fuel issues on early 318i

[Dominick]

so my 85 318i has been running flawlessly for the past year that ive owned it, i always new my intake pump was dead (external one sound like marbles in it). But lately if i run the car til the fuel light comes on, the car will not start after putting in gas. i'd have to turn the car to the on position a couple of times and try to start it a couple of times before its fired up. Its never done that.

so i figured that the external one was dying.

But before i take the dive and spend well over $200 for the pumps, does this sound 100% sure its the pumps and not the fpr or any other fuel related thing?

i read somewhere you can use some old school car in-tank pump. SOmething like a 77 Nova or something with an "N"

Any advice will be appreciated.

[rs4pro3]

I'd toss a fuel pressure gauge on it first, and see what the pressure is when running, and what the holding pressure it after sitting a while.

[arnoldgtr]

It's the Chevy Vega's that had an electric fuel pump. My first two cars were Vega's, and I never had to change a fuel pump in almost 300K miles (1975 to 1994). Contrast that to the E30 in tank pump, which rarely lasts 100K.
Just because the main pump is noisy doesn't mean it is ready to fail. My M3 pump was noisy when I bought the car with 113K miles. After changing the in tank pump, the main pump lasted another 82K miles.
I would never run the fuel that low, even if the main pump wasn't cavitating. IMHO, running any fuel injected car below 1/4 tank is asking for trouble.

[EverWiser]

I would never run the fuel that low, even if the main pump wasn't cavitating. IMHO, running any fuel injected car below 1/4 tank is asking for trouble.

It's cars that never get run below 1/4 tank that end up with problems when they get run below 1/4 tank. If you regularly run the tank near empty it will allow the fuel filter to do its job. It will also minimize the "slug" of crap hitting the fuel pump and its internals. If the small particulates that get into the tank are picked up and filtered out they won't be in the tank long enough to get bigger or join up with other particulates which will help to prevent major wear in the pump(s).

The only way to "pick them up" is to run the tank near empty fairly often. I've done it this way for years and have never had to change a pump on anything I've had except one late '80's Dodge van. I knew the PO and he rarely drove it and always left it sitting with a nearly full tank and would "top it off" regularly. It probably hadn't seen a 1/4 tank in the 8 years he'd had it. Once I got it, it would run like crap once I got down to around 3/8 of a tank. It didn't take long and the in-tank pump died...Had it replaced and I could drive that bitch on fumes and it would run great.

[Dominick]

i remember there being an article on converting the Vega pump into an e30 but i cant find it.

what are the possibilities of using a universal external pump? this $175-$263 for a new one is pricey. what are the specs of the stock external one and i will try to find one similar.

[Dominick]

ok so it officially died on me. anyone know if the relay is causing to problem or should i just go ahead and replace the pump

[rs4pro3]

Jumper Pin 87 and 30 on the relay.. Does the pump now run? if not check to see if voltage is present at the pump with the relay jumpered.

[Dominick]

well i have L-jetronic and i jumpered 30 and 87b. and still got no voltage to the pump.

my question is where does the power go to after the relay? Im guessing the ECU, so im going to check that next when i get a chance. And then the main pump's wiring in the tank.