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SCAN: Lean bank 1 and 2


vschinzel
07-16-2005, 03:03 AM
hey guys, I'm new to t-birds, had a BMW but tranny broke and came by a 95 Thunderbird LX V8... Check engine light was on, and check gauge light is on.

A scan revealed that banks 1 and 2 are running lean. Now I figured ou that that means the 2 of the cylinders are not getting enough fuel.

It was in the shop for something according to the guy I got it from. He said they got the chk eng light to turn off, but it turned back on soon afterward, my guess is they just deleted the code from the computer.

I reset the computer by removing fuse 15, attempting to start engine, replaced fuse and started car. Let it run for 5 mins (idle) no sign of the chk light. Check gauge still on. fairly low on fuel, needs oil change, not worried about the gauge light.

I am in Victorville, CA (Hi desert) today 95degrees wasn't bad today, yesterday 108degrees was. I'm not driving the car, don't want to freeze the engine because of the lean condition. If the Check engine light doesn't turn back on, everything fine? How do I check for the lean condition if there is no light or code being thrown? Should I replace O2 Sensors? Front is about $50 a piece from autozone, OEM BOSCH. The rear monitors are $120 from Ford, can't find them anywhere. PLease help. Sorry for long post. APpreciate it.

E-bird
07-16-2005, 07:51 AM
lean on banks 1 & 2 are all of the cylinders. not just 2 of them. i had that problem, and it didnt happen often @ first, but did become more of a problem the more i drove it. What i found to be the problem was dirt on the maf sensor. it couldnt read the correct amount of air being delivered so it would burn lean on both banks.
change your filter if it needs it. clean the filter box and pull the maf body out of the duct and inspect for dirt or debris. carefully blow it clean if it is found dirty. a dirty maf allows the computer to think its not getting much air so it reduces the fuel delivered which causes the lean banks read by the oxygen sensors.

btw i live in vegas and it was 116 in the shade yesterday. im an a/c tech, and this heat is killing me. i'd take 108, maybe then i could take a break ;)

vschinzel
07-16-2005, 01:33 PM
Thanks for the input, I didn't know that the banks were the rows of cylinders, good to know. I will definitely take out that maf and see if it's dirty. Thanks again, Victor

E-bird
07-17-2005, 02:51 PM
heres a link to find info on cleaning it.http://www.tccoa.com/articles/intake/index.html#

vschinzel
07-17-2005, 08:16 PM
thanks, I read through it a little, it seems my problem could also be caused by the second set of O2 sensors, or monitors as FORD reffers to them. I can't figure out where to get new ones from. I called a dealer and they want $120 a piece, I'd love to find them somewhere cheaper, you know? Thanks for the help.

compewterman
07-18-2005, 09:22 AM
I also own a 95 v-8 and had the same problem.. it was due to MAF sensor... I had replaced all O2 sensors and the problem still existed... I changed out MAF Advance Auto $52.00 and its been running great ever since... I had tried cleaning it over and over and that didnt stop the problem.. I had read somewhere that cleaning might stop the light and codes but usually didnt.. so I just replaced it and have been running solid ever since.....I hope this helps

vschinzel
07-18-2005, 05:07 PM
thanks for the input, I'm gonna change the O2 Sensors, then I will move on to the MAF.

Did you replace ALL 4 Sensors on your t-bird? If so, please let me know if you know of a diffrent place to get them from other than FORD for the rear sensors...

THANKS!

compewterman
07-18-2005, 07:33 PM
Yes all 4.. I got them at AdvanceAuto

coondawg6
07-20-2005, 11:32 PM
fyi..the o2 sensors reading lean means sensors are working it would come up with different codes for faulty sensors lean bank 1 and 2 means
WHOLE engine running lean maf 1st guess, egr sticking/clogged second guess, vacuum leak third guess, or fuel pressure/flow not adequate meaning clogged fuel filter or faulty pump. as long as you can read o2 sensors being rich or lean means they are doing there job i do this for a living and i see younger tech jumping to o2 sensor conclusions all the time i give them same advice :2cents:

vschinzel
07-23-2005, 12:20 AM
thanks man, I appreciate the detailed information...

I looked for a reciept, because the car was in the shop before I bought it, the guy I bought the car from said it was in the car and I found it with the registration...

According to the reciept, the shop cleaned the EGR valve (I don't know what that is :( ), they cleaned the MAF (I know that one :) ) and they checked for vacuum leaks. Totaled about $200. It was a few weeks before I bought the car.

I went and bought the little T-20 tamper proof bit to check on the MAF, where is the EGR valve (what does it do?), how do I know if it's dirty?

I bought new spark plugs for it and got OE replacements for the front O2 sensors, have to call FORD for the part numbers of the rear ones, because neither autozone nor kragen carry them under any description.

Also, I want to get a new fuel filter, where does that go on the T-Bird (sorry, I'm a noob to T-birds). I also got a new air filter element and I'm gonna clean the intake box tomorrow, put the new filter in and check the MAF.

I really appreciate your guys' help. Thanks.

coondawg6
07-23-2005, 11:18 PM
the fuel filter is on passenger side just in front of rear tire mounted to the frame in a small cage you need a strait screwdriver and jack the car up and always use jackstands,dont need anybody getting head crushed ! ignition off take the hose clamp loose that holds the filter in place and you will see 2 clear tabs on the end of the fuel lines (1 on each line) they have 2 "fingers" that lock the lines to the filter they are removed by pulling/prying out on the clear tabs at 90 degrees to line, reverse to install. as for the egr i dont know your abilities but i would recommend a shop unless you are very mech inclined as the egr valve is on the back of engine, below the 90 degree plenum(intake, directly behind throttle body)takes about 45minutes to 1.5 hrs for experienced tech with specialty tools .... oh yeah egr valve=exhaust gas recirculation---recycles exhaust to intake manifold to reburn any leftover hydrocarbons for cleaner emissions and better fuel economy--when not working correctly causes stalling, hesitation, lack of power and poor fuel mileage

vschinzel
07-24-2005, 11:56 AM
thanks, now that makes sense....

The egr valve was cleaned by the shop according to the invoice, but that doesn't mean they did it, or did it right. Bunch of idiot shops here in Victorville, never take anything to MALSCOM'S in VV... morons...

I clean air intake box today, put a new filter in, hopefully change the spark plugs. They say they are pre-gapped, but I don't trust it. What is the recommended gap?

Thanks again, guys.

E-bird
07-24-2005, 12:32 PM
It's .054 inch

gtrtoolman
07-31-2005, 05:15 PM
the fuel filter is on passenger side just in front of rear tire mounted to the frame in a small cage you need a strait screwdriver and jack the car up and always use jackstands,dont need anybody getting head crushed ! ignition off take the hose clamp loose that holds the filter in place and you will see 2 clear tabs on the end of the fuel lines (1 on each line) they have 2 "fingers" that lock the lines to the filter they are removed by pulling/prying out on the clear tabs at 90 degrees to line, reverse to install. as for the egr i dont know your abilities but i would recommend a shop unless you are very mech inclined as the egr valve is on the back of engine, below the 90 degree plenum(intake, directly behind throttle body)takes about 45minutes to 1.5 hrs for experienced tech with specialty tools .... oh yeah egr valve=exhaust gas recirculation---recycles exhaust to intake manifold to reburn any leftover hydrocarbons for cleaner emissions and better fuel economy--when not working correctly causes stalling, hesitation, lack of power and poor fuel mileage

The codes on my 94 came back as no EGR, (originally started MAF sensor question) what kind of special tools are you referring to to change out the EGR valve? I am not sure if I should replace the sensor along with it or not, something is telling the computer that the system is not working, thinking the sensor may be OK.

coondawg6
07-31-2005, 09:46 PM
unless you take apart most of the top of the engine or put engine cradle on engine and pull front frame out you cant get to egr valve to unscrew the pipe from it. if you were referring to--- no egr flow detected--- all that you probably need to do is clean the egr port in lower intake plenum. this requires removing the 90 degree upper intake plenum behind throttle body. once you have removed the plenum you will see half moon shaped channel at back of plenum that is completely filled with carbon buildup you need to scrape the buildup out and clean the channel till its empty and reassemble i would suggest replacing the DPFE sensor and IAC valve only because these parts clog with carbon as well and are common replacement parts(they fail often) doing first time will take pretty much all day depending on your experience level

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