a faulty sensor will cause rich problems, map, 02, , have the pcm scanned for possible fault codes
Any ideas how to resolved a 95 Neon SOHC 2.0l engine that is running rich? I have changed the plugs, cleaned the throtle body, and even installed a cold air intake (intake was more to remove the mess of tubing, air box and baffle attached to the air box). If this was a carburator, the issue would be resolved, but because everything is controlled by the ECU, I really do not know how to resolve this issue. Mike mlawrenc(at)rcc.on.ca
My 97 was running rich also. I did the same things, with the exception of adding a cold air intake. I solved it by getting a new O2 sensor. I was getting about 14 mpg, and changing the O2 immediately changed my gas mileage for the better.
You don't do yourself any favors by putting in a "cold air intake". That "mess of tubing, air box and baffle" needs to be there; put it back. With your Ricky Racer, Jr. "cold air intake", fuel economy will suffer, emissions and engine wear (via oil contamination) will increase. Same as always: Proper diagnosis and targeted repair. Your rich running could be caused by a number of rather minor and inexpensive faults, but guessing and throwing parts at it is the wrong way to do it. Start by checking the codes. To check the computer codes: With the engine off, switch the ignition key on-off-on-off-on, leaving it "ON". Do not go to "start", just "on" during this procedure. Watch the "Check Engine" or "Power Loss" light. It will turn on, then go off, then will begin to flash-out any trouble codes that have been stored. For instance, if it flashes: flash <pause> flash flash <long pause> flash flash flash <pause> flash flash flash flash flash <long pause> flash flash flash flash flash <pause> flash flash flash flash flash Then you have a 12 (one flash followed by two) a 35 (three and five) and a 55 (five and five). 55 means "end of codes" or, if by itself, "No codes stored. Check the codes and report what you find.
Throwing parts at it? Spark plugs are sometimes the simplest fault, and cost $4.50CND for all four and take me about 10 mins tops to change. AS for the cold air intake, I will not argue with you on that one. I know under almost every application, an CAI has been known to add a little without affecting mileage or life of engine. (The down side is noise.) But like I said, I will not argue with you on it as not all add-ons work on every application. Prime example, throtle body spacers, I done not believe they will do anything, but others beleive it does. Now, to the engine codes. The only codes I had when I checked it a few months ago was A/C clutch sensor. I never use the A/C, so this is no big issue. I think I will take a closer look at the MAP and O2 sensors as mentioned in one of the other postings. There has not been any error codes displayed regarding then, but I will have then checked when I bring the car into my neighbour's shops this following week. Mike
OK, but I have to assume you would've posted "95 Neon running rich" a few months ago had the problem been there, so why don't you check the codes *again* and let us know what you find *now*? You don't seem like a very good listener.