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Problems whith tune of VE Table morning afternoon

A

Anders-R32

New member
Joined
Nov 16, 2008
Location
Denmark
Hi

i have some problems whith my tune, when i use the Tunerstudio and VE Analize live tool, and tune the map for my AFR valu'es in the morning. then the car runs great ore as good as the map does :) but when it comes to dinner time ore just if the wheater is warmer the map i differient :-( and the car runs leaner so i dosent run smooth :-( Does enyone know what the problem could be ?
 
He's asking what the difference in IAT temps are. The IAT temps will significantly change your fueling. As your IAT's come up you will run leaner as they go down richer.

Kenny, correct me if I'm wrong but you have a way of lessening the temp compensation for IAT changes within your msq? I'm also troubled by this issue, since my IAT sensor is in my cold side IC pipe it tends to get hear saturated making my AFRs run leaner the hotter my engine gets... not ideal.

So I know of 2 solutions, #1 move the IAT out of the IC plumbing, I've read it suggested in the bumper or around the air filter. #2 change the temperature compensation coefficient that MS uses to calculate req. fuel.

Bondo, can u link me to a how to on changing the IAT compensation for MSnS-e (i've been meaning to do this for a while now)?
 
My point is, if the AFR's seem to be getting leaner when it is warmer out, it is probably due to the MS overcompensating for an increase in IAT. IMO MS is terrible for this.

The compensation is WAY too agressive IMO. You are supposed to be able to fix it using the "Coolant Corrected Air Density"settings but they screw my car up completely. It won't even run with the correction on.


As far as I'm concerned, I would like about +2% fuel at 60 degrees and +4% at 50 and that's it. Just add fuel for cold nights. Don't pull any when it's hot out.

Above 80 degrees I would like some timing retard but I'd just as soon leave the fuel in.

I wish is just had a normal IAT correction table the same as the warmup table.


Anyways sorry for the rant. Review ait's. Even a 10 degree difference makes a noticeable difference in AFR on my car. It's annoying as hell and I can't make it stop. Sorry I'm ranting again. :rofl:
 
just another thought....coolant temp plays a big role too. a cold soaked motor vs a warmed up and cooling motor? hows the grounding of the motor and chassis? efi relys on a 5 volt ref to ground...and with such low voltage any grounding issues show up big time.
 
Here's what the settings look like, to get to this page go to advanced->Coolant Corrected air density:


ait.jpg


The little box comes up when you click "settings"

So in my understanding based on what I have selected, it works like this:

1)Set to corrected. This means the "normal" amount of AIT enrich/enleanment will be modified

2)set to AIT Corrected. You can also set this to coolant corrected. In my case it is AIT. This means that depending on what the AIT is, it will adjust the current amount of AIT enrichment/enleanment base don the curve,

3)"Start to reduce correction at" set to 300. Basically that means it starts using the correction curve at any rpm above 300

4)"End correction at" set to 7500rpm. Basically use the correction right to redline.


3)In the curve, I have 50,60,70 degrees set to 100. That means no correction, use the regular AIT adjustment. Then at 80 degrees is should add 10% more fuel to whatever it thinks the ait adjustment should be, and then 12% beyond that.


All of tis said, my car will not run. Like, not even start, if I haver this **** turned on. Blows. But I believbe that is how it is supposed to work. ;-)
 
Captain Bondo said:
My point is, if the AFR's seem to be getting leaner when it is warmer out, it is probably due to the MS overcompensating for an increase in IAT. IMO MS is terrible for this.

The compensation is WAY too agressive IMO. You are supposed to be able to fix it using the "Coolant Corrected Air Density"settings but they screw my car up completely. It won't even run with the correction on.


As far as I'm concerned, I would like about +2% fuel at 60 degrees and +4% at 50 and that's it. Just add fuel for cold nights. Don't pull any when it's hot out.

Above 80 degrees I would like some timing retard but I'd just as soon leave the fuel in.

I wish is just had a normal IAT correction table the same as the warmup table.


Anyways sorry for the rant. Review ait's. Even a 10 degree difference makes a noticeable difference in AFR on my car. It's annoying as hell and I can't make it stop. Sorry I'm ranting again. :rofl:
Click to expand...

You're skewing too much or too little thre bondo ;-) I leave that table zero'd out. they used to have just an air temp skew table that I and others requested be put in, but then everyone bitched and moaned about that, so they came up with the coolant corrected air temp stuff, which allows you to essentially do the same thing in a roundabout way.

It is for this reason that I leave the air temp sensor completely away from anything on the engine. mine was dangling through a hole in the battery tray. Worked fine that way, no heat soak, no wild swings in the tune.
 
linuxman51 said:
You're skewing too much or too little thre bondo ;-) I leave that table zero'd out. they used to have just an air temp skew table that I and others requested be put in, but then everyone bitched and moaned about that, so they came up with the coolant corrected air temp stuff, which allows you to essentially do the same thing in a roundabout way.

It is for this reason that I leave the air temp sensor completely away from anything on the engine. mine was dangling through a hole in the battery tray. Worked fine that way, no heat soak, no wild swings in the tune.
Click to expand...


Yeah I tried setting it all to 100, which i think is like saying no correction, but it still didn't work. Some kind of config issue maybe even.

My ait sensor current hangs out in or around the healdight bucket on the driver's side. It's better than last year when it was on the hot sid eof the engine, but it still ****s me around. I think it needs to be in the bumper or something like you say. :-D
 
Mine has the same problem, drives me nuts. ms2 extra has a setting for iat correction, but I haven't played with it yet.

What about just putting a resistor in place of the sensor to keep the temperature reading steady?
 
I will have to check the IAT temps on the laptop in my car, did actualy think og moving my IAT sensor much closer to the IC so the engine wouldent heat the sensor up so easy
 
wennstroma said:
Mine has the same problem, drives me nuts. ms2 extra has a setting for iat correction, but I haven't played with it yet.

What about just putting a resistor in place of the sensor to keep the temperature reading steady?
Click to expand...

then your tune will drift with atmospheric changes. you want it to compensate a bit, just not too much.
 
Ive seen the same thing my IAT is in my intake manifold. I tuned with my car hot and its rich when its cold out. mabey its supposed to be in the air filter? I switched to open element seemed to work better.
 
As i use ms2extra i have different settings for iat correction.
there's a table for correction, and a % value.
i have it set at 50% of the calculated correction, and it's still too much.

But as it is an IAT, i find it very slow to resond to temp changes, when i'm on the freeway doing 100km/h, i see the temp drop below ambiant, because of the IC, but if i floor it to lets say 200km/h it only gets about 5 degrees warmer... what i believe is false.

anyone see this too? solutions?
 
Dap_p said:
As i use ms2extra i have different settings for iat correction.
there's a table for correction, and a % value.
i have it set at 50% of the calculated correction, and it's still too much.

But as it is an IAT, i find it very slow to resond to temp changes, when i'm on the freeway doing 100km/h, i see the temp drop below ambiant, because of the IC, but if i floor it to lets say 200km/h it only gets about 5 degrees warmer... what i believe is false.


anyone see this too? solutions?
Click to expand...

Why would it be false? when you idle (hot motor) for a long time then the temp should rise!

Did you use a 'open element' sensor? like the one below? they react faster.
http://www.diyautotune.com/catalog/gm-open-element-iat-sensor-with-connector-p-116.html
 
Last edited:
OK I got this working. Somehow. The first rpm vale "reduce correction at" is actually when it starts to stop applying your new correction table and just use the standard values.
So if you want to correct it all the time, set the start reduce correction to some high rpm value, like redline or higher, and the stop correction even higher than that.

Looks like at 115% at 80 degrees and 120% after that, it's pretty decent. It pulls a little fuel as to not be totally disabled when it's legitimately warm out, but not so much that it cripples the car when it's heatsoaked. I've never had any wired readings when driving when it's colder than 70 out, so I don't apply any additional correction below 70.

Dap,

you shouldn't really get readings colder than ambient with an air-air cooler... a 5 degree rise on a pull like that sounds normal. Going to 200km/hr you are forcing a lot of air through the cooler.
 
Captain Bondo said:
My point is, if the AFR's seem to be getting leaner when it is warmer out, it is probably due to the MS overcompensating for an increase in IAT. IMO MS is terrible for this.

The compensation is WAY too agressive IMO. You are supposed to be able to fix it using the "Coolant Corrected Air Density"settings but they screw my car up completely. It won't even run with the correction on.


As far as I'm concerned, I would like about +2% fuel at 60 degrees and +4% at 50 and that's it. Just add fuel for cold nights. Don't pull any when it's hot out.

Above 80 degrees I would like some timing retard but I'd just as soon leave the fuel in.

I wish is just had a normal IAT correction table the same as the warmup table.


Anyways sorry for the rant. Review ait's. Even a 10 degree difference makes a noticeable difference in AFR on my car. It's annoying as hell and I can't make it stop. Sorry I'm ranting again. :rofl:
Click to expand...
I ran into the same problem with MS1 extra HR. Car was tuned perfectly, started fine cold but if you parked it with a hot engine for half an hour the IAT sensor would heat soak up toward 140f+. When starting it would run extremely lean for about a minute until the temp sensor was brought back down. Eventually found that I needed to add IAT correction starting around 90f (100%, no correction) up to 140f (125%), sort of a straight line. It took forever to figure it out. It was especially frustrating with an automatic transmission and closed loop idle control where the load at idle can change dramatically.
 
Last edited:
From what I've read in this thread, are you guys saying I shouldn't have my Air Temp Sensor inside my intake piping? I should just have it in a neutral air area?
 
B-lennium said:
Why would it be false? when you idle (hot motor) for a long time then the temp should rise!

Did you use a 'open element' sensor? like the one below? they react faster.
http://www.diyautotune.com/catalog/gm-open-element-iat-sensor-with-connector-p-116.html
Click to expand...

What i mean by false is that compaired, running 100km/h with almost no throttle gives a little lower the ambient temperature, what is correct,
but running WOT at 200+ km/h i only see the temp rise about 5 degrees C. what i think is false.
i think at 22psi on a 15g, temps would rise a little more.
 
You can make the correction do whatever you want to do if you play with the IAT calibration curve. Sounds like you could benefit from making it less sensitive at higher temperatures. In other words, when it's truely 90 degrees out, have your MS think that it's only 75 degrees out. At 100 degrees, let it think it's 78 or 80. Stretch out the calibration curve like that and you won't run as lean on hot days.
 
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