Lean on Bank 1

Car is a 1995 Taurus SHO ATX
Getting a code 136.

I've looked for vac leaks (none), replaced the o2 sensor twice, replaced the fuel injectors, etc, etc, etc, etc, etc. I bought a device called a TwEECer the other day, and ran a datalog on the car. The front o2 is only showing .06-.07v, while the rear is showing .7-.9v. Could this be a connection issue, or what? I'm going out of my mind here. I checked the o2 just to see if it was actually running lean, and low and behold, there was a big white spot. The spark plugs are showing a light grey as well. I think I have 1 strand of hair left, and I'd really like to keep it. HELP!!

Mass Air Flow Sensor might be dirty or faulty. Try cleaning it. Are you using a K&N air filter?


Car is a 1995 Taurus SHO ATX
Getting a code 136.

I've looked for vac leaks (none), replaced the o2 sensor twice, replaced the fuel injectors, etc, etc, etc, etc, etc. I bought a device called a TwEECer the other day, and ran a datalog on the car. The front o2 is only showing .06-.07v, while the rear is showing .7-.9v. Could this be a connection issue, or what? I'm going out of my mind here. I checked the o2 just to see if it was actually running lean, and low and behold, there was a big white spot. The spark plugs are showing a light grey as well. I think I have 1 strand of hair left, and I'd really like to keep it. HELP!!

Other than apparently running lean, are there any other symptoms? Does the car idle fine and seem to have decent power? Is it smooth, under load and from idle up to 4000 rpm or so?

I agree with reekor that cleaning the MAF would be a good starting point, along with adding a bottle of fuel injector cleaner in the tank.

When's the last time you gave the car a tune up? Are you sure the fuel filter is flowing freely?

-Rod

I don't own a SHO ... does it have a seperate cat converter for each bank?
If so ... did you check for restrictions in the cat on the faulty bank?
I had one bad plug on my 3.8L that fried the O2 sensor ... raw gas pumped thro to the sensor and converter.

Other than apparently running lean, are there any other symptoms? Does the car idle fine and seem to have decent power? Is it smooth, under load and from idle up to 4000 rpm or so?

I agree with reekor that cleaning the MAF would be a good starting point, along with adding a bottle of fuel injector cleaner in the tank.

When's the last time you gave the car a tune up? Are you sure the fuel filter is flowing freely?

-Rod

Idle is fine, vacuum is excellent (14-16psi...I have shoshop stage 2 cams), fuel pressure is at 32psi at idle, 39-40 at WOT. I did a cylinder balance test, and it showed problems with cylinders 1, 3, and 4. I recently replaced the injectors with a set cleaned and flow balanced by RC Engineering (www.rceng.com) (http://www.rceng.com)), and think there might be an issue with them. Going to pull them out tomorrow after work and test each one. Did another test this morning (7/10), and it showed 1,3, and 5. Definitely going to have to check out the injectors.

Wiring issue.

Is the fuel filter clean?

Shorod: Where is the Idle Air Control on my 03 Vulcan? Every now and then when I stop and idle with AC on the engine will surge up and down when the AC compresor shuts off. Long as the compressor is on it idles smooth as silk.
I cleaned the MAFS and reset the computer but still does it maybe twice or three times a day only when the engine is hot.

EDIT: Called my parts buddy at Advance and he told me where it is on the plenum, $49.95 and they can get it overnight. Said won't take but a few to put it on and he'll show me how to change it at the store. EDIT: Thurs AM. Yesterday it ran fine all day so resetting the computer and cleaning the MAFS must have fixed it.

Yes. I hooked up the TwEECer and it shows the voltage of the o2 at .06v. It is not switching at all. All other issues have been ruled out. Now I just have to chase the wire :popcorn:

Yes. I hooked up the TwEECer and it shows the voltage of the o2 at .06v. It is not switching at all. All other issues have been ruled out. Now I just have to chase the wire :popcorn:

I did a little research for you and read in another forum where Taurus' have some kind of wire to the battery that could cause your problem and several folks concured and had the same problem caused by the wire. No idea where to start looking so someone else will have to take it from there. Good luck.

I did a little research for you and read in another forum where Taurus' have some kind of wire to the battery that could cause your problem and several folks concured and had the same problem caused by the wire. No idea where to start looking so someone else will have to take it from there. Good luck.

Grab the multimeter, and start looking for open loops. Yeehaw. Hopefully the wiring harness doesn't have to be replaced.

Have you checked the battery voltage going to the O2 sensor (may be a ppl/org wire) AND checked that the gry/red (computer ground) is connected between the sensor and the computer. The gry/red is also accessable on the computer test block... so you can test for continuity between the sensor and the test block.

Have you checked the battery voltage going to the O2 sensor (may be a ppl/org wire) AND checked that the gry/red (computer ground) is connected between the sensor and the computer. The gry/red is also accessable on the computer test block... so you can test for continuity between the sensor and the test block.

I grabbed the wiring diagram this morning, and I'm going to check it out.

Thanks for the suggestion Gary.