oil light keeps cominng on

[RapidKiller1392]

my oil light comes on while idling and idles at really low rpms, about 5-600, both in park and in drive sitiing at a stoplight, i got an oil change about 500 miles ago an check the dipstick every week and it looks normal. as soon as rpms go past 1000 the light turns off an it runs fine while im driving but as soon as the rpms go back down the light comes back on and the car acts like its about to stall out

 

[Redslayer]

my oil light comes on while idling and idles at really low rpms, about 5-600, both in park and in drive sitiing at a stoplight, i got an oil change about 500 miles ago an check the dipstick every week and it looks normal. as soon as rpms go past 1000 the light turns off an it runs fine while im driving but as soon as the rpms go back down the light comes back on and the car acts like its about to stall out

Its coming on because your oil pressure is dropping when your RPMs are dipping below idle.

I'd be willing to bet that if you find the source of your idle issues, you'd solve the oil light.

Have you checked your tranny fluid recently ( just for starters )

 

[jrohner]

The question is why is your car idling at 500?

 

[alex209]

Why is idle so low ?

 

[bo0st]

Shouldn't idle be around 750 - 800 ?

 

[Abe'sGST]

I had that same problem on my gst, come to find out turbo models are notorious for it, I'm not too sure about NT, I never had that problem with my RS. I cleaned my throttle body because of the bad idle and it solved my oil pressure light problem somehow. I would do that, maybe that will help you. That might also help your idle as well.

 

[RapidKiller1392]

I check the tranny fluid when I check my oil and both are fine

Could it possibly be the idle air control valve?

 

[Abe'sGST]

I check the tranny fluid when I check my oil and both are fine

Could it possibly be the idle air control valve?

I doubt it's your IAC valve, it usually gets stuck at much higher rpm's...Clean your throttle body and see how it works out for you.

 

[boost97gst]

On the 4g63 theres a pressure sending unit and a "dummy switch" for the oil warning light. I would assume the 420a has a similiar setup. Have you inspected the switch for the dummy light? I would also immediately get a aftermarket oil pressure guage just to make sure. It wont take long at low oil pressure to wreck your main/rod bearings.

 

[RapidKiller1392]

Would that also cause bad mileage? I'm only getting about 10mpg when i'm supposed to be getting 19 to 20

 

[bo0st]

Your getting 10 MPGs wow I get better than that and my 4th gear is out in my auto tranny. What is wrong man have you checked out spark plugs, ignition coil, oil, tire pressure & all the other basics?

 

[DSM1G90]

..even NEONS with the same motor get's better mileage. Definitely, a timing/ECU/A-F situation..

 

[DSM1G90]

420A setup doesn't have the BISS screw...

 

[TheEagle]

My 420a has an adjustment screw

Maybe I'm just an oddball. I can take pics if ya need me 2 .

 

[RapidKiller1392]

I just changed the spark plugs and oil is good and tire pressure is good. An i'm getting 10 if that. Its a 14 gallon tank an i'm getting maybe like 120-130 miles bewtween fill ups so its pretty bad

 

[TheEagle]

How many miles on the engine?

 

[bryanwheat]

id also check for a stuck fuel injector with that mileage

I was thinking about this also. That would explain the low idle, and the bad fuel mileage.

 

[RapidKiller1392]

There's almost 146k on the engine. And how would I be able to check the fuel injectors?

 

[DSM1G90]

Wonderin' if the ECU is getting tired . 1995 - 17 yrs and 146K miles on the original ECU is quite the bit.

Sensors getting tired as well, like O2 sensor, temp sensor and the like to tell the ECU wrong information which give bad gas mileage as the results. It'll stay in closed loop so you won't get a CEL, but communication between sensor and ECU is all scrambled up.

Been there and done that with tired sensors: Had a 1985 Nissan Pulsar with the 1.6L .. and only getting 18mpg. Found out that three sensors were horribly tired. Changed them out and got my 30plus mpg back.

 

[RapidKiller1392]

so maybe new sensors a new ecu?

 

[boost97gst]

There's almost 146k on the engine. And how would I be able to check the fuel injectors?

At 225k miles on my 98 rs i was still averaging 34+ mpg highway. All stock. 5speed. I think i would be looking at o2, MAP, IAT.... along those lines you know? Any sensor thats telling the ecu how to pulse the injectors. I cant believe theres no CEL on. Are you pumping out black smoke from all the unburnt fuel??
I seriously think its near impossible to have a running 2.0L 420a get THAT poor fuel economy.
If its an obd2, you can pay a shop around 75 bucks to do a real time scan. This will log values from a ton of sensors.

 

[RapidKiller1392]

The CEL comes on occasionally but its not consistent. How this car is still running I have no idea black smoke does come out only when it revvs beyond 4000RPMs. I had a friend check while revving

 

[GsxAZman]

It could be something very simple. Had the same problem with my gst and ended up being the wire that goes to the pressure sending unit on the housing was frayed and grounding against metal and also not having good contact with unit. You may want to inspect that.

 

[DSM1G90]

Black smoke = running rich, and you're blowing out all the carbon buildup. High RPM's help blow out the buildup. Why you're basically getting CELS is that rich mixture is making the o2 sensor working overtime.

Get the ECU or o2 checked -all we can tell you outside you need to take the initiative to get it checked/ fixed, for we can't give you the "magic potions" just from talking about what it could be.

 

[boost97gst]

Now that i think of it, after you resolve your problem suck in a can of seafoam through a small tube into the IM and clean that gunk out!! You have any idea of how bad the carbon build up is onyour pistons,valves, and combustion chamber? You can literally get so much buildup it will cause detonation. I know it sounds crazy but it can possibly happen. Please clean that sucker out after its fixed, your engine will thank you . And get your ass up to mechanic and get it solved bro!!