CEL problem

[ber55ber55]

Okay so the CEL comes on about 10 seconds in idle or when rolling down hill. But if I turn my a/c on, it goes away for a while, and then comes back after a while of driving.

idle reg valve?
throttle position sensor?
already replaced 02 and intake manifold gasket.....
also checked over engine for vaccum leak.....
please help.....

[Mendozart]

You need to perform the stomp test. Do you own a Bentley manual. If not go to www.bmwe34.net. It shows how to perform the test and there is a ton of other useful information.

[Holland]

Just remove the Bulb for the check engine light, early m20's like mine don't have one fitted.

[632 Regal]

now heres some solid advice!


Just remove the Bulb for the check engine light, early m20's like mine don't have one fitted.

[ber55ber55]

common though! just remove the bulb? that is so mickey mouse!!!! what about when i do smog! the fact that the light would go on if it had the bulb will still make me fail, right?

[MBXB]

Reboot the car using shogun's procedure. (Search archives)
If it still throws the CEL light, read the codes using either
1. the throttle stomp,
2. a Peake code reader,
3. or have your indy read it using his.
You could even try to meet up w a forum member close by with a code reader.

[ber55ber55]

i have the bav auto code reader.....and it just says its lambda

the stomp test: i did it, it worked, but i didnt see any damn codes...the check engine light just flashed a bunch...where do the codes appear.

isnt there a adapter or something for a laptop to plug into the car and some software.....i did it on my friends mit. 3000 vr-4

couldnt find shoguns post about reseting and then i kinda gave up on it

the peake code reader is like the bavauto one right?

indy? que?

[Alexlind123]

now heres some solid advice!

its always nice to see new experts giving their advice for free...

[Mendozart]

Do you own a Bentley? Did you go to www.bmwe34.net? When the check engine light is blinking, that is the code. After the first initial blinks, if it blinks once/twice/twice/once, your code would be 1221(that is an example). The Bentley has the listed codes, as does e34.net.

[MBXB]

shogun's reset procedure:

http://www.bimmer.info/forum/showthread.php?t=2806&highlight=shogun+reset

Make sure you have your radio code before you disconnect the battery.

Indy = independent (non stealer) shop

-------------------------------------


i have the bav auto code reader.....and it just says its lambda

the stomp test: i did it, it worked, but i didnt see any damn codes...the check engine light just flashed a bunch...where do the codes appear.

isnt there a adapter or something for a laptop to plug into the car and some software.....i did it on my friends mit. 3000 vr-4

couldnt find shoguns post about reseting and then i kinda gave up on it

the peake code reader is like the bavauto one right?

indy? que?

[ber55ber55]

alright so here we go.....
I did the damn reset test. didnt do **** in my opinion. I might try it again 2night. the light still came on and the car runs the same

I did the stomp test and go the code 1222 which is the lambda control 1

I plugged my bavauto codereader/reset tool in, also gave me lambda.

I aint going to no dealer. I can do this myself

What could it be now and what is lambda control 1 and what is the difference between lambda control 1 and 2?

[Paul in NZ]

oxygen sensor

[ber55ber55]

but i already replaced the F*CKING 02 sensor and the intake manifold gasket!!! ahhhhh

[BillionPa]

seriously, my car does it too, just not as often as yours.

I would suggest fuel injector cleaner.

why? because its probably the injectors not pumping out anything at their minumum rate, and the O2 sensor (working perfectly) sees lean and pops a CEL.

i only get this when i drive the car rather hard, then drive it normally again afterwards, during the same conditions you mentioned.

i USED to get it all the time during the conditions you mentioned, but i drove 500 miles with shell vpower and lots of chevron injector cleaner and that made it go bye bye.

[ber55ber55]

ive already done injector clean like 3 times, ran good gas, and 92 octane as well....i even put 108 octane in at one point....because i also thought it may be the injectors. im so totally lost with this issue at this point.....

[BillionPa]

108 octane = bad, run 92 all the time. tried MAF sensor cleaner?

[ber55ber55]

no, i havint tried that. a specific cleaner? or just cleaning it?

[BillionPa]

CRC makes it, i had to use it after i had a K&N filter, because thing started acting a little wierd, turns out the oil was all up in there.

[ber55ber55]

alright....cleaned out MAF, clean idle reg valve again....cleaned everything very well....didnt use anything on the MAF to clean it...just took a cloth and ran in with my fingers a couple of times.....

-----problem is worse now.....idle got worse......drops lower.....and also sounds like its about to die off......idle is jacked up when the car is cold as well....ahhhhh!!!!

[MBXB]

Pull the plugs and check firing order?

[BillionPa]

unplug the MAF and see what happens. it may be toast.

[ber55ber55]

would should happen if i unplug the MAF?

[ber55ber55]

the car dies when i unplug the MAF....
idle reg valve - uplugged - keep running the same

after cleaning th MAF like i said, the is completly jacked....light stillcomes on, and the overall idle is much lower, around 600 instead of 1k

[ber55ber55]

Uplugged idle reg valve---engine ran the same
Unplugged throttle position sensor----engine ran the same
Unplugged MAF----engine died

After unplugging the first two items, i hit the throttle to see if something would change i.e. when i unplugged throttle position sensor assumed the idle would messed up or the throttle would be open or closed too much...but it wasnt.....

I checked for air leaks again.....i didnt find anything.....

Idle is worse then before, engine runs the same, and CEL is still coming on...after about 10 seconds.....

Ran the codes with stomp test....got 1222 or lambda control 1

Did shogun reset test....did nothing in my opinion

Plugged in my bavauto diagnostic tool.....also read lambda

Again, I have replaced the o2 sensor and intake manifold gasket.........

NOTE: when i put my hand by the exhaust....i didnt feel a constant flow....it is very pulsive......and irratic....i dont know if this points at anything...

the car also has new spark plugs and a new muffler, new airfilter and I have run a injector cleaner a couple of times now.....probably 3 or 4 times.....

What else could it be....

ANOTHER NOTE TO CONSIDER: when i turn the a/c on and the compressor starts running...the CEL goes off.....the idle stabilizes...idle is still kinda bumpy.....but eventually the light comes back on.....

[BillionPa]

i think i remember a post a while ago with similar exhaust symptoms, the root of the problem was a melted cat.

touching the hot wire of the MAF is a big no no, and that could have caused a problem.

if the ICV being unplugged did nothing, then that sounds like the root cause. if you shake it you should hear the little air blocker bang around in there. when cleaning it, you need to use enough carb cleaner to remove EVERYTHING from inside of it, a half job will leave gunk in there. I cleaned it out with canned air afterwards, and the engine idle was much better.

I have no idea how to find out the condition of the cat, but the only things that would melt it are if the O2 sensor was dead for a long period of time and the engine was constantly lean (exhaust too hot) or constantly rich (gas burning in the cat), or a fuel injector was stuck in the open position leaking gas into the exhaust.

the exhaust should feel pulsive, but not erratic, and the note at idle should be of a constant purr.

when you turn on the AC it sends a signal to the ECU to increase the idle speed by adjusting the valve, so once again, it sounds like the valve is causing the problem.

your idle speed is supposed to be about 750RPMs, and not 1K. 600 is too low and would indicate that the ICV isnt opening properly. 1K would be stuck in an open position. if i was in your position i would clean that sucker out again, although it could just be toast after 16 years, which would suck.

what the TPS does is allow the DME to adjust for changes in throttle quicker than the MAF would alone, so not having it would make the engine less responsive rather than freak out (i think anyway)

and this is perhaps the most important part. the lambda control code is NOT directly related to the O2 sensor having a problem. what it means is that the O2 sensor (and other stuff) is detecting an emissions problem, and functioning normally itself.

the following are the most likely problems throwing a 1222 code:
Defective MAF
Defective Engine Temp Sensor
Stuck Fuel Injector
Evaporative Emissions Purge Valve stuck open. (and other intake leaks)
Incorrect fuel pressure
Engine mechanical failure (spark plugs, valves, bad compression in cylinder)

attempt to diagnose each possible failure point that could be causing that code (MAF comes to mind right away)
good luck, i think you will need it!

[ber55ber55]

well when i bought the car....the 02 was sensor was already bad...so who knows how long he drove with it like that...but when i replaced the muffler i had the whole system out fromt he headers back, and i looked inside the cat and it seemed fine. i have already the replacement cat sitting at home if i need it....

i didnt unplug the MAFwhen it was hot, i unplugged it while the engine was running and i had just started the engine.....it was warm.....

the ICV when i just turn the ignition and had it out but plugged it....made a humming nose as if it was jammed. i was able to easily move around the elements inside with a screw drive. i guess ill clean it ....again!!! haha but it probably is the root problem. NOTE: there is always a decent amount of oil around the plug area...why? i mean it is by the dip stick but there is no leak

i dont think its a bad sprark plug, valve or injector simply because the engine runs very smoothly when its finally at full operating temp, and the accelration is also very good.....so i also dont think the cat is melted otherwise i would have very bad accel and much less power overall...right?

im thinking it is either the MAF and the ICV at this point....it is 16 yr old car....takin car of by a complete jackass that had it before me....

well thanks a billion...billion haha...no for real...thanks for all the help thus far..i hope i can do this....

[MBXB]

Great differential diagnosis write up, billion

The humming noise is normal.

Oil in the plug area? That'll kill your spark. On V8s it's a valve cover gasket. I'd start there.

[Bill R.]

a simple old afm , airflow meter. He doesn't have a throttle position sensor , he has a throttle position switch. which has three positions, idle, wide open, or everything in between. One bad spark plug on his car can melt the cat since it doesn't have the capability to sense a misfire and shut off that injector. You say you checked for air leaks, How did you check for air leaks? and did you check the purge valve to see if its stuck open?





i think i remember a post a while ago with similar exhaust symptoms, the root of the problem was a melted cat.

touching the hot wire of the MAF is a big no no, and that could have caused a problem.

if the ICV being unplugged did nothing, then that sounds like the root cause. if you shake it you should hear the little air blocker bang around in there. when cleaning it, you need to use enough carb cleaner to remove EVERYTHING from inside of it, a half job will leave gunk in there. I cleaned it out with canned air afterwards, and the engine idle was much better.

I have no idea how to find out the condition of the cat, but the only things that would melt it are if the O2 sensor was dead for a long period of time and the engine was constantly lean (exhaust too hot) or constantly rich (gas burning in the cat), or a fuel injector was stuck in the open position leaking gas into the exhaust.

the exhaust should feel pulsive, but not erratic, and the note at idle should be of a constant purr.

when you turn on the AC it sends a signal to the ECU to increase the idle speed by adjusting the valve, so once again, it sounds like the valve is causing the problem.

your idle speed is supposed to be about 750RPMs, and not 1K. 600 is too low and would indicate that the ICV isnt opening properly. 1K would be stuck in an open position. if i was in your position i would clean that sucker out again, although it could just be toast after 16 years, which would suck.

what the TPS does is allow the DME to adjust for changes in throttle quicker than the MAF would alone, so not having it would make the engine less responsive rather than freak out (i think anyway)

and this is perhaps the most important part. the lambda control code is NOT directly related to the O2 sensor having a problem. what it means is that the O2 sensor (and other stuff) is detecting an emissions problem, and functioning normally itself.

the following are the most likely problems throwing a 1222 code:
Defective MAF
Defective Engine Temp Sensor
Stuck Fuel Injector
Evaporative Emissions Purge Valve stuck open. (and other intake leaks)
Incorrect fuel pressure
Engine mechanical failure (spark plugs, valves, bad compression in cylinder)

attempt to diagnose each possible failure point that could be causing that code (MAF comes to mind right away)
good luck, i think you will need it!

[Ausmpower]

a simple old afm , airflow meter. He doesn't have a throttle position sensor , he has a throttle position switch. which has three positions, idle, wide open, or everything in between. One bad spark plug on his car can melt the cat since it doesn't have the capability to sense a misfire and shut off that injector. You say you checked for air leaks, How did you check for air leaks? and did you check the purge valve to see if its stuck open?

What about the O2 sensor? would the feed back from that cause the dme to lean off the fuel?

What about the crank case vent lines? a collapsed or leaking hose can cause all sorts of rough / stumbley running or codes.

Dead air temp sensor in AFM will drop O2 code also.

[ber55ber55]

Great differential diagnosis write up, billion

The humming noise is normal.

Oil in the plug area? That'll kill your spark. On V8s it's a valve cover gasket. I'd start there.

not spark plugs....the plug to the ICV...and not on the plug....around it.....

[ber55ber55]

a simple old afm , airflow meter. He doesn't have a throttle position sensor , he has a throttle position switch. which has three positions, idle, wide open, or everything in between. One bad spark plug on his car can melt the cat since it doesn't have the capability to sense a misfire and shut off that injector. You say you checked for air leaks, How did you check for air leaks? and did you check the purge valve to see if its stuck open?

PLugs....not bad.....

how did i check for airleaks...very simple...spray gasoline on the engine to see if there are air bubbles anywhere.....or suction....thats how i figured out my intake manifold gasket was bad.......

no i didnt check if my purge valve was open.... i guess ill do that next

NOTE: ALSO DID A VISUAL CHECK ON HOSES TO CHECK FOR LEAKS

the cat is fine.....im 100%...when i had it out...i looks through it and saw no melting or signs of a cloged/melted cat

so....ICV? need to replace spark plugs? what? what should I try next without taking anything else apart......

[ber55ber55]

purge valve.....nother name for it? relief valve? where is it located...

[ber55ber55]

Okay so the CEL comes on about 10 seconds in idle or when rolling down hill. But if I turn my a/c on, it goes away for a while, and then comes back after a while of driving.

idle reg valve?
throttle position sensor?
already replaced 02 and intake manifold gasket.....
also checked over engine for vaccum leak.....
please help.....


Okay, so I go to work ...light comes on after 10 seconds as usual....lunch time rolls around...and i drive home to the misses cuz shes cooking me lunch...well when i left...the light came on....but...the rest of the way there...shes about 5 miles from my work....it didnt come on again....not at stop lights...or in neutral or anything.....even when i got there....i let the car idle for about 5 minutes or so....no light....and good idle.....

i left about 45 mins later...start the car....idle is back to its old self....rising and dropping....and the light came back.....

NOTE: i didnt run a/c either way..there or back....

[ber55ber55]

Alright i just did a nice cleaning to the ICV with a nitro car cleaner (the **** you use to clean lil gas powered rc cars) cleaned the hell outta that valve....let me tell you. anyway....both problem are still there....the CEL and the bad idle.....

ANOTHER NOTE THAT I FORGOT TO MENTION:

when i tap the accelerator slightly or play with the throttle arm under the hoodadn give just a quick "tap" the engine chokes and almost dies....

to me that would look like a AFM problem...how bout you guys?

[MBXB]

Holy ****! The collective consciousness of this board can zero in on the problem yet? Back to square one...

[Ausmpower]

Alright i just did a nice cleaning to the ICV with a nitro car cleaner (the **** you use to clean lil gas powered rc cars) cleaned the hell outta that valve....let me tell you. anyway....both problem are still there....the CEL and the bad idle.....

ANOTHER NOTE THAT I FORGOT TO MENTION:

when i tap the accelerator slightly or play with the throttle arm under the hoodadn give just a quick "tap" the engine chokes and almost dies....

to me that would look like a AFM problem...how bout you guys?

Have you checked for a break in the wiring harness for your O2 sensor?

Vibration or a dodgey contact in the wiring harness WILL cause intermittent faults.

AFM could be sticking from gunk build up, are you running a 'pod' filter or K & n?

Terminals in the plug to the AFM could be loose/ corroded... checked them??

Try swapping your AFM with a known good one and see what happens....

It's all a matter of trial and error if all the basic checks don't turn anything up......

Have you checked your TPS for adjustment and correct signal with the throttle closed? DME needs that Idle switch closed....

Has someone played with the AFM spring tension (black cover should be sealed)? or air bypass screw on the AFM??