main relay caused a lot of troubles for me

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oilcooler
Posts: 43
Joined: Thu Dec 23, 2021 4:51 pm
Location: sacramento, california USA

main relay caused a lot of troubles for me

Post by oilcooler »

i just wanted to pass along my recent experience and troubles with my 1984 635 euro. it was randomly stalling/dying, so after diagnosing fuel pressure, testing the fuel injectors for ohms (these bosch 50 130 injectors should read around 2-3ohms), replacing the reference sensors, replacing fuel pressure regulator (i had an extra 3,0 bar fuel pressure regulator), swapping a spare ECU, replacing the fuel pump relay...it was the main relay that cured a nightmare of issues. having your car repeatedly and randomly stall on a busy california freeway is no joke.

replaced the main relay with this lime green relay and has worked excellent and it was relatively inexpensive. i will be buying another set of main and fuel pump relays as spares. hope this helps others.
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1984 635CSi deutsch modell
1989 535i usa model
Jubilados
Posts: 163
Joined: Sun Mar 08, 2020 4:48 am
Location: So Cal

Re: main relay caused a lot of troubles for me

Post by Jubilados »

Makes sense to proactively replace 20+ year old relays.
What’s the part number for the main relay you used?
oilcooler
Posts: 43
Joined: Thu Dec 23, 2021 4:51 pm
Location: sacramento, california USA

Re: main relay caused a lot of troubles for me

Post by oilcooler »

yes, exactly my reason for posting my experience. a friend who owns an e28 also told me that he had to replace his relays, so it is a good idea to have extras just in case. lesson learned.

here is the link to the lime green relay and website that was helpful in directing me to the lime green main relay.

https://www.bimmerworld.com/Safety-Race ... 1676272395

the orange relay is the fuel pump relay.

https://www.bimmerworld.com/Safety-Race ... 1676272395

and here is the bcg topic that helped me better understand relays and part numbers

https://bigcoupe.com/phpBB2/viewtopic.php?t=16409
1984 635CSi deutsch modell
1989 535i usa model
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