E30 Zone

Posted: **Tue Jan 06, 2026 6:49 pm**

Our '87 325e daily driver (bone-stock, unmodified) will Idle but cannot be accelerated without stalling. I have blown backwards through the fuel filter with compressed air and lots of rust came out, but it still won't run at more than walking speed (if it will run at all). Obviously, I will replace the filter.

The pump hums when the key is turned on as one would expect, but could the pump be the problem?

And is there an in-tank filter which could be clogged?

Any other ideas? I'm really not very "tech-savvy" when it comes to electronic fuel injection, so I may have missed the obvious. Any help will be appreciated.

Posted: **Tue Jan 06, 2026 9:26 pm**

Welcome to the Zone! I would begin by checking for inlet manifold and AFM rubber boot leaks (along with any other rubber hoses associated with the fuel injection), which cause the car to lean out too much under acceleration (high inlet manifold vacuum). You can do this by spraying WD40 or similar around the gaskets/joints while the engine is idling; if it briefly picks up in speed, you have a leak.

It's also worth looking in the Zone Wiki guide, for instance:
https://www.e30zone.net/e30wiki/index.p ... oubleshoot

E30 Zone

'87 325e Starves for Fuel

'87 325e Starves for Fuel

Re: '87 325e Starves for Fuel