Running rich out of nowhere, whats the problem now?

[JDMSIL80]

I had a gasket leak between the turbo manifold and the head last week, so we replaced the four gaskets and the leak had stopped. The car was running smooth and A/F was optimal before the leak, so I thought fixing the gaskets should make the car runs perfect again.

However after the gasket replacment, I am suddenly running really rich!!

When its sitting at idle or very low partial throttle, A/F ratio is fine.

But when you give it gas (like 50% or more), the wideband already reads 10 to 11 (which is really rich).

If you step full throttle it stumbles and misfire a lot then after a couple seconds it revs up and pulls again. I was monitoring the A/F and it's really rich at high throttle.

I don't know whats going on, the car was running fine and now it runs like crap. I took all the charge pipes apart today (thought it may have been a boost leak) and still way rich. Is it possible my maf is dying or maybe I need a new O2 sensor?

I have replaced the O2 sensor just 1 month ago, my BOV is recirculated, and the Horsham stage 3 chip is designed for 255 fuel pump with stock FPR, it was giving me consistent A/F ratio before.

Here's my setup:

Garrett GT28RHorsham stage 3 chipFMICHKS 264/272 camshaftsHKS SSQV recirculatedHKS air filterXS power manifoldXS power O2 pipeXS power downpipeMegan exhaustZ32 MAFBlitz ID-color EBC444cc injectorsWalbro 255 fuel pumpFET coil packAEM Uego wideband

I searched but didnt find any info that helped.

[XTCshri2222]

check ur 02 sensor

[JDMSIL80]

I have checked the O2 has been connected back in the elbow. One thing though is the clips on the connector plug of the O2 was broken, so it has always been tightened using zip ties. I just checked and the connection seems to look right, nothing came loose at all visually.

Should I spend the money on new 02?? Actually I did notice a strange noise everytime putting in 1st gear and street start under 2000rpm, some extra turbine noises which I didn't had before. But once the car get going, the noise sound normal again.

[JDMSIL80]

So tonight I reset the ecu (disconnected the battery for 10mins) and took the car out for a spin. The wideband is still showing me very rich 10s with around 50% throttle and up, so that didn't solve the problem.

On the bright side, the car seem to run a little smoother and sound of the motor is somewhat different after the reset of ecu. The exhaust note is not as loud and some weird noise that I had before has gone away.

Where should I go from here?

[uno]

if you have no boost leaks, then well sounds like you're not getting a complete burn now for some reason. Check ignition components. My backup guess would be mafs may be dirty and reading improperly.

So tonight I reset the ecu (disconnected the battery for 10mins) and took the car out for a spin. The wideband is still showing me very rich 10s with around 50% throttle and up, so that didn't solve the problem.

On the bright side, the car seem to run a little smoother and sound of the motor is somewhat different after the reset of ecu. The exhaust note is not as loud and some weird noise that I had before has gone away.

Where should I go from here?

[JDMSIL80]

So I replaced the O2 with brand new Borsh unit, the car STILL runs way too rich!!

I've also cleaned the MAF sensor, but didn't help at all.

Its driving me nuts, help me out guys!

[kapower06]

Have you checked the ecu codes yet? It almots sounds like a knock sensor acting up. If no codes are present then check the spark plugs and see how they look, if they are black then maybe your FPR is acting up. Good luck

[JDMSIL80]

Upon closer inspection, I found there might be boost leak somewhere.By reading the boost gauge, I notice the A/F gets really rich (10s) only when I'm boosting.Under vacuum, the A/F is anywhere between 12-14 which is correct.

Its hard to tell where the boost leak is, must be small as my idling is still stable and car is driveable.

I dont have a compressor at home, what other ways can I use to find where the boost leak is?

[TurboBen87]

i know this is probably irrelevent, but on my buddies car that was running wayyyyyyyyy to rich, we changed the plugs, because they were fauled from being in for so long, use ngk though, alwayz the best,

[JDMSIL80]

So I took my car to the dyno yesterday and have the shop find out where the possible boost leak is. They used soap with water and sprayed the entire pipings while rolling the dyno at high boost. After an hour of inspection, they confirm there is no boost leak anywhere. The boost is steady and stable.

However, we found more details about the richness problem. Not only when boost the fuel would become very rich (10s), it will be also goes rich (10s) even in vaccuum when you tap on the throttle after each shift, which is before you even hit boost! Because it goes so rich during gear changes, the car would sputter for a few seconds at each shift and really destroy the driveability. Seemed like there's a problem in reading air flow, as the car doesn't like sudden changes in air flow and would go very rich if happens. So the shop suggested me to use another MAF sensor and see the differences, as it sounded like the most logical step to take.

After much headache I decided to buy a Re-manufactured MAF from local parts store for $300, which includes 1 year warranty. I just finished swapping the MAF and took the car out for a spin, but guess what, the problem is STILL there!!

So it is NOT the MAF sensor, O2 sensor nor boost leak. I'm running out of ideas, the gas mileage is killing me. Can someone suggested me next step, I will try the spark plugs, but I dont wanna keep running in to the brick wall..

[kapower06]

Change your damn spark plugs...lol.

If youve been running them at that rich of an a/f ratio chances are they are fouled out, and not helping the problem any.

Have you checked for any codes yet?

What is your vaccum like at idle? 18-22in hg?

One last thing... How is the stage 3 chip? I was thinking about getting one so I wouldnt have to go the piggy back route, but your experience is kinda shying me away from it. Also How much was the total cost of the chip shipped to your door?

Good luck

[Nunook]

my car is also running very rich on boost, and I can't figure out what it is.

Ive checked or replaced:error codesno boost leakstpstemp sensorafmcompression ~150 on all

** Also Ive noticed when driving between ~3000-3500 car gets weak, and vacuum goes from 0 -> 10

setup =FMIC w/ ssqv, sr t25, kaE afm, dump pipe/downpipe, exhaust, walbro 255, sard fpr, air filter