Left4Dead

I am trying to find the source of my car not wanting to Rev past 6k since a fresh rebuild.
I went through all the usual suspects with ignition components all have been replaced with several different brands problem persists.
I have swapped the maf as well. Triple or.more checked the fuel injectors everything is as it should be.
I have been at a loss for a while until I believe I found something through versatuner.

It has an rpm limit on closed loop fuelling at 6000rpm. When I adjust this number higher to 7500 and re flash the car now revs to 7500 for the first time since my rebuild.

So from what I understand the ecu is told by the o2 sensor when it has warmed and then changes from open loop to closed correct ?

So what then tells the ecu to switch back to an open map under wot or past the hard capped closed loop rpm limit ?

I am going to switch the rpm limit back to 6000 and get some logs but this seems encouraging to me that I can at least identify something in terms of what is stopping it.

Any thoughts ?

Loki

iTrader: (1)

Has your car been tuned at all? Closed loop is theoretically foolproof, the car runs itself, but in open loop it follows a map, and if the fuel or timing map is wrong, it will not work well. Can you revert to stock and see if that changes anything?
Yes, under normal conditions once the primary O2 is warm and the engine is past cold-start enrichment, it switches to CL.
I didn't know CL had an rpm limit, but in general wide open throttle at any rpm is OL. On some other cars it's based on manifold pressure, but we don't have a manifold pressure sensor, so my best guess is it's based on calculated load.

One thing you haven't mentioned is confirming the intake valves cycle properly. Being able to change the end rpm is definitely a clue, but I would still double check the valve settings.

Left4Dead

I have confirmed intake valves cycle.

I have Just had a huge break through after re flashing back to the 6000rpm CL limit my car now functions PERFECTLY .
I firmly believe my car was somehow stuck in CL ? Not sure how else to explain why it would previously never pass 6k and now after the manual change back and forth I have a fully revving car for the first time since I started this journey so long ago I dont want to even admit lol !!

dannobre

iTrader: (3)

It sounds like there is a problem in the open loop part of whatever has been done to your map.
If it is OK up to the closed loop trigger amd then gets crappy and follows when you move the closed loop switch over.... it souds like when it hits the open loop map it falls on its face

What are the A/F's doing when it hits the crappy area?

Left4Dead

Well that is an excellent question I am still learning to read these logs to be honest
I did not have any issues while driving taking these logs the car ran what I would consider well but worth posting anyway.

I cannot even get the car to recreate the situation anymore.
The car that hit a wall at 6k for the last year now just revs everywhere
The only thing that makes any sense to me is that it was somehow stuck in closed loop and now will switch into open when called upon but I have zero evidence of this

wcs

iTrader: (2)

Those without VT cannot see those Data Logs. I saved them and uploaded them here as CSV if anyone else would like to view the log data.

I just really quickly looked at the logs (I'm literally getting ready to step out the door)
Of interest/concern:
1) Warm Up log shows the STFT of +25% for both Min and Max. This is a bit of a red flag imo (see uploaded pic named Warming Up)

Logs = Warming up


2) The 3rd Gear Log has a pretty nasty spike in AFR around 6300 rpm. I would want to get that fixed/addressed (also see pic labelled Logs 3rd run )

Logs 3rd Run

Left4Dead

your amazing thanks for taking your time to post that
I am reading lots about what I need to be looking for but clearly that afr is not good
going to flash a stock file and get logs with that , this is the off the shelf mostly stock 91 octane tune from VT
is there anyway to modify values in a stock file , all I see is the option to return to stock but does not let you alter it is that possible

Loki

iTrader: (1)

Is this just a rebuild or what are the mods on the car? Because you may want to reset back to stock and see how she behaves. There's not a ton to be gained by tuning a stock renny, and a lot to lose if not done well

Left4Dead

Its basically stock but I sent my injectors away to injector rehab to get flow tested and for some dumb *** reason I agreed to the 47% increase in flow they offer. So without any tune it ran like crap. So I wanted to take the most basic tune possible and put my injector scaling flow rates in there. So that is what those first logs were of

Brettus

iTrader: (2)

You cant just change flow rates and expect that to work . If it's N/A you should just get some stock injectors and put them back in as you have created a headache for yourself without any upside.
But if you just want some tuning practice ........... see link : https://www.rx8club.com/series-i-eng...7/#post4776388

Left4Dead

I feared that may come up I really dont want to mess with injector wiring its so tough to get at with engine in car last time I had the motor out I still struggled with those connectors but will if that is the only way to solve this

I will start reading the link you gave thanks this is not a DD just a track rat hopefully one day

dannobre

iTrader: (3)

Wrong injector values will.sure do that.... it thinks your secondaries are bigger than they really are by the look of the lean mixture..

Also.. with a +25 at idle you either have a vac leak, or again the injectors are smaller than the tune thinks

Problem with modified injectors are twofold... you don't know the flow.. and if the latency or other characterizations have changed....
And you dont need them for an NA stock or ported motor. There is more than enough there already

Left4Dead

Your AFRs will probably be off, and you'll need to correct them by adjusting either your VE table or your Open Loop fueling tables. It's up to you which method you use - 2 different ways to skin the same cat - both methods are effective if done correctly.


what table is this referring to please

dannobre

iTrader: (3)

If you have changed the injectors and this is the result you need to start someplace and then adjust.

If it was me I would flash back to stock and then change injector numbers in the tune till it behaves.

Doesn't make sense to try and adjust anything else till the injectors are close.

Usually the injectors scaling numbers are really close with stock injectors. Usually you tune the MAF scaling and VE tables and the AFR maps to fine tune the rest.

Left4Dead

Ok all of that makes sense except I still dont know what a VE table is

Left4Dead

and If I flash back to stock I cant change injector numbers can I , I only see an option to return to stock but without being able to modify anything

dannobre

iTrader: (3)

Do you have Versa Tuner software?

You should be able to open a stock tune and modify it and save it called something else.

Make small changes and log and work the values toward where you want to see them.

If you don't know what you want to see... check out a few of the tuning threads to give you some pointers.

Once you have done a few simple things... post some logs here a d your map changes and we can try and help you

Left4Dead

I have versa tuner pro but it does not come with a stock adjustable map , just a one touch back to stock option where you cannot modify any values as far as I can tell unless I am missing something

dannobre

iTrader: (3)

Figuring out how to get VersaTuner working is your first job then 🙂

Left4Dead

the easy flash tune database is updated and provides me with 6 tunes , the one that says stock also says modified afrs so its not all that stock . Do I need to look up stock values and replace them all to achieve a stock map. I clearly have more to learn in all areas but I will get there

dannobre

iTrader: (3)

You will need a map that can be custom adjusted.

Now that the injectors aren't stock you can't use any canned tunes

Left4Dead

Ok so with the pro version I can custom adjust any map correct , so I took the mostly stock map and put in the flow rates but it sounds like I also need to change the latency tables and I still dont know what a VE table is what does that stand for

Left4Dead

Volumetric efficiency in the load table

dannobre

iTrader: (3)

You need to adjust the injector values till the AFR's are whats commanded. Then you need to change the fuel maps to get the AFR's that YOU want... basically leaner at higher loads.

The VE table is volumetric efficiency... it is a global fueling table based on how the engine reacts..

You should also look at oil injection rates and likely fan on and off temps....

Like I said before:
start at a baseline and make small changes and track what they do. If you run logs and you can't see any changes...have a good look at the logic of what you are doing and maybe go back one step and try something different till you see the result...
less likely to mess things up that way

If you think your injectors are 47% more... remove 25% fuel and see what happens
If the results are going in the correct direction the do some more.

Don't make huge changes and expect them to work. Lots of times its not that simple. There are areas that when adjusted make a mess someplace else

Left4Dead

amazzzing thank you !!