Closed loop idle numbers

[84sithlord]

Hello everyone,

i've been noticing my car idling less than desirable. of course it cleared up by the time i found a pen to jot down my scanmaster #'s but i believe this is in closed loop (no dot blinking) in park about 90+ degrees out.

i didn't record o2 millivolts. they were bouncing around
AF 06-07
L8 38-40
BAT 14.0
INT 128
BL 122
NPH 00
CLT 162
ATS 71
R 950 (seems good to me but its normally much lower (400-600)especially when engine is cold and first starting)
TPS .42
IAC 00
CC 91
NAL 00

i have tried to adjust the iac min air screw.. per instructions in the scanmaster instruction booklet. seems like i always go into closed loop before i can get it right. any advice on setting that will be awesome!

 

[projectmoneypit]

You want to adjust the iac in closed loop, should be around 10-40

 

[84sithlord]

mine always goes to 00...i guess maybe its my chip?

 

[Jerryl]

mine always goes to 00...i guess maybe its my chip?

More than likely it's the adjustment. "0" really means that the ECM is unable to control the idle.
Adjust in small increments and be patient when adjusting the IAC / TPS. You WILL get good at it.

 

[84sithlord]

roger that. do i need to reset the ecm after every adjustment?

 

[projectmoneypit]

roger that. do i need to reset the ecm after every adjustment?

no, just turn the screw a 1/4 turn then (burp) the throttle and let the idle stabilize before turning the screw again. Turn no more than a quarter turn at a time and burp the throttle after each turn, watch the tps idle voltage and keep it in spec as it may go out of spec as you adjust the iac.

 

[84sithlord]

i noticed my iac count would change when i burped the throttle but would always settle back to 00. currently my tps has changed to .46 and iac still reading 00. when i burped the throttle, it would show an iac count of 10-20, never steady though. keep at it ?

 

[Jerryl]

i noticed my iac count would change when i burped the throttle but would always settle back to 00. currently my tps has changed to .46 and iac still reading 00. when i burped the throttle, it would show an iac count of 10-20, never steady though. keep at it ?

If the TPS went from 0.42 to 0.46, you are going the wrong way.
Sounds like we need to determine a starting point/baseline setting.

Try this;
Back the idle air adjustment screw completely out, so it does not stop the throttle but barely touches it.
Turn the screw clockwise about 1 - 1.5 turns (this is swag ) . . . reset the TPS to 0.42V.
Use this as a baseline and adjust from there.

Keep turning the screw no more than 1/8-1/4 turn at a time while watching the base tps value.

 

[84sithlord]

when you say touches the throttle, are you refering to spring or the "lever" the cable is attached to? i apologize for my ignorance, just making sure i understanding correctly.

 

[Jerryl]

when you say touches the throttle, are you refering to spring or the "lever" the cable is attached to? i apologize for my ignorance, just making sure i understanding correctly.

Yes, the metal lever that contacts the idle air control adjustment screw.
What we are trying to do is make sure the throttle is fully closed, and then barely open it with the screw.
Once it is barely open, the ECM can/will control the idle rpm . . . . by cycling the IAC motor, AKA IAC count.

Just for reference . . . .
If the throttle is opened too much, and idle rpm is higher than the programmed value in the chip, the ECM can no longer control RPM, resulting in high IAC value of “0”.
If the throttle is not opened just enough, the ECM tries to control the idle rpm value which results in high IAC value.

If there is a vacuum leak, you get the same effect as “Opened too much” and you want to look at the BLM and INT values.
A very small leak will have a great effect on idle BLM value since the % of false air is much greater at idle . . . . . .

 

[84sithlord]

thanks Jerryl!!!

 

[84sithlord]

tuned for 2 hours last night. the closest i ever got was iac 04 and 25. i left it at 04. it still insists upon going to 00. i adjusted tps to .42. that was while running and with key on, engine off. i do hear an exhaust tick on the drivers side. not sure if its exhaust manifold or crossover pipe. not sure about a vacuum leak. seems like i hear something strange when i'm getting into the boost a bit (around 10-15psi). also, on the way to work this morning, the engine had a big "hiccup"...almost like i hit something in the motor. it cleared up and didn't do it again. i'm sure it will come back this evening on the way home if i drive it long enough. should i spray throttle body with carb cleaner and try tuning it again? do you think that hiccup has something to do with the tune? how do i adjust the fuel pressure regulator? thanks!

 

[projectmoneypit]

if the iac wont adjust, take the iac valve off and clean the valve and the port in the throttlebody. if it does not adjust after that then the iac is probably bad. the fuel psi is only adjustable if you have an adjustable regulator. So if yours is adjustable then put a fuel psi guage on the front rail shrader valve and adjust it to 44 psi with engine running and idling with the vac line to the reg disconnected and plugged. You really need to go to gnttype.org and do the spring cleaning procedure on there, you can also learn alot on from the technical section.

 

[84sithlord]

i believe most of the spring cleaning has been done to mine. i'm on 2d fuel pump, i have adj regulator with gauge under hood. 60lb injectors, lt-1 maf, 87 ecm and ignition.....just had head job done, f body radiatior, new h2o pump, currently no thermostat, turbo is newish....i will try the iac cleaning and resetting my fuel pressure. thanks. i was wondering how to set that! lol!

 

[CGASTON]

tuned for 2 hours last night. the closest i ever got was iac 04 and 25. i left it at 04. it still insists upon going to 00. i adjusted tps to .42. that was while running and with key on, engine off. i do hear an exhaust tick on the drivers side. not sure if its exhaust manifold or crossover pipe. not sure about a vacuum leak. seems like i hear something strange when i'm getting into the boost a bit (around 10-15psi). also, on the way to work this morning, the engine had a big "hiccup"...almost like i hit something in the motor. it cleared up and didn't do it again. i'm sure it will come back this evening on the way home if i drive it long enough. should i spray throttle body with carb cleaner and try tuning it again? do you think that hiccup has something to do with the tune? how do i adjust the fuel pressure regulator? thanks!

Have you check the IAC plug for broken wire?

 

[84sithlord]

no i haven't. i will look at lunch time.

 

[84sithlord]

too dang hot for me to do much of anything right now. lol!
here's my scan readings after driving to the parts store and back to work.

af 07
l8 39-40
bat 13.9-14.0
int 128
bl 123
nph 00 I'm in park, foot off gas.
clt 167
ats 71
r 900-1000
tps .48 this seems to vary as well. it was .42 this morning key on, eng off
iac 00 took it awhile to get to 00. it hovered around 25 for 10-20 sec then went down to 00
cc 145
nal 00

i purchased some throttle body cleaner. i will work on cleaning it up this evening under the shade tree. should i reset the ecm just to start fresh.

 

[CGASTON]

too dang hot for me to do much of anything right now. lol!
here's my scan readings after driving to the parts store and back to work.

af 07
l8 39-40
bat 13.9-14.0
int 128
bl 123
nph 00 I'm in park, foot off gas.
clt 167
ats 71
r 900-1000
tps .48 this seems to vary as well. it was .42 this morning key on, eng off
iac 00 took it awhile to get to 00. it hovered around 25 for 10-20 sec then went down to 00
cc 145
nal 00

i purchased some throttle body cleaner. i will work on cleaning it up this evening under the shade tree. should i reset the ecm just to start fresh.

You first need to adjust the IAC.... Back out the idle screw until flush with throttle body. Now turn it in 2.5 turns..... Turn on key, engine off, adjust the TPS to .42v.... Now start the car. This should set you in almost perfect. If IAC continue to be high then you have a vacuum leak. TPS does control your idle. It is for throttle response. Also if you are a new guy to the buick seen then I suggest you do some reading.

www.gnttype.org
http://www.vortexbuicks-etc.com
And here on this site.

Good luck and let us know how things go!

 

[84sithlord]

lol! thanks man. trust me, i've been reading every chance i get.

 

[84sithlord]

the sad thing is, i've owned this car for 2 years and it has spent more time broken down or at a shop than it has on the road....i've been reading the forums for at least a year n a half...so needless to say, i'm beyond frustrated at this point.