P0507, High Idle. Need help lsj Guru's

[recaro86]

Suprisingly yes.
However it does start a bit weird when warm after the zzp tune-which is another issue in itself...
Anyway every spring I was just cleaning the TB, MAF, and after seeing what the map looked like that will now be on the list. One bolt and it's out, easier to get at yet if you have the fuel rail off.

[UltimateBliss]

ok, im having the same issue and was thinking vacuum leak, but this makes a little more sense.

[armcclure]

stock throttle body? porting too far can cause a similar issue to this. i know from experience lol

[recaro86]

Stock throttle body yeah. No porting just slighty f ed up I think, car was smoked hard in the front when I purchased it and other things that got bumped have since shit the bed...
Fwiw, all of the reading I have done on this code (which is countless hrs btw) here and in the service manual 99% of the time it is a vacuum issue although mine is proof that it isn't every time.
Once I got tuned we pulled that code P0507 right out of the computer. Now it I have that problem it won't go into reduced power mode; it will just idle high.
Knock on wood it has been great to date.

[motorbreath]

I have just recently pulled the same code. Have Read somewhere to check the IAC valve.
Ill be doing a vacuum leak check in a minute.

My issue has serious drive-ability problems. It stalled on me during a left turn with traffic after putting and chugging. no MIL light was on though. I pulled the code from my scan tool. no freeze frame was stored either. I managed to clear the code but the issue came back a day later after hours of driving (a vacuum leak would be more constant unless its so small when cold... outside air temps here have been in the 4 to 14's both incidents occurred at night) I managed to replicate the issue in my garage I noted from the sensor data that it idles with the

MAF at .32 or so which sounds a bit high to me. ( they say it should float around .20 however with extreme cold the air density may be quite a bit higher I'm a licensed pilot and can pull the charts on that one
after the incident it rises much higher @ 1.25
Idle 1300-1500 coughing and sputtering and bouncing idle and very rough
Calculated load from the engine goes from about 10% to 80/90%
I also noticed the fuel system reports "open" when usually it indicates "closed"

Right now I feel this is more sensor related than anything. I'm usually pretty good about keeping the MAF sensor clean and recently pulled various other sensors from the intake manifold side and cleaned them up since they were very gunky and sooty. I will review the sensor data again If I can replicate the issue today to look for some more out of whack data. I have no access to TSB information today but read up on one yesterday that seemed plausible Service Bulletin 192030 for Saturn ENGINE AND ENGINE COOLING | AutoMD

http://www.automd.com/tsb/bulletin_b192034/

Wish me luck guys.

[UltimateBliss]

let me know, i cleaned my map and this went away for a while, but came back right before i put the car away for the winter. let me know how you make out

[motorbreath]

It didn't occour to me that this vehicle is drive by wire. My ion has been locked away in the garage for 4 months as I drive trucks for a living. Finally got a loca job and am home now so she's back in action.

I will attempt to look up the relearn procedure and buy alldata or Mit.chell like I've been debating for a long time. I noticed that with the key on and engine off the throttle position indicates 18% when the pedal is in the closed position when the pedal is to the floor it indicates 88% I'd like to know the parameters which are acceptable since in reality a throttle is never completly closed.

Idle on this vehicle is directly controlled by the throttle blade and not an iac valve since the computer controls the throttle blade. I want to rule out the throttle body with a relearn and then review the data via scan tool to see if the indicated information changed or if this information displays true throttle position including trim for its learned idle position.

I do believe this to be most certainly a sensor problem. I checked for.vaccume leaks to no avail and I find it hard to believe that a vehicle can suddenly run so bad after being fine all day. Then you restart it after it dies.and it runs fine for a while longer. Not a whole lot of solid parts can do that. Software on the other hand is a long list of logic checks and if-then-therefore which can change in a heartbeat when inputs and condition change or a piece of the equation is gone.

[Big Knight]

I remember people talking a long time ago about full pedal not being 100%. It may have been 88%, I don't really remember. I don't remember ever reading about no throttle though. Search may help you did up an old thread on the subject. GL

[UltimateBliss]

i think this is scaling done by GM. there is a thread about it on the hptuners website why it maxes at 88%

This is a mistery to me too, im going to replace some gaskets on mine and see if it helps. Maybe it is a sensor issue? I mean, i cleaned my MAP and the car worked great for a month, so maybe the sensor is on its way out. although the car only has 43k on the odo

[armcclure]

The 18-88 mixup happens by the computer incorrectly converting the raw voltage into a percentage. Is you instead scan etc (electronic throttle control) it displays 0-100.