Speed Density Problem
Sep 30, 2009, 08:56 AM
#1
Speed Density Problem
Ok so awhile ago I noticed my car was getting slightly richer as the temperature dropped. Well right now California experienced about a 30F drop in weather so in this nice 40F degree morning my car is running so rich i had to literally switch to my non e85 map to make it to work.
Something is definitely wrong its not just a few AFR points now its like running into the 9's for AFR when its cold. Need opinions on if this is a function of me having the air temp sensor both on the upic and it being connected to the fuel temp spot on the ECU rather than the air temp spot on the MAF.
Probably going to have to unmod now so i can get my car driving for the cold weather.
Something is definitely wrong its not just a few AFR points now its like running into the 9's for AFR when its cold. Need opinions on if this is a function of me having the air temp sensor both on the upic and it being connected to the fuel temp spot on the ECU rather than the air temp spot on the MAF.
Probably going to have to unmod now so i can get my car driving for the cold weather.
Sep 30, 2009, 12:44 PM
#2
Evolved Member
iTrader: (22)
Join Date: Nov 2003
Location: Northern KY near Cincy
Posts: 2,408
Likes: 0
Received 6 Likes
on
6 Posts
Is there a cold weather table that will compensate the fuel for various temperatures?
SD is supposed to not have issues with temperature variances. Makes me glad I havn't made the switch just yet.
SD is supposed to not have issues with temperature variances. Makes me glad I havn't made the switch just yet.
Sep 30, 2009, 01:26 PM
#3
That definitely sounds very weird. I would have guessed that you would start running lean, if anything.
So, you have your temp input into the fuel temp sensor adc and you have your ROM flashed to use the fuel temp adc?
When you log your temp sensor, what values are you getting? You aren't getting any ridiculously low temps are you? Is the richness just during initial start and warmup or all the time?
Did you ever change any of your temp tables in any way? Any baro/IAT table or anything remotely close to that? Any table that deals with the pv=nrt forumla or anything like that? I remember from several different threads where tables were posted that dealt with this kind of stuff. I think it was mentioned not to change them, but I think several people were experimenting with them. Did you happen to change any of these tables?
The temp compensation should follow the pv=nrt formula, so if nothing was changed in that respect, your fueling should stay in check, as long as your temp sensor is reporting accurate values. Maybe your IAT sensor is recording lower IAT values than your actual intake temps (like the IM heatsoaking) and thus resulting in a rich AFR. If that's the case, then it should lean back to normal once you start moving.
So, you have your temp input into the fuel temp sensor adc and you have your ROM flashed to use the fuel temp adc?
When you log your temp sensor, what values are you getting? You aren't getting any ridiculously low temps are you? Is the richness just during initial start and warmup or all the time?
Did you ever change any of your temp tables in any way? Any baro/IAT table or anything remotely close to that? Any table that deals with the pv=nrt forumla or anything like that? I remember from several different threads where tables were posted that dealt with this kind of stuff. I think it was mentioned not to change them, but I think several people were experimenting with them. Did you happen to change any of these tables?
The temp compensation should follow the pv=nrt formula, so if nothing was changed in that respect, your fueling should stay in check, as long as your temp sensor is reporting accurate values. Maybe your IAT sensor is recording lower IAT values than your actual intake temps (like the IM heatsoaking) and thus resulting in a rich AFR. If that's the case, then it should lean back to normal once you start moving.
Last edited by l2r99gst; Sep 30, 2009 at 01:30 PM.
Sep 30, 2009, 01:46 PM
#4
That definitely sounds very weird. I would have guessed that you would start running lean, if anything.
So, you have your temp input into the fuel temp sensor adc and you have your ROM flashed to use the fuel temp adc?
When you log your temp sensor, what values are you getting? You aren't getting any ridiculously low temps are you? Is the richness just during initial start and warmup or all the time?
Did you ever change any of your temp tables in any way? Any baro/IAT table or anything remotely close to that? Any table that deals with the pv=nrt forumla or anything like that? I remember from several different threads where tables were posted that dealt with this kind of stuff. I think it was mentioned not to change them, but I think several people were experimenting with them. Did you happen to change any of these tables?
The temp compensation should follow the pv=nrt formula, so if nothing was changed in that respect, your fueling should stay in check, as long as your temp sensor is reporting accurate values. Maybe your IAT sensor is recording lower IAT values than your actual intake temps (like the IM heatsoaking) and thus resulting in a rich AFR. If that's the case, then it should lean back to normal once you start moving.
So, you have your temp input into the fuel temp sensor adc and you have your ROM flashed to use the fuel temp adc?
When you log your temp sensor, what values are you getting? You aren't getting any ridiculously low temps are you? Is the richness just during initial start and warmup or all the time?
Did you ever change any of your temp tables in any way? Any baro/IAT table or anything remotely close to that? Any table that deals with the pv=nrt forumla or anything like that? I remember from several different threads where tables were posted that dealt with this kind of stuff. I think it was mentioned not to change them, but I think several people were experimenting with them. Did you happen to change any of these tables?
The temp compensation should follow the pv=nrt formula, so if nothing was changed in that respect, your fueling should stay in check, as long as your temp sensor is reporting accurate values. Maybe your IAT sensor is recording lower IAT values than your actual intake temps (like the IM heatsoaking) and thus resulting in a rich AFR. If that's the case, then it should lean back to normal once you start moving.
Yeah i would have guessed it going lean as well but it didn't. I haven't touched any of the baro or air temp tables. The values I read in evoscan look perfectly normal to me.
Fuel problem stays the same no matter if the car is moving or not, if anything it gets a little worse when its not idling. I do have a spare air temp sensor i can see if the sensor somehow got damaged and is reading erratically.
Sep 30, 2009, 02:03 PM
#6
It appears my MAT scaling for IAT scaling table is completely buggered..
God this is going to suck retuning it but i have hope it will work!
Left is mine right is stock banks scaling.. (scaling is set to hex 8) so i can see it
Trending Topics
Sep 30, 2009, 05:19 PM
#12
Many thanks.
Sep 30, 2009, 07:01 PM
#13
I'm paranoid now that mine's messed up and I haven't driven my SD car in wide temp swings yet. I'm not sure what you mean by the "MAT scaling for IAT scaling table"? I have an SD IAT ADC Scaling table under "SD Programming" and a "MAT Scaling" under "MAT Patch." They match in my ROM. What do I need to check? Mine aren't in hex BTW.
Many thanks.
Many thanks.
Results:
So I put in the new temp scaling and it really did help tremendously but i found a secondary problem while i was under the hood. I noticed my o2 sensor stopped working well it was just loose from being tugged around when i replaced the crank sensor yesterday so easy fix.
Car seems to idle pretty darn well now and I'll get more info if the driving improved on this next cold morning.
Once the car is running properly I plan on submitting the file again in the thread for speed desnity patches.
Sep 30, 2009, 07:07 PM
#14
It was under the speed density programming table it probably was the IAT scaling table. I'm using the 94170015 rom patched for speed density.
Results:
So I put in the new temp scaling and it really did help tremendously but i found a secondary problem while i was under the hood. I noticed my o2 sensor stopped working well it was just loose from being tugged around when i replaced the crank sensor yesterday so easy fix.
Car seems to idle pretty darn well now and I'll get more info if the driving improved on this next cold morning.
Once the car is running properly I plan on submitting the file again in the thread for speed desnity patches.
Results:
So I put in the new temp scaling and it really did help tremendously but i found a secondary problem while i was under the hood. I noticed my o2 sensor stopped working well it was just loose from being tugged around when i replaced the crank sensor yesterday so easy fix.
Car seems to idle pretty darn well now and I'll get more info if the driving improved on this next cold morning.
Once the car is running properly I plan on submitting the file again in the thread for speed desnity patches.
Oct 1, 2009, 08:38 PM
#15
Evolved Member
iTrader: (1)
Join Date: Sep 2005
Location: Harpers Ferry,WV
Posts: 751
Likes: 0
Received 0 Likes
on
0 Posts
Ive had my car SD now for 2 weeks and have seen a 35* change and my car hasnt gone threw any noticable change in AFR since Ive been doing this. Ill keep everybody posted but all seems good here and banks said he saw a 40*C change in temps with lil to no change in AFR.
I guess time will tell as we get more feedback from peeple. I will be checking this extensively.
I guess time will tell as we get more feedback from peeple. I will be checking this extensively.