jayurface

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Oct 5, 2016
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I have made previous postings about my car (1994 cobra with X303 Ford Racing Engine), but nothing has really come out of it. I think the problem back then was CEL codes. As many problems I have had with this car (very strong gas smell failing emissions) the car would not pull any CEL codes. Well now you have to wonder how catastrophically wrong that the car suddenly start coding. Here is a list of everything that it said let me know what you think:

KOEO:
157 - Mass air bellow minimum voltage
511 - Read Only Memory Failed replace PCM

KOER:
116 - Engine coolant voltage out of range
137 - Left bank mixture rich
173 - Right bank rich
412 - Idle speed system not controlling idle properly
415 - Idle speed circuit not operational
512 - Memory power PCM pin 1 interrupted

Last but not least the funniest code I pulled in both KOEO and KOER test:

111 - System checks OK.

There are 2 questions here. Is it truly a bad PCM or a bad wiring harness? These test were conducted from the flashing CEL. I attempted to connect my diagnostic tool to the car and the RPMs responded just as the tool displayed it would however after a minute or two the diagnostic screen said "vehicle refuses to follow commands" A rebel without a cause right? The thing about this car too is there is nothing wrong with performance it just smells very bad. It is very responsive, drives strong, does not hesitate, not missing, but I need it to stop smelling bad and pass emissions already! Another thing to note is the PCM was replaced a few years ago. I have also replaced EGR valve, MASS Air, IAC, Temp sensor, TPS, Idle Air Bypass valve, both O2 sensors, Speedometer sensor. all vacuum lines, and fuel injectors,
 
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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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Wow, now thats a list!
I'd check the pcm to make sure it's right for your car and maybe get it checked out to see if it's functional.
Thats all I got.
 

jrichker

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@jayurface

I can give you help on some of the codes, but not all of since they match up with Fox body 5.0 Mustangs.

When specific pin numbers are given, check the 94-95 5.0 Mustangs wiring diagrams to insure that you have the correct pin numbers when you do any tests.

Code 66 or 157 MAF below minimum test voltage.

Revised 10-Feb-2014 to add 95-95 Mustang code 157 and 94-95 ECC diagram

Insufficient or no voltage from MAF. Dirty MAF element, bad MAF, bad MAF wiring, missing power to MAF. Check for missing +12 volts on this circuit. Check the two links for a wiring diagram to help you find the red wire for computer power relay switched +12 volts. Check for 12 volts between the red and black wires on the MAF heater (usually pins A & B). while the connector is plugged into the MAF. This may require the use of a couple of safety pins to probe the MAF connector from the back side of it.

Computer wiring harness connector, wire side
71316.gif


Computer wiring harness connector, computer side side
88243.gif




Diagrams courtesy of Tmoss and Stang&2Birds

ECC Diagram for 88-90 5.0 Mustangs
88-91_5.0_EEC_Wiring_Diagram.gif


ECC Diagram for 91-93 5.0 Mustangs
91-93_5.0_EEC_Wiring_Diagram.gif


Diagram for 94-95 5.0 Mustangs
94-95_5.0_EEC_Wiring_Diagram.gif



How the MAF works

There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element causing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables. Changes in RPM causes the airflow to increase or decrease, changing the voltage output.. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow.

The MAF element is secured by 2 screws & has 1 wiring connector. To clean the element, remove it from the MAF housing and spray it down with electronic parts cleaner or non-inflammable brake parts cleaner (same stuff in a bigger can and cheaper too).

89-90 Model cars: Measure the MAF output at pins C & D on the MAF connector (dark blue/orange and tan/light blue) or at pins 50 & 9 on the computer. Be sure to measure the sensor output by measuring across the pins and not between the pins and ground.

91-95 Model cars: Measure the MAF output at pins C & D on the MAF connector light blue/red and tan/light blue) or at pins 50 & 9 on the computer. Be sure to measure the sensor output by measuring across the pins and not between the pins and ground.


At idle = approximately .6 volt
20 MPH = approximately 1.10 volt
40 MPH = approximately 1.70 volt
60 MPH = approximately 2.10 volt

Check the resistance of the MAF signal wiring. Pin D on the MAF and pin 50 on the computer (dark blue/orange wire) should be less than 2 ohms. Pin C on the MAF and pin 9 on the computer (tan/light blue wire) should be less than 2 ohms.

There should be a minimum of 10K ohms between either pin C or D on the MAF wiring connector and pins A or B. Make your measurement with the MAF disconnected from the wiring harness.

Actually MAF pins C & D float with reference to ground. The signal output of the MAF is a differential amplifier setup. Pins C & D both carry the output signal, but one pin's output is inverted from the other. The difference in signal between C & D is what the computer's input circuit is looking for. The difference in the two outputs helps cancel out electrical noise generated by the ignition system and other components. Since the noise will be of the same polarity, wave shape and magnitude, the differential input of the computer electronically subtracts it from the signal. Then it passes the signal on to an Analog to Digital converter section inside the computer's CPU chip.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel pump, alternator, ignition & A/C wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Computer,. actuator & sensor wiring
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Fuse panel layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

Vacuum routing
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg



Code 66 or 157 MAF below minimum test voltage.

Revised 10-Feb-2014 to add 95-95 Mustang code 157 and 94-95 ECC diagram

Insufficient or no voltage from MAF. Dirty MAF element, bad MAF, bad MAF wiring, missing power to MAF. Check for missing +12 volts on this circuit. Check the two links for a wiring diagram to help you find the red wire for computer power relay switched +12 volts. Check for 12 volts between the red and black wires on the MAF heater (usually pins A & B). while the connector is plugged into the MAF. This may require the use of a couple of safety pins to probe the MAF connector from the back side of it.

Computer wiring harness connector, wire side
71316.gif


Computer wiring harness connector, computer side side
88243.gif


Diagrams courtesy of Tmoss and Stang&2Birds

ECC Diagram for 88-90 5.0 Mustangs
88-91_5.0_EEC_Wiring_Diagram.gif


ECC Diagram for 91-93 5.0 Mustangs
91-93_5.0_EEC_Wiring_Diagram.gif


Diagram for 94-95 5.0 Mustangs
94-95_5.0_EEC_Wiring_Diagram.gif



How the MAF works

There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element causing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables. Changes in RPM causes the airflow to increase or decrease, changing the voltage output.. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow.

The MAF element is secured by 2 screws & has 1 wiring connector. To clean the element, remove it from the MAF housing and spray it down with electronic parts cleaner or non-inflammable brake parts cleaner (same stuff in a bigger can and cheaper too).

89-90 Model cars: Measure the MAF output at pins C & D on the MAF connector (dark blue/orange and tan/light blue) or at pins 50 & 9 on the computer. Be sure to measure the sensor output by measuring across the pins and not between the pins and ground.

91-95 Model cars: Measure the MAF output at pins C & D on the MAF connector light blue/red and tan/light blue) or at pins 50 & 9 on the computer. Be sure to measure the sensor output by measuring across the pins and not between the pins and ground.


At idle = approximately .6 volt
20 MPH = approximately 1.10 volt
40 MPH = approximately 1.70 volt
60 MPH = approximately 2.10 volt

Check the resistance of the MAF signal wiring. Pin D on the MAF and pin 50 on the computer (dark blue/orange wire) should be less than 2 ohms. Pin C on the MAF and pin 9 on the computer (tan/light blue wire) should be less than 2 ohms.

There should be a minimum of 10K ohms between either pin C or D on the MAF wiring connector and pins A or B. Make your measurement with the MAF disconnected from the wiring harness.

Actually MAF pins C & D float with reference to ground. The signal output of the MAF is a differential amplifier setup. Pins C & D both carry the output signal, but one pin's output is inverted from the other. The difference in signal between C & D is what the computer's input circuit is looking for. The difference in the two outputs helps cancel out electrical noise generated by the ignition system and other components. Since the noise will be of the same polarity, wave shape and magnitude, the differential input of the computer electronically subtracts it from the signal. Then it passes the signal on to an Analog to Digital converter section inside the computer's CPU chip.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel pump, alternator, ignition & A/C wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Computer,. actuator & sensor wiring
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Fuse panel layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

Vacuum routing
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg



Code 42 & 92 & 137 & 173 (engine running) System rich - Fuel control or (memory) System was rich for 15 seconds or more (no HO2S switching) - Fuel control. Look for leaking injectors, fuel pressure too high, cylinder(s) not firing due to bad ignition.

Code 42 passenger side sensor, as viewed from the driver's seat
Code 92 is the driver side sensor, as viewed from the driver's seat..

The following is a Quote from Charles O. Probst, Ford fuel Injection & Electronic Engine control:
"When the mixture is lean, the exhaust gas has oxygen, about the same amount as the ambient air. So the sensor will generate less than 400 Millivolts. Remember lean = less voltage.

When the mixture is rich, there's less oxygen in the exhaust than in the ambient air , so voltage is generated between the two sides of the tip. The voltage is greater than 600 millivolts. Remember rich = more voltage.

Here's a tip: the newer the sensor, the more the voltage changes, swinging from as low as 0.1 volt to as much as 0.9 volt. As an oxygen sensor ages, the voltage changes get smaller and slower - the voltage change lags behind the change in exhaust gas oxygen.

Because the oxygen sensor generates its own voltage, never apply voltage and never measure resistance of the sensor circuit. To measure voltage signals, use an analog voltmeter with a high input impedance, at least 10 megohms. Remember, a digital voltmeter will average a changing voltage." End Quote

Testing the O2 sensors 87-93 5.0 Mustangs
Measuring the O2 sensor voltage at the computer will give you a good idea of how well they are working. You'll have to pull the passenger side kick panel off to gain access to the computer connector. Remove the plastic wiring cover to get to the back side of the wiring. Use a safety pin or paper clip to probe the connections from the rear.


Backside view of the computer wiring connector:
a9x-series-computer-connector-wire-side-view-gif.71316.gif


87-90 5.0 Mustangs:
Computer pin 43 Dark blue/Lt green – LH O2 sensor
Computer pin 29 Dark Green/Pink – RH O2 sensor
The computer pins are 29 (LH O2 with a dark green/pink wire) and 43 (RH O2 with a dark blue/pink wire). Use the ground next to the computer to ground the voltmeter. The O2 sensor voltage should switch between .2-.9 volt at idle.

91-93 5.0 Mustangs:
Computer pin 43 Red/Black – LH O2 sensor
Computer pin 29 Gray/Lt blue – RH O2 sensor
The computer pins are 29 (LH O2 with a Gray/Lt blue wire) and 43 (RH O2 with a Red/Black wire). Use the ground next to the computer to ground the voltmeter. The O2 sensor voltage should switch between .2-.9 volt at idle.


Testing the O2 sensors 94-95 5.0 Mustangs
Measuring the O2 sensor voltage at the computer will give you a good idea of how well they are working. You'll have to pull the passenger side kick panel off to gain access to the computer connector. Remove the plastic wiring cover to get to the back side of the wiring. Use a safety pin or paper clip to probe the connections from the rear. The computer pins are 29 (LH O2 with a red/black wire) and 27 (RH O2 with a gray/lt blue wire). Use pin 32 (gray/red wire) to ground the voltmeter. The O2 sensor voltage should switch between .2-.9 volt at idle.



There is a fuse link for the O2 sensor heater power. According to Ranchero50, it is in the wiring near the passenger side hood hinge. Measuring the voltages will give a clue if it has shorted to the O2 sensor signal lead. The O2 sensor voltage should switch between .2-.9 volt at idle.



Code 21 or 116 – ECT sensor out of range. Broken or damaged wiring, bad ECT sensor.

[color= blue]Revised 6-Apr-2017 to add diagrams and resistance check for ECT wiring.[/color]

Note that that if the outside air temp is below 50 degrees F that the test for the ECT can be in error. Warm the engine up until you get good hot air from the heater and then dump the codes again.

The computer Engine Coolant Temperature sensor has absolutely nothing to do with the temperature gauge. They are different animals. The ECT sensor is normally located it the passenger side front of the engine in the water feed tubes for the heater. It has two wires that connect by a weathertight plastic connector.

The water temperature sender for the temp gauge is located in the driver's side lower intake manifold. It has a single wire that connects by a push on connector on the temp sender.


If you have replaced the ECT sensor and are still having ECT like problem symptoms, check the ECT wiring .

Computer wiring harness connector, wire side
71316.gif


Computer wiring harness connector, computer side
88243.gif



See the graphic for the 10 pin connector circuit layout.
68512.jpg


Check the resistance of the green wire on the ECT connector to the green wire on pin 7 of the computer connector. You should see less that 1 Ω (ohm)

The ACT & ECT have the same thermistor, so the table values are the same

ACT & ECT test data:

Use Pin 46 on the computer for ground for both ECT & ACT to get most accurate readings.

Pin 7 on the computer - ECT signal in. At 176 degrees F it should be .80 volts

Pin 25 on the computer - ACT signal in. At 50 degrees F it should be 3.5 volts. It is a good number if the ACT is mounted in the inlet airbox. If it is mounted in the lower intake manifold, the voltage readings will be lower because of the heat transfer.


Voltages may be measured across the ECT/ACT by probing the connector from the rear. A pair of safety pins may be helpful in doing this. Use care in doing it so that you don't damage the wiring or connector.

Here's the table :

50 degrees F = 3.52 v
68 degrees F = 3.02 v
86 degrees F = 2.62 v
104 degrees F = 2.16 v
122 degrees F = 1.72 v
140 degrees F = 1.35 v
158 degrees F = 1.04 v
176 degrees F = .80 v
194 degrees F = .61
212 degrees F = .47 v
230 degrees F = .36 v
248 degrees F = .28 v

Ohms measures at the computer with the computer disconnected, or at the sensor with the sensor disconnected.

50 degrees F = 58.75 K ohms
68 degrees F = 37.30 K ohms
86 degrees F = 27.27 K ohms
104 degrees F = 16.15 K ohms
122 degrees F = 10.97 K ohms
140 degrees F = 7.60 K ohms
158 degrees F = 5.37 K ohms
176 degrees F = 3.84 K ohms
194 degrees F = 2.80 K ohms
212 degrees F = 2.07 K ohms
230 degrees F = 1.55 K ohms
248 degrees F = 1.18 k ohms

Diagram courtesy of Tmoss & Stang&2birds

88-91_5.0_EEC_Wiring_Diagram.gif


94-95_5.0_EEC_Wiring_Diagram.gif
Wiring_Diagram.gif[/

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds
(website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg



Code 12 &412 -Idle Air Bypass motor not controlling idle properly (generally idle too low) - IAB dirty or not working. Clean the electrical contacts with non flammable brake parts cleaner at the same time.

IAC doesn't work: look for +12 volts at the IAC red wire. Then check for continuity between the white/lt blue wire and pin 21 on the computer. The IAC connector contacts will sometimes corrode and make the IAC not work. The red wire on the IAC is always hot with the engine in run mode. The computer provides a ground for the current for the IAC. It switches the ground on and off, making a square wave with a varying duty cycle. A normal square wave would be on for 50% of the time and off for 50% of the time. When the idle speed is low, the duty cycle increases more than 50% to open the IAC more. When the engine speed is high, it decreases the duty cycle to less than 50% to close the IAC. An old-fashioned dwell meter can be used to check the change: I haven’t tried it personally, but it should work. In theory, it should read ½ scale of whatever range you set it on with a 50% duty cycle. An Oscilloscope is even better if you can find someone who has one and will help.

attachment.php


Recommended procedure for cleaning the IAC/IAB:
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. Take the solenoid off the body and set it aside: the carb cleaner will damage some types of plastic parts. Soak the metal body in the carb cleaner overnight. There is a basket to set the parts in while they are soaking. When you finish soaking overnight, twist the stem of the IAB/IAC that sticks out while the blocker valve is seated. This removes any leftover deposits from the blocker valve seat. Rinse the part off with water and blow it dry with compressed air. The IAC/IAB should seal up nicely now. Once it has dried, try blowing through the bottom hole and it should block the air flow. Reassemble and reinstall to check it out.

Gunk Dip type carb & parts soaker:
21hb0QWbOeL._SL500_AA300_.jpg


Setting the base idle speed:
First of all, the idle needs to be adjusted to where the speed is at or below 600 RPM with the IAC disconnected. If you have a wild cam, you may have to raise this figure 100-150 RPM or so. Then the electrical signal through the IAC can vary the airflow through it under computer control. Remember that the IAC can only add air to increase the base idle speed set by the mechanical adjustment. The 600 RPM base idle speed is what you have after the mechanical adjustment. The IAC increases that speed by supplying more air under computer control to raise the RPM’s to 650-725 RPM’s. This figure will increase if you have a wild cam, and may end up between 800-950 RPM

Remember that changing the mechanical idle speed adjustment changes the TPS setting too.

This isn't the method Ford uses, but it does work. Do not attempt to set the idle speed until you have fixed all the codes and are sure that there are no vacuum leaks.

Disconnect the battery negative terminal and turn the headlights on. Leave the battery negative terminal disconnected for 5 minutes or so. Then turn the headlights off and reconnect the battery. This erases the computer settings that may affect idle performance.

Warm the engine up to operating temperature, place the transmission in neutral, and set the parking brake. Turn off lights, A/C, all unnecessary electrical loads. Disconnect the IAC electrical connector. Remove the SPOUT plug. This will lock the ignition timing so that the computer won't change the spark advance, which changes the idle speed. Note the engine RPM: use the mechanical adjustment screw under the throttle body to raise or lower the RPM until you get the 600 RPM mark +/- 25 RPM. A wild cam may make it necessary to increase the 600 RPM figure to 700 RPM or possibly a little more to get a stable idle speed.
Changing the mechanical adjustment changes the TPS, so you will need to set it.

When you are satisfied with the results, turn off the engine, and re-install the SPOUT and reconnect the IAC. The engine should idle with the range of 650-750 RPM without the A/C on or extra electrical loads. A wild cam may make this figure somewhat higher.

An engine that whose idle speed cannot be set at 600 RPM with the IAC disconnected has mechanical problems. Vacuum leaks are the #1 suspect in this case. A vacuum gauge will help pinpoint both vacuum leaks and improperly adjusted valves. A sticking valve or one adjusted too tight will cause low vacuum and a 5"-8" sweep every time the bad cylinder comes up on compression stroke. An extreme cam can make the 600 RPM set point difficult to set. Contact your cam supplier or manufacturer to get information on idle speed and quality


Code 13 & 415 - Key on Engine off - ISC did not respond properly (extends to touch throttle then retracts for KOEO) – ISC

Key on Engine running - Idle Speed Control motor or Air Bypass not controlling idle properly (generally idle too high)

If your idle is above 725 RPM, the computer will set this code. Normal idle speed is 650-725 RPM. Higher than that means that someone has mechanically set the idle speed by use of the idle speed screw, and has effectively disabled to computer’s ability to control idle speed.

Code 415no power at computer pin #1 for keep alive memory and adaptive learning data.

The Fox body Mustangs and SN95 V8 are all OBDI computers and have two type of memory:

Ram which is volatile, meaning the contents vanish when the power for it is removed. This storage contains the last trouble codes and settings for the adaptive learning. This is data that the computer picks up and uses to customize the engine performance for normal driving. It uses 12 volts directly drawn from the battery, just like the stored settings for the radio. If you have ever disconnected the battery and had to put your favorite radio stations back in the radio’s memory, you have a perfect example of how this works.

Rom which is built into the computer program chip when it was manufactured. This is non-erasable and non-changeable under normal operation. It contains the fixed data that the computer uses as a baseline for normal operation.

The computer uses both Ram and Rom when you drive the vehicle; it uses the Rom data and then combines it with the Ram data to get best performance and fuel economy.

Later model cars with OBDII computers use a memory system very similar to the flash drives and thumb drives that many of us are familiar with. It is capable of being read from and written to many times and allows simple reprogramming with a handheld tuner.

Now that we understand the theory, it’s time to go troubleshooting.
Power for computer pin #1 bypasses the ignition switch and CCM module. It should have power as long as the battery is capable of starting the car. If for some reason the Ignition switch is in the Run position and there is sufficient power to start the engine, there should be battery voltage present at pin#1 on the computer. If there isn’t, then you have wiring problems between the computer (PCM) power relay and the computer pin #1
 
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jayurface

Member
Oct 5, 2016
8
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Jrichker,

Thank you for all of the information you provided me. I am sure it will be very useful when I start diving into everything again. The problem is all of these sensors are new so not cleaning is needed. The mass air, IAT, TPS, bypass valve, EGR valve, Fuel injectors, speed sensor, O2 sensors, and PCM. The PCM is the correct configuration for a 94-95 cobra (J4J1). No blown fuses and the relays are good. Not too long ago I did take the PCM apart and did not see any obvious burn spots. All of the vacuum lines are new as well

Something I did forget to mention in my original posting. I have pulled codes several times to see if I get different ones and in the second session I got the code for lean bank 2.
 

Chythar

Recently finished repairing my rear
15 Year Member
Aug 26, 2004
2,274
77
98
50
West Los Angeles, CA
Well, I just had some of those codes on my 94 Cobra clone. I kept getting "bank1/2 lean/rich" codes, and eventually narrowed it down to a bad MAF. They were intermittent codes, so my CEL would go on while driving but go out after a minute or two. You will get a 111 code if the computer does not see any errors at the time of the KOEO/KOER test. The rest of the codes are stored codes, that happened earlier but weren't happening when the test was run.

Our Cobras are OBD1 cars, so our diagnostic plugs are in the engine bay behind the passenger shock tower. Ford was trying to save money in 1994 and 1995, so they installed the same dash in ALL the cars - V6, GT and Cobra. So the GT and Cobra dashboards have the OBD2 plug under the steering wheel, but it has no power. If you tried to plug your scanner into the OBD2 plug under the dashboard, that would explain your "vehicle refuses to follow commands" message.

Code 511 is normally seen if you have a chip in the computer's diagnostic port, and in that case it's normal.
Code 116 usually comes up if you run KOER when the engine is cold. If the engine is warm or hot and you still get that code, the ECT sensor may be bad.

I think your best bet would be to clear the codes, if you haven't done so already, and drive the car for a while to build up new codes. Then come back here with the new codes.
 

jayurface

Member
Oct 5, 2016
8
1
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Chythar,
the diagnostic tool i have connects to obd i, ii, and apparently some foreign vehicles use different ports and protocols. This particular tool will read all of them. I never messed with the obd ii port under the dash mostly because I didn't know it was there untill recently.

When connected to the obd i port on my 1994 the screen displays something to the effect of "increasing engine rpms" and displays the target rpms and actually. The engine responds, you hear and see it on the display and it meets them. After a while it stops and says "vehicle refuses to follow commands"

at a point in time the car had a performance chip installed for years, no problems, there is no change in the way it has driven since day one so i wonder what happened for it to suddenly display all these codes at once. i recently contacted the orginal manufacturer of the chip and they could not tell me whats on it, but the one thing i do know if u physical remove it or put all 4 programs into the off positions the rpms shoot up to 2k and stay there. The timing seems to migrate on its own sometimes also. I set it to 11 degrees originally and the highest i have seen it was 272 degrees advanced. How in the world is it still running let alone like normal? Haunted? Well we affectionately named the car Justine after the killer car Christine in the movie.

Anyways, I have done these tests with the engine hot. I have nit driven it around before tested just left it in the drive way fir about 10 mins running. Right niw i am compiling a list of points to check and planned to check them today but i have to leave for class soon and i think it is supposed to rain. What i will do next is clear the codes and drive around for a few mins, but i dont think that will solve the gas smell problem. I will post an update...

Thank you everyone for your input soo far.
 

Chythar

Recently finished repairing my rear
15 Year Member
Aug 26, 2004
2,274
77
98
50
West Los Angeles, CA
Well then, I can only ask that you check that your diagnostic tool is correctly configured for your car. The one I have is an Autoxray brand, and it will work with many cars as well. I have to choose the correct cable, then set up the tool by selecting the year, make, model and engine code. In my case, a 1994 Ford Mustang with engine code D.

My code reader will only run a KOEO test at first. Once a KOEO test is run, then I can run a KOER test. I don't know if that's just my code reader or if that's how the engine computer does it, but you should be able to do a KOEO test and pull the codes that way.

The computer will advance the timing while the engine is running, it's just how it works. I don't know how high the timing would be at it's max, I never checked. But 272 degrees advanced sounds outrageously high. I presume you know to set the timing with the SPOUT connector pulled? The SPOUT keeps the computer from changing the timing, and you can then rotate the distributor to set the base timing.

I was expecting you to have a performance chip, as the 94-95 computers can't handle the Ford's 'alphabet' cams (yours being the 'X' cam). I believe it has more to do with the lobe separation on the cams, where our computers need a bit more separation than the Fox body computers. Anyway, the 511 code is normal with a performance chip installed so you can ignore it.

The gas smell may be unrelated to the codes. Is the smell coming from the engine bay, or somewhere else? Our cars have an 'evaporative emissions' system, where gas vapors from the tank are stored in a charcoal canister in the passenger fender. The computer will open the CANP valve and vent those stored fumes into the intake manifold. This URL should have great photos and info to check the system, but it's not loading for some reason:

http://www.themustangnews.com/content/2013/04/fix-sn-95-mustang-gasoline-odor-issue/
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
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The charcoal canister in 94-95 stangs are hidden behind the plastic inner wheel well panel in front of the right front wheel.
I think
Pretty sure
Extremely possible
Difenite maybe
 
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jayurface

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Oct 5, 2016
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Chythar,
Yeah, the diagnostic tool i have does the same thing KOEO then KOER test. The newest one have does not need to be configured. It is an Innova brand i think but it automatically detects the protocol and in some vehicles pulls the VIN when it establishes connection. I tried on my new car 2012 focus titanium and it pulled the VIN and displayed it on the screen. This thing does soo many things like change the timing, adjust automatic transmission shift points, and reprogram the Mass. It is just it cannot perform all of the features on all vehicles.

Since my car has a problem with authority and would not follow the commands of the diagnostic tool i got the codes by counting from the flash from the CEL. I also performed the self cylinder balance test and it passed. To me that rules out a worn head gasket.

The timing i have checked a couple of times before. Removing the SPOUT connection then setting my base at 11. The guy at the ford racing parts counter said it should be set between 10 and 11. I know the computer changes the timing as needed but i think it is only something like 2 or 3 degrees right? i guess i will have to research what range the timing will move.

Performance chip i do have, the question mark with this car is it has had all these parts configured the same way for years (since 2003)...why is it just now displaying a CEL? Unfortunately I cannot ignore it. i live in Texas and they will nit even do tge inspection if a CEL is on. If the car fails emissions here then you have 2 weeks to correct the problem and retest. Miss the deadline and the state sends you a fine.

A while back i checked out the evap system. The canister was good, no gas in it, but i was hoping there was because it would have explained everything-ish. I went ahead and replaced the purge valve hoping that was the problem and it was not.

Telling this car may be a demon car lol. I would imagine if it was though it would rather be out exploring the world rather than be stuck in the driveway. I don't know if this will trigger something with anyone out there but a few years ago I tried running seafoam through it. This was the one that sprays through the throttle body. Now the strange part is every video i have seen online about the seafoam the vehicles would make very thick smoke until it was completely out of the system. Which can be a few hours from what i understood. This car? Not one poof of smoke. The engine bogged down like it is supposed to when that stuff is flowing, but no smoke at all.

Today should be a sunny day here and no classes for today so i am going to try and check some voltages today. May be it could help shine some light on the problem.
 

jrichker

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Jrichker,

Thank you for all of the information you provided me. I am sure it will be very useful when I start diving into everything again. The problem is all of these sensors are new so not cleaning is needed. The mass air, IAT, TPS, bypass valve, EGR valve, Fuel injectors, speed sensor, O2 sensors, and PCM. The PCM is the correct configuration for a 94-95 cobra (J4J1). No blown fuses and the relays are good. Not too long ago I did take the PCM apart and did not see any obvious burn spots. All of the vacuum lines are new as well

Something I did forget to mention in my original posting. I have pulled codes several times to see if I get different ones and in the second session I got the code for lean bank 2.
The codes also give instructions on how to test the wiring and the sensor output.
It would not be unusual at all to get a defective sensor right out of the box or have some bad wiring or bad connections in the wiring.