95 Gt Just Barely Passed California Smog - High No

Chythar

Recently finished repairing my rear
Dirt-Old 20+Year Member
Aug 26, 2004
2,370
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Foothill Ranch, CA
As I said, I just passed smog so I have about two years to really worry about this. But my 25mph NO reading was 458, with 498 allowed. I got 233 at 15mph, which is right at the average reading. HC was kinda high at 15mph, at 45 (allowed is 59). Basically, the NO values are both up from two years ago, and the HC readings are up a bit. Since HC and NO are both up from last year, seems to me that something is failing. Just checked for codes, and got the following:

KOEO - 111 PASS, Memory Codes: 212 and 334
KOER - code 116

(Pulled code values from http://www.troublecodes.net/ford/)
If I remember right, 212 indicates a PIP problem, and 334 says "EVP sensor is/was high – EVR". Not sure what that means, except that the EVP sensor is attached to the EGR. I've suspected the plastic vacuum lines were cracked and letting in un-metered air, but never got around to test it. I didn't let the engine warm up for KOER, so 116 (ECT out of range) was expected.

The EGR was replaced 2 1/2 years ago with a Motorcraft unit. My cats are new - I have a Bassani x-pipe with the high-flow cats, and I added two more high-flow cats (a total of 4) to pass smog two years ago.

Some internet research indicates that high NO on a Mustang 5.0 usually indicates the engine is running lean. If I'm getting bad values out of the EGR that could be the reason. I have no idea how to test the EGR system nor if it's really a vacuum issue.

If the PIP is failing, that would explain the small bit of stumbling I get. It only happens when I'm maintaining speed, then step on the gas. If I'm light on the gas pedal (not too often), the stumbling is barely noticeable. The stumble only lasts for a couple of seconds, then it goes away and the engine is back to normal. The engine also seems to run just a bit rough when it's cold, but after a couple of minutes of driving it's back to normal.

Any ideas would be appreciated.
 
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Pulled off the distributor cap and there's no play in the dizzy shaft, so I ordered a new Motorcraft PIP through Amazon. I think it was a dollar more than RockAuto, but free shipping. :D Love some input on testing the 334 code, tho. Never learned how to troubleshoot the EGR.
 
pip either works or doesnt, not aomething that slowy fails

That hasn't been my experience, at least from reading posts on this site for several years. A PIP that's having issues can cause several starting issues. Though if you have another cause for my 212 error code, I'm definitely all ears. I will be one of the first to admit that I can be wrong.
 
That hasn't been my experience, at least from reading posts on this site for several years. A PIP that's having issues can cause several starting issues. Though if you have another cause for my 212 error code, I'm definitely all ears. I will be one of the first to admit that I can be wrong.

I think you are confusing the PIP with the TFI re code 212.
 
Code 18 or 212 - SPOUT out or wiring fault - look for short to ground in SPOUT wiring going back to the computer. Possible bad TFI or defective 22 K resistor in the IDM wiring

Use a timing light to check the timing: remove the SPOUT and observe that the timing retards at least 4 degrees. Put the SPOUT back in place and observe that the spark advances at least 4 degrees.
This code can disable spark advance and reduce power and fuel economy.

Remove the passenger side kick panel and disconnect the computer connector.
There is a 10 MM bolt that holds it in place.
Disconnect the TFI module connector from the TFI and the measure the resistance between the yellow/lt green wire and ground. You should see greater than 100 K (100000) ohms.
Check the resistance from Pin 4 on the computer connector (dark green/yellow) and the dark green/yellow wire on the TFI connector. You should see 20-24 K Ohms (20,000-24,0000 ohms). The resistor is located in the wiring harness about 6” from the connector. You will need solder and heat shrink to replace the resistor if it is bad.
Next measure the resistance between the yellow/lt green wire on the TFI module connector and Pin 36 on the computer connector. With the SPOUT plug in place, you should see less than 2 ohms.

The following is a view from the computer side of the computer connector.
http://www.stangnet.com/mustang-forums/attachments/a9x-series-computer-connector-wire-side-view-gif.71316/[/img

This diagram is the wire side of the computer connector.
[img]http://www.stangnet.com/mustang-forums/attachments/a9x-series-computer-connector-wire-side-view-gif.71316/

Diagram courtesy of Tmoss & Stang&2birds

94-95_5.0_EEC_Wiring_Diagram.gif


Code 34 Or 334 - EGR voltage above closed limit –

Revised 26-Sep-2011 to add EGR cleaning and movement test for pintle when vacuum is applied to diaphragm

Failed sensor, carbon between EGR pintle valve and seat holding the valve off its seat. Remove the EGR valve and clean it with carbon remover. Prior to re-installing see if you can blow air through the flange side of the EGR by mouth. If it leaks, there is carbon stuck on the pintle valve seat clean or, replace the EGR valve ($85-$95).

Recommended procedure for cleaning the EGR:
Conventional cleaning methods like throttle body cleaner aren’t very effective. The best method is a soak type cleaner used for carburetors. If you are into fixing motorcycles, jet skis, snowmobiles or anything else with a small carburetor, you probably have used the one gallon soak cleaners like Gunk or Berryman. One of the two should be available at your local auto parts store for $22-$29. There is a basket to set the parts in while they are soaking. Soak the metal body in the carb cleaner overnight. Don’t immerse the diaphragm side, since the carb cleaner may damage the diaphragm. If you get any of the carb cleaner on the diaphragm, rinse it off with water immediately. Rinse the part off with water and blow it dry with compressed air. Once it has dried, try blowing through the either hole and it should block the air flow. Do not put parts with water on them or in them in the carb cleaner. If you do, it will weaken the carb cleaner and it won’t clean as effectively.

Gunk Dip type carb & parts soaker:
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If you have a handy vacuum source, apply it to the diaphragm and watch to see if the pintle moves freely. Try blowing air through either side and make sure it flows when the pintle retracts and blocks when the pintle is seated. If it does not, replace the EGR.


If the blow by test passes, and you have replaced the sensor, then you have electrical ground problems. Check the resistance between the black/white wire on the MAP/BARO sensor and then the black/white wire on the EGR and the same wire on the TPS. It should be less than 1.5 ohm. Next check the resistance between the black/white wire and the negative battery post. It should be less than 1.5 ohm.

Note that all resistance tests must be done with power off. Measuring resistance with a circuit powered on will give false readings and possibly damage the meter.

Let’s put on our Inspector Gadget propeller head beanies and think about how this works:
The EGR sensor is a variable resistor with ground on one leg and Vref (5 volts) on the other. Its’ resistance ranges from 4000 to 5500 Ohms measured between Vref & ground, depending on the sensor. The center connection of the variable resistor is the slider that moves in response to the amount of vacuum applied. The slider has some minimum value of resistance greater than 100 ohms so that the computer always sees a voltage present at its’ input. If the value was 0 ohms, there would be no voltage output. Then the computer would not be able to distinguish between a properly functioning sensor and one that had a broken wire or bad connection. The EGR I have in hand reads 700 Ohms between the slider (EPV) and ground (SIG RTN) at rest with no vacuum applied. The EGR valve or sensor may cause the voltage to be above closed limits due to the manufacturing tolerances that cause the EGR sensor to rest at a higher position than it should.

The following sensors are connected to the white 10 pin connector (salt & pepper engine harness connectors)
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This will affect idle quality by diluting the intake air charge
 
Pulled off the distributor cap and there's no play in the dizzy shaft, so I ordered a new Motorcraft PIP through Amazon. I think it was a dollar more than RockAuto, but free shipping. :D Love some input on testing the 334 code, tho. Never learned how to troubleshoot the EGR.

In addition to all the great helps you are receiving already concerning your EGR issue, I just did a brief/basic post on EGR trouble. It might be helpful.
 
How to pass emissions testing:

High NO - high combustion temps - retard timing, check EGR for operation.
High CO – Rich condition - fuel pressure too high, check O2 sensors, replace air filter, Clean MAF element.
High HC – Lean misfire, vacuum leak, common misfire due to worn or weak ignition system components. On rare occasions, an overly rich mixture may be the cause. Do the ethanol/E10 fill up as suggested.
High CO & HC - Cat converters, smog pump, and smog pump controls. Make sure the smog pump has good air output at 1200-1700 RPM

How to pass emissions testing:

1.) Make sure all the emissions gear the car was made with is present and connected up properly. That includes a working smog pump and cats. The smog tech will do a visual check to make sure that all the original equipment is present and connected up.

2.) Make sure that you have fresh tune up with spark plugs, plug wires, cap, rotor, fuel & air filters. An oil & filter change is a good idea while you are at it.

3.) [Dumping the computer diagnostic codes on 86-95 Mustangs

Revised 26-July-2011. Added need to make sure the clutch is pressed when dumping codes.

Codes may be present even if the check engine light hasn’t come on, so be sure to check for them.

Here's the way to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

Post the codes you get and I will post 86-93 model 5.0 Mustang specific code definitions and fixes. I do not have a complete listing for 94-95 model 5.0 Mustangs at this time.

Be sure to turn off the A/C, and put the transmission in neutral when dumping the codes. On a manual transmission car, be sure to press the clutch to the floor.
Fail to do this and you will generate a code 67 and not be able to dump the Engine Running codes.

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If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.

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The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.

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The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.


WARNING!!! There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.

What to expect:
You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems. This is crucial: the same wire that provides the ground to dump the codes provides signal ground for the TPS, EGR, ACT and Map/Baro sensors. If it fails, you will have poor performance, economy and driveablity problems

Some codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off, and clutch (if present) is pressed to the floor, and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.

Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

Your 86-88 5.0 won't have a working Check Engine Light, so you'll need a test light.
See AutoZone Part Number: 25886 , $10
4




Alternate methods:
For those who are intimidated by all the wires & connections, see Actron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

Or for a nicer scanner see Equus - Digital Ford Code Reader (3145) – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30.


Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off, clutch depressed to the floor and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.
Cylinder balance test
Warm the car's engine up to normal operating temperature. Use a jumper wire or paper clip to put the computer into test mode. Start the engine and let it go through the normal diagnostic tests, then quickly press the throttle to the floor. The engine RPM should exceed 2500 RPM's for a brief second. The engine RPM's will increase to about 1450-1600 RPM and hold steady. The engine will shut off power to each injector, one at a time. When it has sequenced through all 8 injectors, it will flash 9 for everything OK, or the number of the failing cylinder such as 2 for cylinder #2. Quickly pressing the throttle again up to 2500 RPM’s will cause the test to re-run with smaller qualifying figures.
Do it a third time, and if the same cylinder shows up, the cylinder is weak and isn’t putting out power like it should. See the Chilton’s Shop manual for the complete test procedure



4.) Post the codes and get help to fix them. Don’t try to pass with codes not fixed. Clearing the computer just temporarily removes them from memory, it doesn’t fix the problem that caused the code to be set.

5.) Be sure to do the testing on a hot engine. Drive for 15-20 minutes prior to taking the test to get operating temps up into the normal range. Do not shut off the engine while waiting for your turn on the test machine. An engine up to full operating temperature puts out fewer emissions.
 

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I got a car smogged here in the great state of California and I was talking to the owner of the smog shop and rumor is that in 2020, 1995 and older cars wont need to smog. That would be perfect for my 94 cobra! Dont have to spend more on a carb #. Lets keep fingers crossed even though it is a while away.
 
I got a car smogged here in the great state of California and I was talking to the owner of the smog shop and rumor is that in 2020, 1995 and older cars wont need to smog. That would be perfect for my 94 cobra! Dont have to spend more on a carb #. Lets keep fingers crossed even though it is a while away.

From what I'm reading, the plan is to eliminate tailpipe readings for 2000 and newer cars. The PDF I read says that tailpipe testing will need to continue on pre-1996 cars.

http://www.arb.ca.gov/msprog/smogcheck/march09/transitioning_to_obd_only_im.pdf , page ES-2.
 
Oh, I might as well give an update. Replacing the PIP in my distributor cleared the 212 code. The engine runs smoother than it ever has, so it seems the PIP has been bad for a while.