Hardcore Idle Surge after installation of MAFT Pro (2G DSM)

tvieira24 · Jun 26, 2006, 04:47 PM

I know it's not an evo but there are a few great MAFT experts on here and I'm in desperate need of some help. This is on my 2G AWD DSM.

So I just finished installing my FMIC as well as my MAFT Pro and now my idle is all messed up.

When the car is first turned on, the rpms raise to about 3000 and stay there for a few seconds till it gets a bit warm, then the idle jumps down to 1500 then back up to 2300 over and over very quickly. My car never did this before and I've got the MAFT settings dialed in exactly as most other people have them. MAFT is running in speed density (map sensor and IAT sensor).

I unhooked the MAP and IAT sensor to simulate running without a maf (limp mode) and the idle jumps down to where its suppose to be and the car stumbles.

Here is the log I have hosted on a friend's server:

http://www.vpperformance.com/session8.zip

I posted on the MAFT Pro boards, but thier tech support is terrible, just takes too damn long to get a response and the car's been off the road for several weeks because of this. If I can't get this resolved soon I'm going to have to look into getting a refund and pick up a DSMlink.

Mods:
Intake
3" TBE
Bullseye vtrim
Custom bullseye O2 housing
SBR Exhaust Manifold
SSAUTO FMIC
Stock fuel everything

MalibuJack · Jun 26, 2006, 05:10 PM

What is the MAF output at idle? Either your MAF reading is way high or your fuel trims are WAY out of range.. You'll need to get both in check..

Stock turbo, mostly bolt-on mods, stock injectors, and your idle frequency for 1000rpm should be around 40hz, 30hz at 850rpm.. Make sure your VE table for the speed density setup under idle vacuum (0-19in/hg is set accordingly..)

tvieira24 · Jun 26, 2006, 05:12 PM

To tell you the truth I didn't even know I had a maf reading since its running speed density. Does it say it anywhere in the log I posted? Sorry for the ignorance, this thing is new to me.

Tuner Pro log file:

http://www.vpperformance.com/TPRO46.adl

MalibuJack · Jun 26, 2006, 05:13 PM

Yeah the last 3 or 4 columns in your log.. I see it jumping around from 60hz, 200hz, etc..

thatsMR2u · Jun 26, 2006, 05:17 PM

u didnt break ur idle sensor during install did you?

tvieira24 · Jun 26, 2006, 05:18 PM

I don't think so, the car will idle where it's suppose to when it runs in "limp mode". I've also tried adding or removing fuel all along the rpm range where it's being crazy and it hasn't changed a thing. I've changed the settings as the car was running while wathcing the AFR.

The car drives fine over 4k rpms unless I go WOT due to the lack of tune which I can handle, I just need it to run first!

MalibuJack · Jun 26, 2006, 05:24 PM

Its probably outputting a MAF sensor value much higher than the ECU would typically expect to see, and causing the fuel trims to be really whacked which can cause the symptoms he's describing it'll just hunt like mad, it'll try adjusting trims, then adjusting idle speed, until it can find settings that work but it will never find them, so it will then reset (you'll hear a relay click, and start over).. Once you disconnect the MAFT its like removing the stock MAF and it will run in a limp mode which will run off the ECU map and stock MAP sensor in the intake manifold..

TurboBob · Aug 8, 2006, 08:34 PM

Just an update.

He found the throttle body gasket was folded over, causing a massive air leak.

The ECU was cutting fuel to try to bring the idle speed down......

Everything is peachy now.

Bob

tvieira24 · Aug 9, 2006, 09:39 PM

Yep, everything was running perfect after I sorted that nonsense out. My own mistake, thanks for the advice guys.

TTP Engineering · Aug 10, 2006, 07:56 AM

Argh....