Car running extremely rich at idle

rich

tbird187 said:

Hey guys I have a 89gt and my car is running extremely rich at idle bad enough where my eyes start to water.... anyways fuel pressure is fine I backed it off even and it didnt help.... I have custom gauge cluster so I cant see if the check engine light is on... anyway I can check for codes. any ideas? thanks

Click to expand...

check your codes first,,

http://forums.stangnet.com/735179-code-reader.html


read thru this Jrichker is the man

31= EVP or PFE circuit below min voltage

67= Clutch switch failure or sensor out of rang

81= Air diverter solenoid fault, intake air control circuit fault, air injection diverter

82= integrated relay control module

84= EGR vacuum regulator

85= Canister purge solenoid circuit failure

Yup not having your EGR plugged in will cause issues if you dont do it the right way tune it out and block the egr holes off with a plate like i did. Is there a reason why your egr is unplugged?

rich

Black 93 Fox said:

31= EVP or PFE circuit below min voltage

67= Clutch switch failure or sensor out of rang

81= Air diverter solenoid fault, intake air control circuit fault, air injection diverter

82= integrated relay control module

84= EGR vacuum regulator

85= Canister purge solenoid circuit failure

Click to expand...

well that dont look too bad...no 42/92.....

code 67 .could be acouple of things,,,,,if the ac switch is on during test code 67 will show,,,with stick clutch needs to be pushed in during test or 67 will show


82 can be coming from 67..ac fan always on

the rest looks like emmission related...how much stuff was removed or unhooked?


re connect what you can and retest...see what pops up again..

also try a search on stangnet,,you will find all the answers you are looking for......

look at the idle/surge list some good points in thier for testing componets...

If you don't have catalytic converters, the car will stink of fuel at idle and low speeds.

If you do have catalytic converters, you need to fix the 81 & 82 codes.

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. 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 Lt Green/Black wire to switch from +12 volts to 1 volt or less.
The computer controls the valve by providing a ground path on the LT Green/Black wire for the
solenoid valve.

With the with the ignition on, look for 12 volts on the red wire on the solenoid connector.
No 12 volts and you have wiring problems.

With the engine running, stick a safety pin in the LT Green/Black wire for the solenoid valve &
ground it.
That should turn the solenoid on and cause air to flow out the port that goes to the pipe
connected to the cats. If it doesn't, the valve is bad. If it does cause the airflow to switch, the
computer or wiring going to the computer is not signaling the solenoid valve to open.

Putting the computer into self test mode will cause the solenoid valve to toggle.
If you listen carefully, you may hear it change states.

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.

With the engine running, stick a safety pin in the Red/White wire for the solenoid valve & ground
it. That should turn the solenoid on and cause air to flow out the port that goes to the pipe
connected to the heads. If it doesn't, the valve is bad. If it does cause the airflow to switch,
the computer or wiring going to the computer is not signaling the solenoid valve to open.

Both 81 & 82 codes usually mean that some uneducated person removed the solenoid control
valves for the Thermactor Air system in an attempt to make the car faster. It doesn't work that
way: no working control valves can cause the cat converters to choke and clog.


Did you dump the engine running codes? The procedure is the same, install the test jumper, start
the engine with the A/C off and the trans in Neutral. Thetest light will flash 11, then 4 and then
speed the engine up to do an EGR check. If it doens't abort the test due to bad/missing EGR, it
will dump the codes present while the engine is running.

Some basic theory to clarify how things work is in order…

EGR System theory and testing

The EGR shuts off at Wide Open Throttle (WOT), so it has minimal effect on performance. The addition of exhaust gas drops combustion temperature, increases gas mileage and reduces the tendency of the engine to ping. It can also reduce HC emissions by reducing fuel consumption. The primary result of EGR usage is a reduction in NOx emissions.

The EGR system has a vacuum source (line from the intake manifold) that goes to the EVR, computer operated electronic vacuum regulator. The EVR is located on the back of the passenger side shock strut tower. The computer uses RPM, Load. and some other factors to tell the EVR to pass vacuum to open the EGR valve. The EGR valve and the passages in the heads and intake manifold route exhaust gas to the EGR spacer (throttle body spacer). The EGR sensor tells the computer how far the EGR valve is open. Then computer adjusts the signal sent to the EVR to hold, increase or decrease the vacuum. The computer adds spark advance to compensate for the recirculated gases and the slower rate they burn at.




Troubleshooting:
There should be no vacuum at the EGR valve when at idle. If there is, the EVR (electronic vacuum regulator) mounted on the backside of the passenger side wheelwell is suspect. Check the vacuum line plumbing to make sure the previous owner didn’t cross the vacuum lines.

Diagram courtesy of Tmoss & Stang&2birds. (the diagram says 88 GT, but the EGR part is the same for 86-93 Mustangs)


The EGR sensor is basically a variable resistor, like the volume control on a radio. One end is 5 volt VREF power from the computer (red/orange wire). One end is computer signal ground (black/white), and the middle wire (brown/lt green) is the signal output from the EGR sensor. It is designed to always have some small voltage output from it anytime the ignition switch is the Run position. That way the computer knows the sensor & the wiring is OK. No voltage on computer pin 27 (brown/lt green wire) and the computer thinks the sensor is bad or the wire is broken and sets code 31. The voltage output can range from approximately .6-.85 volt.

The EVR regulates vacuum to the EGR valve to maintain the correct amount of vacuum. The solenoid coil should measure 20-70 Ohms resistance. The regulator has a vacuum feed on the bottom which draws from the intake manifold. The other vacuum line is regulated vacuum going to the EGR valve. One side of the EVR electrical circuit is +12 volts anytime the ignition switch is in the run position. The other side of the electrical circuit is the ground path and is controlled by the computer. The computer switches the ground on and off to control the regulator solenoid.



EGR test procedure courtesy of cjones

to check the EGR valve:
bring the engine to normal temp.
connect a vacuum pump to the EGR Valve
apply 5in vacuum to the valve.
if engine stumbled or died then EGR Valve and passage(there is a passageway through the heads and intake) are good.
if engine did NOT stumble or die then either the EGR Valve is bad and/or the passage is blocked.
if engine stumbled, connect vacuum gauge to the hose coming off of the EGR Valve
snap throttle to 2500 RPM (remember snap the throttle don't hold it there).
did the vacuum gauge show about 2-5 in vacuum?

if not, check for manifold vacuum at the EGR vacuum valve.
if you have manifold vacuum then connect vacuum gauge to the EGR valve side of the vacuum valve and snap throttle to 2500 RPM.
should read about 2-5 in vacuum

To test the computer, you can use a test light across the EVR 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.

Late Model Restoration has the Ford Racing M-12071-N302 kit with the EGR valve & sensor along with the ACT & ECT sensors for $45. See * * * N/A * * * 86-93 SENSOR KIT, 5.0L EFI, INCLUDES EGR VALVE & SENSOR, COOLANT TEMP SENSOR, & AIR CHARGE TEMP SENSOR MUSTANG for more details


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

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 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 second valve, TAD (Thermactor Air Diverter valve or AM2 valve) directs it to the heads or the catalytic converters. Check valves located after the TAB & TAD solenoids prevent hot exhaust gases from damaging the control valves or pump in case of a backfire. The air serves to help consume any unburned hydrocarbons by supplying extra oxygen to the catalytic process. 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.






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.

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.

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.

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.

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. 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")

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.

[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
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 adjusts the air/fuel mixture for cleaner combustion and reduced emissions. 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.

rich

see told ya jrichker was the man..pics help so much


as to vacuum...im just learning...but i think 19.8 is what we shoot for,,,what ive read is a radical cam will lower your vacuum,,,,if that helps

i cant answer how low is still ok,,wish i could be more help,,,but ill keep following this ,maybe some other guys will chime in....like hisson or joel.....they do this stuff in thier sleep

I had a problem once when i changed to a larger maf with the stock one the car seemed fine but once i put a larger one on it took a totaly crap. After trial an error on things ended up needing a new maf sensor. Also i knw they dont like to be pointed certain ways cause of the sensor.