leans out after hot for awhile
 

I have a 90 1.6l mspnp, innovate lc-1, no afm It drives fine for the first while of driving then it slowly leans out and no ae's. it seems like heatsoak but my iat shows normal temps when it does it.

help please

If you could post a data log of the problem happening, a copy of your MSQ file, and a data log of normal operation, I'll be glad to have a look and see what's changing.

Mine does this too after about 10-minutes on the track when its hot out. My sensor is bathed in ambient air too.

here is the msq im working on uploading the datalog it doesnt want to work yet

here is the datalog it runs good for the first 3/4 or so then the last bit it goes lean

It's not really picking up an air/fuel ratio at idle at all, even at the start of the log. Where exactly is the O2 sensor located on this car?

the o2 is right after the header and it shows an afr of 16 at the beginning. sometimes if you dont wait awhile before starting the car the o2 wont change much at first. Its not the beginning of the datalog that matters so much, the car runs fine for the first 3/4 of the datalog its the last 1/4 or so that the problems creep in and makes my idle lean first then my accel enrichments appear to stop kicking in under acceleration

when im driving and it starts to go lean if i turn off the car and turn it back on its fine for a while but then it starts doing it again

i had the same problem for a little while, especially at idle. I changed the sensor and it seemed to clear itself up.

sensor meaning WB02 sensor

One thing I do notice is you're using a TON of Air temp based enrichments. The whole map has tons of extra fuel being added based on your AIT temps. I'd try making your clt-based air density table all 100% first. However, even though you are adding 41% extra fuel in a lot of spots, yours still pegging lean.

Just looking at your fuel map the values look CRAZY high. I cant understand how you're making over 5mpg.



What happened at 68929 sec? did you stall out? looks like it injected a shit ton of fuel and backfired and kill the motor.

the AIT stuff was just added recently, its not part of the tune regularly, it has been doing this for a long time now but wasnt noticeable until i started getting the car closer to drivable. i changed them back and tried putting it on coolant corrected and my idle got a bit better but it will still do it. my ve values have been based off the ve analyzer . my car has been built to flow a lot more air than stock port/polish, 1mm over intake, glass beaded intake mani., full exhaust. i do believe it stalled out around 68929 sec, the idle was yoyoing a bit when i just stopped in front of my driveway then when i started to drive up the driveway it stalled.

I wouldn't use VE live with that bad O2 sensor. what sorta gas mileage are you getting?

I don't know for sure i havent cared to check yet

so its my O2 then huh?

so if i turn off my O2 correction than it shouldnt go lean, kinda as a way to check it before i buy a new one

Well, here's the thing... on that log EGO is only correcting at most +/-5%. So changing that will do nothing. Your AIT corrections however have it adding over 40% more fuel throughout most of the map. I have a feeling the o2 is bad so VE live is adding fuel based off the readings, then to top it off your insane AIT corrections table is dumping in even more fuel, look after 68670sec when the temps hit 90°F, making the thing drive like ass from being too rich.

Disabling o2 will do nothing if the current fuel table has been altered based on false o2 readings.

:2cents:

i have changed the AIT corrections back to the base map settings and it still goes lean doing the same thing. the table works fine for the first 20 min. of driving then it slowly gets lean on idle first then the accel enrich doesnt work so when i accel it leans. it did all of this before i ever touched the AIT corrections

the fuel table itself isnt the problem although it is in need of tuning, the corrections or lack there of seem to be the problem or a sensor

it's always going to show lean IF you have a sensor that shows lean for no good reason.

Then it's going to run like ass if you tune off a bad o2 sensor that likes to go lean (VE Live will richen the fuel map [and yes your map is bad, it's disproportionally rich as shit in areas it shouldn't be], and then add in a shit ton of extra corrections....uber rich. like bill gates rich. like obama money rich.

or you have a plugged fuel filter or something.

so can i buy just the sensor

so if i can get a better fuelmap and turn off corrections, in theory it should stop doing it

yes. that's the theory and how i'd test it out before listening to some braineack.

Like Braineack said earlier, if your O2 sensor is reading poorly it'll screw up your MS, regardless of a good fuel map. The LC-1 can be replaced with a Bosch part that I believe costs $60. Do a search on google, you can find the Bosch part number and just head down to autozone.

yea did all that yesterday bosch #17014, thanks for all the info. still need to test it out today

Just something i'd like to throw out there. If you have any exhaust leaks pre O2 sensor your sensor will read lean. You may even have leaks you cant hear.

^^^that too.

sicklyscott, I actually if he turns ego off it wont use the o2 reading at all. I was suggesting that if his o2 was bad and giving bad reading and he richened the fuel map constantly more and more after each tune, and then once the car got hot and the AIT enrichments dumped in even more fuel it would run like crap.

My lc-1 failed this way, i kept making my tune richer and richer and richer because my sensor was on it's way out and giving me false readings.

This is how rich it got...I couldn't even finish the dyno pull:

http://www.boostedmiata.com/gallery2...ch_as_crap.jpg


I had to tune out the fuel by hand going off the dyno's WB after each pull, here's the progression:

http://www.boostedmiata.com/gallery2...movingfuel.jpg

My wideband started showing very lean too the last time I was driving the car. I did have an exhaust leak though so i'm hoping that was the problem. It was showing so lean that I could idle the car at 17.5 afr and it wouldn't have any issues. It used to get iffy when I got above 14.5.

then that's a leak...that's easy.

I was agreeing with you, I had the same issue which turned out to be a bad sensor, had nothing to do with MS at all until I tried to tune it out which was a bad idea.

Surprised no one mentioned WB calibration as a possible culprit.
--Alex

so with the new snesor things seem to be better so far, i have encountered what i believe is Lack of corrections for AIT bc i only saw a problem when i stopped to check out my ve table #'s and my AIT hit in the 130+ and it went super lean at idle, i shut it off then turned it on and it idled fine even though the AIT were still way up there. Im working on a new table. Any suggestions on ve values or AIT corrections, or well any suggestions welcome... i need to get this car done

Ok i was driving around with ego off and accel off and it is still slowly leaning out over time and if i turn off the car and turn it back on its fine for a little while

this is a datalog of when it leans on idle

this is the new table ,under construction, for these datalogs

this is after the first datalog i turned the car off then back on

I noticed the gauges on my computer werent showing correct readings but the cars gauges were ok. it held at a specific map and/or rpm, first time its ever done this, it happened in tunerstudio

which gauges? mat and clt?

all of the gauges went wierd my rpm stayed below 2000 and went down when i accelled my clt said like 80 after it had just said 190+ my map went to 100kpa first then cam down and stuck at like 40kpa my ae pct started pegging my afr stuck lean it was all messed up but it didnt change how the car was running at the time

I think that was just a glitch with ts or something. But it still leans over time

what exactly is Gair and what affects it? is it the AIT corrections?

got a new WB O2 , moved IAT out of engine bay, updated to hi-res 10g. car still gradually leans out over time of driving. If i turn the car off and back on it acts fine for a little bit but quickly does it again. Any insight appreciated

i put the factory ecu in the car and it still did the same thing. car at operating temp: it idles and accels normal for the first +/-10min. of driving. the idle and accel start to get progressively leaner and leaner until the car maxes out the afr gauge on idle at 22.4 and dies, i turn it back on and its fine for about +/-5min. it cannot be fixed with corrections. when it started doing it i turned up my ego settings and it would get better for a bit , but it would continue to get leaner. If i try to richen for it getting lean it just gets leaner and i end up with a really uber rich tune on restart. I have checked for vacuum leaks with propane when it happens. Injectors ohms are good. when i datalog the problem nothing looks out of the ordinary except the afrs are lean. this is really bumming me out i need to figure this out before i go crazy.

anyone in nearby phx, az want to help?

Yes. Gair is air temperature density correction and goes off the airdenfactor.inc file.

thanks i've figured a lot more out since this whole thing but its still not fixed. i have gone through most evrything. one of the few things left is to check fuel pressure regulator