Warning Light and Gauge Problems

[txgi307]

I'm a new guy to the BMW. I just bought a 1989 725iL last weekend and I've been working on different issues since then. A lot of things have been resolved, but a couple small issues are still nagging me.

I just recently replaced the entire instrument cluster because the digital display on the old one had quit working. When I'm driving, I get a notification on the display saying "Brake Lights." My brake lights all work. The car is in need of a brake job, however, there is also a "Brake Lining" message that I get.

When I shut the car down, it cycles through messages for the driver. One of these is "Trans Program" followed by "Owner's Manual." I don't have the owner's manual for this car, so I don't know what the trans program means.

This car also has a serious fuel problem, and I don't know if it's the car or the fuel sensor (or sending unit). The fuel gauge reads "E" all the time, of course the old cluster had the same issue, so I don't think it's the gauge. The warning light for low fuel comes on occasionally. When I press the "Range" button on the center console it displays the estimated range, which I believe to be inaccurate. I put a little more than 5 gallons in yesterday, and each time I started, the range was significantly different. It went from 200 to 190 to 100 to 70 to 30. It now hovers around 35. There is no way I have driven 200 miles since yesterday (my driving was simply from home to campus to the store a few times). Is this an issue with the system, or is my car actually burning gas at an excessive rate?

To add on to the "Trans Program" issue, my car's an automatic, and it only shows this message after I shut the car off. Apparently the message can appear while driving, too...

[E32FAN]

Hi and welcome to our forum!

Click here, and then you will have a manual for your car: http://www.e38.org/e32/e32_1988_manual.pdf

You will probably find that your car is a 735iL (meaning 3.5 litre engine). You may want to post the last 7 characters of your VIN in your ID pane. This will allow us to zero in on your build date.

Your symptoms will make more sense after you read the manual.

Are you (or a friend) good with electrical schematic diagrams? If so, you will enjoy the wiring details shown here: http://www.e38.org/e32/e32_89_etm.pdf

We're here to help! Your symptoms are mostly "known and common". The fuel level sensor can get gummed up if the car sits a long period. Best to run a can of Seafoam engine treatment through the gas tank before replacing parts.

[tomquic]

Congratulations on yr new car .,.. a few comments which I hope might help. The "brake light" msg is often related to either some corrosion on the contacts for the individual bulbs .. so thats easy to check and clean ... or that one of the bulbs is about to expire ... if you start by taking out each bulb and cleaning the contacts - check each bulb , if they look 'blackish' - just replace them ... the brake lining warning msg is controlled by a wear sensor on the front left and rear right brake pads ( from memory) ... the sensor wears away as the pads get towards the end of their serviceable life-- and the light comes on. Firstly check all the pads to make sure you have plenty of material left on each set. It may be that the previous owner replaced the pads but not a new sensor when they did. The sensors are cheap and very easy to fit ( 5 mins) ... check out your brakes.

The trans prog msg can be caused by a few things .. but one of the main ones is low battery charge. Given you have some gremlins with a few of your gauges , thats the first thing I would check. With a multi meter check battery voltage before starting and when the car is running. Should be at least 12V min when stopped and after starting between 13v and 14v generally. You may find that other problems go away if you do have a voltage problem ... could be the batt is about to leave this world - any idea how old it is?
Also worth disconnecting the battery , leaving for 10-15mins and then re-connecting - this is known as a 'magic' reset and resets a lot of things .. worth doing as it might also help with fuel consumption if that really is an issue ... good luck and welcome to the '7' family ...

[m735is]

If the fuel cleaner doesn't work, the sender can be taken out and checked. The float rides up and down on some very thin wires which can break. Or, as in my case, the rod that the float rides on gets just alittle bent and the float hangs up in the plastic tube. Mine sticks at half (again), so I need to try bending it. I few taps on the fuel tank and or pump housing can dislodge it, but may also knock off rust if there's any in the tank.

[shogun]

the rod where the float goes up and down can also get rusty when one never fills up and has only low level in gasoline tank for a long time. Have found that on some of our cars parked in the warehouse.
OK, now to clean the sensor...
Get the small collar nut off the bottom of the sensor tube - don't lose it. It's the only metal thing on the bottom of the sensor tube.
Pull the sensor tube off the metal tang it slides onto on the underside of the access plate. BE CAREFUL OF THE VERY FINE SENSOR WIRES.
Now you can see the 3 sensor wires - the middle one is just for the low fuel level contacts, so it doesn't matter if it's "slack". The other 2 fine ones are the ones you want.
Check the 2 fine wires are complete and soldered to their mountings. If one of your wires is broken, it is not normal wire - it's "resistance wire" what you can get from electronics stores - problem with that is that resistance wire comes in different "strengths" (ohms/meter). Try taking a sample of a broken wire into a really good electronics hobby shop, or try for a replacement sensor.
Clean your wires carefully - I cleaned mine with an isopropyl-alcohol computer screen wipe, and then ran the thickness of the pad/sheet between the wires and the 2 gold contacts on each side of the float (2 per wire, 4 total).
Use the pad or alcohol or whatever to clean the harness connector pins as best you can, and the plug too. (With mine I found the best jewellers' screwdriver that was just undersize and scratched out the insides of the plug connections too. Remember, the total sensor resistance at full-empty is only something like 60-70 ohms, so any bad connection (slight resistance) is going to indicate as a prematurely empty tank...
Rinse out any silt in the sensor body with clean petrol and discard the dregs; the "lid" on the baffle chamber can be gently popped up enough to clean in there too
Reassemble carefully noting the following things....
Make sure the pump tangs are engaged fully - you don't want a pump with LIVE ELECTRICAL CONNECTIONS floating loose in a metal tank full of petrol vapor
Take care with the hose circlips
Spray the access plate with a rustproofer if rusting (mine was) but AFTER reconnecting the electrics.
Written by Max

[txgi307]

Thanks for all the help! I drained the tank yesterday and some pretty nasty gunk from the old fuel came out with it. I filled it back up after that and ran some seafoam through it, and so far, no issues, but it hasn't even been 24 hours yet. Can I get to the float by taking the pump out, or do I have to drop the fuel tank?

I'm going to check the battery and the brake lights today to see if I can resolve the "Brake Lights" issue and the "Trans Program" issue.

[shogun]

you can get out all thru the opening of the fuel tunk in the trunk.
The fuel pump get's lose when you twist the whole unit inside the tank. Here is a good write up by Johan
http://bmwe32.masscom.net/sean750/fu...t/Fuelpump.htm

fuel sender cleaning
http://bmwe32.masscom.net/johan/fuel...el_sender.html

[m735is]

That's right, it was the metal strap that holds the float tube on the outside that was just alittle bent on mine. I'm going back in today to tweek it so my gauge can read correctly. Sorry for the wrong information.