1995 540i limps home

[Clarksonvalley]

1995 540i 6-speed, 228,000 miles. Got an 'O2 sensor' fault, so I replaced both sensors and also replaced the spark plugs. Work complete and took it for a ride - ran great. The next morning, the power went away after driving 1/4 mile. When I fed in any throttle, the power died. I was able to limp home at slow speed. I used a code reader to find the fault codes as follows:

code 34 - Ignition Coil #5
code 18 - Ignition Coil #4
code OF - Ignition Secondary Monitor
code 32 - Ignition Coil #3
code 16 - Ignition Coil #7
code 31 - Ignition Coil #2
code OC - Oxy. Sensor #2
code C9 - Lambda Control #1
code Od - Oxy. Sensor #1
code Cb - Lambda Control #2
code 33 - Ignition Coil #8

The ground wire to the ignition coil on each bank is attached and the electrical plugs to each coil are seated. I've replaced plugs and O2 sensors many times in the last 20 years, but never a problem like this. I'm using Bosch #13523 O2 sensors (from BMA Auto Parts in Glendale, CA) and Bosch #FR 7 LDC+ plugs.

I have never had so many fault codes at one time. Anyone have any thoughts - sounds like a failure in the computer, but it's strange that it happened after the work mentioned above.

Tom

[ahlem]

I'd check the fuel pressure. Some times you can get fault codes on the way by while the engine is stalling for other reasons. Also major vacuum leaks.
I had an issue with an O2 sensor that had the wire splices in it rather than a new wire all the way to the plug. Those little gray screw connectors didn't keep contact and it caused a similar situation on a 535.

[Clarksonvalley]

I do not see a 'fuel pressure failure' in the fault code list, but I do have a fuel pressure gauge and will check the pressure. I can't help but think that the work I did has something to do with all of the fault codes, but I cannot think of what it would be, especially since it ran great the day of the work and ran like crap the next day.

[ahlem]

Maybe your O2 sensor connector came loose? Can you put them on the wrong plug? Mine only has one sensor.

[shogun]

Maybe your O2 sensor connector came loose? Can you put them on the wrong plug? Mine only has one sensor.

M60 has 2 O2 sensors and pretty often people mix the sensors up and then the reading goes to the "wrong" place. For example if the bank 1 sensor is connected the wrong way and it sends the signals to the Motronic the adjustment is done in the wrong place for bank 2. Had that also on my 750 E32. Have done such replacement quite often, but it happened when I was in a hurry.

[Clarksonvalley]

Shogun,

Sensor #1 is drivers side, Sensor #2 is passenger side. I have replaced both sensors and the electrical connectors look good, not cracked or broken and the two parts seat all the way in. Will look into the fuel pump - I think it is probably way beyond its life span - 228,000 miles and it is the original pump.

[shogun]

Good idea, 1 pump and 2 fuel filters http://www.realoem.com/bmw/enUS/partgrp?id=HE63-USA-04-1995-E34-BMW-540i&mg=16
M60 needs 3.5 bar fuel pressure.
Do not have the other data but should be similar to the ones for M30 and M70, except the M60 needs 3.5 bar, for reference only here:

nominal Bosch pump data M30 and M70
The M30 fuel pump is originally Bosch 0580464995, operating pressure is 3 bar, conveying capcity at 12 V 1.9 liter/minute, conveying capacity against counterpressure 875 ccm/30 seconds, Power consumption is 5A

The M70 has 2 pumps, so 1 for 6 cylinders, each: Bosch part number is 0580112507 (according to an old repair book), operating pressure is 3 bar, conveying capacity at 12 V 1.7 liter/minute = less than the M30 pump
capacity against counterpressure 875 cc/30 seconds, power consumption 5.5A

[Clarksonvalley]

Where is the 3.5 bar pressure taken - at the pump outlet? - at the fuel rail?

[shogun]

see workshop repair manual section 13 31 029, delivery pressure of fuel pump - check , install tester in fuel line in engine bay upstream of pressure regulator

https://www.bmwtechinfo.com/repair/main/

[Clarksonvalley]

Would a good place for the pressure test be at the steel fuel supply line in the engine bay where it connects to rubber tubing?

[632 Regal]

Yes that can be tapped to verify pressure.

From you codes it lookes like you lost power or ground to the engine from the power supply (battery or alternator). look into that first and report. A bad ground will kill all inteligence on the matter.

I would only suspect the computer after a flash or reset. Your good just have a stupid issue.

Report back, I take pride in finding stupid stuff out like this.

[Clarksonvalley]

Battery is good, I see no electrical problems with any accessory equipment, but will see if I can check the voltage to the computer. Looking into new fuel pumps - choice is BMW factory part or a Bosch pump. Anyone have problems with the Bosch pump - it is considerably cheaper that the BMW part. I would think that Bosch makes the pumps for BMW.

[shogun]

Original BMW is using Bosch 69900 http://www.amazon.com/Bosch-69900-Original-Equipment-Replacement/dp/B001C625C2
If you want to have it cheaper, there are pump systems from Pierburg and many others. that are all complete units, or you just buy the pump and install it in the system like shown here with a TRE Performance http://www.bimmerforums.com/forum/showthread.php?1245212-*DIY-E34-540i-Fuel-Pump-Replacement-DIY&highlight=fuel+pump

[Clarksonvalley]

Bought a Bosch fuel pump from BMA Parts in Calif. along with two fuel filters and a seal at the pump. Will let you know how it turns out.

[Clarksonvalley]

OK - I bought a Bosch fuel pump, the rubber gasket at the fuel tank and (2) fuel filters from BMA Parts in Glendale, Calif. (www.bmaparts.com (http://www.bmaparts.com)). I read thru the thread 'DIY E34 540i Fuel Pump Replacement DIY' - that was very helpful. When I received my Bosch pump, I found it came with the two plastic shrouds and the inlet filter already mounted rather than just a bare pump - that simplified the whole project. There are a few points that may be helpful to the next owner tackling this project:

1. The fuel pump cover in the truck - secured by (8) nuts - only goes on one way. All of the (8) holes for the cover fasteners are equally spaced around the perimeter of the cover except for two holes that have a closer spacing and they are the two at the right hand side of the cover. I bought new nuts for the cover as the old ones were pretty rusty - M6 x 1.00 nuts.

2. The Bosch pump comes with spade connectors rather than the BMW original ring type connectors that are each held in place by a nut. Make a note of which wire goes to which connection on the old pump. You will need to cut the old ring type connectors from the two wires and solder on the new spade connectors. A male plastic connector is provided with the Bosch pump that clips into a female plastic connector on the pump. Make sure you get the correct wire to each terminal because once you push the new spade connectors into the plastic connector, they are very difficult to get out.

3. The pump assembly only clips into the fuel tank one way. When you pull the old pump out, note where the hose for the fuel return line is located. There is a mating hole in the fuel tank connector (around 4:00 o'clock on the fuel tank connector) that mates with fuel return line on the pump assembly. My old pump failed with the fuel tank 3/4 full of fuel, so I was working with my right hand submerged in fuel when I return and replaced the pump assembly. If you can schedule your replacement, run the fuel tank nearly dry - a lot less messy. The rubber gasket also only goes on one way. Look at the (8) gasket holes on each side of the gasket and you will see the holes have a recess on one side of the gasket - this side faces down to mate with shoulders on the threaded fuel tank studs.

4. Replacing the (2) fuel filters was no big problem - they are located just to the rear of the passenger side halfshaft. Jack the car up, place a jack stand under the car for safety and remove the right rear wheel - this make the removal and replacement easier. I bought a pair of fuel hose 'pinch-off' pliers to stop fuel drainage from the fuel and engine - clamped them on the single fuel lines before they branch off to the two filter, one on each side of the twin filters.

Attached are two photos, one showing the parts I bought from BMA Parts and another showing the new wiring connections to the new pump. I show one wire already plugged into the connector and another ready to plug in - I used 'shrink tubing' on the spade connectors.

Took a 5 mile ride after completion, ran great, no fault codes like mentioned in my opening post. The pump I removed was the original German 'Pierburg' pump that lasted only 228,912 miles. BMW needs to work on the life of their parts.83268327

[Clarksonvalley]

One more note - I never checked the pressure the old pump was delivering - at 228,914 miles, I figured it just ran out of luck and threw a hole bunch of fault codes as it finally died.

[shogun]

Thanks for the pics and info. One thing I would like o add, when you change the fuel filters, better also change the short fuel hoses before and after the filters, they are usually very hard and sometimes it leaks there
4 x Fuel hose 13 31 1 288 284 32MM-210MM Only with automatic transmission ... — '95, April
http://2009.bmwfans.info/parts/catalog/E34/Sedan/USA/540i-M60/LHD/A/1995/april/browse/fuel_supply/fuel_supply_double_filter/

I use standard fuel pressure hose and cut it from my stock fuel hose instead of buying these expensive ones.

[Clarksonvalley]

Shogun,

Good idea - next time I get the fuel level down, I'll drain the tank and do it. I used the 'pinch pliers' on the rubber lines to stop fuel leakage when I replaced the fuel filters - can't do that on the metal lines when the tank is full. Probably 20 years on rubber fuel lines is asking a lot.

[genphreak]

Nice teamwork gents, well done. Glad to read it's all well sorted.

Always pays to remember that codes on these early computers are indicative or symptomatic, they seldom take you directly to root-cause.