new HPT questions - Tuning Forum

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new HPT questions
Monday, May 17, 2010 4:47 AM
couple new questions... first of all, everytime we flash the ecm, the car needs to relearn how to idle... i'm pretty sure this is normal, as it does get better as i go, but just double checking here...

second of all, we changed the fuel and spark cutouts to set the rev limit at 7200 RPM. however when the car reaches around 6500 rpm, the rpm stops climing momentarly, and then slowly raises up to 7200 RPM... is there something we missed here?

third of all, is there anyway to force it in to open loop without making the car rich out? changing the value for the coolant temp sender to force it in to open loop for tuning caused my car to stay below 10:1 AFR.

i may have a couple more but this is all i can think of right now...




Re: new HPT questions
Monday, May 17, 2010 5:30 AM
1. I have found that when I reflash my car I then turn the key off for about a minute before starting. I have still found that it can take a few minutes before the flash really takes. Not sure why.

2. Not sure.

3.Regardless of how you force the car into open loop it is going to run off the tables in the tune. So sounds like you still have tuning to do.



FU Tuning



Re: new HPT questions
Monday, May 17, 2010 5:53 AM
well on number one, it takes about 25 - 75 miles to really get it to idle right again... initially it dies without any rev... then it will slowly idle but most times it bounces down to 500 rpm then bounces up to 1500 and dies on the bounce back down... it also dies between gears... but over 25 - 75 miles it slowly stops doing it and settles and idles around 1200 rpm before it hits 5mph and around 1000 below 5 mph



Re: new HPT questions
Monday, May 17, 2010 7:01 AM
probably due to the fact that you cant adjust spark advance in hpt beyond 6400rpm and you can only adjust fuel to 7000, besides do you have the valvetrain and cam upgrades to even make power that high? if not your just wasting your time and lifespan of your engine



1989 Turbo Trans Am #82, 2007 Cobalt SS G85





Re: new HPT questions
Monday, May 17, 2010 7:07 AM
Speedline02 (GME Chat!!) wrote:well on number one, it takes about 25 - 75 miles to really get it to idle right again... initially it dies without any rev... then it will slowly idle but most times it bounces down to 500 rpm then bounces up to 1500 and dies on the bounce back down... it also dies between gears... but over 25 - 75 miles it slowly stops doing it and settles and idles around 1200 rpm before it hits 5mph and around 1000 below 5 mph
Something sounds off... Either you missed a table, or you modified something in the wrong direction...





P&P Tuning
420.5whp / 359.8wtq

Re: new HPT questions
Monday, May 17, 2010 7:10 AM
Also the car should not have to "learn" idle settings, you record the VE error percentage off what your aiming for (14.7) make the adjustment off that error and then when you start the car the next time open or closed loop it should idle fine, providing of course you were doing your log in open loop in the first place to get the data as you should have been

Theres a FAQ in here on how to get the car into open loop and all the settings to change it, also disable DCFO

Also did you make sure your injector constant is right?



1989 Turbo Trans Am #82, 2007 Cobalt SS G85





Re: new HPT questions
Monday, May 17, 2010 9:26 AM
Rodimus Prime wrote:probably due to the fact that you cant adjust spark advance in hpt beyond 6400rpm and you can only adjust fuel to 7000, besides do you have the valvetrain and cam upgrades to even make power that high? if not your just wasting your time and lifespan of your engine

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so if hpt won't allow (or the PCM won't allow) spark won't go above 6400, and fuel won't go above 7000, what would need to be done to set rev limit to 7200?

Rodimus Prime wrote:Also the car should not have to "learn" idle settings, you record the VE error percentage off what your aiming for (14.7) make the adjustment off that error and then when you start the car the next time open or closed loop it should idle fine, providing of course you were doing your log in open loop in the first place to get the data as you should have been

Theres a FAQ in here on how to get the car into open loop and all the settings to change it, also disable DCFO

Also did you make sure your injector constant is right?

Injector constant is right... I'm running LSJ injectors & my tuner figured out what to set it to. We then confirmed that number with other people here running the same injectors...

DCFO was disabled during tune... the problem we have with open loop, is that the PCM is commanding the car run rich... and my tuner can't find any table that has settings to command it rich...




Edited 2 time(s). Last edited Monday, May 17, 2010 9:37 AM


Re: new HPT questions
Monday, May 17, 2010 11:14 AM
I believe writing a calibration resets the fuel trims, so that may partially explain your issues after reflashing IF you are going back to closed loop.

Mine always commands 14.0:1 out of PE in open loop, and commands whatever is in the PE table during PE. Are your PE delay settings really low? Is it rich when cruising/idling and at WOT? I agree it sounds like you need to tune the VE tables. Any fuel pressure changes by chance? It does sound like something global - like pressure or a constant.

You can set the rev limit to 7200 and it should rev there. What rod is saying is that we cannot make further adjustment to the spart advance above 6400 and we can't make fueling adjustments above 7000. I haven't determined if its static or interpolated after those points.



Re: new HPT questions
Monday, May 17, 2010 11:47 AM
its static for both, I confirmed that years ago on my cav



1989 Turbo Trans Am #82, 2007 Cobalt SS G85





Re: new HPT questions
Monday, May 17, 2010 4:41 PM
i tried it again on my way home, i hit 6500 ish, it bounces 2 to 3 times like it hits the limiter, then slowly continues to climb and once it hit 7000 i let off.

now as soon as we forced it in to open loop, the wideband read 10.0, and remained 10.0 from startup, over the 5 mile road test, and continued until i shut it off. the car ran pretty rough too acting like it was running rich...



Re: new HPT questions
Monday, May 17, 2010 5:08 PM
What do you guys have the command AFR set at?



FU Tuning




Re: new HPT questions
Monday, May 17, 2010 6:04 PM
Speedline02 (GME Chat!!) wrote:i tried it again on my way home, i hit 6500 ish, it bounces 2 to 3 times like it hits the limiter, then slowly continues to climb and once it hit 7000 i let off.

now as soon as we forced it in to open loop, the wideband read 10.0, and remained 10.0 from startup, over the 5 mile road test, and continued until i shut it off. the car ran pretty rough too acting like it was running rich...
Send me a log and the current file... pnptuning@gmail.com







P&P Tuning
420.5whp / 359.8wtq

Re: new HPT questions
Tuesday, May 18, 2010 6:06 PM
Speedline02 (GME Chat!!) wrote:i tried it again on my way home, i hit 6500 ish, it bounces 2 to 3 times like it hits the limiter, then slowly continues to climb and once it hit 7000 i let off.

now as soon as we forced it in to open loop, the wideband read 10.0, and remained 10.0 from startup, over the 5 mile road test, and continued until i shut it off. the car ran pretty rough too acting like it was running rich...


Mine does the same, when I force it into open loop via cts vs closed loop and in a couple minutes the afr goes super rich.



13.3 @ 106 mph Cammed
Re: new HPT questions
Wednesday, May 19, 2010 7:21 PM
QWK LN2 (aka ImPhat0260) wrote:
Speedline02 (GME Chat!!) wrote:i tried it again on my way home, i hit 6500 ish, it bounces 2 to 3 times like it hits the limiter, then slowly continues to climb and once it hit 7000 i let off.

now as soon as we forced it in to open loop, the wideband read 10.0, and remained 10.0 from startup, over the 5 mile road test, and continued until i shut it off. the car ran pretty rough too acting like it was running rich...
Send me a log and the current file... pnptuning@gmail.com
my tuner has the tuning file, not me. He browses these forums but doesn't have an account here.

(Tom) S/C Fire wrote:
Speedline02 (GME Chat!!) wrote:i tried it again on my way home, i hit 6500 ish, it bounces 2 to 3 times like it hits the limiter, then slowly continues to climb and once it hit 7000 i let off.

now as soon as we forced it in to open loop, the wideband read 10.0, and remained 10.0 from startup, over the 5 mile road test, and continued until i shut it off. the car ran pretty rough too acting like it was running rich...


Mine does the same, when I force it into open loop via cts vs closed loop and in a couple minutes the afr goes super rich.

Mine goes rich immediately after flashing it forcing it in to open loop via the CTS

---------------------------------
As of right now, the car is iding perfectly and not cutting out between gears or revving higher between gears... it took about a day after the last flash for it to balance out...

My tuner texted me and informed me that i have about 5 degrees knock retard at idle, and we suspect this is due to excessive exhaust rattle.

i need to put it up in the air and see what i can do to reinforce it.



Re: new HPT questions
Thursday, May 20, 2010 10:31 AM
Speedline02 (GME Chat!!) wrote:
QWK LN2 (aka ImPhat0260) wrote:
Speedline02 (GME Chat!!) wrote:i tried it again on my way home, i hit 6500 ish, it bounces 2 to 3 times like it hits the limiter, then slowly continues to climb and once it hit 7000 i let off.

now as soon as we forced it in to open loop, the wideband read 10.0, and remained 10.0 from startup, over the 5 mile road test, and continued until i shut it off. the car ran pretty rough too acting like it was running rich...
Send me a log and the current file... pnptuning@gmail.com
my tuner has the tuning file, not me. He browses these forums but doesn't have an account here.

(Tom) S/C Fire wrote:
Speedline02 (GME Chat!!) wrote:i tried it again on my way home, i hit 6500 ish, it bounces 2 to 3 times like it hits the limiter, then slowly continues to climb and once it hit 7000 i let off.

now as soon as we forced it in to open loop, the wideband read 10.0, and remained 10.0 from startup, over the 5 mile road test, and continued until i shut it off. the car ran pretty rough too acting like it was running rich...


Mine does the same, when I force it into open loop via cts vs closed loop and in a couple minutes the afr goes super rich.

Mine goes rich immediately after flashing it forcing it in to open loop via the CTS

---------------------------------
As of right now, the car is iding perfectly and not cutting out between gears or revving higher between gears... it took about a day after the last flash for it to balance out...

My tuner texted me and informed me that i have about 5 degrees knock retard at idle, and we suspect this is due to excessive exhaust rattle.

i need to put it up in the air and see what i can do to reinforce it.
Give your tuner my email addy and tell him to send me the current file and log. As for that much knock at idle, there is no way that your exhaust can be causing that unless its literally resting on the frame at all times... Something else is wrong here....





P&P Tuning
420.5whp / 359.8wtq

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