Author Topic: Oxygen Sensor fails again after 25 miles (Read 6169 times)

sqlpython · « **Reply #15 on:** May 11, 2011, 04:16:22 PM »

Quote

I'm betting vacume leak or bad injector.. Lean = vacume leak, rich usually a bad injector.

I am thinking along those lines as................................
The Check Engine light finally went Out while Driving..
Now that is replaced with Intermittent surges during acceleration and rough idle.
This symptom will sometimes stop but only to return during the same drive.......
... Threw in some Injector cleaner but I doubt that will have any effect.
One of the main reasons I purchased this car last month was how impressive and responsive the Engine / Drivetrain was... very Disappointing..
.......Any input on similar experiences?

sqlpython · « **Reply #16 on:** May 12, 2011, 12:35:03 PM »

My posts on this thread are being Held for Review...Don't know Why?
Anyway, I am attempting to post a solution again.

I the leak theory air/vacuum has a lot of merit.
On a whim, I replaced the Old Gas Cap with a New OEM.
Currently, Check Engine Light Out.... and Vehicle runs smoothly.
Matter of fact I thought it ran great before but Now, maybe perception it seems to run better.
Time will tell... Will post in 48 hrs

DesktopDave · « **Reply #17 on:** May 12, 2011, 04:58:46 PM »

I approved the posts, you can edit/delete/merge as you see fit.

Gas cap?!?! Well, it is a critical part of the emissions control system and a frequent CEL cause. There is a good length of vac lines and a purge valve that are also part of that system, but they've been very reliable in my experience.

I'm thinking that alcohol fuels might have something to do with it...but that's just a hazy guesstimahunch. I have absolutely no evidence to back it up.

sqlpython · « **Reply #18 on:** May 17, 2011, 01:45:51 AM »

Well, Times up! and the Gas cap while it has definitely altered the symptoms the Check engine light is back.
The situation is that now it will go out more frequently but when it does the on board CPU will make Fuel adjustments and the Car will run horrible.. Once the the Check engine light resumes and lights up then the CPU backs away and the car runs very good.
The mechanic that sold me the car is taking it back this week to try a replacement Onboard CPU to see if that is part of the issue.

sqlpython · « **Reply #19 on:** May 23, 2011, 09:15:11 PM »

Conclusion:
Changing the OBC (On Board Computer) cured all ills.......
Not only does the E36 now run correctly but better then ever

DesktopDave · « **Reply #20 on:** May 23, 2011, 10:01:02 PM »

That's great news. I was going to start encouraging you to take a look at the coil box next, but I'm glad you avoided all that.

The OBC or the DME? The OBC is the little display unit in the center console for date, time, instant MPG, etc. The ECU is the one that runs the motor...Bosch calls their fuel injection computers a "DME" (short for Digital Motor Electronics) or Motronic.

sqlpython · « **Reply #21 on:** May 24, 2011, 09:03:14 AM »

Quote

The ECU is the one that runs the motor...Bosch calls their fuel injection computers a "DME" (short for Digital Motor Electronics) or Motronic.

The ECU........
Now it is on to the Front struts which I ordered at $115 apiece..

And they rear Window defroster which lights at the switch but does not heat the rear Window... Got a 2nd had Heater Control unit to try for that one
So.. I will post these in other threads when/If I have issues....

Thanks to All who lent their experience and expertise to help solve the Oxygen sensor mystery...because it was a mystery to me..