Service Engine Soon Light

[cwmartin59]

I own a 1986 Late Model Year (Aluminum Heads) Coupe. Car runs great. When I am driving 65 or higher (smile) for any time (with or without cruise) the Service Engine Soon light comes on. Driving under 65 the light does not come on. I have read out the codes and indications are the EGR system. I have replaced the valve (a lot of work) and the same thing occurs. The EGR switch seems to be working properly. Vacuum lines are good. I have had the car at the Chevy dealer and they couldn't find anything wrong. I am the third owner of the car. I have discovered that the tube that runs from the air pump switch (right front) to the exhaust system (Catalytic Converter) is missing and the remaining hose is not plugged. The exhaust system had been replaced by a previous owner. Other than the annoyance of the light, everything seems to work fine. Any ideas...Thanks in advance. :cool

 

[JT ZR-Won]

Try hooking up the remaining pieces of the EGR system. Also, are you running a stock chip? An aftermarket one might help. A friend of mine with an '85 removed the entire EGR system (had a Hypertech StageII chip) and had no engine light problems......

Jay

 

[Jim]

I had the same problem and no one could find it! @ $75 a pop!!! I replaced the EGR valve and solenoid but still the light would come on but only when I would drive @ 60+. Here's what it turned out to be for me. There are two hard plastic vacuum lines that come off of your EGR solenoid and throttle body that come down to a "two into one" fitting at the valve cover, This fitting was plugged up when someone (ME!) tryed to glue a broken line, two bucks and a new 5/32 fitting from the local parts store and problem fixed. Hope this helps. Jim