idle surging issues w/ small cam ?? HELP
10-10-2011, 09:27 AM
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idle surging issues w/ small cam ?? HELP So after getting everything installed including a tune the idle is still not right on the SS its surging in traffic and at start up.
it stalled when put into reverse and giving a little gas and the motor was hot.
after a car cruise it almost stalled at the traffic light. idle is at 750-800 drops to 400 then up to 1k then back down.
how would i go about tracking down a vacuum leak ? the motor has been torn apart 3 times so i have no idea.
mods
224/228 cam @ 114
6.0 ltr stage 2.5 ported heads
3800 stall
ls6 intake
kooks headers w/ cats
S3 ported stock throttle body - i think this is the issue
85mm slp maf - unplugged and still had idle issues... cars tuned with this maf
25% slp under drive pulley. - had this on and off still had idle surging issues.
at first we thought it might be the Idle Air Control valve motor so we bought a new one and that didnt change anything. Im running out of ideas what it might be.
car is running great otherwise... ran strong the whole 1/4 mile and even the tuner said its tables are good and all things have the right amount of electricity etc. So no idea why this car is surging and having idle issues.
Anyone have anything we should try ??
it stalled when put into reverse and giving a little gas and the motor was hot.
after a car cruise it almost stalled at the traffic light. idle is at 750-800 drops to 400 then up to 1k then back down.
how would i go about tracking down a vacuum leak ? the motor has been torn apart 3 times so i have no idea.
mods
224/228 cam @ 114
6.0 ltr stage 2.5 ported heads
3800 stall
ls6 intake
kooks headers w/ cats
S3 ported stock throttle body - i think this is the issue
85mm slp maf - unplugged and still had idle issues... cars tuned with this maf
25% slp under drive pulley. - had this on and off still had idle surging issues.
at first we thought it might be the Idle Air Control valve motor so we bought a new one and that didnt change anything. Im running out of ideas what it might be.
car is running great otherwise... ran strong the whole 1/4 mile and even the tuner said its tables are good and all things have the right amount of electricity etc. So no idea why this car is surging and having idle issues.
Anyone have anything we should try ??
Last edited by boseman350; 10-10-2011 at 10:12 AM.
10-10-2011, 10:32 AM
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Well first off, that's not a small cam, I'd call it medium. A4s will always be harder to tune for idle, because you have to deal with both in and out of gear.
I would have stuck with the stock MAF.
What makes you think the TB is a problem? Is the hole in the blade not the proper size? Or did they smooth out/fill in the IAC inlet area? I could see that causing some idle weirdness with an A4 + cam.
Do the fuel trims indicate a vacuum leak?
That tune may still need to be worked on further. Idle speed may need to be bumped a little as well.
And lastly, I noticed that mine was more difficult to tune (at idle) with cats. Not sure why, but with the ORY I was able to get the idle and hot starts perfect, but with the cats there was always a bit of surge no matter what I did.
I would have stuck with the stock MAF.
What makes you think the TB is a problem? Is the hole in the blade not the proper size? Or did they smooth out/fill in the IAC inlet area? I could see that causing some idle weirdness with an A4 + cam.
Do the fuel trims indicate a vacuum leak?
That tune may still need to be worked on further. Idle speed may need to be bumped a little as well.
And lastly, I noticed that mine was more difficult to tune (at idle) with cats. Not sure why, but with the ORY I was able to get the idle and hot starts perfect, but with the cats there was always a bit of surge no matter what I did.
10-10-2011, 11:46 AM
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Well first off, that's not a small cam, I'd call it medium. A4s will always be harder to tune for idle, because you have to deal with both in and out of gear.
I would have stuck with the stock MAF.
What makes you think the TB is a problem? Is the hole in the blade not the proper size? Or did they smooth out/fill in the IAC inlet area? I could see that causing some idle weirdness with an A4 + cam.
Do the fuel trims indicate a vacuum leak?
That tune may still need to be worked on further. Idle speed may need to be bumped a little as well.
And lastly, I noticed that mine was more difficult to tune (at idle) with cats. Not sure why, but with the ORY I was able to get the idle and hot starts perfect, but with the cats there was always a bit of surge no matter what I did.
I would have stuck with the stock MAF.
What makes you think the TB is a problem? Is the hole in the blade not the proper size? Or did they smooth out/fill in the IAC inlet area? I could see that causing some idle weirdness with an A4 + cam.
Do the fuel trims indicate a vacuum leak?
That tune may still need to be worked on further. Idle speed may need to be bumped a little as well.
And lastly, I noticed that mine was more difficult to tune (at idle) with cats. Not sure why, but with the ORY I was able to get the idle and hot starts perfect, but with the cats there was always a bit of surge no matter what I did.
the tuner said even he doesnt know why its surging... all the tables look right and the car pulls great. hes a reputable tuner too ! pcmforless.
10-10-2011, 11:58 AM
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If the VE table and Maf tables are not dialed in Correctly, then you will have idle issues like you are talking about. Did your tuner do drivability tuning with a WB02 or just dyno tune it?
Chris
Chris
10-10-2011, 12:03 PM
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he did a tune while driving the car and tweaking from there. not a dyno tune.
10-10-2011, 12:04 PM
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I see your tuner is pcm4less. Did you just tell them what was done to the car and they mail you a pcm or did you get it on a dyno? Either way I had a 224R cam installed into my M6 car and I drove it home with no issues. A day or two later I was having idle and surging issues like you and I looked for vaccum leak swapped MAF's and adjusted the idle screw a little bit (all at the suggestion of my tuner) he assured me my tune looked great and it had to be a different issue. Well I finally convinced him to put it back on the dyno and look at it and voila he had to adjust the tune a little to make it stop surging. Bottom Line is your tune needs worked on if he isn't willing to admit that there may be a problem in the tune then I'd look at a different tuner.
10-10-2011, 12:10 PM
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I see your tuner is pcm4less. Did you just tell them what was done to the car and they mail you a pcm or did you get it on a dyno? Either way I had a 224R cam installed into my M6 car and I drove it home with no issues. A day or two later I was having idle and surging issues like you and I looked for vaccum leak swapped MAF's and adjusted the idle screw a little bit (all at the suggestion of my tuner) he assured me my tune looked great and it had to be a different issue. Well I finally convinced him to put it back on the dyno and look at it and voila he had to adjust the tune a little to make it stop surging. Bottom Line is your tune needs worked on if he isn't willing to admit that there may be a problem in the tune then I'd look at a different tuner.
