Do u raise or lower the Fuel Injector Flow Rate
10-28-2002, 07:03 PM
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Re: Do u raise or lower the Fuel Injector Flow Rate You lower the table in order to take your +ltrims and make them negative. Good luck. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />
10-29-2002, 09:58 AM
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Re: Do u raise or lower the Fuel Injector Flow Rate My take on this issue is to NOT change the injector flow table but to alter the MAF table.
Our fuel injectors are very consistent and the flow table is very close to actual. What is off in our engines is the air flow rate thru the MAF if we made cam/head/headers/intake/MAF changes.
I was very successful in recalibrating the MAF table for my MMS head/cam/LS6 intake/FLP headers/GMAF mods.
If you are running positive LTFTs, you would increase the MAF table values in order to acheive slightly negative LTFTs. By increasing the MAF table values, you are telling the PCM that more air in entering the cylinders, in turn, the PCM will increase the pulse width and get you more fuel which will decrease the LTFTs values.
Our fuel injectors are very consistent and the flow table is very close to actual. What is off in our engines is the air flow rate thru the MAF if we made cam/head/headers/intake/MAF changes.
I was very successful in recalibrating the MAF table for my MMS head/cam/LS6 intake/FLP headers/GMAF mods.
If you are running positive LTFTs, you would increase the MAF table values in order to acheive slightly negative LTFTs. By increasing the MAF table values, you are telling the PCM that more air in entering the cylinders, in turn, the PCM will increase the pulse width and get you more fuel which will decrease the LTFTs values.
10-29-2002, 08:37 PM
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Re: Do u raise or lower the Fuel Injector Flow Rate </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Doc99SSx:
<strong>My take on this issue is to NOT change the injector flow table but to alter the MAF table.
Our fuel injectors are very consistent and the flow table is very close to actual. What is off in our engines is the air flow rate thru the MAF if we made cam/head/headers/intake/MAF changes.
I was very successful in recalibrating the MAF table for my MMS head/cam/LS6 intake/FLP headers/GMAF mods.
If you are running positive LTFTs, you would increase the MAF table values in order to acheive slightly negative LTFTs. By increasing the MAF table values, you are telling the PCM that more air in entering the cylinders, in turn, the PCM will increase the pulse width and get you more fuel which will decrease the LTFTs values.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I used to think this as well until I saw this post..
https://ls1tech.com/ubb/ultimatebb.p...;f=23;t=002908
Now I need to check my timing since I'm at the top end of the MAF scale as well..
<strong>My take on this issue is to NOT change the injector flow table but to alter the MAF table.
Our fuel injectors are very consistent and the flow table is very close to actual. What is off in our engines is the air flow rate thru the MAF if we made cam/head/headers/intake/MAF changes.
I was very successful in recalibrating the MAF table for my MMS head/cam/LS6 intake/FLP headers/GMAF mods.
If you are running positive LTFTs, you would increase the MAF table values in order to acheive slightly negative LTFTs. By increasing the MAF table values, you are telling the PCM that more air in entering the cylinders, in turn, the PCM will increase the pulse width and get you more fuel which will decrease the LTFTs values.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I used to think this as well until I saw this post..
https://ls1tech.com/ubb/ultimatebb.p...;f=23;t=002908
Now I need to check my timing since I'm at the top end of the MAF scale as well..
10-29-2002, 09:06 PM
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Re: Do u raise or lower the Fuel Injector Flow Rate </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Doc99SSx:
<strong>My take on this issue is to NOT change the injector flow table but to alter the MAF table.
If you are running positive LTFTs, you would increase the MAF table values in order to acheive slightly negative LTFTs. By increasing the MAF table values, you are telling the PCM that more air in entering the cylinders, in turn, the PCM will increase the pulse width and get you more fuel which will decrease the LTFTs values.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Then what that says is to control the injector pulse width, change the MAF tables,
then why not directly change the injector flow in the first place and not trick the PCM with MAF value changes when its the fuel that needs changing not the amount of airflow.
Mucking with the MAF will effect PCM calculations for AFR, produces incorrect delivered torque and line pressure values along with timing issues.
The MAF is a read only device that the PCM reads, the injector is a device the PCM can control, thus the injector flow is what should be adjusted unless a larger change to airflow was done via a larger MAF inatalled.
IMHO, in most cases these smog cars run lean, thus for performance needs more fuel, so injector flow should be the adjustment.
<small>[ October 29, 2002, 09:14 PM: Message edited by: Team ZR-1 ]</small>
<strong>My take on this issue is to NOT change the injector flow table but to alter the MAF table.
If you are running positive LTFTs, you would increase the MAF table values in order to acheive slightly negative LTFTs. By increasing the MAF table values, you are telling the PCM that more air in entering the cylinders, in turn, the PCM will increase the pulse width and get you more fuel which will decrease the LTFTs values.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Then what that says is to control the injector pulse width, change the MAF tables,
then why not directly change the injector flow in the first place and not trick the PCM with MAF value changes when its the fuel that needs changing not the amount of airflow.
Mucking with the MAF will effect PCM calculations for AFR, produces incorrect delivered torque and line pressure values along with timing issues.
The MAF is a read only device that the PCM reads, the injector is a device the PCM can control, thus the injector flow is what should be adjusted unless a larger change to airflow was done via a larger MAF inatalled.
IMHO, in most cases these smog cars run lean, thus for performance needs more fuel, so injector flow should be the adjustment.
<small>[ October 29, 2002, 09:14 PM: Message edited by: Team ZR-1 ]</small>
10-30-2002, 12:22 AM
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Re: Do u raise or lower the Fuel Injector Flow Rate </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Team ZR-1:
<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 Doc99SSx:
<strong>My take on this issue is to NOT change the injector flow table but to alter the MAF table.
If you are running positive LTFTs, you would increase the MAF table values in order to acheive slightly negative LTFTs. By increasing the MAF table values, you are telling the PCM that more air in entering the cylinders, in turn, the PCM will increase the pulse width and get you more fuel which will decrease the LTFTs values.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Then what that says is to control the injector pulse width, change the MAF tables,
then why not directly change the injector flow in the first place and not trick the PCM with MAF value changes when its the fuel that needs changing not the amount of airflow.
Mucking with the MAF will effect PCM calculations for AFR, produces incorrect delivered torque and line pressure values along with timing issues.
The MAF is a read only device that the PCM reads, the injector is a device the PCM can control, thus the injector flow is what should be adjusted unless a larger change to airflow was done via a larger MAF inatalled.
IMHO, in most cases these smog cars run lean, thus for performance needs more fuel, so injector flow should be the adjustment.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I tend to agree, because when I copied Ed Wright's file his MAF table was stock. So my next question is if the injector flow rate is where it should be. If you raise it...won't you burn out the injectors???
<img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
Jason
<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 Doc99SSx:
<strong>My take on this issue is to NOT change the injector flow table but to alter the MAF table.
If you are running positive LTFTs, you would increase the MAF table values in order to acheive slightly negative LTFTs. By increasing the MAF table values, you are telling the PCM that more air in entering the cylinders, in turn, the PCM will increase the pulse width and get you more fuel which will decrease the LTFTs values.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Then what that says is to control the injector pulse width, change the MAF tables,
then why not directly change the injector flow in the first place and not trick the PCM with MAF value changes when its the fuel that needs changing not the amount of airflow.
Mucking with the MAF will effect PCM calculations for AFR, produces incorrect delivered torque and line pressure values along with timing issues.
The MAF is a read only device that the PCM reads, the injector is a device the PCM can control, thus the injector flow is what should be adjusted unless a larger change to airflow was done via a larger MAF inatalled.
IMHO, in most cases these smog cars run lean, thus for performance needs more fuel, so injector flow should be the adjustment.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I tend to agree, because when I copied Ed Wright's file his MAF table was stock. So my next question is if the injector flow rate is where it should be. If you raise it...won't you burn out the injectors???
<img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
Jason
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10-30-2002, 10:48 AM
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Re: Do u raise or lower the Fuel Injector Flow Rate There is another point that should be taken into consideration.
People running ported MAF's, MAF ends, Aftermarket MAFs should make the bulk of their adjustments to the MAF transfer table.
Messing with the Injector Flow table on an in-accurate MAF is only going to compound problems.
People running a stock MAF, I don't see a problem adjusting the transfer table +/- 5%. Once you have messed with the intake track of the vehicle, the MAF is no longer 100% accurate anyways.
People running ported MAF's, MAF ends, Aftermarket MAFs should make the bulk of their adjustments to the MAF transfer table.
Messing with the Injector Flow table on an in-accurate MAF is only going to compound problems.
People running a stock MAF, I don't see a problem adjusting the transfer table +/- 5%. Once you have messed with the intake track of the vehicle, the MAF is no longer 100% accurate anyways.
10-30-2002, 01:23 PM
#9
Re: Do u raise or lower the Fuel Injector Flow Rate Adjusting a stock MAF 20%, no matter what the setup, I think is just asking for trouble.
The stock MAF does deviate a little bit when you modify the intake track, but by no more than ~5%
You are running a very in-sensitive MAF. You SHOULD have made your changes to the MAF transfer tables.
Advising people with a STOCK MAF to mess with their MAF tables any more than 5% I think is bad advice.
The stock MAF does deviate a little bit when you modify the intake track, but by no more than ~5%
You are running a very in-sensitive MAF. You SHOULD have made your changes to the MAF transfer tables.
Advising people with a STOCK MAF to mess with their MAF tables any more than 5% I think is bad advice.
10-30-2002, 02:07 PM
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Re: Do u raise or lower the Fuel Injector Flow Rate If your maf is stock...why would you change it? Mine is 100% stock. When I a-tap my car, my Ltrims are about +8.8. Is that bad? I was told to raise my maf table by +108% to even out the ltrims. Very confusing stuff? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
10-30-2002, 04:57 PM
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Re: Do u raise or lower the Fuel Injector Flow Rate Who said anything about a stock MAF???????
In my staements, I discussed modified MAFs throwing off the stock MAF calibration.
If you have a stock MAF, you should not be off 20% on the LTFTs. I had +20% LTFTs with both the GMAF and also with the stock MAF having nylon ends.
However, according to SuperchargedZ, his MAF is completely stock and his LTFTs were +8.8%. So the MAF calibration can be off for some people. It's not the injector table thats off 8.8%. A positive LTFT means that the PCM is adding additional fuel (due to a perceived lean condition while cruising around). Your fuel pressure would have to be about 68psi instead of stock 58psi for the injector table to be off 8.8%.
Thats simply not feasible.
But whatever, the proper way to tune the LTFTs is to modify the MAF table if no changes were made to the fuel system.
In my staements, I discussed modified MAFs throwing off the stock MAF calibration.
If you have a stock MAF, you should not be off 20% on the LTFTs. I had +20% LTFTs with both the GMAF and also with the stock MAF having nylon ends.
However, according to SuperchargedZ, his MAF is completely stock and his LTFTs were +8.8%. So the MAF calibration can be off for some people. It's not the injector table thats off 8.8%. A positive LTFT means that the PCM is adding additional fuel (due to a perceived lean condition while cruising around). Your fuel pressure would have to be about 68psi instead of stock 58psi for the injector table to be off 8.8%.
Thats simply not feasible.
But whatever, the proper way to tune the LTFTs is to modify the MAF table if no changes were made to the fuel system.
10-30-2002, 05:46 PM
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Re: Do u raise or lower the Fuel Injector Flow Rate </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>Who said anything about a stock MAF???????
In my staements, I discussed modified MAFs throwing off the stock MAF calibration.
If you have a stock MAF, you should not be off 20% on the LTFTs. I had +20% LTFTs with both the GMAF and also with the stock MAF having nylon ends.
However, according to SuperchargedZ, his MAF is completely stock and his LTFTs were +8.8%. So the MAF calibration can be off for some people. It's not the injector table thats off 8.8%. A positive LTFT means that the PCM is adding additional fuel (due to a perceived lean condition while cruising around). Your fuel pressure would have to be about 68psi instead of stock 58psi for the injector table to be off 8.8%.
Thats simply not feasible.
But whatever, the proper way to tune the LTFTs is to modify the MAF table if no changes were made to the fuel system.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">So, then why are my LTFT's so high? My cruising fuel pressure is 60psi and when get on the gas it starts to drop. That reading is with an autometer fuel pressure gauge. Don't know how acurate they are? I copied Ed Wright's tuning and he has the stock maf settings but with his tuning his LTFT's were about the same. Any ideas?
<strong>Who said anything about a stock MAF???????
In my staements, I discussed modified MAFs throwing off the stock MAF calibration.
If you have a stock MAF, you should not be off 20% on the LTFTs. I had +20% LTFTs with both the GMAF and also with the stock MAF having nylon ends.
However, according to SuperchargedZ, his MAF is completely stock and his LTFTs were +8.8%. So the MAF calibration can be off for some people. It's not the injector table thats off 8.8%. A positive LTFT means that the PCM is adding additional fuel (due to a perceived lean condition while cruising around). Your fuel pressure would have to be about 68psi instead of stock 58psi for the injector table to be off 8.8%.
Thats simply not feasible.
But whatever, the proper way to tune the LTFTs is to modify the MAF table if no changes were made to the fuel system.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">So, then why are my LTFT's so high? My cruising fuel pressure is 60psi and when get on the gas it starts to drop. That reading is with an autometer fuel pressure gauge. Don't know how acurate they are? I copied Ed Wright's tuning and he has the stock maf settings but with his tuning his LTFT's were about the same. Any ideas?
10-30-2002, 06:07 PM
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Re: Do u raise or lower the Fuel Injector Flow Rate SuperchargedZ,
I dont know why your LTFTs are +8.8%. If your fuel system is stock as well as your MAF, I would think that you should be closer to 0%, BUT no system is completely accurate and there is some factory variation. 8.8% does seem high is me.
What are all of your mods? Can you list them?
Maybe you have a clogged fuel injector. Run some fuel injector cleaner thru your engine. I do this every 3 months. Also, I think that the fuel pressure is supposed to go up at WOT from what it is at idle. But I may be wrong about this. Investigate your fuel pressure over the entire RPM range.
After one or two tanks of injector cleaner, get some more ATAP files and see where you are for LTFTs. If it stays up near 8 to 9%, I would tune it out with the MAFT or with LS1Edit.
I dont know why your LTFTs are +8.8%. If your fuel system is stock as well as your MAF, I would think that you should be closer to 0%, BUT no system is completely accurate and there is some factory variation. 8.8% does seem high is me.
What are all of your mods? Can you list them?
Maybe you have a clogged fuel injector. Run some fuel injector cleaner thru your engine. I do this every 3 months. Also, I think that the fuel pressure is supposed to go up at WOT from what it is at idle. But I may be wrong about this. Investigate your fuel pressure over the entire RPM range.
After one or two tanks of injector cleaner, get some more ATAP files and see where you are for LTFTs. If it stays up near 8 to 9%, I would tune it out with the MAFT or with LS1Edit.
10-30-2002, 08:12 PM
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Re: Do u raise or lower the Fuel Injector Flow Rate </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>SuperchargedZ,
I dont know why your LTFTs are +8.8%. If your fuel system is stock as well as your MAF, I would think that you should be closer to 0%, BUT no system is completely accurate and there is some factory variation. 8.8% does seem high is me.
What are all of your mods? Can you list them?
Maybe you have a clogged fuel injector. Run some fuel injector cleaner thru your engine. I do this every 3 months. Also, I think that the fuel pressure is supposed to go up at WOT from what it is at idle. But I may be wrong about this. Investigate your fuel pressure over the entire RPM range.
After one or two tanks of injector cleaner, get some more ATAP files and see where you are for LTFTs. If it stays up near 8 to 9%, I would tune it out with the MAFT or with LS1Edit.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">My fuel system is not really stock, 38lb lucas injectors, Vortech's in line fuel pump, but the intank fuel pump is stock. What kind of injector cleaner would you recommend?
My mods: Vortech 10lbs w/Aftercooler, Upgraded aftercooler, JBA
Headers, FRA, TB Bypass,
Ed Wright Tuning, Holley Intake,
BBK 80MM TB,SMC Alcohol Injection,
Ls1 edit, Vortech Ice Box,
<small>[ October 30, 2002, 08:14 PM: Message edited by: superchargedZ ]</small>
<strong>SuperchargedZ,
I dont know why your LTFTs are +8.8%. If your fuel system is stock as well as your MAF, I would think that you should be closer to 0%, BUT no system is completely accurate and there is some factory variation. 8.8% does seem high is me.
What are all of your mods? Can you list them?
Maybe you have a clogged fuel injector. Run some fuel injector cleaner thru your engine. I do this every 3 months. Also, I think that the fuel pressure is supposed to go up at WOT from what it is at idle. But I may be wrong about this. Investigate your fuel pressure over the entire RPM range.
After one or two tanks of injector cleaner, get some more ATAP files and see where you are for LTFTs. If it stays up near 8 to 9%, I would tune it out with the MAFT or with LS1Edit.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">My fuel system is not really stock, 38lb lucas injectors, Vortech's in line fuel pump, but the intank fuel pump is stock. What kind of injector cleaner would you recommend?
My mods: Vortech 10lbs w/Aftercooler, Upgraded aftercooler, JBA
Headers, FRA, TB Bypass,
Ed Wright Tuning, Holley Intake,
BBK 80MM TB,SMC Alcohol Injection,
Ls1 edit, Vortech Ice Box,
<small>[ October 30, 2002, 08:14 PM: Message edited by: superchargedZ ]</small>
10-30-2002, 08:20 PM
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Re: Do u raise or lower the Fuel Injector Flow Rate </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by superchargedZ:
<strong>I tend to agree, because when I copied Ed Wright's file his MAF table was stock. So my next question is if the injector flow rate is where it should be. If you raise it...won't you burn out the injectors???
<img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
Jason</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">No the injectors are working in mSecs and if you really think about it, allowing the LTFTs to be lets say 15% too lean, that means the PCM is also increasing the ON time of injectors and in fact could be driving injectors to 100% duty cycle.
I noticed in some of the responses, what is forgotten is they are talking about LTFTs, which is Long Term FUEL Trims,
so again if you want to adjust the fuel, then why would someone muck up the MAF table when that does not change the amount of air going to the pistons at all, just fooling the PCM, where injector flow is for just that, adjusting the flow just as we do with a carb by changing the size of the jets.
No matter what the values are changed to in the MAF table, the MAF is still producing and sending the same frequency values but MAF table values not in sync with the freq values.
Yes if MAF was replaced with a larger one then changes are needed in the table, but in most cases the engine is running too lean and it is not a larger MAF needed or its tables mucked with but larger injectors are needed and a short term fix is to asjust the injector flow to force PCM to drive LTFT closer to zero by using a control function, not a read only of what MAF outputs.
<strong>I tend to agree, because when I copied Ed Wright's file his MAF table was stock. So my next question is if the injector flow rate is where it should be. If you raise it...won't you burn out the injectors???
<img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
Jason</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">No the injectors are working in mSecs and if you really think about it, allowing the LTFTs to be lets say 15% too lean, that means the PCM is also increasing the ON time of injectors and in fact could be driving injectors to 100% duty cycle.
I noticed in some of the responses, what is forgotten is they are talking about LTFTs, which is Long Term FUEL Trims,
so again if you want to adjust the fuel, then why would someone muck up the MAF table when that does not change the amount of air going to the pistons at all, just fooling the PCM, where injector flow is for just that, adjusting the flow just as we do with a carb by changing the size of the jets.
No matter what the values are changed to in the MAF table, the MAF is still producing and sending the same frequency values but MAF table values not in sync with the freq values.
Yes if MAF was replaced with a larger one then changes are needed in the table, but in most cases the engine is running too lean and it is not a larger MAF needed or its tables mucked with but larger injectors are needed and a short term fix is to asjust the injector flow to force PCM to drive LTFT closer to zero by using a control function, not a read only of what MAF outputs.
10-30-2002, 09:08 PM
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Re: Do u raise or lower the Fuel Injector Flow Rate I am only a bolt ons car but it sounds to me that the fact that I adjusted my injector flow rate table is now bad. I have a ported maf. I don't get it. It seems like I can't win. I do know however that after zereoing my maf table back to stock values and adjusting through the injector table (lowering the table) increased my timing and my car seems to run better now. I don't believe that I need increased size injectors with only boltons. Look at all the heads and cam cars with stock injectors. I deffinately can be wrong but all of these oposing opinions do nothing bet confuse me. <img border="0" alt="[Fluffy]" title="" src="graemlins/fluffy.gif" />
10-30-2002, 09:17 PM
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Re: Do u raise or lower the Fuel Injector Flow Rate TeamZ, you do not understand that the MAF is a measuring device. Measuring devices are never perfect. They can only estimate something. In this case, the MAF measures (senses) incoming air as frequency, putting out a specific frequency in cycles/sec as air runs thru it. The PCM reads the frequency and goes to the look up table (which is our MAF table) to "know" what amount of air is coming into the engine at that moment in time. The PCM now having a value for the amount of air coming in (right amount or not) makes a calculation for injector pulse width base on several parameters, including the fuel injector table. If the reported value of air from the MAF table is lower than actual, the LTFTs values will be positive.
The fuel injector table is not wrong for the factory fuel system. In fact, it is very accurate for our stock fuel systems. The fuel injector is NOT a measuring device as the MAF sensor is. However, there is an amount of variation in manufacturing of fuel injectors. If you had your specific fuel injectors flowed tested and balanced, then I think that you should alter the fuel injector table to reflect your tested injectors.
The MAF will under report the amount of air or over report the amount of air due to a mis-calibrated MAF table for that specific MAF sensor. There may have been mods made which require a new MAF calibration.
And be the way, nobody said to "muck around with the MAF table". If the MAF sensor was altered or we have a situation of forced air, the MAF table must be logically re-calibrated.
SuperchargedZ: I used Snap fuel injector cleaner before and it got rid of a miss in my Eagle Talon, but I guess that any name brand should be OK.
As for as your car is concerned, you have a Vortech. I would not expect the stock MAF to report the correct amount of air going into your engine. Also, you have a unique fuel system, 60psi fuel pressure and 38#/hr injectors. When those injectors were installed, it is obvious that the fuel injector table should have been modified. After that table was updated, then it is time to go out and see what the LTFTs are. And re-calibrate the MAF table to bring the LTFTs down to between -5% and 0%. Then its time to do the WOT fuel table, then time for the timing table if that has not already done.
Lots to do and lots of fun if you go about it in a logical manner.
The fuel injector table is not wrong for the factory fuel system. In fact, it is very accurate for our stock fuel systems. The fuel injector is NOT a measuring device as the MAF sensor is. However, there is an amount of variation in manufacturing of fuel injectors. If you had your specific fuel injectors flowed tested and balanced, then I think that you should alter the fuel injector table to reflect your tested injectors.
The MAF will under report the amount of air or over report the amount of air due to a mis-calibrated MAF table for that specific MAF sensor. There may have been mods made which require a new MAF calibration.
And be the way, nobody said to "muck around with the MAF table". If the MAF sensor was altered or we have a situation of forced air, the MAF table must be logically re-calibrated.
SuperchargedZ: I used Snap fuel injector cleaner before and it got rid of a miss in my Eagle Talon, but I guess that any name brand should be OK.
As for as your car is concerned, you have a Vortech. I would not expect the stock MAF to report the correct amount of air going into your engine. Also, you have a unique fuel system, 60psi fuel pressure and 38#/hr injectors. When those injectors were installed, it is obvious that the fuel injector table should have been modified. After that table was updated, then it is time to go out and see what the LTFTs are. And re-calibrate the MAF table to bring the LTFTs down to between -5% and 0%. Then its time to do the WOT fuel table, then time for the timing table if that has not already done.
Lots to do and lots of fun if you go about it in a logical manner.
10-30-2002, 09:41 PM
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Re: Do u raise or lower the Fuel Injector Flow Rate DailyAluminumBlock:
Your case is very interesting. Is it possible that the PCM was using the low octane table while you did your ATAPing and then after making your changes, the PCM went back to the high octane table, and thus getting more timing for you?
You see, this could explain what happened. I can not figure out why by putting the MAF table back to stock then altering the injector table got you back to typical timing.
I really dont know what happened in your case. More info and testing would be nice, in order to get a better understanding of this.
I'm running 27.5* or 28* of timing at WOT with a heads/218cam car with 400Hp and no KR. I have only modified the MAF table to bring the LTFTs under control (-4% to -2%) and the WOT fuel percentage. Of special note on this, my O2s run about 960mV at WOT when the AFR is reportedly 13.2:1.
Your case is very interesting. Is it possible that the PCM was using the low octane table while you did your ATAPing and then after making your changes, the PCM went back to the high octane table, and thus getting more timing for you?
You see, this could explain what happened. I can not figure out why by putting the MAF table back to stock then altering the injector table got you back to typical timing.
I really dont know what happened in your case. More info and testing would be nice, in order to get a better understanding of this.
I'm running 27.5* or 28* of timing at WOT with a heads/218cam car with 400Hp and no KR. I have only modified the MAF table to bring the LTFTs under control (-4% to -2%) and the WOT fuel percentage. Of special note on this, my O2s run about 960mV at WOT when the AFR is reportedly 13.2:1.
10-30-2002, 09:55 PM
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Re: Do u raise or lower the Fuel Injector Flow Rate Ok, now I am confused? I thought messing with the MAF table was bad? My injector flow rate table is(should)be adjusted for my injectors. So, now reading...I should mess my MAF table?
Also timing is done...I am running 25* at WOT. I just need to get my a/f under control. Whenever I went to the dyno and messed with my MAF table. My a/f would be very messed up.ie:up and down alot.
Jason
Also timing is done...I am running 25* at WOT. I just need to get my a/f under control. Whenever I went to the dyno and messed with my MAF table. My a/f would be very messed up.ie:up and down alot.
Jason
10-30-2002, 10:00 PM
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Re: Do u raise or lower the Fuel Injector Flow Rate Both my low and high octane table have the same values in them inputted by me. When I initially did the first read on my pcm with ls1 edit my timing values in 4000+rpms and over .56g/cyl (I don't know the exact measurement used right off the top of my head but you understand what I am saying) was 19. I don't understand this either. Is the computer always changing the timing table? I get timing values over 19. My maf is stock and just has the stock aluminum ends ported and without any kind of tuning runs my ltrims around +15.