Lean WOT

[REGL8R]

Car is great great at idle and driving around...all the numbers are where they are suppose to be. The only thing is it is way lean when I go WOT.

@15 lbs of boost the 02s are 734 at 50 mph on scanmaster (0.0 knock)
@17 psi and 02s=715 at 50 mph ~2.0 knock

I let off as soon as the 02 is that low. Anyone have an idea what could be the problem.

-TT chip
-New K&n
-All vacuum lines are good
-VSS is good
-Speedo is off (3.73 gears, 28" tall tire, cant figure it out could this be causing that much of a problem?
-Could plugs make a difference?

Thanks for your help I'm so close but now stuck

 

[notacarlo]

With the tuning features of the TT chip, I would add a little fuel - or- Bump it up a pound or two with the regulator.

Your 02's are where the car would be if you were running alky.

 

[bmackinnon]

With the tuning features of the TT chip, I would add a little fuel - or- Bump it up a pound or two with the regulator.

Your 02's are where the car would be if you were running alky.

+1 I'd bump the fp a pound or two first..... :wink:

 

[notacarlo]

Make sure you are taking your WOT 02's at the TOP of third. Make sure the gear selector is in third, get her up to 5100-5200. This is where the 02's count the most. WOT at 50 mph indicates the middle of a gear.

I assume you are aware of the adjustable fuel pressure process. Line off - then set the pressure. Make another run and use that as your base FP. WRITE down all of your data at that fuel pressure. Start bumping it up a pound at a time and recording the data.

Best advice I ever got : Dial her in with data, not your arse. Your arse leads to supporting the head gasket industry.

 

[REGL8R]

Those numbers are actually at 46 psi on a new gauge... I bumped it up to 50and no change. It seems like the fp is getting to a certain point then doesnt rise regardless of boost or what idle fuel pressure is set at. My regulator is the only thing that has any age on it everything else is new.

This is 60 lb'es w/ a te-60 so I should have plenty of injector left.

???

 

[Mr.Spool]

regl8r,if you are just using straight gas and no alky than go into the chip and add wot fuel.

 

[notacarlo]

You are running out of fuel then. Look to the pump/fuel filter, etc. If you can't fatten it up using the regulator there is an issue elsewhere. Is the pump hotwired?

50 psi line off is FAT. You are correct in the statement that you have plenty of injector left....but they aren't getting fed.

 

[paint it black]

i have had the same problem before, i have the same chip and i just added fuel at wot using the chip, and it is fine now. some times when its hot out it will knock. my o2 is about the same as yours with out knock.

 

[bmackinnon]

You are running out of fuel then. Look to the pump/fuel filter, etc. If you can't fatten it up using the regulator there is an issue elsewhere.

You are correct in the statement that you have plenty of injector left....but they aren't getting fed.

Truth.....

 

[REGL8R]

Still lean when I changed the chip parameters +20%.

In the process of doing the fuel filter although I find it hard to beleive that this is the problem b/c it was fairly new.

I am running out of ideas other than dropping the tank and looking at the pump. And yes its hotwired

 

[bmackinnon]

Still lean when I changed the chip parameters +20%.

In the process of doing the fuel filter although I find it hard to beleive that this is the problem b/c it was fairly new.

I am running out of ideas other than dropping the tank and looking at the pump. And yes its hotwired

Reinforces the likelyhood that the pump is taking a dump. It's been happening alot lately..... maybe due to the apparent abundance of chinese fake Walbros... Visually looking at the pump won't tell you anything. You need to do whatever it takes to monitor fuel pressure under boost.... bet it's not rising properly... maybe even dropping... not good.... just rig a hose to your fp gage and tape it to the windshield and go for a run. Probably will find your problem..

 

[Silver 'T' Top]

Same issues I had with mine up till the end. Only got 59-61 PSi of fuel pressure, tried new pumps, regulators, ran a seperate hose from connection above rear axle to rail, no change. Was running 23 PSI of boost at the time.

 

[REGL8R]

Man I figured I could put in a new filter fairly easily but no matter what I do it will not stop leaking!! Its a stock fuel filter but it has these adaptors on both ends, is this stock? It looks like it shouldnt be and is only there because the filter is not long enough. I really do not understand why it is leaking though I have new o-rings where they were on the adapters and everything is tight what gives??


Silver T- You never solved the problem? Did you run too much boost lean and blow up?

 

[Silver 'T' Top]

Man I figured I could put in a new filter fairly easily but no matter what I do it will not stop leaking!! Its a stock fuel filter but it has these adaptors on both ends, is this stock? It looks like it shouldnt be and is only there because the filter is not long enough. I really do not understand why it is leaking though I have new o-rings where they were on the adapters and everything is tight what gives??


Silver T- You never solved the problem? Did you run too much boost lean and blow up?

Should just be a "regular" Fram G 3727 filter, correct? Forget the AC number at the current time. Never solved my problem, was getting ready to go to an external sump and pump and all that stuff, but unfortunately right after the holidays, someone "permanently borrowed" my car. Never found it either.:frown: Kinda keeping my eyes open for another one to replace it.

 

[REGL8R]

I had the AC number in hand and they cross referenced it to a purolator filter. While I was searching for the AC number I ran across people using these so I just grabbed it. Just took off the filter again to notice it ate an o-ring, tommorow I'm going out to find a o-ring with the same ID but bigger OD and another new filter hopefully I can ate least get the leak gone.

I've also decided that regulator is next on my list to get rid of this problem. It is a brand new hot wired XP pump in there so since my regulator is old i figure it is the easier/cheaper/ more sensible to replace. Friggin money pit

 

[Chuck Leeper]

Oversize o'rings can/will bind up in the seal area, and get "pooched"...Stick w/ the correct GM rings, lube them, and assemble.
Have you checked out the rubber feed/return lines under the A/C?
Is the tank vented like it is designed to be?
What have you done w/ the charcoal cannister?

 

[WIKEDV6]

I think the AC number is GF481 not sure. Eric give me call when you get a chance.

Prasad

 

[REGL8R]

New pump, new fuel filter, new 02 sensor, chip maxxed out turned fuel pressure up and still no difference. Fuel pressure does rise with boost and holds pressure when car is turned off, is there ANY chance it could still be the regulator? I am at a total loss here

Anyone got ideas??

 

[REGL8R]

Looks like I have stumped the experts....

 

[WIKEDV6]

Eric, did you say that the O2 improved when you added fuel in the big end? What do you have? a Trasolator? or TT chip? How are you adding fuel?

Prasad