Can I change the Idle on P5?

[Tzar177]

Shouldn't need to adjust your idle via this route unless you have seriously modified your engine internals and have thus affected your idle considerably.

Listen to Shane, and find your idle problem and fix the real issue.

Clean your EGR valve, IAC valve, clean your air filter and check for vac leaks. Then check your spark plugs, ignition coils & wires.

How would you up the idle otherwise? I have intake, header and exhaust and needed it to raise idle up a bit to get rid of the lower rpm's vibrations.

 

[McBadass]

so I should use seafoam first, check for a leak in my vac line, and then if idle is still messed up tamper with those screws???

 

[ucMP3]

How would you up the idle otherwise? I have intake, header and exhaust and needed it to raise idle up a bit to get rid of the lower rpm's vibrations.

The point is that the "lower rpm's vibrations" are caused by something else, (i.e. a vac leak, dirty IAC valve, dirty EGR valve, worn out ignition coil, etc...) so increasing your idle is just masking the problem, not fixing it. I personally, would rather fix the problem, than sweep it under the rug.

 

[justanothermp5]

yea i dont think your idle changes at all from bolt on mods, i think my lower compression and .020 over bore made the idle a little bit lower, my car idles at like 400, its not bumpy at all thats just where it idles so im gonna try to raise it up

headers and intakes should not make your idle rough or bumpy or w/e

 

[ucMP3]

yea i dont think your idle changes at all from bolt on mods, i think my lower compression and .020 over bore made the idle a little bit lower, my car idles at like 400, its not bumpy at all thats just where it idles so im gonna try to raise it up

headers and intakes should not make your idle rough or bumpy or w/e

Nope, until you start messing with your compression, more aggressive cams, aggressive timing, etc... You're idle shouldn't be affected much.

 

[Tzar177]

The point is that the "lower rpm's vibrations" are caused by something else, (i.e. a vac leak, dirty IAC valve, dirty EGR valve, worn out ignition coil, etc...) so increasing your idle is just masking the problem, not fixing it. I personally, would rather fix the problem, than sweep it under the rug.

New egr, cleaned IAC, new coils and wires recently, new plugs last week, no vac leak that I see....vac gauge doesnt display a leak. Been seafoamed plenty of times

 

[ucMP3]

New egr, cleaned IAC, new coils and wires recently, new plugs last week, no vac leak that I see....vac gauge doesnt display a leak. Been seafoamed plenty of times

lol, the fs-de is a finicky little bastard ain't she?

You replaced coils and wires recently, did you replace coil packs? coil boots? or just wires and their respective coil boots? Air filter is clean?

 

[Tzar177]

lol, the fs-de is a finicky little bastard ain't she?

You replaced coils and wires recently, did you replace coil packs? coil boots? or just wires and their respective coil boots? Air filter is clean?

I installed aem dryflow filter last summer. I did the 1.8 coil swap

 

[ucMP3]

I installed aem dryflow filter last summer. I did the 1.8 coil swap

Pulls fine at all times just has a choppy idle? If you accelerate gingerly (keep your foot/accel pedal depressed the same distance) can you feel it hit different parts of your powerband? or is it smooth the entire way?

 

[Tzar177]

Pulls fine at all times just has a choppy idle? If you accelerate gingerly (keep your foot/accel pedal depressed the same distance) can you feel it hit different parts of your powerband? or is it smooth the entire way?

I don't have an idle problem. Car runs fine. I just didnt like the feel with it at stock 700rpm, so I up it to 800. Thought you were disagreeing with the method your suppose to do for adjusting idle, so I was just simply asking if there were other ways that maybe I didnt know about

 

[ucMP3]

I don't have an idle problem. Car runs fine. I just didnt like the feel with it at stock 700rpm, so I up it to 800. Thought you were disagreeing with the method your suppose to do for adjusting idle, so I was just simply asking if there were other ways that maybe I didnt know about

Gotcha. All I was saying was that the idle @700-750 really shouldn't be a problem, and that if its not idling well, the problem isn't your idle speed, it's that your motor needs a tune up...

 

[whatusername]

Do not touch the screw with the hex nut at the butterfly. That is not to be adjusted. On the right side of the throttle body near the front, theres a recessed hole that contains a philips head screw. You will need to turn that screw counter clockwise to up the idle. But first, you will need to jump TEN and GND in the little diagnostic box in the upper right hand corner of the engine bay. Warm up the car to normal operating temperature, while car is running jump TEN and GND, then turn the recessed screw til you reach the rpm you want

sooo what happens if u did manage to adjust that hex screw say oh i dunno bout 10 maybe 15 turns?

 

[Sport23]

Put it back!

My car is modified so I don't know if my readings are exactly right but it should get you close. Hook up an OBDII scanner that lets you view live data. Monitor the TPS PID and re-adjust that screw until the TPS reads ~9%. I know the actual calibration is done differently and I'm sure is much more precise but that should get you close with tools you can actually get at home. GL

 

[whatusername]

Well I do have an obd2 scanner But it does not show live data it shows freeze frame is this some way to make that would work

 

[Sport23]

Not that I know of. Freeze frame is stored by the ECU when a fault occurs. Do you own a multimeter?

 

[whatusername]

Not that I know of. Freeze frame is stored by the ECU when a fault occurs. Do you own a multimeter?

yes i do

 

[Installshield 2]

you can do it with a multimeter, but i don't know the factory calibration for the TPS...meaning i don't know what voltage shows zero throttle input (maybe sport23 does, though?)...Whats happening is that the TPS will never sit at 'zero throttle position' if you open up that plate adjustment...therefor, the computer will always 'see' the pedal as being pushed...and you'll get a really wonky idle as it won't step the IAC properly...

The easiest would probably be to get a live reader, like an elm coupled with torque for android...I can verify the TPS function works with the stock PID read outs set up in the app...instead of looking at the voltage of the TPS, it'll just correlate that into a % open figure in any gauge format you want...so when you are not pressing the throttle pedal, you need to close the plate until the app is saying 0%...and no more after that (i'm not sure if it goes into a negative percentage, but you only want it adjusted back to 0%)

the other option is to simply scrap the TB and buy a used one...a wrecker may have one for very cheap, and a few get let go on the FS section every so often...for way less than it would be for a digital scan-gauge...and only slightly more than the app + elm 327 thing...thing is, if you don't have an android phone, i don't think that app works with any other mobile OS...

 

[Sport23]

I don't have the factory specs. I'm pretty sure that it should read 10% or less @ idle. I have a couple TB's at the house I can get some closed and fully open ohm checks to get an idea. Once I have that he can hook up his multimeter and adjust the screw until he's in the ballpark

 

[whatusername]

I don't have the factory specs. I'm pretty sure that it should read 10% or less @ idle. I have a couple TB's at the house I can get some closed and fully open ohm checks to get an idea. Once I have that he can hook up his multimeter and adjust the screw until he's in the ballpark

ok but how do u test it with a multimeter?

 

[Sport23]

I checked it with the Torque app yesterday (Key on engine off.) Mine read 10.6-11% with my foot off the gas and about 86.7% with my foot to the floor. My readings my be slightly high because my throttle cable my be a little tighter than spec after my thermal spacer install. (I adjusted it but I recently read spec is 1-3mm play.) Due to the possiblility of my throttle cable being a little tight, I wanted to bench test some throttle bodies. All you need to do is unplug the TPS and ohm check it with the throttle closed, then adjust the screw until it reads right. I tried before work but forgot that our TPS has three pins; I'll have to double check which are the right ones to ohm between.