Ocassionally check engine light comes on engine runs bad

[Ankh599]

I have a '93 with 123k miles and ocassionally my check engine light comes on and the car idles bad. If I'm at a stop with the car in drive or park it will idle bad and cut off. Then in about 30 seconds it will stop and the check engine light goes off.

I've had the Mass Flow cleaned as well as my IAv and the problem still remains. Anyone know what can it be???

[icingdeath88]

Originally Posted by Ankh599

I have a '93 with 123k miles and ocassionally my check engine light comes on and the car idles bad. If I'm at a stop with the car in drive or park it will idle bad and cut off. Then in about 30 seconds it will stop and the check engine light goes off.

I've had the Mass Flow cleaned as well as my IAv and the problem still remains. Anyone know what can it be???

Check the code. If the check engine light comes on, then the ECU has stored a code. There are instructions in this document: http://www.subaru-svx.net/forum/atta...7&d=1330285331

[Green1995SVX]

As he said, check the code(s) and report back to us with what you find.

[kwren]

MAF?...smells like it!

Keith

[Ankh599]

Thanks for the guide, I'm on it and will respond back today.

[Ankh599]

Checked on the price of a MAF...over $200. Does anyone know of a cheaper price.

Also, cleaned the MAF again, changed the fuel filter and then did the Seafoam process...AND this car is running like brand new. What a PUNCH when you floor it. BUT the check engine light still comes on and it runs bad.

[1986nate]

Originally Posted by icingdeath88

Check the code. If the check engine light comes on, then the ECU has stored a code. There are instructions in this document: http://www.subaru-svx.net/forum/atta...7&d=1330285331

Originally Posted by Green1995SVX

As he said, check the code(s) and report back to us with what you find.

Originally Posted by Ankh599

Checked on the price of a MAF...over $200. Does anyone know of a cheaper price.

Also, cleaned the MAF again, then did the Seafoam process...AND this car is running like brand new. What a PUNCH when you floor it. BUT the check engine light still comes on and it runs bad.

Did you actually check the codes?

Also, it is highly possible that the solder joints in the MAF have gone bad. Many people have had success opening them up and resoldering. The other option is to buy a used MAF typically. Or fork out the money for a new one.

[Ankh599]

Just found out how and checked the codes.

32 - O2 Sensor RH
31 - Throttle Sensor (Been Changed)
37 - O2 Sensor LH
24 - By Pass Air Control Solenoid Valve
23 - Air Flow Sensor

Looks like I'm spending a good part of my day under the hood. Hopefully one of these is likely the issue.

Then I can concentrate on the 5 speed swap.

[1986nate]

Start with the lowest number code first, replace/fix and clear the codes. You may want to also think about clearing the codes as they could be stored from the past. Then wait for the light to come on again and recheck.

[dannmarr]

Check all your vacuum hoses for disconnections or cracks.

[Ankh599]

It was the Mass Air Flow Sensor. Yeah, but now the damn thing cuts off when you put it in gear. My dad said back in the day it was the pollution pump, now if your car does that it's the O2 Sensor. Which my car showed were bad. So I'm trying that next.

[92snowmachine]

you may want to do more checking before you run out and replace the o2 sensors. if you have a voltmeter you can do quite a bit of checking to see what the car actually needs before replacing parts. did you replace the maf? is the new tps calibrated correctly? do the o2 sensors respond to a forced lean or rich condition?

[Ankh599]

The MAF was definitely the problem. The new situation when I'm in drive or reverse and mash the brake the damn thing cuts off. Turns out it was the transmission. So my trans is completely gone!

But I was able to get all the '98 Legacy parts to do the swap to a 5 speed. Just waiting for them to arrive and my mechanic to come back from his honeymoon.

[BackWoodsBob]

Can anyone tell me what colors the error diagnostic test plug uses?
I have a swapped car and need to run the diagnostic but the harness didn't' come with the plug, so I'm stuck using wires .

[Tapani]

Down load all 1992 US spec manuals from here:

http://phantomotaku.com/SVX/

Tapani