When tuning this table do you mult the whole table by say 95% to richen the car 5%? Or do you just do certain cells in there?

I never really looked at it untill today and was just curious. NOGO reccomended that if my LTRIMS didnt really respond to tuning the MAF table I should tune the IFR table instead?

I tuned the MAF from 1500-6000 buy 107%/scaled down, but it didnt even seem to do anything, maybe it needs learning miles though?

 

Are you averaging your Lterms.

After a PCM reset, it usually takes a little bit before the car kicks out of emmissions 'learning' and starts moving the LTerms around again.

As for the IFR table, you multiply the entire table.

 

Lets think about this a little.

You want to richen the engine. So you want to increase the PW of the fuel injector. Right.

In order to have the PCM equation to calculate a longer PW, you need to fake out (Adjust) the PCM into thinking that lower fuel rate injectors are installed. Therefore, you accomplish this by multipling the injector table by a value smaller than 100%, such as, 95%.

It is apparent from this post and ypour other one that you are not allowing the PCM to learn the changes that you made to the MAF table.

Also, I dont agree with NoGo (please dont be offended Nogo) that you average the LTFTs because there is a unique LTFT value for each fuel cell. I saw this in reference to re-calibrating the MAF table. If you change the IFR table, then do as Nogo says, average the LTFTs.


NoGo: How does the PCM determine the LTFT value used for WOT???? Is it an average or is it the last part throotle LTFT seen before the PCM goes into WOT??? Or other???

 

well everyone was right, the PCM did relearn my programming, it just took a few miles. I didnt need to tweak the IFR table. But thanks for the info on tuning the IFR table, atleast I know what to do if i need to tune that <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Doc99SShome:
<strong> Lets think about this a little.

Also, I dont agree with NoGo (please dont be offended Nogo) that you average the LTFTs because there is a unique LTFT value for each fuel cell. I saw this in reference to re-calibrating the MAF table. If you change the IFR table, then do as Nogo says, average the LTFTs.


NoGo: How does the PCM determine the LTFT value used for WOT???? Is it an average or is it the last part throotle LTFT seen before the PCM goes into WOT??? Or other??? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I was asking if he was averaging, because I was going to tell him not to. Averaging just isn't a very good way to make Lterm adjustments.

The amount of fuel that is going to get added to WOT comes from the last seen Lterm and Sterms. At this point the PCM will freeze the value and factor it into the WOT fueling. This occurs at the point that the PCM switches to PE mode.

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by NoGo:
<strong> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Doc99SShome:
<strong> Lets think about this a little.

Also, I dont agree with NoGo (please dont be offended Nogo) that you average the LTFTs because there is a unique LTFT value for each fuel cell. I saw this in reference to re-calibrating the MAF table. If you change the IFR table, then do as Nogo says, average the LTFTs.


NoGo: How does the PCM determine the LTFT value used for WOT???? Is it an average or is it the last part throotle LTFT seen before the PCM goes into WOT??? Or other??? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I was asking if he was averaging, because I was going to tell him not to. Averaging just isn't a very good way to make Lterm adjustments.

The amount of fuel that is going to get added to WOT comes from the last seen Lterm and Sterms. At this point the PCM will freeze the value and factor it into the WOT fueling. This occurs at the point that the PCM switches to PE mode. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">NoGo: I wasnt averaging them. I saw in one of your posts where you said just to look at the LTRIMS on light throttle and see where they go to. Still they jump up to +5, but cruising the LTRIMS are down to -4 to -2. But as soon as i hit the gas a tad, say 25% throttle if that they hit positive numbers.

 

Crappy. What kind of injectors are you using.

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by NoGo:
<strong> Crappy. What kind of injectors are you using. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">the stock 98 ones.. i believe they are 28's?

 

Bummer, I was hoping you had some SVO's. They cause that problem as well, but it can be fixed with the Injector Offset Curve.

As for your problem, there are a couple things I would try.

You have more room to take your LTerms more negative. I would look at -10% as the lowest you want to go with your Lterms. Try shifting them down a little bit more and see if that will drag down your "get on the gas" Lterms that you are seeing.

Another thing you can do is make your WOT transition happen sooner. Adjusting the MAP to Enable value in the fuel section as well as the WOT Hot and cold table will allow you to make power enrichment (and hence locking the LTerms) occur at less throttle.

If that doesn't work then there is always locking your LTerms. Some setups (I think it is the MAF personally) do this and it is a pain. Yours isn't that bad. If you really want to get rid of your LTerms you can get rid of them once and for all. Set the close loop enable temperature to a very high value and turn off all O2 codes. This will lock your Lterms at 0 and you are no longer using your oxygen sensors at all.
Most people look at this as a pandamonium, but remember that only cars that have to comply with strict emmissions regulations have oxygen sensors. All of these cars that are sold over in the middle east don't have oxygen sensors (or catalytic converters for that matter). Our cars run just fine without oxygen sensors (in fact they make more power actually).

The only downfalls of doing this.
1) No emmissions compliance AT ALL
2) Your gas mileage will suffer (it gets worse if you care)
3) You now have 2 more oxygen sensors that you have no idea what to do with but their too damn expensive to throw away.

<small>[ February 09, 2003, 03:28 PM: Message edited by: NoGo ]</small>

 

They dont have o2 sensors in the middle east because they run leaded gas. I believe if not for that, all the middle east cars would have O2's.

Eric

 

Whatever the reason is, the point is they don't have O2 sensors.

 

To answer one of the original questions, it is my experience that the IFR table does not follow the LTrims.

With the stock tuning, my motor ran +20% LTRims across the board (determined after much analysis of MAP and LTRim readings).

Since it was across the board, I figured I'd just reduce the entire IFR table by 20%. However, instead of obtaining LTrims close to zero, I was now getting LTrims close to -10%.

Okay, so I figured I overshot and that I only needed to reduce the IFR by 10%. Nope, that made my Ltrims average back up to +5%.

I finally tried -15% (the old bisection method <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> ) and now my LTrims are just slightly negative.

The point is, that a -15% reduction in the IFR effected a -20% change in the LTrims, so I don't think there is a linear relationship between the two.