E30 and E46 Fuel pump relay , are they the same?

[zippy320]

Hi Guys

Does anyone know if the E30 and E46 fuel pump relays are the same ?

The my E30 . its the one that goes in the engine bay under that plastic piece in a row on the left hand side of the engine bay , My one is Yellow in color.

On my E46 , its the light mint green relay that goes behind the glove compartment at the front .

Are they the same ? Is the one on the E46 just an updated part? Can I use that on the E30?

They both seem to have the correct pin layout and the E46 one does fit in the place where the E30 one would go , so im not sure .

Thanks guys .

 

[zippy320]

Hmm Would I cause any damage if I tried it out ?

 

[Tinuva]

It is just a relay right? So what is important about it?

A relay is usually rated for a set amount of amps it can handle and you generally want to be lower than that. Pumps can reach up to 6x their rated amps at start up. So if its a 10w pump, the relay should be able to handle amps for up to 70w (adding safety margin).

So basically, if the pump on the e46 is stronger than the pump on the e30, the e46 pump relay should be fine on the e30.

Worst that can happen is, if the e30 pump is stronger than the e46 pump, is you will burn out the relay and need another one. So as long as the burning doesnt cause a bigger fire in the car...then you are fine.

So the above is not advice, only guidance in your choice trying it out on your own account. I am not responsible if your car burns down (I dont think it will...but just in case)

 

[Peter@AEW]

They are different
The car will not start as the fuel pump is activated among other things by the Airflow meter whereas the e46 runs on an air mass sensor.

 

[zippy320]

Hi Guys! Thanks so much for the information and advise Tinuva and Peter , I really appreciate it .

So I have to make a correction to what I said above .

The Mint green relay has 5 connectors and the Yellow Relay from the E30 has 4 connectors .

I found this information but its for the E30 M3 , so im not sure if its relevant to the M20 engine .

Main/Fuel Pump relays - S14.net

s14net.vbulletin.net

Its very confusing , Some say , just match up the diagrams to match whats on the cars relay , some say the mint green one will work , the car just wont use the extra connector circuit etc.

I thought id visit BMW tomorrow and see which or what relay they offer me should I ask for a fuel pump relay for the E30 .

 

[zippy320]

Hi Guys! Just an Update , Its been a long long time . Sorry for the long text.

So an update on the 88 E30 320i Automatic and its non starting / intermittent starting issue ,

As you know , the cars been sitting in the garage as per normal covered in dust ,I decided to have a crack at it once more , I removed the Throttle body , adjusted the TPS properly and reinstalled , Same issue , no start , Getting fuel , spark and the car has compression .
I had already replaced the Fuel pump , Distributor cap , Blue temp sensor , and a host of other pieces previously , I cant remember them all .
I had also replaced the fuel pressure regulator .
Still the same symptoms . I had thought about replacing the timing pickup sensor , but when I looked at it , it was in really good shape and the ohm readings were spot on , I know I had BMW replace this for me years ago and I had only done about 2000 km on it so it couldn't be this .

I went through the complete wiring test once more , checking each and every wire under the dash related to the ECU , and decided to check the wiring on the Blue Temp sensor . Tested the sensor and it seemed to be working ok . Tested the wiring and I was getting a reading but not the same reading as I was getting on the sensor . So i peeled back the tape and found that somebody had twisted the two wires together so basicly the circut was sort of always complete or shorting .

I then repaired that , extended the wire a little and re soldered them . Now I was getting the same reading at the ECU plug as I was getting at the sensor itself .

Put everything together , Turned the Key and On the first turn , it started up . I have been starting it every day for the past week now and it hasn't once not started . I will continue doing this for at least a month . I'm pretty excited . I believe this may have been causing an over fueling and flooding issue?

I Managed to take it out of the garage this past weekend and gave it a good wash after years of it sitting in there gathering dust .
My next step is to replace the Coil , and the ignition wires ( They are all original and over 34 years old now ) just as a preventative maintenance issue.

My biggest problem now ( if the starting issue does not return ) is the timing belt, which was replaced over 14 years ago , although its sat and I have hardly done any Kms on it , I think it should be replaced before I even think about driving the car anywhere .

The other problem is the exhaust , its rusted out with holes all over the place, the car sounds like a truck . I wish to replace it with a normal standard system , but when I asked bosel , they tell me that they no longer make it and will have to "make one up " I don't want that .

Which do I do first? If I take it to BMW and have them replace the timing belt , will they have an issue with the exhaust well , being shot? Will it impair the work done? Also the water pump and pulleys were done at the same time as the belt and only has about 2000 kms on it , should I replace those as well?

OH before I forget , I removed the Yellow original Relay and used the Green E46 fuel Pump relay and it worked , No problems at all . It worked perfectly . I went to SMG and tried to purchase a new E30 fuel pump relay and the gave me the same thing . So I just used the spare that I had .

Thanks guys for all your assistance and advice , This car has been a part of this forum for years now lol !