Pig rich

[larrym]

So I was repairing some exhust leaks PS header was leaking at heads had blown out a gasket, turbo to down pipe connection was leaking. I installed studs in the exhuast housing replaced the gasket at the header.
I was suffering from a high blm condition and a lean stubble at tip in, WOT it pulled great before the repairs.
 
Finished it late last night reset the ECM fired it up and it warmed up a little rich but that is not unusual, took it for a road test and started to ease into it got about half throttle WB drops to 10.0 it sputters and stops accelerating let off and wb gets back to 14-15 drives fine hit the throttle again same thing.
 
Pull it into the shop block learn is 115 and its idling pig rich.
SES lights up 02 sensor rich, so I'll check the 02 sensor it is brand new, see if I bumped the TPS and check all my hose conections any thing else I should look for tomorrow night?
 

[Steve Wood]

maf number and fuel pressure

[Scoobum]

CC's and 02's moving normally on the SM?

[larrym]

maf number and fuel pressure

Don't recall MAF numbers but FP was 42lbs line off

[larrym]

CC's and 02's moving normally on the SM?

 When the wide band was pegged so was the narrow band and the cross counts weren't moving which I assume they shouldn't until the narrow band sees a lean condtion, the voltage was varing slightly but it was always 800 plus or minus 50 or 60 mlvolts

[larrym]

so if  I had an a intake leak of unmetered air after the MAF what sort of symtoms would I be showing?

[Steve Wood]

low o2s, high blms

[larrym]

thats what I figured, maybe I wacked the new 02 sensor if all else fails I have a known good one I can toss in.

[Steve Wood]

so what is the maf reading?  It sounds like a classic maf failure

[larrym]

i'll double check tomorrow its new a month ago, z06 and 4inch pipe.

[Steve Wood]

check the coolant temp reading as well to make sure it has not suddenly gone very low.....that should throw a code, but?

Hard to see it could be the O2 as it would seem to read low to make the ecm add a lot of fuel via the blms, and it is reading high, but if everything else looks right, then I would pop another one in to be sure

[larrym]

 


Pretty simple fix finally got to see it in the light of day, everything looked good except for the hose at the inter-cooler to up pipe. Funny thing is I never disconnected the up pipe, it was in place and almost looked connected when I pressed the hose it slipped inside the up pipe.

[Steve Wood]

strange, would have thought there was so much air there was no way it could get a rich o2 by adding fuel .....learn something every day, eh?

[larrym]

What about the power enrichment don't the injectors dump fuel after the tps reaches a certain point? 

[Steve Wood]

Most chips bring PE somewhere around 2.5 v as it is triggered by load when driving more than tps voltage...but, it seems to be around that range.  In Park,  it triggers off tps and is up around 3.0 as I recall.

But, that is not a ton of fuel unless the load is way up there....I have forgotten your particular condition when it occurred.  But, it is never excessively rich and would be a lot less with that much air coming in.

I have seen it happen many a time and the car usually bogs due to a lean out.  Drove a hundred miles once to see what was up with my son's T.  It bogged and did not want to climb hills when he gave it gas.   hose was pulling away from the turbo inlet but it took me twenty minutes to notice that it moved away when I blipped the throttle.