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idle issues.

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TDCRacing

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Car surges at idle only. Doesent seem to be a real pattern with this but i do notice it a lot more when the engine is cold rather than warm. This just started not long ago and cant remember doing anything to my tune before it started. The engine will surge in small amounts lets say from maybe 600-1000 then will slowly climb to like 600-1500 then eventually just kill. starts right back up and pretty mucch does the same thing.



Give it a little gas and hold it it is fine. Also when it's doing it it is only in neatural. As soon as i put it in drive or reverse it stops.Another thing i noticed was when driving and comming to a stop the rpms surge up maybe around 400 or 500 rpm's and the car jumps foward a little and then everything is fine. Going to check the iac now. And just for kicks i adjusted the idle to 850 across the board so i could rule that out. Trims are out of wack but have been way worse with no problems. Working on that also.



Ideas?



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TDCRacing said:
Car surges at idle only. Doesent seem to be a real pattern with this but i do notice it a lot more when the engine is cold rather than warm. This just started not long ago and cant remember doing anything to my tune before it started. The engine will surge in small amounts lets say from maybe 600-1000 then will slowly climb to like 600-1500 then eventually just kill. starts right back up and pretty mucch does the same thing.

Give it a little gas and hold it it is fine. Also when it's doing it it is only in neatural. As soon as i put it in drive or reverse it stops.Another thing i noticed was when driving and comming to a stop the rpms surge up maybe around 400 or 500 rpm's and the car jumps foward a little and then everything is fine. Going to check the iac now. And just for kicks i adjusted the idle to 850 across the board so i could rule that out. Trims are out of wack but have been way worse with no problems. Working on that also.

Ideas?

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Click to expand...

I would say it is tune related....and weather related. I noticed that if my tune is off, it matters more in colder weather. And I would get this surging. I would suggest doing a VE tune, then MAF tune and see if that helps. If not, you are probably going to have to bump your tables up a little in that area. I would say it is trying to run too lean at idle.
 
you know i read something about that the other day. I'm probably comanding a 14.7 A/F wich i read was to rich. He said he lowered it to a 10.0 or something like that and everything was good. I dont have a wideband so you got any tips or suggestions? What did you do?
 
Oh well mine was stock anyway. never messed with it to begin with. Have any other ideas? It was doing it again today, and the engine was nice and warmed up.
 


Zef_66 said:
Have you done a VE and MAF tune recently like I suggested?
Click to expand...

Maf yes VE no. The reason i have not done a ve tune yet is because it wasent surging before and if VE does correct it any (wich I have heard from others that it has) i consider that a baind aid to the problem.


Sorry if you feel like im disregarding your suggestions. I did do a maf tune and that didnt help. But my trimms are back in line :D.....
 
Here is a scan after the MAF tune. As you can see the trims are all out of wack. But i can go start my car up and drive it right now and they will be at zero -3 at idle and lock in at 0 under heavy PT to WOT. I think the trims are related to the issue im having.


You can see where it starts to surge at first then stops. Then i start messing with it by putting it in drive and park and trawds the end of the scan it starts again and then dies.



surging problem from tdcracing -- Scan Depot dot net
 
TDCRacing said:
you know i read something about that the other day. I'm probably comanding a 14.7 A/F wich i read was to rich. He said he lowered it to a 10.0 or something like that and everything was good. I dont have a wideband so you got any tips or suggestions? What did you do?
Click to expand...

fwiw 10.0:1 is a LOT more rich than 14.7:1:)
 


I also know that the car is suppose to be rich to a certain extent to compensate for the inconsistiencies that the engine has when it is cold
 
Is it possible that you have an exhaust leak? Your O2s look really low sometimes.

Just guessing here since you don't want to do a VE tune. :rolleyes:
 
We wont get into that lol...I have pacesetters...but am going with togs in a week or so at the most...just waiting on payday....



Again the exhaust has been the same way forever as like everything else has...And to be honest i really dident even want to do a maf tune becuase that had not changed just like everything else lol....
 
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This is the problem to see for yourself exactly what is happening. Now what i did was also log IAC Position and IAC desired rpm. I just placed the two gauges right on top of the other ones so sorry if it is hard to see. The bottom line is the iac does not seem to be the culprit. They are on the bottom of the rpm gauge if for some reason you cant find them. Thanks for any additional help
 


Dont know if this is normal or noy but im just trying to trouble shoot things....



When the Vac line to FPR is disconected the car wont run pretty much at all...



When the MAF is unplugged the car surges and I cant tell any difference in how it runns at idle and when reving it up in park or neutral.seems the exact same.


Iat(im trying anything) same....



IAC- when i unplug it the car revs to aout 3000 rpm's and just sits there...maybe slowly climbing at times
 
As you can see in this screen shot the car is surging...will a second set of eyes look this over and see if something abnormal is there. Not sure if this is tune related or not.





chartdisplay.jpg
 
My MAP is right at 50 and my timing is rock solid. It's odd how your timing bounces around like that and the MAP being so much lower than mine.

My idle was in gear though.
 
the scan above was with the car in gear. Take it out of gear and it would have been surging till about 3000 rpm's and eventually kill.....
 
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