replaced (external) fuel pump but still no start....

[E30nub1]

OOOOOOOOKKK so i replaced the external....the external is getting fuel as i tried it and put the hose from the external into a jug and it pumped a decent amount into it..so my next guess is either a FPR or Vapor lock anything else I should be checking?

*Back story...*

Car was extremely low on fuel but i thought i could make it to the nearest gas station and she decided to cut out about 300 yards away and had to push it....get to the station put in about 15 bucks in and she started right up....But even when i got it back on, the throttle was not responsive at all as there was a hesitation if i would try and rev the engine..finally after about a min or two i tried to rev it again and then it cut out..and after that it would crank and crank but no start...not even a hint of starting... and i checked the pump and there was no fuel getting to the pump at all so i replaced it (today) after I figured there would be a hiccup signaling fuel was getting to the engine but nothing before or after the pump replacement...so.. back to square one....

I really need this car so any help would be great...

[E30_fiend]

your main relay is probably shot. Replace it with a known good unit and see if it helps. If it doesnt fix it then at least youve replaced something that commonly fails in e30s.

good luck


Taylor

[E30nub1]

your main relay is probably shot. Replace it with a known good unit and see if it helps. If it doesnt fix it then at least youve replaced something that commonly fails in e30s.

good luck


Taylor

if the relay is shot would the new external still be receiving/pumping fuel?

[jlevie]

It would be a help to know what car you have. If an early car with the dual pump configuration did you replace the in-tank or external pump in the "back story"? And have you replaced the fuel filter?

It sounds like you may have replaced both pumps by now and have proved that the in-tank pump is working. The next step is to see what the rail fuel pressure is when cranking the engine and to check to see if fuse ii is hot when cranking (diagnostic for a bad fuel pump relay).

[jlevie]

your main relay is probably shot. Replace it with a known good unit and see if it helps. If it doesnt fix it then at least youve replaced something that commonly fails in e30s.

If the engine has spark when cranking or you can feel the ICV buzz when the ignition is on the main relay is good. Since the engine fired in the "back story", but just didn't run right the main relay isn't likely to be a suspect.

[E30nub1]

If the engine has spark when cranking or you can feel the ICV buzz when the ignition is on the main relay is good. Since the engine fired in the "back story", but just didn't run right the main relay isn't likely to be a suspect.

86 325e sedan. (so yes dual pump system) I replaced external pump and the fuel filter is less than a year old and when I disconnected it to get to the external pump the fuel coming out was clear as crystal. the internal pump has been gone for a loong time (as i recently found) and the external went out a couple days ago. external has been replaced which is the main pump as well for the dual pump system.

and yes the engine did fire.

[E30Gus]

If the in-tank pump has not been replaced then I would suspect that the pre screen filter is blocked or you sucked enough crap into your in-tank pump to break it. This same thing happened to me when I ran very low on fuel. Sucked up a bunch of crap and killed both pumps.

[jlevie]

86 325e sedan. (so yes dual pump system) I replaced external pump and the fuel filter is less than a year old and when I disconnected it to get to the external pump the fuel coming out was clear as crystal. the internal pump has been gone for a loong time (as i recently found) and the external went out a couple days ago. external has been replaced which is the main pump as well for the dual pump system.

and yes the engine did fire.

So is there a working transfer pump in the tank now?

If you ran the tank out of gas and don't have a working transfer pump, $15 worth of gas may not be enough for the high pressure pump to work properly. Furthermore, if there is rust in the tank running it dry could have pumped enough rust into the filter to clog it.