Check engine light

[DejaEntendu]

My commute to work is somewhere around 25 miles each way, and it seems about 3/4 of the way either way, my check engine light comes on. It's off when I start it back up to leave, but then comes on pretty consistently each time I reach that distance until I shut it off. My temp gauge doesn't read that it's getting too hot, and it seems to be running fine.. Is there a way to hook these up to a code reader? (89 carbed L)

[TominMO]

My commute to work is somewhere around 25 miles each way, and it seems about 3/4 of the way either way, my check engine light comes on. It's off when I start it back up to leave, but then comes on pretty consistently each time I reach that distance until I shut it off. My temp gauge doesn't read that it's getting too hot, and it seems to be running fine.. Is there a way to hook these up to a code reader? (89 carbed L)

No, you read the codes by grounding something in the engine compartment (don't have my manual with me right now, and not familiar with the carby procedure), and reading the code flashes on the CEL. Someone else can chime in with the exact procedure. If you don't have a Haynes manual, we can tell you what the code reading means, after you get it.

[tooldude]

The test connector is a single terminal connector (next to a 6 position connector) hanging from the wiring harness near the driver's side corner of the firewall. With the ignition off, ground that terminal. Turn the ign key to "on" and the check engine light should come on. If it goes back off, there are no codes. With 2 digit codes, the count of the slower flashes of the light are the first digit and the faster flashes are the second digit. There's a pause between sets of flashes. The code/codes will keep repeating. Turn off the ignition, then disconnect the test terminal wire. If you get codes 15 & 17, the O2 sensor is probably beginning to be degraded, but the engine still runs well enough to not be too noticeable and mileage will drop.

[DejaEntendu]

I finally got around to checking it out.. I got code 17. Does that mean O2 sensor?

[TominMO]

I finally got around to checking it out.. I got code 17. Does that mean O2 sensor?

Yes. If you get a new one, get the Denso brand. Part #2341019, $23, from www.rockauto.com

[william]

Mine does this very thing when very cold out if I drive it easy.
I have a new o2 and still dose it. It hasn't done it lately and I contribute it to my grill and radiator block.
These cars run cool and the o2 is not heated it throws a code when cold. If I floor it when the light comes on it will go off.

[DejaEntendu]

Where exactly is the o2 located on these things?

[dalebwilson]

In the exhaust manifold on the passenger side.


Sent from my iPhone using Tapatalk

[granny]

My 89 had a code 9 temp sensor put brand new one on still get a code 9 and check engine light still on. any help

[ricko1966]

A code doesn't mean that part is bad you need to find what Conditions set the light,a perfectly good o2 sensor will throw a code if it is doing it's job right it will read out of range with an intake leak,bad plug or wire exhaust leak etc.etc. coolant temp sensor same deal find out what it takes to make it set a light.Stuck tstat,broken wire, low coolant etc. before you replace parts verify they are bad temp sensors can be tested so can oxygen sensors,I've seen just as many good ones replaced as bad ones. Checking on O2 sensor is child's play with a propane torch and a multimeter.

[Movin]

Only easy if you happen to be checking the right temp sensor, or replacing the right one. The ecm 2 wire sensor is the one you want to replace for this problem. If the T stat is not new replacing the two together makes sense. Mainly replying to Grannie and the code 9.

[granny]

Thanks Movin, that is the one I replaced.Just don't know with this 89

[tooldude]

Granny, since I don't know you and I don't know if you understand fixing cars the way I'm betting you understand fixing turkey and pie, let me explain it this way: if for some reason the computer is not getting the right voltage signal from the coolant sensor, it will set code 9. Reasons can be: voltage is too low, voltage is too high, or there is no voltage reaching the computer. The first thing to check is whether the engine temperature gauge is reading about halfway up the scale when the engine is completely warmed up, because if the coolant is not as hot as it should be, the voltage is too high. In that case, the thermostat is probably not controlling the temperature and needs replacing as Movin is suggesting - unless you have left the nice warm state of Georgia to drive around in some very cold place. The voltage return signal should be 3V or more cold, drop to around 0.5V hot, and spec is 0.15V - 0.35V @ 180 Degrees.

[granny]

tooldude, just so you know I can cook a turkey and a pie but I am also 58 years old and been working on cars with my husband since I was 17. It is just sometimes you can do all you can and things still are not fixed. have you not ever asked a question about something before? It just seemed you were putting me done without knowing anything about me. Next time don't jump to conclusions.

[Movin]

OP..if your carb is a little too far from perfect mixture you can get a code 17 because the sensor even though it may be good is out of range. The light comes on during cruise conditions? Say 35 mph?

Grannie, check the inside of the plug for any sign of corrosion, a good connection is required for the temp measurement to be accurate. Feel the wire for a bit to make sure the engine vibration has not caused a break in the wire. Pull on the wire a bit to see if it feels stretchy, these kind of breaks leave the wire insulation intact but breaks the wire inside.

There is a great list of checks in this thread as well, coming from pros.