1991 Mazda MX6 check engine light (1 Viewer)

[Tim Hoover]

Since this place has steered me (no pun intended) right when it comes to my car troubles, I thought I'd come here asking for advice about my fiance's car. It's a '91 Mazda MX6. When she starts it, a lot of white smoke comes out the tailpipe accompanied by the check engine light coming on. The vehicle idles very roughly and 80% of the time dies. I pulled the code for her, but since she wasn't ready to count, we're not sure if it pulled a fault code 7 or 8. I've tried pulling the code again, but the light just stays on instead of flashing the code now.

Doing some internet research, I've found that a code 7 indicates a defective knock sensor. However, the knock sensor apparently only comes on turbocharged vehicles, which hers is not. A code 8 indicates a defective air flow meter or sensor. Could someone please shed some light on the situation based on these two possible codes and the physical symptoms?

 

[KurtEP]

An airflow meter or sensor can make your car run quite poorly when it's defective. I don't remember the exact symptoms, but it seems like it would be like this.

Usually (at least around here) Autozone will put a reader on your car for nothing, so you don't have to guess about the code. It's usually worth a try, especially if you are handy enough to make the repair yourself.

 

[Jimi C]

Could be a dirty MAF sensor. Sometimes just cleaning it off with rubbing alcohol can fix that. Otherwise i'd say it sounds like a bad spark plug or wire.

 

[Tim Hoover]

Thx for the replies. Pulling the code at Autozone is out of the question, as the nearest location is 20 miles away, and I wouldn't want to drive 3 blocks in the car right now. Besides, the car doesn't need a code reader to pull the code as the check engine light will flash the code. The main problem right now is to get the code to appear again. Any ideas on resetting the computer? That way I could reset it, start the vehicle, and the the code should be present again...

 

[KurtEP]

Try doing a search for resetting the code. Is this something you want to fix yourself? If so, I'd highly recommend looking around for a service manual. That would tell you a lot of what you'd need to know. Otherwise, you may be better off taking it to a competent mechanic. Sometimes you can diagnose these things right the first time, other times, it's a lot harder, and you won't know until you've wasted money on parts it didn't need.

Good Luck

 

[Jimi C]

All you have to do to clear the code is unplug on of the battery terminals for a few hours.

 

[Tim Hoover]

I figured that would do the trick, but found something online saying I had to also pump the brake pedal five times. It was storming yesterday evening, so I'll get a chance to mess around with the car again this evening.

 

[Paul_Dunlop]

sounds like the symptoms of a blown headgasket

has she ever replaced it?
my civics' went after 160,000 kms

 

[Tim Hoover]

Nope, it's never been replaced to my knowledge.

 

[Paul_Dunlop]

it's medium expensive, so research it first
but that would be my guess

 

[Tim Hoover]

Yup, I definitely want to research this thing first. Money's rather tight with us, so I'm going to do all I can personally. We also live out in the sticks, so taking it to a mechanic would almost be prohibitively expensive right now...

 

[Chu Gai]

White smoke certainly suggests a coolant leak. After running the car for a bit, assuming you can, turn it off and after a few minutes, smell the area around the tailpipe. See if you can pick up the smell of antifreeze which typically has a sickly sweet odor when heated. That odor comes from one of the ingredients in antifreeze, benzotriazoles and their derivatives.

 

[DanHal]

Good advice. You should also check the coolant for oil, and vice versa for the oil. The two liquids should not be mixed together.

You most likely had a code 8, a Vane Air Flow Signal (VAFSIG) error. Make sure everything is plugged in, and no wires are shorted or visually broken. According to what I've been reading, there is no code 7.

1990-1992 [2.2L Non-Turbo]
Code Sensor or Description
01 Ignition Diagnostic Monitor (IDM)
06 Vehicle Speed Sensor (VSS)
08 Vane Air Flow Signal (VAFSIG)
09 Engine Coolant Temperature Sensor (ECT)
10 Vane Air Temperature Sensor (VAT)
12 Throttle Position Sensor (TP)
14 Barometric Pressure Sensor (BP)
15 Exhaust Gas Oxygen Sensor (EGO)
Lean - Voltage Always Below 0.55V
16 EGR Valve Position Sensor (EVP)
17 Exhaust Gas Oxygen Sensor (EGO)
Rich - Voltage Stays At 0.55V
25 Fuel Pressure Regulator Control Solenoid (PRC)
26 Canister Purge Solenoid Valve (CANP)
28 EGR Control Solenoid Valve (EGRC)
34 Idle Speed Control Solenoid Valve (ISC)
55 Torque Converter Speed Sensor (TCS)
60 Shift Solenoid #1 (SS1)
61 Shift Solenoid #2 (SS2)
62 Shift Solenoid #3 (SS3)
63 Torque Converter Clutch Control Solenoid (CCC)

 

[Tim Hoover]

Well, I finally had an afternoon with nothing to do AND with good weather, so I poked around the air flow meter and discovered the wiring harness had pulled just a teeny little bit loose. Problem solved!