E32 750iL questions to electronic gurus (long)
Have tried to help a friend here in Japan yesterday.
The VIN is DC55265, it is a Japanese model E-G50. Built 05/1990.
Here what he posted on roadfly:
This afternoon for the first time, I started my car and the engine had this vibration and it sounded low pitched. I thought maybe I was in limp mode so I popped the hood to check. Both sides were running. So I shut the car off.
Now a little history:
Just prior to starting I checked the fluids and added about a liter of water to the resovoir tank. (Note: I had recieved a check coolant level in the past couple months and have been topping up) I can not see any coolant leaks and I am afraid it could be a head gasket? The oil level hasn't changed nor is there any usual signs of coolant and oil mixing (ie white sludge under oil cap, frothy oil on dipstick)I couldn't smell any coolant burning nor was there any on the ground. I started it up again and noticed a little bit of white exhaust (I live in Tokyo and the temp is above 0 celcius but still a little cool) After warm up the white exhaust disappeared. I think this is normal. The engine still has the vibration, and after driving around the block and letting the engine warm up the temp gauge reads normal (12 o'clock), with no overheating problems prior.
In the past month I changed the catalytic converter on the left side, from the exhaust manifold to the muffler with a non OEM part (BMW after market part bought from ArizonaAZ)The catalyizer did not have a spot on the pipe to insert the exhaust temp sensor. I doubt however, this could be the problem as there have been no instances of this vibration until today. The funny thing is that I drove the car this morning and aside from it being cold from the night before it ran normally.
Does anyone have any ideas on what I should be looking for? I know I have to find the coolant leak, but is that the probable source of the problem?
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I have driven the car and could compare it with my 750iL. There is almost no power, hardly can climb up a small hill, engine revs up very slow.
Checked with the PEAKE: left side bank (drivers side LHD) says OA = emission (lambda) control.
It looks to me the engine runs in limp mode, but I have never had my car in limp mode, so I am not sure.
The temp. sensor on the new cat from USA has not been connected and hangs loose, see pic. The next pic is the other old oroiginal cat on the right (pass side) with the temp sensor connected.
We have a query for all the experts
is the exhaust temp sensor within the engine control loop?
nothing shown in Bentley Repair Manual
Car occasionally runs well but most often it sounds like its dieseling, vibration does not disappear with higher revs, is worse when cold, better when warm
intake manifolds look to be tight
the exhaust smells very rich and fuel consumption is poor
very little power.
Also posted question on the German board. One comment was, that maybe the cat(s) are partly blocked and we should remove the exhausts from beg. of the cats and then rev the engine to see if any change.
That we will do asap.
But apparently no one knows about the function of this temp sensor and what effect it has when it is not connected.
Any advise and comment is welcome. Thanks for reading the long posting.
PS: The leak in the cooling system we found apparently. It has nothing to do with the power problem of the engine, just a leak at a place difficult to find.
it has, Winfred, I was also surprised to see it
and there is nothing on the Bentley book about this temperature sensor.
look at number 28 http://www.realoem.com/bmw/showparts...44&hg=18&fg=05
Did not pull yet the spark plugs, as it is a pain in the a** on the V12, especially the number 12 plug. Started to get dark in the evening. Will do that next Saturday. Removing all 12 spark plus on a V12 takes more than 2 hours (and ones wishes to have the arms 3 times broken or rubber arms to get to all these places in that packed engine room).
As you know, I know the V12 M70 very well, and also Mike (Hairywithit) from roadfly was here. He is also not that unexperienced on the V12, as we usually wrench on that car together. But we could not yet solve it.
Will continue next week. Just need some opinions and ideas what to check next.
We are now somehow fixed to that temp sensor, because we do not know what effect it has on the Motronics. As you know, there are DME 1 and DME2, and all is somehow supervised by the EML.
Both throttle valves are synchron in running, so that was checked by us already, as this is often the case that the car goes into limp mode.
EML light comes on at the beginning and goes off after 2 seconds as it should do. Battery voltage and alternator also o.k., enough charging voltage.
One DME has now the signal from the one side temp sensor, the other side does not have this info. But does that have so much effect, that the car runs like in limp mode like a 50 HP car? So the one DME now always gets the signal "cat cold" we assume. So the DME will change the fuel air ratio so that the cats reach the required temp of at least 300 degree Celsius.
Well, lets see, maybe someone has the correct wiring diagrams and knows to which pin this temp sensor sends the signals and what it does with it. The online wiring diagrams do not have it. I already checked that.
Thanks, Winfred :)
Here is what Real wrote after further tests
-quote-
ECT readings
I was able to (finally!) get to the ECT a little tight in there. I tested it and I had the 5 VDC and 4.9 VDC (from both sides of the connector) and on the sensor itself I got a proper reading (I don't have my Bentley's in front of me right now). I then checked the sensor itself, the coolant temp, was tested with thermometer in resovoir and was 106.6 F and the reading I got, I can not remember at the moment, was right in the middle of the two readings in the Bentley chart, 11 ohms maybe?
I have recieved corrensondence about a possible CAT blockage as being the problem. As I just replaced the left side and the right is the original, should I try the orginal one (on right side) even though a PEAKE check gave a 0A fault for the left side?(probably because the exhaust temp sensor is not attached) In my opinion the new one should be good, so I'll try the old first. Should I notice the difference in the idle if I just disconnect the CAT from the manifold to the resonator (ie before CAT)? If I do this the O2 sensor will probably not work seeing as the exhaust is not travelling trough the pipe. Will that still cause a problem and an inaccurate idle? If there is an increase in RPM I will completely remove the CAT and clean it out.
Furthermore, I checked the engine cold and when I first started it (running for about 10 seconds) I tried to rev it up and it hestiated climbed to about 2500 RPM then almost stalled.
Looking into an electrical issue further I tested the coils with the key in the stop position. As per Bentley's I tested the ohms across terminals 1 and 15 and I got a good reading on both (I'll send the numbers later,(I am at work now), however, when I tested the 15 and 4 terminals and when I put the multimeter leads to the top of the coil point #4 I didn't get any readings, when I placed it deeper inside on the bottom of the pin I recieved a reading of 10.4 and 10.35 Kohms. This didn't seem right to me, any ideas?
My apologises for the unclear numbers in the readings, however at the time I checked them my Bentley was there and the readings were within range except the coil reading as mentioned above.
-unquote-
Any comments on this which I can pass on?
Thanks to all for reading.
Thanks whit, told him your suggestions
Just could call him and he sent me emails:
Well I think I finally found the problem. One more 5:00 am morning checking things before work!!
After checking and swapping MAF's, DME's, DME relays, I made a breakthrough discovery, My car was in a sort of Limp Mode. I crawlled under the car to check the CATS and noticed that the one side was cold to touch. Thinking spark or fuel issues I checked the fuel pump relays, coil, induction test on the plugs, vacuum lines, fuses - all checked ok. After recieving an idea from Shogun and Harywithit I was heading to Johan's site for the fuel pressure regulator change. Part way through it details jumping the fuel pump relays to check for fuel quantities. Sure enough, the side that wasn't working wasn't receiving any gas!
All I can think of is in the morning I'll check the connector at the tank to ensure everything is good to that point, before coughing up $200 or so for a new fuel pump.
Having said all this and seeing the light at the end of the tunnel, does anyone have any other ideas in case this doesn't pan out?
Real
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That is the status as of now.
If any ideas/proposals, just me me know.
I am checking now for a used pump in Japan. Or does anybody know what other maker than Bosch can be used. BMW p/n for the pump only is 16141179710.
Bosch p/n (not sure) is E300-150664
Regular price is $ 306,-, so it will cost here in Japan abt. double that price.
Checked various online vendors in USA like expressautoparts.com, autopartswarehouse.com, prices 237,22 and 215,47.
But there is a pump at bavauto.com with their p/n GFP316 which costs $ 199,95.
That seems to be not a Bosch pump. Does anybody know the maker of another brand for this pump and/or the specification/size etc. for the pump? Maybe they are also available in other japanese cars, so then we could get a pump much quicker and probably cheaper herre in Japan.
Thanks
New update since last post (from Real)
Well I thought it was the fuel pump and it still maybe. I was pressed for time so I went ahead and installed it without checking if there was fuel between the pump and the fuel filters. I checked at the engine and I still do not have any fuel to the left bank (7-12 cyls?).
Jim and others mentioned "Limp Mode" is there a way that the engine can go into limp mode and not display an EML or other warning? As I stated in a previous post I have swapped MAF, DME, DME Relays, Fuel pump relays, inductve spark check on both sides. The problem remains on the left side.
The only other thing I can think about is that I will rout a piece of hose from the sending unit to a bucket to see if I have fuel there, if so, I'll check the fuel filters. I doubt that if it is a fuel filter issue that it would have clogged so abruptly (working in the morning and not in the afternoon). Any ideas on this. If there is fuel at the sending unit the only thing between there and the engine bay is the fuel filters right?
Shogun has asked about the EML. Prior to start up it lights for a couple seconds and then shuts off.
Does anyone know of any other reason why fuel is not making its way to the engine?
Still plugging away at this, hopefully it will be solved soon.
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I tested the fuel pmup in the engine bay as described in the previous post. At that time I checked the fuses again and noticed that since I installed the new pump my fuse #24 (fuel pump) was blown. I changed it out with a new one had then had my wife check the car after starting it. That same fuse is burnt out again. Is it possible knowing what I know now that the fuel filter may be pugged solid not allowing any gas to go through, in turn causing the pump to over work and blow the fuse?
Car runs again, thanks to all advice and help
:D Got the following email:
Erich & Mike,
The car is running!!!! It is amazing what happens when you get a working
part. Thanks for the help that you and Mike have provided.
This is what i posted on Roadfly this morning:
The problem has been solved it was a fuel pump. The new fuel pump that I
purchased was defective which caused the fuse to blow. This did not occur to
me as a possibility at first so I assumed it was a short somewhere else.
In the future I suggest the following in troubleshooting a rough running
engine with no power and hard shifting. Bear in mind this is what I found
would have helped me resolve this problem more quickly:
1. Check and see if the EML light turns on during start up - No EML suggests
Limp mode;
2. If you are not in Limp Mode check the exhaust pipes between the engine
and CATS - helps identify if both banks are running;
3. If one side is hot and the other is cold than I considered the problem to
be fuel or spark related. Check the fuel supply by following the procedure
to check if fuel is making it to the engine as detailed in Johan & Sean's
webpage at:
http://bmwe32.masscom.net/sean750/fu...Regulators.htm
If no fuel at the engine check the fuel pumps as detailed at:
http://bmwe32.masscom.net/sean750/fu...t/Fuelpump.htm
Note: When I tested my voltage I did not get reading that were similar to
what people suggested I should get;
5. A good way to check the pump is to apply 12V directly to them. Keep in
mind that these are immersed in the gas tank and that the petrol is what
cools them so when testing do not allow the pump to run for long periods of
time. Also, because it is a pump expect a shot of petrol to come out of the
pump, use caution in where this petrol will fly;
6. If there was fuel at the engine as described above, I would consider
spark as the next check;
7. I was able to check the spark by using an inductive timing gun and
attaching the connector to the individual plug wires at the distributor. I
loosened the tubing to the MAF to provide better access;
At this point I had no electrical problem so I will not proceed any further
along this vein. Bentley's does detail a series of tests for the coil and
other electrical components.
I understand that there maybe better or easier ways to accomplish what I
have detailed above,but if this can help one person I'll be happy. Thanks to
all who assisted on this adventure!
Real