Contour Enthusiasts Group Archives Forums Modifications Duratec Maintenance Bank Two Lean- long reading but id appreciate help

I'm on fastcougar.com every day but i just remembered that more of the guys who actually know their [censored] spend their time here.

Lemme e'splain my problem...

6 months after installing my SVT UIM/TB, i get a "rear bank lean" cel. Im smart so I figure extreme fuel consumption plus eggy smell from the cat means one of my O2 sensors is dying. I figured the ECU is in reality overcompensating in gas because of the lean (lower voltage) reading its getting from the O2 sensor, so I replace both upper O2 sensors with some Bosch units from Autozone ($160).

Immediately it's a different car. Mileage goes WAY up, like 35mpg highway and this yields the first over 300mile run on a full tank of gas ive seen since i put my intake on back in 2002.

Fast forward 4 months after replacing the O2's. I buy a cold air extention from GrandMasterKhan and install that [censored]. Everything's rad except for the next day when I nearly overheat the car because I didnt notice I had not hooked up the ground wire for the radiator fans when I installed the intake extention. I fix that, change the oil, everythings rad again.

3 days later I get "rear bank lean" and "egr flow excessive". I drive the car like that for a good while. This time i think it really IS lean cuz accompanying the CEL the car is pinging. I run 89 octane and this helps, but the CEL still stares me in the face.

I bring it to Ford, they charge me $88 to hook it up to their diagnostics computer, find ONLY the Lean condition, NOT the DPFE(egr) code, tell me it must be intake manifold gaskets and play it like I obviously [censored] it up cuz I told them i installed my SVT plenum myself. They also want to charge me another $88 to have them "smoke" the intake tract- involving forcing some inert smokey gas into the intake and using a sniffer to see where its coming from. I decline, buy new upper/lower/iacv/egr gaskets and drive the car home.


2 days ago I installed the SVT lower i'd been dreading to install and along with it, the new lower, upper, egr and iacv gaskets and all new injector o-rings. I was extremely careful when torquing the manifolds down to 100in/lb.

Even in the ecu's learning stage, the car feels super awesome. Im impressed by the additional power and am relieved and confident that I fixed the CEL.

Today, after putting about an accumulative 150 miles on the new LIM and a complete set of new induction gaskets, the [censored] CEL comes back on!!! I swing to autozone and they read "rear bank lean" and "egr flow excessive" just like it did the first time i ever got the lean CEL. Funny how the dpfe code is back but ford didnt catch it.

I did the upper O2's
I did ALL gaskets and o-rings
Its still getting too much air / not enough fuel.

I still have the original lower O2's.
It's been awhile since i did my fuel filter.
I dont really like to run injector cleaner but I did about 6000 miles ago after the first time the lean cel came on.

I replaced the original DPFE sensor with a Wells unit last spring. I have a hard time believing it went bad already and have a harder time believing the EGR valve itself is bad. However If the valve is bad that could cause pinging but i doubt the "bank 2 lean" condition.

and that's where i'm at.

Thoughts? Comments? !

thanks for reading

This wouldnt have anything to do with the plugs i installed, would it? Im running Motorcraft single plat's and I know that on the front bank, spark travels from node to tip and on the rear bank from tip to node, or vise versa...

argg If the rear bank's plugs are wearing faster and arent burning the mixture properly id think it would cause a rich condition if anything... im so frustrated with this car

Single plats are a problem... these cars just don't run properly without doubles. Not sure if that is what is causing your rich condition, but I doubt it has anything to do with the EGR flow issue.

-Lance

im doubting its my plugs. this friday im going to swap front and rear O2 sensors. If the cel comes back and the banks have changed, ill know its the sensor. If it stays the same, i hope i didnt toast a valve when it overheated...

That DPFE design is THE worst POS ever. I went through 3 of them before I ended up getting turboed which involve pitching that POS sensor into the trash!

After having it cleared the cel came back... I went to autozone for the 3rd time in 2 months for this and they only found the lean condition, NOT the dpfe code... I dont know what that means, [censored] it i guess

Im really running out of ideas. Could the ECU need to be re-flashed? Every time i reset the ECU it runs like a bat out of hell untill the CEL pops on, then its slow and pings.

I have a vaccuum pump and tested the EGR valve itself and its definitely not stuck open. For kicks I unhooked the vaccuum line for it and within minutes got EGR flow insufficient. I still havent swapped O2 sensors to see if the lean condition moves from back to front but im skeptical that anything will change.