Fuel pump not priming

[tjclemens2]

Hey all,

My 318i has been struggling recently starting up. Seems like the pump doesn’t want to turn on and prime. I replaced the fuse and the relays looks fine but the issue still happens. I even checked the connections to the pump and they were good. Any ideas on what this may be? The pump was replaced 6 months ago, and the issue seems to happen spontaneously to the point where is runs I park it then 5 mins later I try to start it and nothing happens. I linked a video down low to show you all what I mean.

[tjclemens2]

https://youtube.com/shorts/vBI6sv29I3g?feature=share

[tjclemens2]

This basically shows that the car is cranking just no sound from fuel pump when I turn key

[It's Soda Not Pop]

unless the inline 4s are different the fuel pump doesn't prime on a E30. The fuel will not turn on until you are actually cranking the engine over.
Is it cranking every time you try to start it? I had an issue with my Main relay going out when it got hot. I had to replace my relays and because I went with a higher flowing pump it would pop the 7.5 fuse ( went to a bigger fuse). Could also be a ground or the harness grounding out.

[digger]

What I'm about to write might be of no use to you but on a 325i the pump wont run until engine is rotating. Not sure if 318i is the same. I've had issues with injectors cause a no start after sitting for 10min i.e. hot/warm restart

[tjclemens2]

Ok thanks for the quick responses. So I may have explained it wrong but basically when I turn the key I don’t hear a buzz which I normally hear meaning the pump isn’t getting power I belive. I left the car for 5 hours cause I was at work and it was in the shade so it wasn’t hot. I will look into the relays, and as for the fuse I put a 15 in there but other than that I’m a little lost on what to do. I’m going to pick it up tmrw morning so I’ll see if it starts up so I can bring it home and take a look. Any ideas of where the ground it on the harness?

[tjclemens2]

unless the inline 4s are different the fuel pump doesn't prime on a E30. The fuel will not turn on until you are actually cranking the engine over.
Is it cranking every time you try to start it? I had an issue with my Main relay going out when it got hot. I had to replace my relays and because I went with a higher flowing pump it would pop the 7.5 fuse ( went to a bigger fuse). Could also be a ground or the harness grounding out.

. Is a good way to check relays by jumping them to see if it’s the relay that’s not completing the circuit?

[It's Soda Not Pop]

. Is a good way to check relays by jumping them to see if it’s the relay that’s not completing the circuit?

you could do that or if you have a friend with an E30 borrow from them. That's what I did. Or you could just order some anyway. Peace of mind.

[It's Soda Not Pop]

On the M20's the ICV buzzes when you turn over the key.
These cars are old and after a million hot and cold cycles things tend to not work as good/or at all. I'm a while you're in there kind of person. So I would replace what is very old if you haven't already done that. But jumping the fuel pump relay while the key is in the on position should make the pump run. If it doesn't could be the wiring. more than likely it's a fail relay or worn component.

[It's Soda Not Pop]

Just thought of something. Open up your icv so that there is a vacuum leak. See if the car will start. It will idle high. Maybe your ICV is bad or stuck closed.

[tjclemens2]

Just thought of something. Open up your icv so that there is a vacuum leak. See if the car will start. It will idle high. Maybe your ICV is bad or stuck closed.

A lot of great information!! I’ll go ahead and go over a little checklist tmrw when I go to try and get it started. Really appreciate the help and I’ll let you know if any of that works🤘

[It's Soda Not Pop]

No worries sometimes it will be the simple things that we overlook.

[It's Soda Not Pop]

Any news?

[nando]

What year is your car? only the M42 cars prime the pump. the M10 318i doesn't, neither do any of the M20 cars or the S14.

[dnguyen1963]

Don't forget to check the infamous CPS. If it is dead, no amount of cranking will fire up the engine.