I got my car last Janruary in 2009. I replaced the serpintine belt, water pump, radiator, when i first got it. it drove ok, then i replaced the fuel filter, fuel pump, and O2 sensor...after replacing these 3 things..i notcied that my check engine light would only come on if i was driving on the interstate. i let my mechanic know, he ran a diagnostic on it and said it was running rich..said it was not a bad thing, i am a girl so im not sure what rich means. he said it was no big deal and that was all what is wrong with my car. i replaced the EGR valve, and i got all new spark plugs and wires this year thinking maybe it would help..still not improvement.. is there anyone who is knowledgeable about 89 chevy caprices?
Chevrolet Q&AAsk Your Question
1990 Chevrolet Caprice Question: 89 caprice classic
Answer #1ernesttiauli July 21, 2010, 13:25Enthusiast
running rich means burning more fuel then it needs. your new pump might be pulling more fuel then your old one, or sometimes depending where you purchased your 02 sensor it might be slightly different from stock. dealer would be the best place to purchase an 02. but if it was me i would find a performnace shop and tel them your running rich and see what they say
jpsthesecond July 22, 2010, 11:39Enthusiast
THERE COULD BE A FEW THINGS, IT COULD BE THAT YOUR FUEL PUMP IS GIVING TO MUCH FUEL OR YOUR TIMING IS OFF A LITTLE TRY REPLACING THE CAP AND ROTOR AND GETTING THE TIMING STRAIGHT ON IT, THIS HAPPENS SOMETIMES ON THESE CARS AND WHEN YOU TIME IT MAKE SURE YOU DISCONNECT THE ADVANCE TIMINIG WIRE OR EVERYTHING WILL BE ALL OVER THE PLACE
ReplyVisitor, July 22, 2010, 17:00
Isn't the cap and rotor like changing the spark plugs? I've done that already. Where is the advance timing on it ?
ReplyVisitor, March 15, 2011, 08:39
changing the cap and rotor is almost like changing the plugs, but still different becauseif they are giving spark to the plugs at the right timeor enough spark it can screw up how the car runs. the advance timeing on this car should be along the right fender inside the hood. should be a single brown wire and a plug.
Answer #3Carter S March 15, 2011, 01:57Rookie
Hello, I have the same car and I am a Master ASE Auto tech. I have some questions for you before I can say what might be wrong with your car. First was the Check Light coming on before you replaced the O2 Sensor or after the O2 was replaced? What was the Brand of the O2 Sensor? Please let me know the answers.
ReplyVisitor, March 15, 2011, 20:09
the check engine light came on after the 02 sensor was installed. AC DELCO Is the brand of the O2 sensor I believe.
Does that help any?
Does your trunk leak when it rains, and fills up with water?
ReplyVisitor, March 15, 2011, 23:37
If it was definitely an AC Delco O2 then I would say that you have what is called a "Lazy O2 Sensor" I would replace it with another O2 Sensor and please make sure it is an AC Delco. What is happening is the O2 Sensor is swinging to slow and that is what is setting the Rich code on the highway. Around town the throttle is up and down and on the highway it is at a fixed position and the O2 is swinging to slow between rich to lean and back to rich. This should be very fast and a lazy O2 moves to slow causing that rich code.
Do this and let me know how it turns out.
Thanks for your reply;
ReplyVisitor, March 19, 2011, 12:09
hi i have a 1990 caprice but after driving it on the interstate the service engine light comes on but the car drives fine still but sometimes when diving for a while i start hearing noises when i'm pushing the accelerator but once i turn the car off the service engine doesn't come back on.