Exhaust Some issues resolved but still running bad

Jun 14, 2020
81
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Las Vegas
So I've been reading on here a ton lately and im aware of most people consensus on removing the AC or air pump. However, when I bought my car it was already a bit "special." The previous owner had removed most of the AC equipment but stopped at the compressor and left me a vacuum leak from the vacuum tee. After much research and inspection I have ordered all new vacuum hoses as well as caps to stop the leaks I already have. The former owner had also broken a vacuum line to the thermacter bypass. I removed one of the smog pump tubes from the back of the passenger side head and it's completely clogged. So....my question is, what purpose is my smog pump even serving at this point, other than being a vacuum leak and clogging? And would you advise removing it or putting in new vacuum lines even if it's clogged to high heaven? Thanks for any advice, whether I listen to it or not haha
 
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Potomus Pete

Gretchen Whitmer is eating at me
Mar 7, 2019
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Well. if you keep it you dont have to get a delete pulley for fourty bucks. If you get rid of it you have to hunt for a new belt to compensate for the missing pulley. If the bearings are good I would keep it and plug everything. Mine started making noise so I got rid of it. I like it gone so I can see everything.
 
Jun 14, 2020
81
9
18
34
Las Vegas
Well. if you keep it you dont have to get a delete pulley for fourty bucks. If you get rid of it you have to hunt for a new belt to compensate for the missing pulley. If the bearings are good I would keep it and plug everything. Mine started making noise so I got rid of it. I like it gone so I can see everything.

Do I just unplug and get rid of the solenoids as well? What codes, if any, will the computer start showing?
 

Potomus Pete

Gretchen Whitmer is eating at me
Mar 7, 2019
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My bad I have a chip. If you dont have a check light I would work with it the way it is. I have been told a check engine light may come on. You may want to work around it for now. Wait till somebody can give you a definative answer on the light. I pulled mine, and did not get a light. Like I said mine was making a terrible noise .Using a string to get a new belt gave me a hard time. Four trips to Autozone.
 
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Jun 14, 2020
81
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Las Vegas
My bad I have a chip. If you dont have a check light I would work with it the way it is. I have been told a check engine light may come on. You may want to work around it for now. Wait till somebody can give you a definative answer on the light. I pulled mine, and did not get a light. Like I said mine was making a terrible noise .Using a string to get a new belt gave me a hard time. Four trips to Autozone.
I do have a check engine light. EGR not opening, but that vacuum line is broken too, and then 41 and 91 for running lean. But again, I've got three vacuum leaks so. Thought maybe if I fix all the vacuum leaks that it might take care of all the codes. If not, I wouldn't want to trade codes for different ones.
 

Potomus Pete

Gretchen Whitmer is eating at me
Mar 7, 2019
1,192
408
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Sarasota Florida
Work the leaks and go from there ,makes sense. Keep reading up on the smog pump. Lots of info on here on that. You will be surprised how well it runs with no leaks.
 
Jun 14, 2020
81
9
18
34
Las Vegas
Work the leaks and go from there ,makes sense. Keep reading up on the smog pump. Lots of info on here on that. You will be surprised how well it runs with no leaks.
Yeah, I've read a bit but I haven't seen anyone address when the lines are completely logged at the heads. I just don't see what purpose they're serving if they're half clogged. I'll keep reading though.
 

jrichker

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Quick summary...
Codes 44 & 94 - AIR system inoperative - Air Injection. Check vacuum lines for leaks, & cracks. Check for a clogged air crossover tube, where one or both sides of the tube clog with carbon.

Revised 21 Sep 2012 to correct the description of the process that sets the code and include Thermactor Air System diagram.



If you have a catalytic converter H pipe, you need to fix these codes. If you don't, then don't worry about them.

Code 81 – Secondary Air Injection Diverter Solenoid failure AM2. The solenoid valve located on the back side of the passenger side wheel well is not functional.

Code 82 – Secondary Air Injection Diverter Solenoid failure AM1. Possible bad wiring, bad connections, missing or defective solenoid valve. Check the solenoid valve for +12 volts at the Red wire and look for the Red/White wire to switch from +12 volts to 1 volt or less. The computer controls the valve by providing a ground path on the Red/White wire for the solenoid valve

None of the above codes will set the Check Engine Light or have any affect on a car with no catalytic converters. If you have catalytic converters, you need to fix the problems.



Thermactor Air System
Some review of how it works...

Revised 25 May 2019 to re-order paragraph sequence and add lean burn description for newer cars

The Thermactor air pump (smog pump) supplies air to the heads or catalytic converters. This air helps break down the excess HC (hydrocarbons) and CO (carbon monoxide). The air supplied to the catalytic converters helps create the catalytic reaction that changes the HC & CO into CO2 and water vapor. Catalytic converters on 5.0 Mustangs are designed to use the extra air provided by the smog pump. Without the extra air, the catalytic converters will clog and fail.

The Thermactor air pump draws air from an inlet filter in the front of the pump. The smog pump puts air into the heads when the engine is cold and then into the catalytic converters when it is warm. The air provided by the air pump serves to help consume any unburned hydrocarbons by supplying extra oxygen to the catalytic process. With a warm engine, the computer operates on closed loop mode, taking input from all the sensors.

The Thermactor control valves serve to direct the flow. The first valve, TAB (Thermactor Air Bypass) or AM1 valve) either dumps air to the atmosphere or passes it on to the second valve. The computer tells the Thermactor Air System to open the Bypass valve at WOT (wide open throttle) minimizing engine drag. This dumps the pump's output to the atmosphere, and reduces the parasitic drag caused by the smog pump to about 2-4 HP at WOT. The Bypass valve also opens during deceleration to reduce or prevent backfires.

The second valve, TAD (Thermactor Air Diverter valve or AM2 valve) directs it to the heads or the catalytic converters. Check valves located after the TAD solenoid prevent hot exhaust gases from damaging the Diverter control valve or air pump in case of a backfire.

Code 44 RH side air not functioning.
Code 94 LH side air not functioning.

How the O2 sensors affect the operation of the Thermactor Air System.
The computer uses the change in the O2 sensor readings to detect operation of the Thermactor control valves. When the dump valve opens, it reduces the O2 readings in the exhaust system. Then it closes the dump valve and the O2 readings increase. By toggling the dump valve (TAB), the computer tests for the 44/94 codes.

Failure mode is usually due to a clogged air crossover tube, where one or both sides of the tube clog with carbon. The air crossover tube mounts on the back of the cylinder heads and supplies air to each of the Thermactor air passages cast into the cylinder heads. When the heads do not get the proper air delivery, they set codes 44 & 94, depending on which passage is clogged. It is possible to get both 44 & 94, which would suggest that the air pump or control valves are not working correctly, or the crossover tube is full of carbon or missing.




Computer operation & control for the Thermactor Air System.
Automobile computers use current sink technology. They do not source power to any relay, solenoid or actuator like the IAC, fuel pump relay, or fuel injectors. Instead the computer provides a ground path for the positive battery voltage to get back to the battery negative terminal. That flow of power from positive to negative is what provides the energy to make the IAC, fuel pump relay, or fuel injectors work. No ground provided by the computer, then the actuators and relays don't operate.

One side of the any relay/actuator/solenoid in the engine compartment will be connected to a red wire that has 12-14 volts anytime the ignition switch is in the run position. The other side will have 12-14 volts when the relay/actuator/solenoid isn't turned on. Once the computer turns on the clamp side, the voltage on the computer side of the wire will drop down to 1 volt or less.

In order to test the TAD/TAB solenoids, you need to ground the white/red wire on the TAB solenoid or the light green/black wire on the TAD solenoid. The TAB and TAD solenoid are located on the passenger side shock strut tower. Uneducated owners sometimes remove them to get more HP. This does not work, it just causes 81 & 82 codes.

For 94-95 cars: the colors are different. The White/Red wire (TAB control) is White/Orange (Pin 31 on the PCM). The Green/Black wire (TAD control) should be Brown (pin 34 at the PCM). Thanks to HISSIN50 for this tip.

Testing the system:

To test the computer, you can use a test light across the TAB or TAD wiring connectors and dump the codes. When you dump the codes, the computer does a self test that toggles every relay/actuator/solenoid on and off. When this happens, the test light will flicker.

Disconnect the big hose from smog pump: with the engine running you should feel air output. Reconnect the smog pump hose & apply vacuum to the first vacuum controlled valve: Its purpose is to either dump the pump's output to the atmosphere or pass it to the next valve.

The next vacuum controlled valve directs the air to either the cylinder heads when the engine is cold or to the catalytic converter when the engine is warm. Disconnect the big hoses from the back side of the vacuum controlled valve and start the engine. Apply vacuum to the valve and see if the airflow changes from one hose to the next.

The two electrical controlled vacuum valves mounted on the rear of the passenger side wheel well turn the vacuum on & off under computer control. Check to see that both valves have +12 volts on the red wire. Then ground the white/red wire and the first solenoid should open and pass vacuum. Do the same thing to the light green/black wire on the second solenoid and it should open and pass vacuum.

Remember that the computer does not source power for any actuator or relay, but provides the ground necessary to complete the circuit. That means one side of the circuit will always be hot, and the other side will go to ground or below 1 volt as the computer switches on that circuit.

The computer provides the ground to complete the circuit to power the solenoid valve that turns the
vacuum on or off. The computer is located under the passenger side kick panel. Remove the kick panel & the cover over the computer wiring connector pins. Check Pin 38 Solenoid valve #1 that provides vacuum to the first Thermactor control valve for a switch from 12-14 volts to 1 volt or less. Do the same with pin 32 solenoid valve #2 that provides vacuum to the second Thermactor control valve. Starting the engine with the computer jumpered to self test mode will cause all the actuators to toggle on and off. If after doing this and you see no switching of the voltage on and off, you can start testing the wiring for shorts to ground and broken wiring. An Ohm check to ground with the computer connector disconnected & the solenoid valves disconnected should show open circuit between the pin 32 and ground and again on pin 38 and ground. In like manner, there should be less than 1 ohm between pin 32 and solenoid valve #2 and pin 38 & Solenoid valve #1.

If after checking the resistance of the wiring & you are sure that there are no wiring faults, start looking at the solenoid valves. If you disconnect them, you can jumper power & ground to them to verify operation. Power & ground supplied should turn on the vacuum flow, remove either one and the vacuum should stop flowing.

Typical resistance of the solenoid valves is in the range of 20-70 Ohms.

What happens when there is no extra air from the smog pump...
As engines age, the quality of tune decreases and wear causes them to burn oil. We have all seem cars that go down the road puffing blue or black smoke from the tailpipe. Oil consumption and poor tune increase the amount of HC the oxidation catalyst has to deal with. The excess HC that the converters cannot oxidize due to lack of extra air becomes a crusty coating inside the honeycomb structure. This effectively reduces the size of the honeycomb passageways and builds up thicker over time and mileage. Continuous usage under such conditions will cause the converter to fail and clog. The extra air provided by the Thermactor Air System (smog pump) is essential for the oxidation process. It oxidizes the added HC from oil consumption and poor tune and keeps the HC levels within acceptable limits.
[
b]Newer catalytic converters do not use the Thermactor Air System (smog pump) because they are designed to work with an improved computer system that runs leaner and cleaner [/b]
They add an extra set of O2 sensors after the catalytic converters to monitor the oxygen and HC levels. Using this additional information, the improved computer system monitors the health and efficiency of the catalytic converters. If the computer cannot compensate for the added load of emissions due to wear and poor tune, the catalytic converters will eventually fail and clog. The periodic checks (smog inspections) are supposed to help owners keep track of problems and get them repaired. Use them on an 86-95 Mustang and you will slowly kill them with the pollutants that they are not designed to deal with.

Theory of operation:
Catalytic converters consist of two different types of catalysts: Reduction and Oxidation.
The Reduction catalyst is the first converter in a 5.0 Mustang, and the Oxidation converter is the second converter. The Oxidation converter uses the extra air from the smog pump to burn the excess HC. Aftermarket converters that use the smog pump often combine both types of catalysts in one housing. Since all catalytic reactions depend on heat to happen, catalytic converters do not work as efficiently with long tube headers. The extra length of the long tubes reduces the heat available to operate the O2 sensors and the catalytic converters. That will cause emissions problems, and reduce the chances of passing an actual smog test.


Now for the Chemistry...
"The reduction catalyst is the first stage of the catalytic converter. It uses platinum and rhodium to help reduce the NOx emissions. When an NO or NO2 molecule contacts the catalyst, the catalyst rips the nitrogen atom out of the molecule and holds on to it, freeing the oxygen in the form of O2. The nitrogen atoms bond with other nitrogen atoms that are also stuck to the catalyst, forming N2. For example:

2NO => N2 + O2 or 2NO2 => N2 + 2O2

The oxidation catalyst is the second stage of the catalytic converter. It reduces the unburned hydrocarbons and carbon monoxide by burning (oxidizing) them over a platinum and palladium catalyst. This catalyst aids the reaction of the CO and hydrocarbons with the remaining oxygen in the exhaust gas. The "lean burn" technology of newer cars means there is more O2 for the oxidation process to work with.

For example:

2CO + O2 => 2CO2

There are two main types of structures used in catalytic converters -- honeycomb and ceramic beads. Most cars today use a honeycomb structure." Quote courtesy of How Stuff Works (HowStuffWorks "Catalysts")


Code 45 & 46 are very uncommon, this is the first time in 20+ years here at Stangnet that I have seen them posted.

The TAD solenoid and its plumbing are the probable source since it appears that the TAD solenoid is stuck open during self-test. Check for vacuum at the Diverter valve when running the self-test routine.
 
Jun 14, 2020
81
9
18
34
Las Vegas
Quick summary...
Codes 44 & 94 - AIR system inoperative - Air Injection. Check vacuum lines for leaks, & cracks. Check for a clogged air crossover tube, where one or both sides of the tube clog with carbon.

Revised 21 Sep 2012 to correct the description of the process that sets the code and include Thermactor Air System diagram.



If you have a catalytic converter H pipe, you need to fix these codes. If you don't, then don't worry about them.

Code 81
– Secondary Air Injection Diverter Solenoid failure AM2. The solenoid valve located on the back side of the passenger side wheel well is not functional.

Code 82 – Secondary Air Injection Diverter Solenoid failure AM1. Possible bad wiring, bad connections, missing or defective solenoid valve. Check the solenoid valve for +12 volts at the Red wire and look for the Red/White wire to switch from +12 volts to 1 volt or less. The computer controls the valve by providing a ground path on the Red/White wire for the solenoid valve

None of the above codes will set the Check Engine Light or have any affect on a car with no catalytic converters. If you have catalytic converters, you need to fix the problems.



Thermactor Air System
Some review of how it works...

Revised 25 May 2019 to re-order paragraph sequence and add lean burn description for newer cars

The Thermactor air pump (smog pump) supplies air to the heads or catalytic converters. This air helps break down the excess HC (hydrocarbons) and CO (carbon monoxide). The air supplied to the catalytic converters helps create the catalytic reaction that changes the HC & CO into CO2 and water vapor. Catalytic converters on 5.0 Mustangs are designed to use the extra air provided by the smog pump. Without the extra air, the catalytic converters will clog and fail.

The Thermactor air pump draws air from an inlet filter in the front of the pump. The smog pump puts air into the heads when the engine is cold and then into the catalytic converters when it is warm. The air provided by the air pump serves to help consume any unburned hydrocarbons by supplying extra oxygen to the catalytic process. With a warm engine, the computer operates on closed loop mode, taking input from all the sensors.

The Thermactor control valves serve to direct the flow. The first valve, TAB (Thermactor Air Bypass) or AM1 valve) either dumps air to the atmosphere or passes it on to the second valve. The computer tells the Thermactor Air System to open the Bypass valve at WOT (wide open throttle) minimizing engine drag. This dumps the pump's output to the atmosphere, and reduces the parasitic drag caused by the smog pump to about 2-4 HP at WOT. The Bypass valve also opens during deceleration to reduce or prevent backfires.

The second valve, TAD (Thermactor Air Diverter valve or AM2 valve) directs it to the heads or the catalytic converters. Check valves located after the TAD solenoid prevent hot exhaust gases from damaging the Diverter control valve or air pump in case of a backfire.

Code 44 RH side air not functioning.
Code 94 LH side air not functioning.

How the O2 sensors affect the operation of the Thermactor Air System.
The computer uses the change in the O2 sensor readings to detect operation of the Thermactor control valves. When the dump valve opens, it reduces the O2 readings in the exhaust system. Then it closes the dump valve and the O2 readings increase. By toggling the dump valve (TAB), the computer tests for the 44/94 codes.

Failure mode is usually due to a clogged air crossover tube, where one or both sides of the tube clog with carbon. The air crossover tube mounts on the back of the cylinder heads and supplies air to each of the Thermactor air passages cast into the cylinder heads. When the heads do not get the proper air delivery, they set codes 44 & 94, depending on which passage is clogged. It is possible to get both 44 & 94, which would suggest that the air pump or control valves are not working correctly, or the crossover tube is full of carbon or missing.




Computer operation & control for the Thermactor Air System.
Automobile computers use current sink technology. They do not source power to any relay, solenoid or actuator like the IAC, fuel pump relay, or fuel injectors. Instead the computer provides a ground path for the positive battery voltage to get back to the battery negative terminal. That flow of power from positive to negative is what provides the energy to make the IAC, fuel pump relay, or fuel injectors work. No ground provided by the computer, then the actuators and relays don't operate.

One side of the any relay/actuator/solenoid in the engine compartment will be connected to a red wire that has 12-14 volts anytime the ignition switch is in the run position. The other side will have 12-14 volts when the relay/actuator/solenoid isn't turned on. Once the computer turns on the clamp side, the voltage on the computer side of the wire will drop down to 1 volt or less.

In order to test the TAD/TAB solenoids, you need to ground the white/red wire on the TAB solenoid or the light green/black wire on the TAD solenoid. The TAB and TAD solenoid are located on the passenger side shock strut tower. Uneducated owners sometimes remove them to get more HP. This does not work, it just causes 81 & 82 codes.

For 94-95 cars: the colors are different. The White/Red wire (TAB control) is White/Orange (Pin 31 on the PCM). The Green/Black wire (TAD control) should be Brown (pin 34 at the PCM). Thanks to HISSIN50 for this tip.

Testing the system:

To test the computer, you can use a test light across the TAB or TAD wiring connectors and dump the codes. When you dump the codes, the computer does a self test that toggles every relay/actuator/solenoid on and off. When this happens, the test light will flicker.

Disconnect the big hose from smog pump: with the engine running you should feel air output. Reconnect the smog pump hose & apply vacuum to the first vacuum controlled valve: Its purpose is to either dump the pump's output to the atmosphere or pass it to the next valve.

The next vacuum controlled valve directs the air to either the cylinder heads when the engine is cold or to the catalytic converter when the engine is warm. Disconnect the big hoses from the back side of the vacuum controlled valve and start the engine. Apply vacuum to the valve and see if the airflow changes from one hose to the next.

The two electrical controlled vacuum valves mounted on the rear of the passenger side wheel well turn the vacuum on & off under computer control. Check to see that both valves have +12 volts on the red wire. Then ground the white/red wire and the first solenoid should open and pass vacuum. Do the same thing to the light green/black wire on the second solenoid and it should open and pass vacuum.

Remember that the computer does not source power for any actuator or relay, but provides the ground necessary to complete the circuit. That means one side of the circuit will always be hot, and the other side will go to ground or below 1 volt as the computer switches on that circuit.

The computer provides the ground to complete the circuit to power the solenoid valve that turns the
vacuum on or off. The computer is located under the passenger side kick panel. Remove the kick panel & the cover over the computer wiring connector pins. Check Pin 38 Solenoid valve #1 that provides vacuum to the first Thermactor control valve for a switch from 12-14 volts to 1 volt or less. Do the same with pin 32 solenoid valve #2 that provides vacuum to the second Thermactor control valve. Starting the engine with the computer jumpered to self test mode will cause all the actuators to toggle on and off. If after doing this and you see no switching of the voltage on and off, you can start testing the wiring for shorts to ground and broken wiring. An Ohm check to ground with the computer connector disconnected & the solenoid valves disconnected should show open circuit between the pin 32 and ground and again on pin 38 and ground. In like manner, there should be less than 1 ohm between pin 32 and solenoid valve #2 and pin 38 & Solenoid valve #1.

If after checking the resistance of the wiring & you are sure that there are no wiring faults, start looking at the solenoid valves. If you disconnect them, you can jumper power & ground to them to verify operation. Power & ground supplied should turn on the vacuum flow, remove either one and the vacuum should stop flowing.

Typical resistance of the solenoid valves is in the range of 20-70 Ohms.

What happens when there is no extra air from the smog pump...
As engines age, the quality of tune decreases and wear causes them to burn oil. We have all seem cars that go down the road puffing blue or black smoke from the tailpipe. Oil consumption and poor tune increase the amount of HC the oxidation catalyst has to deal with. The excess HC that the converters cannot oxidize due to lack of extra air becomes a crusty coating inside the honeycomb structure. This effectively reduces the size of the honeycomb passageways and builds up thicker over time and mileage. Continuous usage under such conditions will cause the converter to fail and clog. The extra air provided by the Thermactor Air System (smog pump) is essential for the oxidation process. It oxidizes the added HC from oil consumption and poor tune and keeps the HC levels within acceptable limits.
[
b]Newer catalytic converters do not use the Thermactor Air System (smog pump) because they are designed to work with an improved computer system that runs leaner and cleaner [/b]
They add an extra set of O2 sensors after the catalytic converters to monitor the oxygen and HC levels. Using this additional information, the improved computer system monitors the health and efficiency of the catalytic converters. If the computer cannot compensate for the added load of emissions due to wear and poor tune, the catalytic converters will eventually fail and clog. The periodic checks (smog inspections) are supposed to help owners keep track of problems and get them repaired. Use them on an 86-95 Mustang and you will slowly kill them with the pollutants that they are not designed to deal with.

Theory of operation:
Catalytic converters consist of two different types of catalysts: Reduction and Oxidation.

The Reduction catalyst is the first converter in a 5.0 Mustang, and the Oxidation converter is the second converter. The Oxidation converter uses the extra air from the smog pump to burn the excess HC. Aftermarket converters that use the smog pump often combine both types of catalysts in one housing. Since all catalytic reactions depend on heat to happen, catalytic converters do not work as efficiently with long tube headers. The extra length of the long tubes reduces the heat available to operate the O2 sensors and the catalytic converters. That will cause emissions problems, and reduce the chances of passing an actual smog test.


Now for the Chemistry...
"The reduction catalyst is the first stage of the catalytic converter. It uses platinum and rhodium to help reduce the NOx emissions. When an NO or NO2 molecule contacts the catalyst, the catalyst rips the nitrogen atom out of the molecule and holds on to it, freeing the oxygen in the form of O2. The nitrogen atoms bond with other nitrogen atoms that are also stuck to the catalyst, forming N2. For example:

2NO => N2 + O2 or 2NO2 => N2 + 2O2

The oxidation catalyst is the second stage of the catalytic converter. It reduces the unburned hydrocarbons and carbon monoxide by burning (oxidizing) them over a platinum and palladium catalyst. This catalyst aids the reaction of the CO and hydrocarbons with the remaining oxygen in the exhaust gas. The "lean burn" technology of newer cars means there is more O2 for the oxidation process to work with.

For example:

2CO + O2 => 2CO2

There are two main types of structures used in catalytic converters -- honeycomb and ceramic beads. Most cars today use a honeycomb structure." Quote courtesy of How Stuff Works (HowStuffWorks "Catalysts")


Code 45 & 46 are very uncommon, this is the first time in 20+ years here at Stangnet that I have seen them posted.

The TAD solenoid and its plumbing are the probable source since it appears that the TAD solenoid is stuck open during self-test. Check for vacuum at the Diverter valve when running the self-test routine.
I've seen this post already. I was actually just reading through it all. Thank you!! I do have cats but I'm not opposed to removing them. Is the car significantly louder without cats? Or will the mufflers primarily take care of the noise? Also, I'm worried about pushing a huge plug of carbon into the heads. That's what worries me most about just cleaning the air pump system. Any suggestions?
 
Jun 14, 2020
81
9
18
34
Las Vegas
Sorry to keep bothering everyone with so many questions but..... I've started to notice a loud popping noise from underneath the car when I'm starting to accelerate in first and second. It only does it before the car is warmed up. Am I just back firing? Or.... I'm not sure. I've revved it in place and that doesn't happen. Only when it's under load and right when you start to accelerate and let off the clutch in first and second.
 

Steel1

Mustang Master
Aug 18, 2017
1,136
514
143
51
Connecticut
"IF" you can do it safely get the rear tires off the ground , block the front (better yet put it on a lift if available)
and slowly let the clutch out to engage.
This should tell you if it's clutch related.
The fact that it only does it when the car is cold leads me to believe it is probably a backfire.
 
Jun 14, 2020
81
9
18
34
Las Vegas
"IF" you can do it safely get the rear tires off the ground , block the front (better yet put it on a lift if available)
and slowly let the clutch out to engage.
This should tell you if it's clutch related.
The fact that it only does it when the car is cold leads me to believe it is probably a backfire.
Yeah, I'm not going to even try that and have the car fall off adlnd drive through the wall into my living room lol. But yeah, it only does it before it's warmed up. I'm doing cap, rotor, wires and plugs now. I'll see if that has any effect.
 
Jun 14, 2020
81
9
18
34
Las Vegas
Yeah, I'm not going to even try that and have the car fall off adlnd drive through the wall into my living room lol. But yeah, it only does it before it's warmed up. I'm doing cap, rotor, wires and plugs now. I'll see if that has any effect.
Okay, so I've just done cap, rotor, wires and plugs. Everything is motorcraft and it was seemingly running amazing! Then, as soon as I started to get into operating temp, my exhaust seems to sputter and the engine hesitates only over 2,000 rpm. I triple checked everything I did and it is all fine. The motor sounds healthier than when I got it and I was incredibly happy until I started feeling the exhaust sputter and the engine seem to hesitate. I got it home and ran codes again. KOEO I'm getting 31, 41 and 91 as usual. But KOER I'm getting 13, 41 and 91. Any thought? I feel like the cats are screwed cause it doesn't want to go above 2,100 to 2,200 rpm. Or are my codes still the culprit? Is there a forum where I can have people help track my progress slash issues instead of posting all over the place? Thanks guys
 

7991LXnSHO

Now I want a 10 year badge
10 Year Member
Sep 1, 2010
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“Is there a forum where I can have people help track my progress slash issues instead of posting all over the place?“
Without the attitude and a with a little patience, this is the best place to post.

I do not guarantee the biggest issue is not still ignition, but the problems those codes indicate are not helping the car run well and need addressed.

A quick search says-
41/91 are about fuel mixture. You can find many posts about these codes. How long have these codes been “normal”?

13 is about the Idle Speed Control-
“Code 13 & - 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.” (jrichker)

31 looks like
“CODE: 31 (KOEO) - EVP circuit below minimum voltage. Vref (5 volt reference voltage supplied by the computer) missing or broken wire or bad connection in circuit.”
See the rest of Jrichker’s post here
While you are reading posts on those codes, I hope someone will put the overall problem together for you!
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
17,456
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polk county florida
Are you posting these problems in several threads?
Have you done the 'surging idle checklist'?
Keeping your problems in one thread will help members responding know what you have and what has been done and not repeat advice.
 
Jun 14, 2020
81
9
18
34
Las Vegas
Are you posting these problems in several threads?
Have you done the 'surging idle checklist'?
Keeping your problems in one thread will help members responding know what you have and what has been done and not repeat advice.
I have not done the surging idle checklist. My idle was fine until I did the tune up. Timing was set at 10 degrees until I did tune up, after it was 8 degrees so I set it back to ten and it threw a code 13 at me. I'm assuming because my idle was too high. I'll go through the check list. Also, yes I have been posting a couple of different threads. I guess I wasn't supposed to do that. I'm sorry! Is there anyway to combine the relevant ones? Or should i just continue with this one?
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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This happens a lot, the issue is the members that respond may make suggestions that have been done or a modification far from stock, that renders the suggestion moot. Different year, model and engine size may have different wiring or diagnostic tests.
 
Jun 14, 2020
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This happens a lot, the issue is the members that respond may make suggestions that have been done or a modification far from stock, that renders the suggestion moot. Different year, model and engine size may have different wiring or diagnostic tests.
Gotcha. I'll just keep everything here from now on. I'm just going to go through the checklist and see how it goes. I thought about putting the old cap and rotor back on too just to see what that does. Cause it was running a little rough before but now it doesnt want to accelerate beyond 2,100 or so. Weird thing to me was how it felt like it was better than ever until it warmed up completely and the idle creeped up to 1,100. Sucks to put on new stuff and have other things seemingly get worse.