Where is the location of DME Relay?

[Learning]

Dear fellows,

My car (1991 BMW 318i E30 M42) stopped on the road. Changed the alternator and battery, yet car is still not running smoothly and check engine light came on. Hesitating. I did a stomp test and the code is 1231

- "Battery Voltage / DME Main Relay error code can mean that battery voltage is out of range (either too high or too low), or that battery was disconnected. Test charging system and /or battery to find problem cause."

But. I can't find the location of the DME relay. Where is it? What color is the DME relay? I know most relay colors are black. Also, how do I identify it once I find it among other relays?
Please help. Thanks so much!

[hakentt]

if DME relay was bad then engine would not even start. Battery Voltage error is common, you got other issues

[Learning]

I thank you so much for your response, hakentt!

I think I agree with you. Here's a brief story:
Few months ago, I ran out of gas, yet I was stupid enough trying to start the car over and over again. I then I realized I had a little gas in my gas can I left in the trunk. I poured the little gasoline into the gas tank and the car started and I drove to the nearest gas station, but with the car not running so smoothly on the way to the gas station because of so little gas in the tank. My car stopped right when I got on the lot of the gas station. I filled it up, but the car was running rougher for the next 5 days and since that occurrence, I've noticed occasionally (not all the time) a burnt smell coming out from the back of my car whenever I had my window opened. I don't think the burnt smell comes from the engine. Could it be that my fuel pump finally gave up? I had a new one installed about 3 years ago.

Thanks so much in advance for any response!

[aaverhulst]

As you ran the pump dry for quite a while, you may have over heated the pump. Hope you didn't pay someone to install a Pump. An e30 fuel pump is almost as easy as changing a light bulb. And the pumps are a lot cheaper than they use to be. I paid $60 for the last and I have had it for 3 years.

[Learning]

Thanks goodness you came to the rescue before I pay someone to install a fuel pump, aaverhulst!

Could you please tell me briefly on how to change it on E30 or if there's any link you could provide me or any video (such as YouTube), I would be most appreciative!

Another thing before I forget: I was told before by a mechanic that E30 had 2 fuel pumps. If this is true, how will I know which one is bad and needs changing?

Thanks so much in advance!

[aaverhulst]

Your E30 should only have an in tank pump. The early ones have two pumps.
There is a lot of info on the web - search e30 fuel pump removal

Here is a video

https://www.youtube.com/watch?v=ATmzI-ZN3gQ

[Learning]

Thanks so much again, aaverhulst!

Could the fuel pump relay also become bad if the fuel pump overheated (how do I check it if it's become bad)? How do I know for sure the problem here is the fuel pump? Could we conclude that it is most likely the fuel pump that went bad (because of overheating as you said) based on my story above?

After watching the video you provided, I went to AutoZone website and found this: https://www.autozone.com/external-engine/fuel-pump and
this link : https://www.autozone.com/productComp...2Ffuel-pump%3F
(in which I compared the 2 fuel pumps listed on the first link). Which fuel pump do you think I should get?

Both fuel pumps don't come with a strainer. Do I really need a strainer?

Thanks so much in advance again!

[Learning]

Should I just replace the fuel pump or the whole assembly?
Thanks!

[aaverhulst]

Check on ebay for the complete unit. It's a pain to take apart and solder.

Here are my answers to some of your questions. Hopefully someone else can give better answers as I am no expert on this.
As always be careful with gas.

To check to see if old pumps gas: pull wire from coil - prevents car from starting.
pull fuel hose from a connection, put rag under hose, have some one crank engine to see if gas comes out.

To test to see if relay works, check to see if 12v present at fuel pump hot wire when engine is cranked.
You could use multi-meter or test light. The fuel pump unit has two sets of connections. one for the fuel pump, the other for the gas level.

[Learning]

Check on ebay for the complete unit. It's a pain to take apart and solder.

Here are my answers to some of your questions. Hopefully someone else can give better answers as I am no expert on this.
As always be careful with gas.

To check to see if old pumps gas: pull wire from coil - prevents car from starting.
pull fuel hose from a connection, put rag under hose, have some one crank engine to see if gas comes out.

To test to see if relay works, check to see if 12v present at fuel pump hot wire when engine is cranked.
You could use multi-meter or test light. The fuel pump unit has two sets of connections. one for the fuel pump, the other for the gas level.

Thanks so much for the explanation, man!

I thought you said it would be as easy as changing a light bulb to replace a fuel pump on this E30

[aaverhulst]

That is relative to changing fuel pump on almost all cars where you have to drop the gas tank.

It's not really that hard. The last two tests you can do basically the same time at the fuel pump.
Check to see if relay is working. If relay works then pull fuel hose to see if pump works.

Have you priced what some one wants for doing it?

[Learning]

No, I haven't. I'm trying to find a mobile mechanic to see how much he's going to charge me.

I believe my fuel pump is in the tank very similar to the one in the video you provided.
I won't have to drop the gas tank I believe.