Service engine soon indicator has been coming on. This normally occurs after a longer ride at consistantly higher speeds. Is this commonly an indicator for an emmission problem? The car does not seem to have any engine issues (besides leaky intake manifold).....drives great. I am looking for a little history and education prior to bringing it in.

 

When that light comes on a code has been set. Have you pulled the codes. Also if you have messed with the timing or the timing has somehow got off it can trip the SES light.

 

Only way the CE light comes on for timing on a 91 is if you unplug the set timing connector. Otherwise, it will set no code. More than likely, it probably has something to do with the EGR valve. If you can pull codes from shorting the 2 pins on the diagnostic connector, it will tell you.

 

Thank you for your replies. I am a bit of a novice so I am not sure how to pull the codes. Is this something a novice like myself can do? Or should I bring the car to the local shop and have it checked? I try to avoid bringing it in as it usually sets me back a nice chunk as you probably know! Thank you for your help!

 

You can use a paper clip to get codes. The diagnostic connector is just above your right leg sitting in the driver's seat. It will have 2 rows of pins. Use the paper clip to short together the 2 pins in the upper right hand corner of the connector. Turn your ignition switch to the run posistion and watch the CE light as it will blink the codes out. It will blink each code 3 times. Pay no attention to code 12 as it will come up first, only the codes afterwards. Code 12 will be 1 long, 2 short and so on. Get back to us with the codes. [8D]

 

I tried what you said and the only thing that came up was a SYS code that blinked 3x's about every 30 seconds. Is this what I was looking for?

 

I figured out the code.....32. It went 32, 12 ,32 3x's. What does this indicate? Thank you.

 

Code 32 is EGR (valve and/or circuit). The most common cause of this code is a bad or intermittent EGR switch which is located on the EGR pipe between the exhaust manifold and the intake manifold. Replace this switch first when you get this code. Next, check electrical connections at EGR valve solenoid and then the ECM. Check all vacuum lines for leaks especially around the EGR valve. Possible ECM failure.

 

That's what I figured. Seen it too many times. You can test the temp sensor with an ohm meter. On a warmed up engine (operating temp), the sensor should have continuity to ground since it provides a ground for the vacuum solenoid for the EGR valve. If it does, the it's probably like Lee said, the solenoid. Also check and make sure you have vacuum to one side of the solenoid which is next to the thermostat housing.

 

I think the vacuum leak is more common the cause of the 32 than the electrical failure, isn't it?