I swapped back to my stock intake a few weeks ago and oddly enough I made more power from it, and I also swapped the TurboXS diverter valve for a Greddy type RS with the single spring mod that fixed all my surge issues and smoothed my part throttle driving. Everything during cruise and any throttle situation seems to perform 10x better than the old setup I used except for my idle. I can understand it bouncing a little bit due to the cams (even though they aren't that large) but when the car's warmed up it drops to the normal 750-800 range and my afr's bounce all over, usually anywhere from 12.2 all the way up to 20 before it struggles to get back to near the 14.7 range where it starts the cycle all over again. Evoscan says my fuel trim low is off by almost 9%, so is it possible that my maf needs to be rescaled to compensate? I'm still on stock injectors and stock turbo for now, but I need to upgrade them soon since I'm ticking off some 96% IDC's and I have a IX turbo to toss on.

Any ideas for what I should look for or do?

 

Did you rescale your maf for your aftermarket intake? Did you reset the ecu after the swap? I just swapped back to the stock intake also, but I reset the ecu. It idled a little goofy the first day, but now it's great. Since you didn't mention that you reset the ecu, you should try that. It should work.

 

my car (as well as many others i think) does this with a whole crapload of more mods/fuel/turbo/etc.

there must be something in common (ic pipes/intercooler/cams maybe?). could be the maf signing out. i did notice my maf screen was canted a little. i have changed my front o2 sensor, installed a cometic o2 housing gasket (for my gt35r 4 bolt outlet housing), cleaned throttle body, cleaned maf sensor, tried many different scalings/flashes/fuel pressure/etc, intake pipes (stock, APR, dejon), different K&N cones, boost leak test with leak tester blowing up in face at 20ish PSI w/air hose diconnected....and....same results lol.

i have now started to throw the p0172 (fuel system too rich) once in a while when in a lot of traffic putting around in the 800-2000 RPM range. also, i get random stutter 1K-2K RPM's with AFR's jumping lean. above, its perfect for some damn reason. went through a whole box of bpr8es's with different gappings and some oe replacement plug wires too . i'm thinking my MAF has had it.

on a side note, if you have been running an open element filter (oil or non-oiled), clean the MAF as the open elements just let a lot of crap through--hasn't helped me though lol.

Good Luck.

EDIT: oh yeah, i changed my stock plugged PCV valve too...

 

In the club too. If it wasn't for map to maf my car wouldn't even run. Its gotta be the ETS Intake. I think I am going to try my hand at making my own

 

double post

 

1. Do a boost/vacuum leak check.
2. Try using a softer spring in DV.
3. Rescale MAF/ adjust injectors for better trims.

 

I've reset the ecu once already (had a few codes last week after whacking into my boost cut again) and it never really seemed to make a difference. The idle smoothes out if I hold the throttle at around 1k, and I did a leak test on it just to make sure and no leaks. The Type RS valve has the softest spring out of the 2 in it and it's adjusted almost all the way loose, any looser and it actually leaks, which might not be such a bad thing since lately I've been spiking up to 28psi or so. I never rescaled the maf when I had the matching Injen intake on there, my trims were always under 5% at that point so I never saw a reason to. Today was a pretty warm day (mid 50's), and it actually idled worse in the warmer weather to the point of wanting to stall out compared to the much colder temps I've been having up here lately (mid 20's usually). I'll try cleaning the maf up and see if that makes a difference although I cleaned it once already about 3 months ago.

 

i'm gonna say the maf has failed or is failing.

i have had this problem long before the map to maf patch. the OE mitsu MAF sensor, although it can push serious power, is built not so well. dirt, condensation, oil, etc can get easily trapped into the two very small hot-wire ports/channels and jack up the wires. i think thats what happened to mine. (i opened up a spare MAF to see what's inside, wasn't happy.)

i finally used some MAF cleaner and the problem got worse lol (stutterbox/jacked up idle).

i just swapped in a 3.25" OD gm MAF with v2.05 gen II translator (stock location) with all base settings only and idle reads 14-16 afr just after the 1 for 1 swap. never goes rich. all stuttering is gone and my tune is for the most part in tact. lean tip-in is noticable now, it dissapeared one day lol. NOW--this could mean the a part of the MAF might be ok, because the translator fixes the BARO and IAT variables, so i don't know how/what resistor, but you can try this to make sure those sensors in the maf are good by fooling the ECU. some logging might help (my logs looked good though/the numbers stay pretty fixed anyways).

i think the maf sensors are prone to having their two mini hotwires jacked up after years of abuse/oiled filters/open element filters/lots of power/etc. under the WOT, the problem seems not really apparent...

$0.02

 

Evoredy didn't you try swaping in a oem maf into your car when por idling started before map to maf??

So now you no longer using map to maf and have gone GM maf w/translator??

 

yes, i did. my other other oem MAF is bad too-same stutters and stuff/also the screen is bad. thats what i get for buying a used MAF to replace my other MAF. they did work without stuttering, but they got progressively worse over that last month or two. thats all I have to explain this/i'm pretty confident. they both worked fine at WOT though. part throttle cruise started becoming VERY jerky with the current MAF i just replaced.

I still have the map to maf patch as the idle will dip on occasion (but a lot less/the gm maf and gen II translator keeps the idle stable at the target MUCH better then the stock maf). i think the map to maf is good too if you don't want to go blow-thru with the gm maf and have a VTA--as it will beat the idle back to submission rather than killing the car on high rpm lift off to idle.

i ran around without the map-to-maf patch last night, it stumbled on hard lift off, but not nearly every time like before. the problem i think we all are having (repost?) if the stock MAF--not the ECU.

on another side note, the idle does swing from 14ish to 17ish now, so i may have moved the problem over toward the lean afr side lol. i put the gm MAF there to solve another problem, as i am at peace with the swinging afr's lol. the stock maf is great for WOT pulls, even when hacked up, but it plain sucks for some during non-WOT operation. there needs to be some code added to drive the GM MAF without a translator....

OP: sorry to swing off-topic on my troubleshooting....

 

Not a problem, if enough people share their ideas/fixes/mods eventually something always comes out of it. I personally would rather use the map sensor to control idle and part throttle/no positive manifold pressure type of situations, as it's just plain easier to tune speed density type of setups.

 

Yea I still get the AFR swings at idle but the car falls to idle fine and most of all its driveable