M42club.com - Home of the BMW E30/E36 318i/iS
DISCUSSION => Engine management => Topic started by: Petebee on December 11, 2011, 03:44:25 PM
-
Hey guys,
My poor little 318i has been acting up lately. She has about 160k miles and has run like a champ until recently.
On a road trip she started misfiring and throwing a CEL, which would go out if I lifted the throttle (most apparent when under load i.e. up a hill).
Got home, ran stomp test and got 1222 (lambda). Listened and could hear a slight vacuum leak from the mess under the intake, so over Thanksgiving I replaced all of that crap and gave her a tuneup.
Took her out for a spin and she ran beautifully, but bogged heavily on an aggressive 1-2 shift and flashed another CEL. After 30 seconds the CEL went away and she ran fine. This time stomp code resulted in 1221 (oxy). I figured that I might have pulled the intake boot slightly on my aggressive shift, causing a lean condition, resulting in the code.
So fast forward a few weeks and now she's acting up again. I am getting the original 1222 code and random bogging/misfiring after running fine.
Figure I have some type of engine management issue, as a vacuum leak would be more persistent - plus I used a propane torch around the engine and found no evidence of vacuum leaks.
Does anyone have a reference for testing out the electronic sensors (ISV, TPS, CTS, crank sensor, cam sensor)? I don't think it is a coil as that would likely cause it to run crappy all the time, right?
Maybe my ECU is on its way out. I have a Dinan chip installed. Any advice/insight is appreciated.
Thanks,
Pete
-
You're doing everything I'd have done. 1221's are usually vac leaks, like you've been tracking down. How old is the O2 sensor?
Coil drivers in the ECU have been known to develop solder cracks as well. I have a DME with one coil driver burned out. We had a heck of a time troubleshooting that one. When it heats up from running under load, the solder joint cracks open up and you get misfires. A bad coil can damage the driver and vice-versa. So switching a coil might not be the answer. They're usually replaced in sets.
-
Thanks Dave...what is the fix for the DME with bad coil driver - replacement DME? The oxy sensor is only about 20K miles, but I'm gonna pull it anyway and check it - what should I do? Test for voltage at plug? Is there a continuity test for the oxy sensor? It is a spliced in unit, but we soldered and shrink wrapped the wires.
Oh and the drive we were taking was to test drive an 88 M3. I think my little 318i got pissed at me! The M3 was a POS anyway.
-
No need to replace it, I just open them up & reflow the transistor joints with solder. Most can be saved.
The O2 sensor has to be hot for testing. I haven't done that myself, but when it's warmed up and running normally it should rapidly tick between 0.5 and 1vdc. You might want to check the O2 heater relay. That might cause troubles like you're having. If the heater isn't running the sensor will cool off at idle and cause rough running.
An e30 M3...nice. Not too many of them around anymore...at least outside of collector's garages.
-
How would I check the heater relay - can I make a jumper? I searched and found out where it is - leftmost of the three on the firewall under the plastic cover.
-
I'd just put 12v to the relay's control terminals to be sure the relay is actuating. ETM shows that it's a slightly non-standard 4-pin relay, pins 85 & 86 switch the load on 87 & 15.
Do you have the electrical troubleshooting manual? I printed out a copy of the '89 325i/is ETM from here. (http://wedophones.com/BMWManualsLead.htm) The '91 318i/is ETM is missing some pages but it's useful as well.
If you made a jumper I'd use thick wire on 87 & 15 (if that's what they're actually labeled) and be sure to pull it when the car is off. It's only hot in start or run, that heater will flatten the battery, I'd suspect.
-
Thanks Dave...I'm not good with electrical stuff, should I bridge the pins 85 and 86 (or the other way around)? I assume that I bridge from a battery as a source and listen for a click.
-
Hey Dave,
My poor car is driving me nuts. The erratic idle and bogging issue seemed to go away for a week or so. Well I jinxed myself...on the way to work admiring the way the car had been acting (thinking perhaps we had a bad tank of gas) it started bogging down and throwing the 1222 CEL.
I've noticed when it is cold, my cranking time is considerably longer. Had the battery tested and it is fine.
I've seen notes on voltage test for the O2 sensor, but my question is actually how to I test it? While the car is running? If so, do I simply unhook it at the connector and test for voltage, or do I have to somehow tap into the wiring while it is still hooked up?
I plan to run the gamut of tests for the various sensors, relays and the airflow meter this weekend.
I did try looking for vacuum leaks using a propane torch...I might have a slight leak at the oil filter housing as it is certainly leaking oil and I got a very slight idle lift twice while focused with the propane in that area for a good 60 seconds or so.