WOT lean condition, VIDEOS

[williillii]

Hey guys, trying to figure out this lean condition on my 2g...

Relevant mods are 14b, FMIC, intake, 2.5'' exhaust, evo 9 fuel pump w/ rewire. boost set at 9-10psi for troubleshooting.

The car feels like it runs fine at idle, part throttle, and WOT, but my wideband is just giving me scary readings..

at idle it is fine at 14.7:1. The gauge also reads "AIR" when it is exposed to air. So it seems like the sensor is working, no? When I get on the gas, if I stab at it around 3k, the AFR will drop to about 12-12.2:1. If I just roll on the throttle it will drop to about 13:1 at 2-4psi then when boost comes on it just stays put at 13 and slowly climbs sometimes as high as 13.5:1. Yikes.

My first thought was exhaust leaks, so I checked the gaskets and found some leaks, replaced the manifold gasket and the turbo gaskets to no effect. Just to make sure its not an exhaust leak I took the front o2 sensor out and moved the wideband further up the stream. This gives me roughly the same readings. I checked my plugs and o2 sensors and they look kinda whiteish. So I'm thinking it is actually running this lean.

Fuel filter was changed about 15k ago btw.

Any one have any idea whats going on here? I should be at 10-10.5:1 with my "setup." Thinking I'll try replacing the FPR since they're cheap. Any other ideas? Here are some videos of the car to see whats happening..

Light cruising, once I take a left I go WOT for a sec, then again after the next turn

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Pulling out onto the street, 1st and 2nd pull

<embed width="600" height="361" type="application/x-shockwave-flash" allowFullscreen="true" allowNetworking="all" wmode="transparent" src="http://static.photobucket.com/player.swf?file=http://vidmg.photobucket.com/albums/v337/osh/video-2010-03-24-19-06-11.flv">

getting on the highway, 2-3 pull, 4th WOT from 60-80 a couple times.

<embed width="600" height="361" type="application/x-shockwave-flash" allowFullscreen="true" allowNetworking="all" wmode="transparent" src="http://static.photobucket.com/player.swf?file=http://vidmg.photobucket.com/albums/v337/osh/video-2010-03-24-14-54-36.flv">

YES, I know my speedo is broken. Thanks for any help.

 

[shinzon]

Completely off topic, but what cluster gauge pod is that? I've seen a few of that design which are glossy, but that looks closer to the matte stock plastic.

 

[EagleTSIawd]

what wide-band are you using? i know the LC-1 needs to be calibrated and re calibrated every now and then

 

[John H]

what wide-band are you using? i know the LC-1 needs to be calibrated and re calibrated every now and then

I'd see if you could barrow another WB and see if you are getting the same reading, other then that check your fuel pressure. Maybe your pump is on its way out?

 

[williillii]

Good idea about another wideband...although I have no greasemonkey friends....im using an old plx m300. No need to calibrate.

Ill see if I can get a fuel pressure gauge. The pump is an oem evo 9 with about 30k so its probably fine though.

The pod I got off ebay. Couldn't tell ya what seller. It was like 10-15 bucks. Fitment is ...ok..finish is nice.

 

[twister7]

Wide band is before or upstream of the cat right?

Is that you check engine light on it the video?If so ,if there is a miss-fire code on one of the cylinders check that injector it maybe clogged causing it to go lean and causing the miss-fire code i just had my 98gst toss a miss-fire code cause of #2 injector!

 

[williillii]

The wideband was right after the flex section. Just had it moved up to in front of the flex section...about 2ft away from the exhaust ports. I changed all the gaskets on the turbo/mani/housing/exhaust.

I also had 550cc injectors and an SAFC so I put them on to see if I could tune this problem out. No such luck. In fact it has gotten worse over the last couple weeks. I cant even run stock boost now without leaning out too much.

When I get on it at 3k afr will drop to 11.5-12:1 depending on how it feels . Then when it gets to about 5500rpm it leans out all of a sudden to ~13:1 and knocks like crazy.

SAFC settings don't seem to matter much. Right now I have it set at -7% across on hi thrtl. If I go any richer, it just blasts fuel out and spools really loud, doesnt move anywhere. I figure I should be at around -15 to -18% anyway because of the injectors I have so I dunno wtf is goin on...pretty sure its running this lean too because I pulled the plugs and o2 sensor and they are straight white.

I tested the fuel pump voltage and its 13.5 at idle. MAFS was reading like 1700hz@around 15psi, sounds ok right?..Fuel filter has like 20k on it so its probably not that. I dont have a fuel pressure gauge...was gonna get one but its like $45 and I can just buy a new pressure reg for less than that, so I might try that.

Could a bad fpr make the car run lean like this?

 

[habitatguy187]

Could a bad fpr make the car run lean like this?

Oh yeah. There's a vacuum line from the intake manifold to the fpr which will either send the fpr vacuum or boost. For every 1psi of boost the fpr gets from that vacuum line it's supposed to raise the fuel pressure 1psi.

A buddy was just having this problem yesterday but it was leaning out to the 14-15s. We popped his hood and found that the vacuum line to his fpr had popped off, so it wasn't raising the fuel pressure under boost at all. So first check your vacuum line to the fpr and make sure there's no holes or cracks in it before you change out the fpr.

 

[williillii]

I pressure tested the intake and I did have a very small leak from there due to the hose stretching out. I put a new hose and ties on it, even a dab of silicone and it did not make a difference. So Im thinking the diaphragm might have gone bad. I read that if this is the case, when you pull the vacuum line off while its running it will squirt fuel? If it doesnt do that, does it mean its good? Or just that its possibly good/not all the way broken?

 

[habitatguy187]

Never heard of them squirting fuel out of the vacuum line, but that doesn't mean it's not true. Do some research first.