Please Help My Car is Running Rich at idle.

daryl_db

New Member
Jul 12, 2007
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I have been having this problem for the last couple of weeks. My 93 lx is running really rich at idle. I have tried to pull the codes but everything looks fine. I have also replaced the o2 sensors about 1500 miles ago. I am currently running 24lb injectors with a matching C&L tube. Please point me in the right direction. I am running out of ideas.

Thanks for your help.
 
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So have you actually retrieved codes? I ask because the various systems adapt and 'cover' eachother pretty well.

Have you cleaned the MAF wires recently?

Did it run better before (with 24's and your current intake)?

Good luck.
 
The only code that I got was 11 and according to the manual it means the system is good. I cleaned the MAF this past weekend. When i bought the car it had 30lb injectors installed and shortly after i downgraded to 24lbs. It has ran really well for about 3 weeks then the richness came to play.
 
I am having the same problem at the moment with my car, not to hi-jack the thread or anything but can an exhaust leak at the header flange cause it to run rich? (I'm thinking this is my problem)
 
have you done anything to cause this change? any new mods??? my c&l causes some problems until i clock it just right....

No I haven’t done anything to cause this change. No new mods. The only thing that has happened is the colder weather in my area for the last couple of weeks.


Do you have an adjustable fuel regulator? How much fuel pressure are you running and have you pulled a plug to see what they look like?

No, I do not have an adjustable fuel regulator. The last time I checked I was pulling 39psi at idle with the vacuum pulled. The plugs look fine. They don’t look excessively rich. But then again I didn’t let the car idle for a long time before I checked them.
 
Does it idle fine? It could be a small vac. leak starting, You could try to re-clock your C&L there always a pain in the arse, what thermostat you running the change in temp could cause it to richen up. I would let it idle a bit and check all your plugs maybe you have an injector hanging up a bit. just some stuff to try!!
 
Does it idle fine? It could be a small vac. leak starting, You could try to re-clock your C&L there always a pain in the arse, what thermostat you running the change in temp could cause it to richen up. I would let it idle a bit and check all your plugs maybe you have an injector hanging up a bit. just some stuff to try!!


It idles fine. I have noticed the when i come to a stop it will hang at 1000-1200 for a second or 2 and go down to about 800 rpm.

If i were to clock the C&L should i rotate the sensor toward the fender or toward the alternator?

I am currently running a 180 degree stat. I did notice this morning that the temp gauge was only 1/4 up from the cold position. I think i am going to change the stat out this weekend to a 192 degree.

I thought that it could be a vaccuum leak so i changed most of the plastic lines to flex vaccuum line.
 
The C&L can go either way thats the finicky thing about them, I would go for the195 stat and go over all your intake bolts to while your at it. Just rule some things out also give your idle air motor a good cleaning that usually cures your hanging idle problem.
 
I'd want to see AF ratios or exhaust content before assuming something went wrong. A lack of cats and changes in the weather can create a stinky exhaust. And a leak in the EVAP system lines can cause a fuel smell at idle.

I only mention this so you don't have tunnel vision and drive yourself nuts.

Good luck.
 
MAP sensor....could be the problem. Will make the car run extemely rich, double check all your vacuum lines, you'd be amazed the difference a vacuum leak will make.

He has a 93, ergo no MAP sensor. If it was SD, you had a great idea.