibration which was showing up as knock and making the situation worse. It also doesn't help that i cant adjust the evo rom with lancer knock filtering maps.

I am currently running stock lancer injectors and scalings. I'm only hitting 65% duty cycle as of yet and haven't needed to upgrade yet.


I have five more days to get this tune straight so at this point i'm just gonna make the best of what i can. After that i may try and fight to swap another maf on the car again which is gonna throw me head first into this 4K rpm thing again. For the life of i cant figure out whats causing it.

 

All of those issues are easily cured but do take a lot of training in adjusting the right maps. You probably would do better with something that started as a lancer rom like my auto maps. You'll still run into the maf cap and fuel cap with the stock lancer rom.

Whats your boost? Did you ever change plugs and gap them smaller?

 

^ No boost, its a full bolt-on NA car.


But no, I think I have figured out the problem, or at least have a good hypothesis...

I think its the stock 4G94 cam shaft! I believe the factory camshaft is simply unable to evacuate enough exhaust gasses at full load 4k rpm and the resulting gasses being left in the combustion chamber are causing an uncontrollable rich misfire condition. No amount of fuel, timing or maf corrections seems to fix it other then cutting the airflow back by throwing the smaller diameter maf sensor back on the car. Even then it only just narrows the issue down to a manageable level. The factory map is tuned around this issue as well and its obvious that it was there long before i started modifying the car and that leads me to believe its simply a poor designed factory cam shaft. It make be something else in relation to the camshaft but not sure if were gonna see any guru's in here to break it down as to what may or may not cause the subject inadequacies.

But from what i can tell the larger maf and my supporting mods open the airway up more then you would see normally causing this little hiccup to grow as an issue. You would think that you could scale the maf to accommodate the problem but since the issue is only present at 4k rpm and the air flow seen at 4k rpm is also used at other rpms you would only solve one issue in order to add another one else where. I imagine the boosted, the ported head and RRM cam guys don't see this issue as hard because all of that helps to counteract the problem. But in my naturally aspirated stock motor with full race bolt ons the problem only grows as I open the intake airway to a point that's larger then anyone else to my knowledge has tested as of yet on this type of setup.

Ive tried fixing it in the tune with everything from 0 timing to 20, a map afr into the 18+ wouldn't correct it. Rescaled maf wouldn't correct it, swapping to an evo Rom and then tephra Rom wouldn't correct it. Reacaled load and the use of 1byte load logs didn't correct it.

So for the moment I am back on and working to finish a Lancer Rom with stock 602 maf tune to check the end results. The issue is still present but im able to control the AFR in the effected cells again and i no longer feel or see it on the graph. I was making 80-90whp before mods with no tune, making 126whp after mods no tune, and am currently making 170whp and 179tq with the current tune that still needs the fuel dialed in completely. I'm hoping to break into 180whp as it sits but i honestly feel like I'm reaching the choking point of the stock maf and may not reach it with out being able to swap it out.

Next week I may do some more maf testing and see what i can come up with. I plan on looking into the cams a little more and comparing to the 4G93 cam for the possibility of a fix. But other then that, I can't find anything else that can explain what's happening. It doesn't seem like its an ecu controlled issue and there's nothing left to check mechanically other then the head its self and the cams.


Helpful thoughts, comments and suggestions are welcomed...



^Ninja Edit.

 

Ah makes sense now why it went crazy rich all the maf maps for those sensors are geared toward turbo cars which push a lot more airflow through the motor at the same cfm thanks to the turbo helping push the air in.

If you plan on running a larger maf you are going to have to learn how to scale it back so its right again. To do this simply log airflow in HZ, Wideband AFR, and afrmap setting. Use those three values to determine your percentage that the AFR is off and correct the corresponding MAF values in the smoothing table to dial it in would be the fastest but you can do it with the maf scaling too just more course of an adjustment.

BTW if you wanted a way to control fuel through the entire rpm and pressure range something like my 3d speed density maps would be ideal.

 

I have scaled the maf, but nothing i did would fix the 4k rpm issue after it was scaled. The rest of the power band acted correctly, fuel and timing.

On the 602 maf you don't feel the issue but you can see it on the fuel and timing maps. With a 501 or 399 maf how ever the car stumbles face first and slams max rich from 3900-4100 rpm every full throttle run. No amount of timing or fuel would correct it.

 

Now i could be completely wrong on the whole thing and I'm just missing something in order to get the maf to line up correctly, but other then adjusting the scaling like mentioned above.... i don't know what else to do. I did not making any adjustments to the smoothing tables other then the initial maf settings so i could give that a try maybe. But i just don't understand how it all lines up to cause this very specific issue im seeing at 4k. I could see the air flow of the maf at this rpm and the car falls on its face, and then see the same air flow later and the car was fine. Different RPM ranges on the fuel map and yada yada but adjustments made at 4K made no difference.

Ill play with it again after i finish the 602 maf tune and see what happens i guess. At least that way if i can get it to work i'll know if it was worth all the trouble or not, lol.

 

what values did you end up trying? The car from my point of view was running so rich that it was bound to missfire without a turbo boosting the pressure. That should be correctable with the fuel map to lean it back out to something that would combust.

 

Have two solid tunes today at 12.5 and 13 afr from start to finish making 170whp and 183lbtq. But even on this tune with the stock maf, the afr is richer then it should be. I have to run these three cells 80, 90, 100 load at 4000 rpm a whole afr point leaner in order to bring it down close to where it needs to be. Sadly I only have three fuel cells to adjust here and at 3500 rpm the fuel is spot on, 4000 rpm is too rich, and 4500 cell is correct again. But if I addjust 4000 any more, it makes 3600, 3700, 3800, 4200, 4300, 4400 rpms too lean. So I just have it in the middle with slight leaning before and after and slight rich at 4000.

There's obviously something going on here and the same issue is what's making a maf swap so difficult. Right now I can middle it out like a bandaid but was un-able too with the increased airflow of the larger maf. There was no, getting it to the middle becouse its rich beyond the fuel maps control. I can see it on the logs that the airflow picks up a great deal with the larger maf and it simply amplifies the issue to the point of a fall on its face situation.

The rest of the tune is fine and i ran a 12.5 afr map first and then a 13 afr map which made some extra torque. The 13afr is a little aggressive but I'm fine with that for the moment.


P.S: I also think that I may have just broke the NA Lancer whp record. If not, then at least the stock motor NA record, lol.

 

I think your misunderstanding something about the fuel tables. They really aren't scaled to be AFR but are more like a VE map. The table basically is a percentage map which effects injector time vs load. The map has a scaling applied to it to simulate an AFR but never really end up being the real AFR like in some other cars namely a subaru for example where the AFRmap really does end up being the AFR that it outputs.

 

The afr I'm talking about is my wide band afr. I'm running a 13 afr on my wideband through the entire logged run. I corrected said afr on the map and then when its all said and done you see that at 4000 rpm something is odd. The afr is higher in these three cells on the map compaired to the rest of the map and to add on to it, I'm unable to gett a smooth solid wideband afr on my logs before and after these cells becouse of it.

I can tune the area three ways. The first is with 3500 wideband afr correct, 4000 rich, 4500 correct. The second is 3000 wideband correct, 3100-3900 lean, 4000 correct, 4100-4400 lean, and 4500 correct. Or the last is in the middle like I have it. And I understand this is only 1000 rpm range to play with but I'm seeing a huge difference in afr's in this area. A 1-3 wideband afr difference that I can't tune out.

There's only three cells on the map I can adjust hereand there 3500, 4000 and 4500. But somehow I see a change in afr at 3900-4100 that is not what its set too on the map. It's based on a percentage but if 3800 wideband afr is on target based on the difference of the cells before and after it, why is 3900 two wideband afr in the wrong direction.

 

When I'm on my phone I tend to ninja edit my posts a great deal, sorry about that.


But if I could get an evo Rom or tephra Rom to work correctly so that I had the larger fuel maps I could ideally scale this area down to 100 rpm increments for a finer adjustment of the area. That would allow me to keep a correct afr up untill the problem area of 3900 and correct it again after it at 4100. The 4000 area would still have a hiccup but would only effect 300 rpm rather then 1000 rpm. How ever, that's just anouther band aid and I would much rather know the ruite of the issue so that I can make efforts to correct it.

This also doesn't fix the larger maf issue where this 300 rpm may still fall on its face.

 

You don't happen to have an intake on the car do you? I've seen this sort of thing happen with odd shaped intakes cause vortex problems with the MAF sensor so it would suddenly show a huge drop in AFR thinking a lot more air is flowing than it really is. This also gets exasperated if you take off the airflow straightening grid on the MAF too.

Still seems like it would be ideal for you to try something like speed density and just remove the maf aspect all together.

 

It's a long tube 2.5" cold air intake with a normal un-modified maf. I can see the air flow readings on the log and there's nothing abnormal going on, it reads and climbs like it should.

And I need tephra to work correctly before I could mess with SD. Why don't you send me a copy of your map so I can take a look at a completed lancer SD tune, I may give it a try later. But even then I just don't know if its gonna fix the issue

 

My maps are in my post with my roms just search for "roadspikes huge map roms" and you should find it with ease.

 

no offense but your whp is way off. No way a car that makes hardly 100WHP stock, with bolt ons is now making 170whp. It takes at least 6lbs with an aggressive tune to make that. Hell im at 14 on my oz and that was only 230~. Anyways wish you luck with getting the maf swapped the 605 is a bit of a joke.