Taurus Car Club of America : Ford Taurus Forum banner
1 - 20 of 37 Posts

·
Registered
Joined
·
34 Posts
Discussion Starter · #1 ·
Ok, so I have a lovely 99 Ford Taurus SE DOHC that I bought from an Auction back in August of last year. I have done many many many things to make this car run well, including new water pump as well as reservoir, new drums, rotors, brakes, two new tires, a new bearing, new MAF sensor (twice), new EGR sensor, new fuel filters, new exhaust pipe, and miscellaneous hoses and wires.

My car ran fine from September to April, but I have always had my check engine light on. It always said "Lean Fuel Bank 1, Lean Fuel Bank 2" (or P0171, P0174). Always, no matter what I did on the car. Since it had been running fine for so many months, I just ignored it.

Then, I drove from my house to the nearest "town" which was about 15 miles. I turned into a Moe's and my car shut off. I pushed it into a parking spot, waited about ten minutes, and it turned right back on..stayed on for a few seconds, and shut off. I called my grandfather who is a mechanic and went inside to eat. When he arrived from his house (about 40 miles away) we turned on the car and it ran fine for ten minutes. Then it shut off again. He inspected the car--my fuel pump was running, my battery, alternator, and starter were fine. He told me to change the fuel filter and try it again. Everything he could think to check was fine besides the possibility of the fuel filter. I got it towed back to my house and changed the fuel filter the next day. It turned right back on and I drove it for 10 miles before it shut off again. Unable to afford another tow bill, a friend who lived nearby pulled it into his yard (about a mile away) with his truck. His friend who is also a mechanic happened to be there. They checked it out while I was at work and told me that it was my catalytic converters.

I let it sit in their yard for about a week until I could come up with the money to replace the cats, and then had my cousin (also a mechanic..sad, really, no one can figure it out!) tow it to a muffler shop. They told him after examining it that it wasn't my cats--it was my EGR sensor. My cousin replaced the EGR sensor and drove it to where I work and left it there. I got off of work about seven hours after he left it off, turned it on, and drove 15 miles back home with no problem (aside from my squeaky struts!) except for random surges of power I would get every few miles for a few seconds. About a mile from my house the check engine light came back on..the two original codes P0171, P0174 and a new one P0401.

It seems to be running okay, but why would it tell me I have an insufficient EGR flow as well as Lean Bank 1 and 2 if the problem was resolved?
I spoke to my the mechanic that thought it was the cats, and he said I may need a new DPFE sensor..well all the auto part stores in the area have no idea what that is.

Anyone have any idea what the problem is?

Quick rundown for those who don't want to read so much:

Random shutting off after 15 mile drive
Turns on and stays running for a few seconds to minutes before shutting back off
Not catalytic converter, fuel pump coming on, replaced EGR sensor, have also previously replaced MAF sensor twice and new fuel filter.
Car running after replacing EGR sensor but getting surges of power.
3 codes P0171, P0174 and P0401.
Auto part stores unaware of DPFE sensor or what it could even be?




Thanks so much to anyone who has any idea.
 

·
Registered
Joined
·
34 Posts
Discussion Starter · #3 ·
I haven't replaced them, no. I do recall there being a code when I first bought the car (I have my own scanner because I needed it to drive a P.O.S. VW I used to own) about an O2 sensor in Bank 2 but I'm not exactly sure which one that is. Do you think that could cause these problems?
 

·
Registered
Joined
·
2,425 Posts

·
Registered
Joined
·
34 Posts
Discussion Starter · #5 ·
I didn't actually get the cats replaced because the muffler shop said that wasn't the problem. The 02 sensors should be next to the cats though, right?
 

·
Registered
Joined
·
3,377 Posts
if the egr is stuck open it can cause it to run lean. did you replace the egr tube or check and see if it was plugged? its not everyday you get 2 bad o2 sensors at the same time. if you pull the plugs they should be white if its been runnin lean for awhile
 

·
Devoted Member
Joined
·
2,426 Posts
A G3 Tec ehh? Have these EGR passageways been cleaned out?


A new EGR can't flow through that gunk, and a lot of "mechanics" are not aware of these passageways on Tecs. If your EGR and DPFE are new, I would start there.

also, ^+1 on the HEGO (O2) sensors. Dying sensors throw CEL codes for lean a lot. An intake manifold gasket leak will also cause lean codes from good sensors, (unmetered air getting around the MAF sensor). You did say MAF is new, but an oiled air filter can foul the MAF as well. Running too long with lean codes causes your PCM to try and compensate by throwing more fuel into the engine, this will eventually clog your cats beyond repair, and they are not cheap.
 

·
Registered
Joined
·
34 Posts
Discussion Starter · #8 ·
I didn't check it because I didn't actually put the part on. My cousin did while I was working, and it ran fine for about ten miles until the light came back on then it started surging. I'll attempt to go look, but I'm not as handy as a should be coming from a family full of mechanics. The most I've ever done under the hood is switch out a few water pumps and batteries and air filters.
 

·
Devoted Member
Joined
·
2,426 Posts
Yup dogg, 1 before and 1 after each cat. It's the ones before that you need to worry about. The above passageways are on the face of the UIM under the throttle body gasket. Gasket is completely reusable. The top left side of the passageway runs all the way back to the EGR in the pic, and "spray cleaner" will not get the goo out by itself. Toothpicks, soft solid wire (copper) little screwdrivers, and even dental hygienists picks are all highly recommended.

After some cleaning:
 

·
Registered
Joined
·
3,377 Posts
clean the passages and make sure nothing is clogged for the egr before moving on to the o2 sensors. if 2 sensors are giving you a lean code more then likely its a clog somewhere.
 

·
Devoted Member
Joined
·
2,426 Posts
Wow.. so how would I go about figuring out which one isn't working?
Bank 1 = firewall side of engine.
Bank 2 = radiator side of engine.

Both are before the cats (upstream). After cat sensors (downstream) throw different CEL codes. You would check them with an OBDII scan tool.
 

·
Registered
Joined
·
2,425 Posts
Dan, my gasket was horrible, had carbon "prints" on it, I had to replace it.
And my passage was identical with yours - 6 years ago and again now...

 

·
Devoted Member
Joined
·
2,426 Posts
Dan, my gasket was horrible, had carbon "prints" on it, I had to replace it.
And my passage was identical with yours - 6 years ago and again now...

A-hahaha! You thought that was my Tec in the pic! Funny!

(edit: my Tec EGR passages are just like my rear wheel well edges, nothing there!)
 

·
Premium Member
Joined
·
17,415 Posts
If you need a hand with the car and are near Columbia, SC, just shoot me a PM.
 

·
Registered
Joined
·
23,578 Posts
Omgcrista, you need to clean that entire c-channel (esp. the tunnel top left and the 3 notches at the base). I would remove the egr valve (at the left) and clean it up at this time also. Then, right below the c-channel on the left in the pic sits the black plastic pcv valve. Change it and its u-shaped hose on top. Then, with the throttle body still removed, change out the dpfe sensor (egr backpressure sensor) which sits to the right and rear of the c-channel with a borg-warner #egr155 from advance auto or oreilly. Guaranteed or your money back!
 

·
Registered
Joined
·
34 Posts
Discussion Starter · #20 · (Edited)
DPFE sensor has been changed, everything appears to be cleaned..and now it won't start. It's only telling me p0171 and p0174 now, but two 02 sensors failing at once?! And would that make a car not start? It cranks but won't turn over.

Edit: Also, fuel line isn't clogged. Unlikely it's the MAF because I've changed that twice and it still appears to be okay visually.

This car did have a huge vacuum leak problem when I got it..could that be the problem for these codes now? And where exactly would these leaks be if it were the problem?
 
1 - 20 of 37 Posts
Top