sen2two

the problem: Idle is clean when idling at about 2500 and higher. but when i bring it down lower it bounces. the lowest i had it bouncing was from 1500-2000.



some info: i got some water in a bottle and sprayed it all the places i thought there might be a vacuum leak. and it had no changes to it. i also doubt theres a vacuum leak anyways. i adjusted the TPS becuase i port and polished the Throttle body and thought it might need it after that.



i used this site to adjust the TPS: http://howto.globalvicinity.com/gv_wiki.ph...p;co=1&vi=1



also, this is for an S5 TII



and the Idle for AB was is spec. and both WOT were in spec. but i cant get the ED in spec without the AB getting outside the range again. there is only one screw i know of to adjust it.





one thing i tryed was swapping the MAF to another i had. no change at all. but i tryed pushing in the cone on the MAF and this had an effect. the jumping idle went away and got lower. the more i pushed it in, the lower the idle got. if i pushed it in all the way, it shut the car off... does this mean anything? what else might my problem be?

sen2two

aslo, i found this to make the light tool. but where do i plug it for an S5? this only shows where to plug it for an S4...



http://www.teamfc3s.org/info/article...odes/main.html

j9fd3s

afm basically = airflow, so the more you push it in, the more fuel the ecu will output, until its too much. so if you push it in a little and it gets better, this might mean the car is too lean.



i like the light myself, its the OUTPUT from the ecu, you can set the tps all you want with the voltmeter, but since we really only care if the ecu is happy, and it tells us, then why not just do that?



S5 has the same 3 pin green plug, the t2 is kinda by the oil filler, i wanna say the NA is by the airbox, but its been a while since i played with one

RE_TurboFB

WOW I have the same exact problem with my S5 Turbo... It idles fine and hols a nice smooth RPM above 2000RPM's, But between 1500 - 2000RPM's It bounces and surges...



I have played with the TPS more that person should be allowed to. I also have the test lights.. My TPS is set dead on. the onny other thing I can think of is that I must have a vaccum leak some where..



My vacuum/Boost gauge reads -11 at idle. I know that is to low, But the engine has a street port on it also(If that make a difference.??).

sen2two

well, i did this to check codes from the ECU:



http://howto.globalvicinity.com/gv_wiki.ph...p;co=1&vi=1



and either my check engine light dosnt work, or the car isnt giving any codes. the engine check light dosnt show up when i turn the key to "ON". but most of the others do. so i really cant check it that way. i made the LED test light thing. but i guess thats only used on S4's...



so maybe the car is a little lean when idling that high. but that wouldnt cause it to jump from 1500-2000 would it?



im willing to bet its not a vacuum leak on mine. i went over that very thouroughly...

RE_TurboFB

I have The LED test lights and I use them on my S5. you hook the test light up to a Blue/Red(2O pin out on the ECU) and a Blue/Yellow wire(2P pin on the ECU) The other wire is just a 12V source.



So I unwraped my wiring harness. made sure all the wires were going thee right places. I cut Off damaged groung wires, Even thoe they looked like they had a fine connection. Then I Solderded new wire,ring terminals on, And heat shrinked the conections.



I also regrounded the MAP sensor, and ran a few extra engine grounds.



Started the car up after all the wiring stuff was said and done. Now it does not cut out between 1500 and 2000 RPM's...

sen2two

so your problem cam out to be grounds huh? maybe i should go through and check all mine... cant hurt

RE_TurboFB

Yeah.. I never thought that grounds could cause a problem like that.. I unwraped the whole harness and replaced anything that looked shotty..



I fired it up again today for another test run, And it is still running smooth. No more surging/bouncing between 1500 - 2000 RPM's.



Well I also replaced a MAP sensor that I bought from a forum member. The MAP sensor was a N/A(N350)sensor. Witch I replaced with the turbo sensor(N370). That might of had somthing to do with it, But I dont know for sure...

sen2two

i was also thinking my MAP sensor might be bad. cause when i unplugged the vacuum port to it, it didnt make any noticable difference. but i dont have any N370 ones sitting around to try it out...



the car starts perfect also, everytime you turn the key, it cranks right the **** up. but will turn right off unless i hold the throttle for a few seconds at around 2000-2500. then i let it down to bounce from 1500-2000.



if the grounds do not work, i think i know someone who will let me borrow a MAP sensor for a test try...

sen2two

ok, so i checked the grounds, and sanded down under them to make sure they were touching good clean metal. no change at all...



and no one i knew had an extra one that i could use to test it out. they all have N350's. I need a N370. so before i buy one, could a bad MAP sensor cause this problem? or am i watsing my time/money thinking its the MAP sensor?