Check engine light on 88 325is

autopasse · 09-14-2002, 05:14 PM

My check engine light comes on every once in a while when I drive my 88 325is. I brought it to a shop and they plugged in and ran codes, but it came up clean. Is it safe to continue driving the car?

Jared at Pelican Parts · 09-16-2002, 09:30 AM

When you say the check engine light comes on, are you reffering to the Check light in the dash? If so, you should have one of the lights light up in the display at the top of the windshield. Which light up there is turning on?

autopasse · 09-16-2002, 09:40 AM

The check engine light is the only one going on. It's not the flashing check light, but the check engine light. The only light up top that goes on is the license plate light (I've ordered a replacement part from you guys).

Jared at Pelican Parts · 09-16-2002, 09:41 AM

I would check the display up top by pushing the check button and see that all the light bulbs illuminate. Are there any dead bulbs?

autopasse · 09-16-2002, 09:59 AM

Done that. I think we're talking cross-purposes. I'm talking about the red check engine light. The owner's manual says that it turns on when there are problems with the emissions system.

Jared at Pelican Parts · 09-16-2002, 10:11 AM

Excuse me,

Youre right, I didnt think of that light. Does the light come on when you turn the key to the first position, before starting the engine? Have you noticed any problems with engine smoothness or fuel economy? It's possible the O2 sensor may be on it's way out. How many miles do you have on the car?

autopasse · 09-16-2002, 10:13 AM

What's been happening is that it's lighting up while I'm driving. Sometimes from the time the car is turned on until it's turned off, sometimes just for a few seconds.

I guess it would be an O2 sensor on its way out. The car has 132K on it, so it's probably old enough to need to be replaced. I'm just more worried about being safe while driving (no catastrophic failures).

Jared at Pelican Parts · 09-16-2002, 10:19 AM

Ok, have you noticed any strange smells coming form below the car? This is usually any indication of O2 meltdown if you smell sulphur like odors. If the O2 sensor has not been replaced before 132K, I would def. reccommend replacing it anyway. BMW says to replace O2 senors at 30,000 mile intervals.

autopasse · 09-16-2002, 10:34 AM

Come to think of it, there is a weird smell at times. Like something is burning.

You know, other than that, the car is really great. I appreciate your assistance (via email) helping me w/the 3-series decision.

-- Dan

Jared at Pelican Parts · 09-16-2002, 10:38 AM

feel free to email me at Jared@pelicanparts.com if you have any tech questions.

I'd replace the O2 sensor if I was you. You might be surprised how well the car runs afterwards.

Matt Smith · 10-13-2002, 07:42 PM

Interesting. I get that sulphur smell only when starting up in the morning momentarily. The car is Cat delete from the factory, so I guess it can't be that. How does the O2 sensor cause that smell?
It's not startup smoke either..

I'm beginning to like this BMW forum. UH OH! there goes more wk productivity!

Wayne 962 · Wayne 962's Garage

Actually, (and I'm not a CAT expert) I believe that a faulty O2 sensor will make the car run rich, which will make it smell a bit sulfury (is that a word)?

The rich running, I believe, causes the smell, and also causes the CAT to stop working effectively. Again - not 100% sure here, but I think that the cause and effect are backwards. Rich causes smell and ruined CAT, not ruined CAT causes smell...

-Wayne

autopasse · 10-14-2002, 07:23 PM

Replaced the O2 sensor. Everything is great. Thanks for all your help.

SuperWheel · 10-14-2002, 09:41 PM

Great! Another mystery solved. Honestly, the O2 sensor is one of those very common, very easy to replace parts that has a tendency to fix a lot of problems.

Jared at Pelican Parts · 10-15-2002, 02:48 PM

Quote:

Originally posted by autopasse
Replaced the O2 sensor. Everything is great. Thanks for all your help.

No prob. Glad it's going smoothly now.

stolleee · 02-09-2003, 07:53 AM

Due to the car being OBD1 (manufactured before 1996) the codes can only be read while the MIL is illuminated. Any AutoZone in the US can do this for you

CraigD · 02-10-2003, 06:24 AM

You can get information from the ECU regarding the source of trouble. All it involves is getting in the car, turning on the ignition, pushing the throttle to the floor and releasing 5 times. The check engine light will then flash a code to indicate the source(s) of the problem. Click here to learn more about flash codes

Wayne 962 · Wayne 962's Garage

On my 325is (OBDI), I can read codes without the light being illuminated...

We have a great technical article on reading fault codes:

http://www.pelicanparts.com/bmw/techarticles/Mult-Code_Reading/Mult-Code_Reading.htm

-Wayne

Wayne 962 · Wayne 962's Garage

One more thing - if the O2 sensor is a bit off, it can generate an ultra-rich or lean mixture, which can trigger the lamp coming on. As this situation fixes itself, the light should go off. This sounds like what was happening...

-Wayne

gott · 02-13-2003, 05:07 PM

I agree with Wayne. I have an 89 with the later Motronics system. I believe it retains the codes even with the light off. The codes can be read as mentioned earlier by CraigD and Wayne.

--Gregg