Idle Dips In Reverse Only
12-25-2011 | 11:02 AM
#21
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Thanks for the info edcmat-lt1. I've never driven a car with a SD tune so I'm not going to get into the tuning wars; I'm just trying to get my car to idle a little better 
. I strongly suspected, as far as the old school methodology I've been using, that my injector data (the original data I mean) is correct as far as keeping my fuel trims slightly negative.
BTW, when you say "plot the idle airflow histogram, and copy it to the tune" do you mean the Base Running Idle Airflow table? Thanks again.
. I strongly suspected, as far as the old school methodology I've been using, that my injector data (the original data I mean) is correct as far as keeping my fuel trims slightly negative. BTW, when you say "plot the idle airflow histogram, and copy it to the tune" do you mean the Base Running Idle Airflow table? Thanks again.
12-25-2011 | 11:11 AM
#22
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Look, don't come in here after buying a book and a CD and exclaim to have the answers for everyone's problems. Injector data is not the holy grail of tuning. Remember, the data supplied by Banish is his calculations, not those of the injector manufacturer. And while I have great respect for Greg, his knowledge, and abilities, I take issue with you and the rest of the injector ***** thinking that it's the root cause of everyone's tuning issues.
The SVO 30s are a no brainer to tune. You can have a perfectly working tune even if you left the IFR stock. All that's going to happen is your MAF and VE table are going to be off. The 30s are small enough that the low speed (low pulse width) behavior of them is so close to stock the offset doesn't matter.
Much larger injectors are a different story. If we were talking about 60s, or 80s, that would be different. But to mislead the OP and anyone else reading this that for some all encompassing reason the tune cannot possibly work without the set-in-stone injector data handed down from the tuning Gods, well, that's just wrong.
As for scaling injectors being 90s technology. It's still done today. What do you do when you drop 80s in an E40 car? Yep, ya gotta scale em. They work pretty good too. Why do you have to scale them? Hard coded 63.5 lb. per hr.
What do you do in the computers that don't have the fancy offset tables, etc, that the GMs do? Yep, ya just plug in the numbers for the data you DO have, and ya make it work.
What do ya do in a boost ETC car, when you can't keep it from going into REP, even with a maxed P1514 table? Yep, ya scale the VE and IFR and then all is good and peaceful in the world again.
Merry Christmas to everyone.
Flame on............
The SVO 30s are a no brainer to tune. You can have a perfectly working tune even if you left the IFR stock. All that's going to happen is your MAF and VE table are going to be off. The 30s are small enough that the low speed (low pulse width) behavior of them is so close to stock the offset doesn't matter.
Much larger injectors are a different story. If we were talking about 60s, or 80s, that would be different. But to mislead the OP and anyone else reading this that for some all encompassing reason the tune cannot possibly work without the set-in-stone injector data handed down from the tuning Gods, well, that's just wrong.
As for scaling injectors being 90s technology. It's still done today. What do you do when you drop 80s in an E40 car? Yep, ya gotta scale em. They work pretty good too. Why do you have to scale them? Hard coded 63.5 lb. per hr.
What do you do in the computers that don't have the fancy offset tables, etc, that the GMs do? Yep, ya just plug in the numbers for the data you DO have, and ya make it work.
What do ya do in a boost ETC car, when you can't keep it from going into REP, even with a maxed P1514 table? Yep, ya scale the VE and IFR and then all is good and peaceful in the world again.
Merry Christmas to everyone.
Flame on............
12-25-2011 | 08:28 PM
#23
Thanks for the info edcmat-lt1. I've never driven a car with a SD tune so I'm not going to get into the tuning wars; I'm just trying to get my car to idle a little better . I strongly suspected, as far as the old school methodology I've been using, that my injector data (the original data I mean) is correct as far as keeping my fuel trims slightly negative.
BTW, when you say "plot the idle airflow histogram, and copy it to the tune" do you mean the Base Running Idle Airflow table? Thanks again.
. I strongly suspected, as far as the old school methodology I've been using, that my injector data (the original data I mean) is correct as far as keeping my fuel trims slightly negative. BTW, when you say "plot the idle airflow histogram, and copy it to the tune" do you mean the Base Running Idle Airflow table? Thanks again.
12-25-2011 | 09:12 PM
#24
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So after correcting me by stating the OP could just use stock values and use VE/MAP to tune his SVO 30lb. injectors your recommendation is he start with correct IFR table data? Which are you teaching people to use? I'm confused? My 90's tuning reference is directed to such pro tuner (baked tuning) advice by the way.
12-25-2011 | 09:20 PM
#25
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Predator: Use the below link for idle tuning adjustments AFTER you copy your corrected (not stock) IFR table from my previously attached image. You will need to type the values in for each rpm level matching your stock tunes measurement (i.e. lb/hr).
http://www.hptuners.com/forum/showthread.php?t=36318
http://www.hptuners.com/forum/showthread.php?t=36318
12-26-2011 | 05:19 AM
#26
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Thanks fellas, edcmat-l1, 2TR. I have a couple different options on the table here. Most enlightening though is to know that there's not just one absolute best way to approach this. Thanks again.
--Senator Predator lol.
Thanks again.--Senator Predator lol.
12-26-2011 | 06:57 AM
#27
So after correcting me by stating the OP could just use stock values and use VE/MAP to tune his SVO 30lb. injectors your recommendation is he start with correct IFR table data? Which are you teaching people to use? I'm confused? My 90's tuning reference is directed to such pro tuner (baked tuning) advice by the way.
The importance of "correct" injector data is even less of an issue the smaller the injector is. In the OPs case, 30 SVOs are not critical to properly "characterize" to have a well functioning tune. And again, it is not the root cause of his issues. Installing the "proper" injector data incuding IFR will not fix his issues. Proper IAC/TPS/throttle blade adjustment, combined with spark and VE/MAF tuning will.
No, I believe the point of my post was clear to anyone who read it.
12-26-2011 | 09:12 AM
#28
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I had the same problem and it had nothing to do with any of the above...I had a pin size hole vaccum leak in my pcv line ( right where it connects into my intake)..Everytime I'd go only in reverse rpms would drop and it wanted to stall...Any small vaccum leak on such a sensitive engine will cause these type of problems.. I've read post like this before and they almost all tied into vaccum leaks.
12-26-2011 | 10:50 AM
#29
My point was, injector data is not the root cause of his issues. Just as it is not the root cause of MOST tuning issues. Guys, including myself, have been tuning cars since way before "correct" injector data was even available, and were having good and great results. AND who's to say the injector data you and anyone else reading the material are using, is indeed correct? It is a calculation by a third party.
The importance of "correct" injector data is even less of an issue the smaller the injector is. In the OPs case, 30 SVOs are not critical to properly "characterize" to have a well functioning tune. And again, it is not the root cause of his issues. Installing the "proper" injector data incuding IFR will not fix his issues. Proper IAC/TPS/throttle blade adjustment, combined with spark and VE/MAF tuning will.
No, I believe the point of my post was clear to anyone who read it.
The importance of "correct" injector data is even less of an issue the smaller the injector is. In the OPs case, 30 SVOs are not critical to properly "characterize" to have a well functioning tune. And again, it is not the root cause of his issues. Installing the "proper" injector data incuding IFR will not fix his issues. Proper IAC/TPS/throttle blade adjustment, combined with spark and VE/MAF tuning will.
No, I believe the point of my post was clear to anyone who read it.
i agree.. 
12-26-2011 | 07:01 PM
#31
Also.. Just to add...
If you adjust the Throttle blade, and do a TPS reset(unplug/key on for 30 seconds/key off, plug back in...)
and it doesnt read 0 or 0.4...
then you have gone too far and the PCM cant reset it to 0.. which means either drilling the TB Blade with a second hole, or slotting/modifying the TPS sensor to get the voltage back in range to be considered closed throttle.
Something that can effect the Shift into Reverse, but not into Drive or any other forward gear...
Line Pressures/Shift Pressures
if it shifts into gear too hard, then its going to put extra load and its going to dip..
might need to soften up the pressures going into reverse(yes there are tables you can modify to change just reverse)
If you adjust the Throttle blade, and do a TPS reset(unplug/key on for 30 seconds/key off, plug back in...)
and it doesnt read 0 or 0.4...
then you have gone too far and the PCM cant reset it to 0.. which means either drilling the TB Blade with a second hole, or slotting/modifying the TPS sensor to get the voltage back in range to be considered closed throttle.
Something that can effect the Shift into Reverse, but not into Drive or any other forward gear...
Line Pressures/Shift Pressures
if it shifts into gear too hard, then its going to put extra load and its going to dip..
might need to soften up the pressures going into reverse(yes there are tables you can modify to change just reverse)
12-26-2011 | 07:10 PM
#32
Also.. Just to add...
If you adjust the Throttle blade, and do a TPS reset(unplug/key on for 30 seconds/key off, plug back in...)
and it doesnt read 0 or 0.4...
then you have gone too far and the PCM cant reset it to 0.. which means either drilling the TB Blade with a second hole, or slotting/modifying the TPS sensor to get the voltage back in range to be considered closed throttle.
Something that can effect the Shift into Reverse, but not into Drive or any other forward gear...
Line Pressures/Shift Pressures
if it shifts into gear too hard, then its going to put extra load and its going to dip..
might need to soften up the pressures going into reverse(yes there are tables you can modify to change just reverse)
If you adjust the Throttle blade, and do a TPS reset(unplug/key on for 30 seconds/key off, plug back in...)
and it doesnt read 0 or 0.4...
then you have gone too far and the PCM cant reset it to 0.. which means either drilling the TB Blade with a second hole, or slotting/modifying the TPS sensor to get the voltage back in range to be considered closed throttle.
Something that can effect the Shift into Reverse, but not into Drive or any other forward gear...
Line Pressures/Shift Pressures
if it shifts into gear too hard, then its going to put extra load and its going to dip..
might need to soften up the pressures going into reverse(yes there are tables you can modify to change just reverse)
Nevertheless, in reverse, there's max line pressure, causing a greater load on the engine, than in drive. I've only run into this causing a significant problem, a couple times, and it was in cars with fairly large cams. Nothing like the one the OP is working with. Hence the reason I didn't even mention it. I didn't find it relative to the application.
12-26-2011 | 07:14 PM
#33
Both very good points, and I was going to let this run it's course before going into the line pressure deal. I figure if he gets the IAC/TPS/throttle blade right, it will probably take care of itself.
Nevertheless, in reverse, there's max line pressure, causing a greater load on the engine, than in drive. I've only run into this causing a significant problem, a couple times, and it was in cars with fairly large cams. Nothing like the one the OP is working with. Hence the reason I didn't even mention it. I didn't find it relative to the application.
Nevertheless, in reverse, there's max line pressure, causing a greater load on the engine, than in drive. I've only run into this causing a significant problem, a couple times, and it was in cars with fairly large cams. Nothing like the one the OP is working with. Hence the reason I didn't even mention it. I didn't find it relative to the application.
I agree, it shouldnt be an issue...its usually only with guys with built transmissions that have really high line pressures..
12-26-2011 | 07:19 PM
#34
My point was, injector data is not the root cause of his issues. Just as it is not the root cause of MOST tuning issues. Guys, including myself, have been tuning cars since way before "correct" injector data was even available, and were having good and great results. AND who's to say the injector data you and anyone else reading the material are using, is indeed correct? It is a calculation by a third party.
The importance of "correct" injector data is even less of an issue the smaller the injector is. In the OPs case, 30 SVOs are not critical to properly "characterize" to have a well functioning tune. And again, it is not the root cause of his issues. Installing the "proper" injector data incuding IFR will not fix his issues. Proper IAC/TPS/throttle blade adjustment, combined with spark and VE/MAF tuning will.
No, I believe the point of my post was clear to anyone who read it.
The importance of "correct" injector data is even less of an issue the smaller the injector is. In the OPs case, 30 SVOs are not critical to properly "characterize" to have a well functioning tune. And again, it is not the root cause of his issues. Installing the "proper" injector data incuding IFR will not fix his issues. Proper IAC/TPS/throttle blade adjustment, combined with spark and VE/MAF tuning will.
No, I believe the point of my post was clear to anyone who read it.
Last edited by Ryne @ CMS; 12-26-2011 at 07:26 PM.
12-26-2011 | 07:22 PM
#35
I totally missed the M6 in his signature...
Dipping in reverse on an M6.. sounds like an airflow issue...
suddenly creating a vacuum in front of the car, keeping some air from getting to the engine..
Idle airflow, or possibly just VE/MAF tables need tweaking slightly
Dipping in reverse on an M6.. sounds like an airflow issue...
suddenly creating a vacuum in front of the car, keeping some air from getting to the engine..
Idle airflow, or possibly just VE/MAF tables need tweaking slightly
12-27-2011 | 02:41 AM
#37
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I totally missed the M6 in his signature...
Dipping in reverse on an M6.. sounds like an airflow issue...
suddenly creating a vacuum in front of the car, keeping some air from getting to the engine..
Idle airflow, or possibly just VE/MAF tables need tweaking slightly
Dipping in reverse on an M6.. sounds like an airflow issue...
suddenly creating a vacuum in front of the car, keeping some air from getting to the engine..
Idle airflow, or possibly just VE/MAF tables need tweaking slightly
As Justin said I'm going to order a new pcv hose to eliminate another variable; I already replaced my IAC sensor a couple weeks ago (the throw money at the problem technique) haha.
Thanks for all the help, you guys are the best!
Last edited by Predator; 12-27-2011 at 03:08 AM.
12-27-2011 | 05:30 AM
#38
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Only problem with mine at the time is that I couldn't find the little 3" hose that connects the pcv valve to the intake.....anywhere..... So I had to "goop" it with mending silicone. Or buy the whole 120$ pcv hose system..
12-27-2011 | 07:42 AM
#39
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I've had my car apart so many times (intake change, shorted knock sensors, heads swap, etc.) it's possible the hose got damaged. If not, I don't mind putting a new part on. One less variable to worry about at the very least. Thanks again.
