• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

Idle surge causes?

Wow! I was just simply stating that I was looking for advice, not criticism. Why is it that you know it all, but can't offer me simple advice Scotty? There's much reward in being humble, maybe one day you'll learn this. I've been taking pics of my entire build, and wanted to do a full build post. I have the exact opposite of a "sloppy mess", I just wanted to post everything when it's driveable. Sucks that I've put over $12,000 into everything to be belittled over an idle surge. Not saying, just saying.
 


GTPChristopher said:
Wow! I was just simply stating that I was looking for advice, not criticism. Why is it that you know it all, but can't offer me simple advice Scotty? There's much reward in being humble, maybe one day you'll learn this. I've been taking pics of my entire build, and wanted to do a full build post. I have the exact opposite of a "sloppy mess", I just wanted to post everything when it's driveable. Sucks that I've put over $12,000 into everything to be belittled over an idle surge. Not saying, just saying.
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maybe you should have documented your build while you did it, so you could of had help...but your to good for that crap lol

12 g's, what you f ing smoking over there? send me 5 bucks worth will ya.
 
If that o2 is stock. ..get a new one.
Like the maf it is a trusted sensor which means that the degradation overtime is not noticed or diagnosed by the PCM.
If that O2 sensor has 50000 miles or more it should be replaced with a new Denso, Delphi or AC Delco narrow band sensor.
do not buy the Bosch
 
how about instead of snarking at him let's be a little more analytical in the approach.

let's ask "how does the PCM set the P0300 code?" it looks for excess oxygen in the exhaust stream and knowns which cylinder fired when it saw the lean condition. (remember, a misfiring cylinder will have *excess* oxygen and read lean to the O2 sensor, not rich, because the unburned fuel did not consume the oxygen in the cylinder). If its a random misfire on all cylinders then the cam could absolutely explain the P0300 code, you have enough overlap on each cylinder that some fresh air is getting into the exhaust and the PCM interprets it as a misfire.

what causes surge? the PCM is cycling the IAC valve in response to *something* because it thinks the mixture is wrong (i.e., O2 readings are not responding as expected) for the given RPM, MAFF, and IPW. Vacuum leak can cause a lean condition, PCM blasts the IAC closed to richen up, then it's too rich, so it opens it again, etc.

taking both of these together: check for obvious and non-obvious vacuum leaks. all hoses, MAFf sensor gasket, EGR tube. Even injector O rings. make sure the O2 sensor wiring is not being rubbed or burned. Make sure the O2 is in the right place and is getting hot enough. then try a new O2 sensor.
 
last night we talked about the tune in the chatbox, and another likely cause is that the tune might not have adjusted for the 2 bar map sensor now installed. we are talking about a zzp canned tune, so in my opinion, adjusting the tune for the different map, and doing a maf sensor adjustment on the car should make a huge difference, at least it should unless there really is something wrong with the car. and the P0300 should also be disabled.
 




i took the purge solenoid off and the line for it just hangs out back there open to air with no fvcks given lol all 12 codes iirc are deleted.

i had evap codes due to a large leak, so instead if fixing it i deleted it all. i later found the filler vent tube was rotted and fell off. im sure that was the issue. ive since fixed that cause i was smelling gas from it, why it was found, you smell gas you start to look for things.
 
Turns out that a simple MAF replacement solved the surge. Strange thing was that it was working perfectly okay last year before my teardown. Just went to show me that everything needs to be questioned when changing everything lol
 


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