100mm Maf kickin my Butt!!!

[silverzz28]

Let me explain it like this, the way you are doing it is not exactly wrong, but it is also not right. You could take temps at different points and do a sanity test, example my IAT temp says 90 degrees but its 70 ambient. So this would be a 20 degree difference that you could change in the box. But when you start the car you do not know how much temp is changing from the heat effect of the intake. So you would have to do sanity tests at all those different temps from -40 through 284 in order to make your curve correct. So you say you don't need them, well I live in VA and I have a temp spread between 25 degrees and 100+ degree during the year. It makes a huge difference, the IAT temp is used in calculating fuel so it really needs to be spot on. The easier way would be for you to find a file for a LS3 or LS7 and copy the IAT transfer function and past it into your E40 and your done. The LS1B ecu is not as easy but just as important for it to be done correctly.

Why did subracting -12 work for me?

[GXPLS4]

Let me explain it like this, the way you are doing it is not exactly wrong, but it is also not right. You could take temps at different points and do a sanity test, example my IAT temp says 90 degrees but its 70 ambient. So this would be a 20 degree difference that you could change in the box. But when you start the car you do not know how much temp is changing from the heat effect of the intake. So you would have to do sanity tests at all those different temps from -40 through 284 in order to make your curve correct. So you say you don't need them, well I live in VA and I have a temp spread between 25 degrees and 100+ degree during the year. It makes a huge difference, the IAT temp is used in calculating fuel so it really needs to be spot on. The easier way would be for you to find a file for a LS3 or LS7 and copy the IAT transfer function and past it into your E40 and your done. The LS1B ecu is not as easy but just as important for it to be done correctly.

we are apples and oranges which is why i stated i was on the godforsaken LS4/E40 PCM. And Temp change is importan here in AZ to, i assure daily i see almost 30 degree changes. for me copying the IAT tables still left my IAT readings out of whack. did some searching and saw to do this subtract by 15 but that was off the mark.12 is perfect and stays reading accuratley throughout the day/driving cycle.

[Jabbott]

Wow, not trying to make you supset, just pointing out the science in it. First off the two meters are not linear ok. That means that do not follow a straight line, so example lets say at 50 degrees you are off by only 5 degrees, at 60 degrees you are off by 7 at 70 degrees you are off by 20. If you remove 12 you may get closer or on the others side of where it is supposed to be. Second the two meters do not have the same curve so it makes the spread even worse in areas, better in some. But here is the biggest one, how do you know you are not off. The only real way you can check it is to have another temp probe in there that you know is correct and comparing temps through the normal operating range. You have to trust the math to go into the other area of the table because personnly I am not interested in going anywhere below 0 degrees to test anything. The reason the -12 works for you is because that how far it was off or close to it where the car is running. This is not a guessing game, it is just science and if the two sensors do not follow a straight line but have a curve and the two do not match each other one number does not fix it. Nothing to argue over, the OP asked a question and I answered him the proper way to do it. Are you more interested in the way to do it properly or to just get by. Kind of like the IFR table that some people talk about just subtracted by the same number in your original table over to the new table. There is math for that also to do it correctly.

we are apples and oranges which is why i stated i was on the godforsaken LS4/E40 PCM

Again this does not matter that you are in a E40. We have a LS4 E40 being changed over to a E67 right now in a Fiero. The sensor is what matters, the data that is in the ECU is just representing the meter being used. The apples to oranges would be the way the E40 reads vs. the LS1B, which the OP has a LS1B. The correct way is still the correct way no matter what ECU is being used.

[Jabbott]

Why did subracting -12 work for me?

How do you know it is working? You can check the IAT on startup vs. ambient temp and depending on where that was could have been a 12 degree difference. How do you know it is following it after that?

[Jabbott]

GXP, I remember when I found this issue, I was working on a C5 that was supercharged and everyone was telling me to do it exactly like you are saying you did. We tested it and it did not work, it was accurate in one spot and still over 10 degrees off and more in others. That is why we took some steps backwards and figured out the correct way to do it. It is much easier on a the E40 plateform than the LS1B, I had to write a excel spreadsheet to figure it on the LS1B but it was the correct way to do it and not a guess. Sometimes you have to travel the path that is the least taken.

[silverzz28]

How do you know it is working? You can check the IAT on startup vs. ambient temp and depending on where that was could have been a 12 degree difference. How do you know it is following it after that?

Outside temp vs my IAT sensor. Also my coolant temp was pretty the same. Car has been sitting for 2 weeks. So I have three readings the same. The IAT temp stayed pretty much the same driving around. Not sure what part you didnt understand on my previous post

[Jabbott]

Not sure what part you didn't understand on my previous post

You did not state that earlier, you also can't do a sanity check once the engine is running. You really think your method is how they come up with the string. You ask me what part do I not understand, that is a pretty nasty comment. What is it that you don't understand that the curve is not the same so one number does not fix it. Keep on making mistakes, these forums are here to help poeple which is exactly what I tried to do, give you the correct method of fixing the IAT. So do you want to know the correct way of doing it or do you want the method that will only work sometimes.

[Jabbott]

Mine is about 20 degrees off. How do I change it?

Why did subracting -12 work for me?

This worked for me it appears. Was the same before start up and car stayed at temp cruising down the road.(Ram air) intake

How am I supposed to understand this? Your temp is off by 20 degrees and you subtract 12 from it and now it is correct??? Does 2+2=8. The reason you can drive down the road and the temp stays the same is because it is the same. Your ambient air intake temp is not changing so it is in the same cell as it was before you started driving. You can't check it like that, that is like saying your maf curve is right because you don't smell gas fumes out the exhaust.
Go back to my previous posts, I explained how you get the correct curve, that is the only way to get the correct curve, everything else is a bandaid.

Also my coolant temp was pretty the same

So your saying your coolant temp stayed ambient temp also. If so you have some other problems you need to work on.

[Pulse_GTO]

I had to write a excel spreadsheet to figure it on the LS1B but it was the correct way to do it and not a guess. Sometimes you have to travel the path that is the least taken.

Would you mind sharing this information, or a way to get to it?

[Jabbott]

You have to convert the ohms to voltage and then to a/d counts.

[silverzz28]

How am I supposed to understand this? Your temp is off by 20 degrees and you subtract 12 from it and now it is correct??? Does 2+2=8. The reason you can drive down the road and the temp stays the same is because it is the same. Your ambient air intake temp is not changing so it is in the same cell as it was before you started driving. You can't check it like that, that is like saying your maf curve is right because you don't smell gas fumes out the exhaust.
Go back to my previous posts, I explained how you get the correct curve, that is the only way to get the correct curve, everything else is a bandaid.

So your saying your coolant temp stayed ambient temp also. If so you have some other problems you need to work on.

I moved the sensor that reads the outside temp for the cockpit to the intake boot for you. Drove the car and they both are within 1 DEGREE throughout. Temp got to 100 degrees today idling. It started off at 51 degrees. Hows that for you? Understand that one?

My coolant temp was the same at cold start up dufus! keep up

[Jabbott]

I moved the sensor that reads the outside temp for the cockpit to the intake boot for you. Drove the car and they both are within 1 DEGREE throughout. Temp got to 100 degrees today idling. It started off at 51 degrees. Hows that for you? Understand that one?

My coolant temp was the same at cold start up dufus! keep up

So your saying in your case 2+2=8. You can't change the science or the manipulate a math problem because you think it works. No matter what language you speak 2+2=4 and 5+5=10 always. Two different curves never follow each other period. You asked how to correct, I gave you the answer, not how to bandaid something. There is no way that in a 50 degree sweep they stayed within 1 degree, that's BS. If you did it they way you said you did you should already be starting off with a 8 degree difference since you said you were 20 degrees off at a certain cell you and subtracted 12. Maybe some remedial math is in your future if you want to keep tooning.

[Jabbott]

My coolant temp was the same at cold start up dufus! keep up

Ok you got me on that one..... Maybe you should have said that instead my coolant temp stayed the same. So you are name calling now? Who is the one asking how to correct a 20 degree problem on the IAT sensor, and I'm the dufus!

[silverzz28]

Ok you got me on that one..... Maybe you should have said that instead my coolant temp stayed the same. So you are name calling now? Who is the one asking how to correct a 20 degree problem on the IAT sensor, and I'm the dufus!

Ummm I replied and quoted what you said so I did say that the 1st time dufus See below bud. Is bud okay? I got the answer from the other guy and it worked. I call BS on you knwoing it all Maybe my car is special





http://www.hptuners.com/forum/showpo...&postcount=126

[carlrx7]

make a new thread to whatever you guys are talking about, im tired of getting emails

[DrLoch]

make a new thread to whatever you guys are talking about, im tired of getting emails

Roger that

[Jabbott]

Ummm I replied and quoted what you said so I did say that the 1st time dufus See below bud. Is bud okay? I got the answer from the other guy and it worked. I call BS on you knwoing it all Maybe my car is special





http://www.hptuners.com/forum/showpo...&postcount=126

Ok, you are obviously a kid. Let me put this in perspective. The IAT temp is a curve. The two do not match. Which means at one point they are 40 degrees off, at another they could be 20 at some points they are close within a couple of degrees. If you choose one number to subtract it may get you closer in some areas, it may make it further off in others. You understand that right. I would hope that since you bought HP tuners and are tooning you have some understanding of what I am talking about. Getting the right IAT transfer function is not difficult there is a way to do it which I gave you the answer, but using ONE number is not the proper way. You are resorting to name calling when I tried to help you, that is pretty petty and immature. Remember you are the one asking how to do this, not I. Did not say I know everything, but I do know a bit. There are plenty who know more than I and they would be telling you the same thing. I learned this from a OEM calibrator so the information is solid. Anyone on here that understands how the system will work tell you the same thing. You have to take allot of "advice" on this forum and really any forum with a grain of salt. I have given you the correct way to do it, whether you choose to do that or not is up to you, but don't make fun of me because I know the correct way to do it, I can tell you that I will be very tight lipped in giving out information in the future.

[98S10]

Ok, you are obviously a kid. LOL? And your kinda of foolish. I am not really sure what you dont get either. Also it aint your thread, be a bigshot somewhere else. I think he gets how the sensor works. No need to reply with a "WoW did not mean to supset you" or whatever your poor grammar meant. Help the people out if you want, if not get lost. For as much as you pro tooners with fancy paint on the walls and a polished up dyno jet have completely screwed many people over the years(not me) help out, without the smug comments or get out. Remember anyone with half a brain can do what you do everyday. It is a factory GM ecm, It is from GM, got it? It is a screwed up piece of crap, really it is. GM and the other two US car makers have been screwing over the american public for forty years with the complete crap they build lol. It does not take 1500 plus tables to get a simple engine to run. You do realize their are more than 650 tables in a LS1 ecm, dont you? A pro GM tuner that advertises as such is a freakin fraud. So spare us all the ohms and voltage bs. Sorry for goin off topic on carls thread, but I certainly did not derail it like aboutwhat did. Like carl asked politely start your own thread about the basics of iat tuning abott.

[GXPLS4]

apologies to carl RX-7 for getting off on this thread i started a new one so the topic can be discussed in a more positive manner http://www.hptuners.com/forum/showthread.php?t=42343

[98S10]

For even a more bolder statement, There are no oem calibrators (that have publically been known anyway) ever on this forum that I am aware of that have first hand development on the ls1b gen3 or the E38 gen4 ecm. Sure their are a few that have oem type experience and may know how they are meant to function. But not first hand experience. So making the claim that I /we have been taught by an oem guy is goofy. Even the people that sell dvds or books does not know completely how a gen3 or 4 ecm works entirely. If he/ they did, this forum surely would not exist.