high HC emissions problem - Taurus Car Club of America : Ford Taurus Forum
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post #1 of 31 (permalink) Old 08-16-2012, 10:27 PM Thread Starter
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high HC emissions problem

My '95 sable failed emissions on the HC twice. The rest of the numbers are okay. The HC numbers are:

1st test:
157ppm/15mph, 186ppm/25mph

2nd test:
206ppm/15mph, 238ppm/25mph

The max allowable numbers are:
85ppm/15mph, 50ppm/25mph

I did what I could to get it fully warmed up at test time, but it ended up sitting there for about 15 mins before the actual test. There are some smells that suggest combustion problems. It's never really been all that fuel-efficient since I acquired it which was about a year ago. I'll start going through the usual suspects, but one thing I'm wondering about is whether there might be a fuel system problem in the ECU.
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post #2 of 31 (permalink) Old 08-17-2012, 05:19 AM
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It would be nice to know the other numbers as well (NOX, CO, CO2, and O2 if you have it). Scanning the slip would work too. Example (thanks to Troy):


I would start by performing an OBD self test to see if you have any codes. All you need to do this is a paper clip to ground the self test connector. Count the blinks to get the codes.

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post #3 of 31 (permalink) Old 08-24-2012, 12:28 AM Thread Starter
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The rest of the numbers:

%CO2 | %O2 | HC(PPM) | CO(%) | NO(PPM) |
------------------------------------------------------------------------------------
Test | RPM | MEAS| MEAS | MAX GP MEAS | MAX GP MEAS | MAX GP MEAS |
------------------------------------------------------------------------------------
15mph | 2109 | 14.2| 0.5 | 85 271 206 | 0.50 2.00 0.31 | 695 1918 439 |
25mph | 1532 | 14.1| 0.6 | 50 221 238 | 0.47 1.97 0.28 | 717 1718 561 |
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post #4 of 31 (permalink) Old 08-24-2012, 06:31 AM
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The other numbers are fairly high as well, so your catalytic convertors are probably not working very well. But HC are still really high so you have some sort of combustion problem (running a bit rich).

You mentioned a dirty air filter, so I would replace that and clean the MAF. You might also think about changing the oxygen sensors?

Did you get around to running the OBD self-test yet to see if you have any codes?
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post #5 of 31 (permalink) Old 08-24-2012, 07:24 PM
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A leaking fuel pressure regulator also can cause rich running/poor fuel economy/high HCs.

"Spare the duct tape, spoil the job."
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post #6 of 31 (permalink) Old 08-24-2012, 10:39 PM
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Quote:
Originally Posted by WJC View Post
A leaking fuel pressure regulator also can cause rich running/poor fuel economy/high HCs.
Another good thing to check. Pull the vac line off and let the engine idle for several minutes. Smell/look for gas coming out of the vacuum nipple on the diaphragm.
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post #7 of 31 (permalink) Old 08-26-2012, 05:58 PM Thread Starter
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I installed a new air filter. I think the air filter housing was not attached correctly. An image is attached showing where there might have been a leak (right in the center of the picture). It's hard to tell from the manuals how it sets up exactly. I think I've set it up correctly, but now the metal clips are a little loose. Also, are all models supposed to have an air intake resonator? There isn't one in this vehicle.

There may be some codes in the vehicle. The EEC terminal plastic is warped/ melted. My digital multimeter fluctuated when probing terminal #4, but nothing from the analog multimeter. I know the CEL is working, because it came on a number of times when I happened to leave the MAF sensor connector out one time several weeks ago.
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post #8 of 31 (permalink) Old 08-26-2012, 06:14 PM
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I think the CEL will flash the codes one you get it into self-test mode if you don't like watching a multimeter under the hood.
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post #9 of 31 (permalink) Old 08-26-2012, 06:40 PM Thread Starter
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The codes are:

335 (EGR sensor)
326 (EGR sensor)
452 (Vehicle speed sensor)
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post #10 of 31 (permalink) Old 08-26-2012, 08:36 PM
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Well, I would have a look at the EGR pressure sensor. Make sure the tubes are attached, aren't cracked, and the sensor isn't melted. Also make sure the EGR valve is working by applying vacuum and listening for the engine to stumble (it should practically stall at idle).

VSS code says signal is too "small" so not sure if that means the sensor is bad, disconnected, or the wires are damaged.

Do you know which codes were on demand and which ones were memory?
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