One bank seems to be on and off ? - Fixed

[wrightbenz]

My quest to get this car running better isn't going well.
I had the car running fairly well considering it had no o2 sensors and what looked like original plugs.

This is weekend I installed new csv valves and one way valves. I also removed the hvac blower motor since it was seized.

Anyway once i reassembled everything the far the car started running poorly as if one bank was out.
I quickly noticed the EML light was not lighting when I turn the key to on. I pulled the cluster and checked things out and it seemed fine. I reinstalled just the board and the eml light was working again.
Put the cluster back in and things seemed better.

Problems the the eml sometimes lights and sometimes does not. GREAT !

The car is obviously running on all cylinders for a few moments then dropping to and misfiring. Then it will take off and run great then back to sputtering.

I know now everyone will say make sure I installed everything correctly and I have checked. It really isn't a very complex job doing the csv valves. I did remove the throttle bodies from the intake cleaned them out a bit just the butterflies. Reinstalled with new gaskets. They are both opening when the car runs poorly.

Feels ls like ignition issues to me. Possible a crank sensor or the spark sensor but I'm just going from experience here.

any help would be great.

[shogun]

Difficult without more background info.
Did you check the ignition coils, distributors and distributor rotors? Check spark plug 6 and 12 where the cylinder identification sensors are on the ignition cables. If 6 or 12 do not spark, not good.
Both fuel pumps working? Squeeze both fuel hoses in engine bay where they come up from the left wheel housing near the coolant expansion tank, both should be under pressure.
Battery is fully charged for starting the engine?

[wrightbenz]

the issue is intermittent shogun. Car runs good for a bit then sputters. I Have not check the coils as I have never had issues with coils but I can. I did remove the distributor cab while I was changing the csv and just cleaned it up a bit. Didn't look to bad. Possible I damaged something I suppose and I will have another look. The EML light on the dash lights when I turn the key sometimes but not always and this seems odd to me. Possibly something going on with that circuit but I did not no. Is this normal for the EML LEDs to not always light when key is turned ? I will ill also check the fuel hose pressure. But like I said the car runs good on and off. I may not be able to tell if the pump is intermittent

[shogun]

Ignition coils usually last very long, but in the E31 forum wuffer commented he has seen more than 5 ignition coils meanwhile damaged and some even damaged the Motronic. But that can often be seen that the housing of the ignition coil cracks, often at the bottom.
Seems the EML light is your problem, when EML does not go on, it can run in limpmode. As you have worked in the area of MAF's and throttle valves, a shot in the dark: I have seen broken wires in the wire looms mainly going to the MAFs, the outer sheath is stone hard and when that breaks it cuts into the wires inside. Sometimes these wires might still have contact and sometimes not. Usual damage is in the bend of the wire loom just before it plugs into the MAF. Also the plugs of the MAF break, the inner ring breaks and then one can pull the connector out without unlocking it.

[wrightbenz]

EML may be it but it's kind of odd. Any idea why the EML would light sometimes when I turn the key on and not other times ? Understand I do not have an EML light when the car is running I am only talking about the test when key is turned to on.

[shogun]

Normally when you switch ignition on to both throttle valves start to run in stand-by mode and you can hear them hum, they make the test and open slightly and then go back. The EML light should always go on when you switch ignition on and then go out after 2-3 seconds. If it does not come on at all or never goes out, limpmode.
Maybe a wire problem, contact problem or something like that.

Just as example what can happen: Weird electrical problem - throttle wiring is hinky, sends DK into spasm http://www.bimmerboard.com/forums/posts/644209/

[wrightbenz]

[QUOTE=shogun;29440259]Normally when you switch ignition on to both throttle valves start to run in stand-by mode and you can hear them hum, they make the test and open slightly and then go back. The EML light should always go on when you switch ignition on and then go out after 2-3 seconds. If it does not come on at all or never goes out, limpmode.
Maybe a wire problem, contact problem or something like that.

Just as example what can happen: Weird electrical problem - throttle wiring is hinky, sends DK into spasm http://www.bimmerboard.com/forums/posts/644209/[/QUOTE

possibly when I move the dks out of the way I caused a problem.
I need to do some digging. I had it running so much better and now I am worse off than I started.

[shogun]

Did you connect the hoses again going from the throttle valves to the fuel breather valves and then to the charcoal canister? http://www.realoem.com/bmw/enUS/show...diagId=13_0181
Check if the breather valves are connected with the electric plug.
Fuel hoses to fuel pressure regulators go crosswise
wrong shown http://bmwe32.masscom.net/sean750/fu...eRegulator.jpg
correct as we did it here http://2.bp.blogspot.com/-swlVIV5RYo...0/P1160580.jpg

update your profile with month/year E32 model, I do not know where to look in realoen and ETM: My Cars:98 M3 sedan

[wrightbenz]

Thanks shogun I will recheck everything. You
Must have a list of bookmarks at the ready man. Good job.
This really feels like something intermittent though. The car will run normal for a few seconds then back to the low power them back to normal. I bet I have a bad wire or something.

[shogun]

You Must have a list of bookmarks at the ready man. Good job.

no, the brain of the old man still works, when I read the problem, I remembered that erwin had the same problem back in 2009, so I just used the search on Bimmerboard: search words: erwin throttle DK, restrict search to with posts with pics only and only E32 forum, and there we got it.

[wrightbenz]

no, the brain of the old man still works, when I read the problem, I remembered that erwin had the same problem back in 2009, so I just used the search on Bimmerboard: search words: erwin throttle DK, restrict search to with posts with pics only and only E32 forum, and there we got it.

well thanks for the effort your a big help.

So tonight I installed the new blower motor and looked into the issue.

I have no no spark on the left bank. Now I need to sort out why ?

I did have the distributor cap off on that side while I was changing the esv bits. I am thinking possibly I damaged the spark sensor donut. Other possibility is that when I removed the blower motor I had to move the main wiring harness out of the way causing quite a bit of stress on a big mess of wiring.

Looking for ideas here as I work through the issue.

If if I ever get this thing running right shogun I am getting a set of your performance chips.

[shogun]

I have a inline spark tester like this for $5 , where you can see the sparks http://www.harborfreight.com/inline-...ker-69014.html cheap and useful
Go step by step, check the ignition coil, use the workshop manual https://www.bmwtechinfo.com/repair/main/481en/index.htm or your Bentley repair manual, which is better for the DIYer, as the workshop manual refers too often to "use special tool yxz...."
https://www.bmwtechinfo.com/repair/m...es/4810155.jpg
you can also swop the ignition coils from one side to the other, the bracket will not fit, but for a test o.k. If you need new coils, I still have new Bosch on stock for left and right side, but shipping from Japan takes abt. 2 weeks and the coils are heavy, so shipping cost is also to be considered, local shops have stock.use the forward button to go to checking crankshaft position sensor.
Check sparkplugs 6 and 12, that are the ones with the donut, are they wet? Or dry = working/sparking.
Swop main relays and see if the fault goes to the other side. http://www.e32-schrauber.de/bmw/s-relaisbelegung.htm
Distributor testing, maybe in the Bentley are data, but you can compare each pin and especially the center carbon pin, have seen distributor caps without that carbon pin.
Bentley manual page 120-7 has the data for ignition system resistance

[wrightbenz]

Shogun, I have a similar spark tester and had no spark on the left bank. I will spend some time on it tonight. I had a bit of difficulty reinstalling the distributor cap so my money is on that.
I also plan to swap the ECU's left to right and see if there is an issue with that, but cap first as it is likely something I tampered with that is the problem.

[shogun]

ECU's are seldom defective, but just to be sure, swap them, quickly done. More likely distributor and/or rotor, and also the main relay K212, K213, location: IMPORTANT
in 1988 http://www.e32-schrauber.de/bmw/date.../arb_08_88.pdf
from 1989 http://www.e32-schrauber.de/bmw/date...8_88-07_94.pdf

[wrightbenz]

thanks again shogun. More ore checking tonight here is what I found. No spark from the left bank coil at all. I pulled the distributor cap (new ones on the way) continuity from plug socket to the center pin so looks good. Ignition lead looks good as well measuring 2k ohms I believe. I have 14v at the coil when car is running. Main relays appear to be working. Swapped them with no change.
Next I plan to check the cps. There are cam sensors as well will these cause a no spark situation ? I did disconnect them while changing the blower fan.
Will the the spark sensor donut cause a no spark ? Coil resistance is good as well

[shogun]

Cam sensors aka donuts aka cylinder identifications sensors are the donuts on cylinder 6 and 12. Make sure you plugged the 4 plugs into the correct counter part, see here http://www.bimmerforums.com/forum/sh...osition+sensor
without cps the engine will not run, without donuts:
According to an old repair hand book in German language which I have also it should be 1 ohm for cylinder identification = donut. But about the donut importance there has been written a lot of controversial info, and maybe they are all correct. Some people say the engine does not start at all, some say it starts, some say it starts only when engine is at operationg temperature. etc.
Bill R, a very experienced BMW indy shop owner once said when talking about the donut on M30: ...If the inductive sensor on the plug wire fails then it goes into gang firing as Winfred said, since the m30 is a semi sequential design meaning that it triggers the injectors in 2 banks of 3 every other revolution, when it goes into the gang fire as he calls it, then it triggers all six at the same time every revolution but decreases the volume of fuel by 50% ..

So that is why I mentioned to check spark plug 6 and 12, if they are wet, no firing and no signal for the donuts.

http://www.bimmerforums.com/forum/sh...ight=secondary

[wrightbenz]

So it would seem that the cylinder identification sensor would not cause a no spark which is what I have. I have checked more than one plug wire and the coil wire and nothing.

I will measure the resistance of the cps tomorrow.

Any idea if the black cover under the oil filler on the front of the engine comes off ?
Access would be much easier to the 4 sensor plugs under there if it does.

[shogun]

24 Covering plate from 12/1991 11141736687 here are pics from all sides, if I remember right, just pull it off http://www.ebay.ca/itm/262613508873?rmvSB=true or 1 bolt in the middle at bottom
Cannot check, have the older M70 with oil filler cap at the valve cover rear.

[wrightbenz]

Looks like it snaps over a pin or something in the middle. No fasteners that I can find.

[wrightbenz]

24 Covering plate from 12/1991 11141736687 here are pics from all sides, if I remember right, just pull it off http://www.ebay.ca/itm/262613508873?rmvSB=true or 1 bolt in the middle at bottom
Cannot check, have the older M70 with oil filler cap at the valve cover rear.

I cannot get this cover off. Something seems to be holding it tight.
I guess I have to work around it unless someone has some idea how it comes off.

I had had to pull the car out of the garage today to do an emergency rear brake job on our Lexus gx470.
Drove the 750'down the street and the engine started firing on all cylinders briefly. It kept doing that firing well then half the engine. It was very obvious and intermittent.
I did not have a chance to measure the crank sensors but I am really suspecting I may have one failing.
What do you think shogun ?

[shogun]

From the drawing there could be a screw #25 http://www.realoem.com/bmw/enus/show...diagId=11_4598
Crank sensor is high probability. But with an ohmmeter only difficult to find out 100%, usually the shops do it with an osci to see the peaks when engine is running.
Don't forget to check spark plug 6 and 12.

[shogun]

Searched more and found these, just for info:

a post from RF E31 by a rather experienced forum member Mark in SBA . He showed a service diagram for DME 1.7 indicating that:
"If plug lead 6 or 12 (the ones with the inductive pickup donuts on them) are disconnected or short, a protection circuit embedded within the Motronic will severely clip the duty cycle of the injectors for that side to protect the catalysts from being drenched in raw, unburned fuel."

Called the "Catalytic converter protection function", apparently this is for DME 1.7 only (?)

My own test result years ago with MOTRONIK 1.2 http://www.bimmerboard.com/forums/posts/660913

Tim Meek: "The sensors on ignition leads 6 and 12 are not there to disrupt the injector duration, they are there to identify the camshaft position and are a direct forerunner of the camshaft sensor. The sensors are called 'cylinder identification sensors' and detect when cylinders 6 or 12 fire, they do not measure the primary circuit, how could they, they are stuck on the ignition leads! This is not part of the EML system, any failure will not light the EML indicator. It is a basic ECU input that is found on straight-6's that do not have EML as well as EML variants of both the M30 and M70.

Without the cylinder identification sensors, the ECU's do not know which of the two unique revolutions the crankshaft is on. This does not matter to the ignition as the spark is directed to the correct cylinder by the distributor. It does matter to the injection circuits which should fire every two crankshaft revolutions or every one camshaft revolution.

During cranking the only reference signal is the crankshaft sensor and 'double injection' is maintained until the ignition from cylinders 6 and 12 are detected. From this point on the ECU is aware of the correct camshaft position and can fire the injectors every two crankshaft revolutions. If the cylinder identification sensors fail to detect ignition pulses then the injectors continue to fire every crankshaft revolution but the injector duration is reduced to prevent damage to the catalytic converters."

an updated copy of the TIS BMW software,in the engine alert for M70 engines there's one called "O2 Sensor termal shock" named:SI 110896164 released by BMW AG in 01/1997.

Symptom: Irregular idle and shaking when driving.
Cause: stop and go driving and short distances will cause water residues on the cat,a cold start can cause the failure of the O2 sensors caused the termal shock
Solution: O2 Sensor delayed heating with a relais... Parts: O2 Sensor 11781733628 ,Delayed heating relais 11781745829,Cables kit 12511745758

http://s71.photobucket.com/user/shog...l?sort=6&o=242

[wrightbenz]

Shogun I am not sure where you are headed with this. I understand that the spark reference sensors can shutdown injection but I have no spark from the coil. It seems to me that only the cps,dme or s wiring issue is going to cause this. I have new cps units on the way since they are quite likely the issue.
If this doesn't work well. They are due for replacement anyway at this point 150k and 26 years.

[shogun]

That was just as additional info. Let's wait till you have installed the new CPS units.

[wrightbenz]

Yes fingers crossed. It seems like a good assumption that the CPS is going bad. It could certainly be other problems but I have checked what I could and this seems to be good place to begin.