Car running really rich, Help with codes?

kdog_x · May 25, 2004

Went for emmisions the other day, got a 3.9 on the hydrocarbons -- 0.8 is the limit. So the car is running really rich. Right now it is set to 12 degrees BTDC for timing. So I decided to start by running the codes. When I first ran the codes I got one for the Throttle Position Sensor being out of range. Checked it, and it was at 0.7. So I adjusted it by moving it as much as I could by hand (only went to about 0.82) and turning the adjuster screw in a little bit. It's now set at 0.95V.

Ran the codes again, this time I got (11) which was a pass. So then I ran the engine running test. The only codes that came up were (94) and (44)
Secondary Air system inoperative was what they both meant.

The smog pump is still hooked into the serpentine belt and still spins. The tube that comes off of it and runs down to the cats is disconnected b/c theres no hookup for it on my O/R pipe. And the steel lines that connect to the back of the heads are plugged up. Those are the only emmisions related mods.

So I have a few questions if anyone can help

1) Is it the lack of emmisions equipment thats causing her to run rich? If not, what else?
2) The car idled at about 750-800 while I was running the tests and immediately after. But after I went for a ride, the idle now wants to wander around 1000-1100 RPMs every time I come to a stop, should I leave the TPS out of range and back off the adjuster screw for a lower idle?
3) How does the computer know that the smog stuff isn't there, is there any way to trick it? I figure maybe it's making some sort of adjustments which are causing the rich condition.

thanks

Any help would be GREATLY appreciated

jrichker · May 25, 2004

Codes 94 & 44 - Check vacuum lines for leaks, & cracks. 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 wheelwell 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 any power, 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.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif

kdog_x · May 25, 2004

Thanks jrichker, I couldn't find that info anywhere. Even my Mitchell on Demand program wasn't much help.

I've got one more question though. I got the TPS set where I wanted it like I mentioned above. The car was idling at about 1100 RPMs. Then I tried unplugging the Idle Air Bypass valve and the RPMs dropped to around 500-600. When setting the TPS and the idle should I do it with the IAB plugged or unplugged?

jrichker · May 25, 2004

See the attached file courtsey of Tmoss for idle setting proceedure.

TPS is set Key ON Engine Off (KOEO) after the manual setting of the idle speed screw.

The smog pump puts air into the exhaust system to burn up any leftover hydrocarbons. If the smog pump isn't working correctly, your chances of passing emissions check are very small.

Tips to reduce hydrocarbons include getting the engine hot prior to having the smog check, using gasahol (alcohol + gasoline), lowering fuel pressure 2-4 PSI (only if you have an adjustable FPR) and some of the auto parts store gas additives. All these assume that your car is in good tune with new spark plugs, rotor, cap, wires, air filter and good O2 sensors. The O2 sensors are about $30-$45 each, so they are the last thing to replace in most cases.

kdog_x · May 27, 2004

I thought the smog pump only kicked out a small amount of air, so I figured it wouldn;t make that much of a difference. I should only have to hook the pump down to the H-Pipe though, right? The hookups on the back of the heads are for when the engine is cold -- or do I have that backwards? MAybe I should just go get a supercharger and have it force air into the exhaust rather than the intake

jrichker · May 28, 2004

kdog_x said:
I thought the smog pump only kicked out a small amount of air, so I figured it wouldn;t make that much of a difference. I should only have to hook the pump down to the H-Pipe though, right? The hookups on the back of the heads are for when the engine is cold -- or do I have that backwards? MAybe I should just go get a supercharger and have it force air into the exhaust rather than the intake

You are correct about the pipe on the back of the heads being for a cold engine. As long as you wait for things to heat up, the air pipe to the cats is the one to work on for emissions testing.

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