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"check engine" light

douglas

Chocolate Milk Doug
May 15, 2002
9,889
0
Shut up and Ride
any ideas why after sitting for 2-3 months the check engine light will now stay on?

details: 98 grand cherokee, had to jump start, and it was tough to start, kept stalling - would idle up, I'd let off the gas and then it would stall - I had to keep the revs up for a while to get it to not stall.


thanks
 

TreeSaw

Mama Monkey
Oct 30, 2003
16,676
444
Dancin' over rocks n' roots!
Hmmm....could be a fuel injection problem, dirty fuel filter or air filter as well or perhaps something to do with the Catalitic (I have no idea how to spell it) converter. I had some similar issues with my stratus.
 

ALEXIS_DH

Tirelessly Awesome
Jan 30, 2003
5,374
164
Lima, Peru, Peru
a check engine light is just because a sensor is not working right.
if the car doesnt idle fine, and you have to step on it. check all the filters first.
 

douglas

Chocolate Milk Doug
May 15, 2002
9,889
0
Shut up and Ride
ugh.....the gas is really low, I know some people have had vapor lock(gas) that made the light go on, I was going to put some primium in it today.......sucks cause the inspection is expired and I dont want to have to spend $$ to be able to sell it


I :nuts: myself for being lazy and not selling it months ago
 

stinkyboy

Plastic Santa
Jan 6, 2005
15,192
0
¡Phoenix!
Dude I used to know wrenched at a Chrysler dealership told me they come on at mileage intervals (60,000, etc.). He reset my Wrangler light that was stuck on for a 12 pack of Budweiser. :dead:
 

Sorgie

Monkey
May 20, 2005
228
34
Rochester
When my car sits out in a heavy rain the check engine light comes on, then goes off after I drive enough to dry out whatever sensor got wet. If it's running okay I would just drive it around (not far from home ;) ) and see if it goes off. The easiest fix would be to put electrical tape over the light...all Gone! :sneaky: :D
 

LordOpie

MOTHER HEN
Oct 17, 2002
21,033
1
Denver
The infamous "check engine light". I hate it. Did you know that on some vehicles, the light will go on (and stay on) if your gas cap isn't tight enough?

They want upwards of $200 to diagnose and turn the light off... even if it went on for no serious reason. I hope the light burns out cuz it's on... again.
 

douglas

Chocolate Milk Doug
May 15, 2002
9,889
0
Shut up and Ride
Sorgie said:
When my car sits out in a heavy rain the check engine light comes on, then goes off after I drive enough to dry out whatever sensor got wet. If it's running okay I would just drive it around (not far from home ;) ) and see if it goes off. The easiest fix would be to put electrical tape over the light...all Gone! :sneaky: :D

ghostrider said:
Best thing to do is ignore the nebulous 'check engine' warning and wait for something more obvious to occur, such as a blown head gasket.


umm, yeah but I want to SELL it !

maybe theres cobwebs in the muffler :blah: , I'll drive it around a bit after I put some fresh gas in
 

robdamanii

OMG! <3 Tom Brady!
May 2, 2005
10,681
0
Out of my mind, back in a moment.
I'd say perhaps a fouled O2 sensor in the exhaust system. The "Check Engine" light generally refers to the emissions system.

I know if I put a batch of gas in the car, from a station that has just filled their holding tanks, my car will run like **** for months and the check engine light will pop on and such.
 

SkaredShtles

I love NEWCASTLE and will ONLY drink NEWCASTLE!!!!
Sep 21, 2003
49,331
3,251
In a van.... down by the river
LordOpie said:
The infamous "check engine light". I hate it. Did you know that on some vehicles, the light will go on (and stay on) if your gas cap isn't tight enough?

They want upwards of $200 to diagnose and turn the light off... even if it went on for no serious reason. I hope the light burns out cuz it's on... again.
If it's a Subaru you can turn it off yourself. Way I see it - if it's actually something wrong, it'll come on again. :D

The only things that I've ever been told by a "professional" reading the codes was:

1) Misfire on cylinder X
2) Probably a loose gas cap

I think one of the local auto parts stores will read your code for free (in hopes of selling you a part to fix whatever set it off). Autozone, maybe?
 

binary visions

The voice of reason
Jun 13, 2002
21,670
433
NC
Just find a place that does free diagnosis and have 'em diagnose it. You don't have to get it fixed, and they may say that the computer codes were relating to something stupid that doesn't need attention.
 

SkaredShtles

I love NEWCASTLE and will ONLY drink NEWCASTLE!!!!
Sep 21, 2003
49,331
3,251
In a van.... down by the river
binary visions said:
Just find a place that does free diagnosis and have 'em diagnose it. You don't have to get it fixed, and they may say that the computer codes were relating to something stupid that doesn't need attention.
With a Subaru, this is almost *always* the case, apparently. :mad:
 

-dustin

boring
Jun 10, 2002
7,165
1
austin
what stoney said...take it to Autozone and get the code.

with Toyotas, the CEL is generally an O2 sensor, or the MAF. likely the MAF, which can be cleaned by most anyone.
 

I Are Baboon

Run, Forrest, Run!
Aug 6, 2001
29,457
2,028
MTB New England
LordOpie said:
The infamous "check engine light". I hate it. Did you know that on some vehicles, the light will go on (and stay on) if your gas cap isn't tight enough?
I don't know if other manufacturers/dealers do this, but Acura used to set my light to go ON once my next scheduled oil change came around. I friggin HATED that. Subaru does not appear to do that.
 

SkaredShtles

I love NEWCASTLE and will ONLY drink NEWCASTLE!!!!
Sep 21, 2003
49,331
3,251
In a van.... down by the river
I Are Baboon said:
I don't know if other manufacturers/dealers do this, but Acura used to set my light to go ON once my next scheduled oil change came around. I friggin HATED that. Subaru does not appear to do that.
Subaru does not.

But apparently they set it to come on for random, annoying crap. :p
 

SkaredShtles

I love NEWCASTLE and will ONLY drink NEWCASTLE!!!!
Sep 21, 2003
49,331
3,251
In a van.... down by the river
stoney98 said:
I've had too many mis-fires to count. I do have a feeling that it might be because I keep my car aroun 4500-5500 rpm 90% of the time though.
Yeah. I just took to removing the fuse for about 10 minutes and resetting the light that way.
 

C.P.

Monkey
Jan 18, 2004
547
8
SouthEastern Massachusetts
Best purchase I made last year: Carchip
All cars since 1996 have what's called a ODBII connector.
It's the recepticle your mechanic plugs his shop computer into to access your veichles on board diagnostics (read computer).

A car chip is a basic version of the tool your mechanic uses to download the codes that your vehicles on board diagnostics originally generated (which show up to you as a lousy "check engine" light.)

http://www.davisnet.com/drive/products/carchip_products.asp

The codes are generated when a sensor senses a condition that is out of the default range for normal (and safe) operating conditions. With the codes you can diagnose the problem a LOT easier. You ca also RESET the check engine light!!
I got mine on ebay - it was the best 50 bucks I ever spent.
 

narlus

Eastcoast Softcore
Staff member
Nov 7, 2001
24,659
26
behind the viewfinder
I Are Baboon said:
I'd check the engine.
LMAO!

and like jerry seinfeld said about roadside breakdowns, most men have zero clue but get out of the car anyway, stride purposefully to the popped hood, look at the engine, and hope there's a huge switch that's suddenly been set to the "OFF" position.
 

dh girlie

MISS MISSY (geek)
douglas said:
any ideas why after sitting for 2-3 months the check engine light will now stay on?

details: 98 grand cherokee, had to jump start, and it was tough to start, kept stalling - would idle up, I'd let off the gas and then it would stall - I had to keep the revs up for a while to get it to not stall.


thanks

Hmmm...that sounds like what just happened to me...my battery was bad...got a new one and it runs like a champ...but as for the check engine light...mine came on and turns out I needed just a new gas cap...
 

Ian F

Turbo Monkey
Sep 8, 2001
1,016
0
Philadelphia area
Yikes... :think:

Either go to Autozone and have them scan it or spend a few bucks for an OBD-II code-reader and do it yourself. The nice thing about these tools is they are universal for all US market cars made after '97.

A CEL when the engine seems to run fine usually means something in EVAP system is malfunctioning. Often, it's a vacuum problem and a new gas cap will fix it.

A CEL when the engine runs like crap usually means something is broken.

A bad battery and inconsistant voltage will also trigger a CEL. How well does your desktop run with a bad power supply?

The code reader will tell you which is right and allow you to turn off the CEL.

Modern CEL and the OBD-II systems are great. For a cheap code-reader, just about any running problem can be diagnosed and fixed. I wish it were so easy on my '73 Volvo...
 

HOOWAH

Monkey
Sep 16, 2001
105
0
portland, maine USA
you should be able to get the code manually without a code reader, and then search for the engine codes for your make and model on the net or call autozone. here's how it's done. (i know this works for gm, ford, and dodge, but should work for all).

get in the car and put the key in the ignition.

you have to turn the key in the ignition 3 times in a row on and off (but don't turn it so far that the car starts, only so the radio and lights come on) and then leave it on. it's a fairly quick action that goes like this:

turn key to on; quickly turn off;
turn key to on; quickly turn off;
turn key to on; leave it on;

after this the check engine light will start flashing a sequence. it will be a few short flashes and short pauses followed by a long pause to seperate the numbers. count the number of short flashes in each number and string it together to find the code. if there is more than one code it gets confusing, but you should be able to figure it out.

so a code 232 would be;
flash flash;
pause;
flash flash flash;
pause;
flash flash;
long pause then repeats, or moves to next code.

then search the net, or call autozone or whatever and find the reason for the code. sometimes a common cause is a blip in the oxygen sensor for a split second and then the light just stays on.
 

blt2ride

Turbo Monkey
May 25, 2005
2,334
0
Chatsworth
Wumpus said:
Could be an O2 sensor, too.


Our Mustang's* light goes on and off at random intervals.








*It was free.
It sounds like it might be the O2 sensor. However, since the check engine light is on, I would take to a mechanic who can hook it up to a computer.
 

C.P.

Monkey
Jan 18, 2004
547
8
SouthEastern Massachusetts
HOOWAH said:
you should be able to get the code manually without a code reader, and then search for the engine codes for your make and model on the net or call autozone. here's how it's done. (i know this works for gm, ford, and dodge, but should work for all).

get in the car and put the key in the ignition.

you have to turn the key in the ignition 3 times in a row on and off (but don't turn it so far that the car starts, only so the radio and lights come on) and then leave it on. it's a fairly quick action that goes like this:

turn key to on; quickly turn off;
turn key to on; quickly turn off;
turn key to on; leave it on;

after this the check engine light will start flashing a sequence. it will be a few short flashes and short pauses followed by a long pause to seperate the numbers. count the number of short flashes in each number and string it together to find the code. if there is more than one code it gets confusing, but you should be able to figure it out.

so a code 232 would be;
flash flash;
pause;
flash flash flash;
pause;
flash flash;
long pause then repeats, or moves to next code.

then search the net, or call autozone or whatever and find the reason for the code. sometimes a common cause is a blip in the oxygen sensor for a split second and then the light just stays on.
Good tip - although I think this method is only useful with OBDI equipped vehicles, not OBDII.