A few weeks ago while driving my car died on me. After It sat a day it turned over fine and I thought my problems were over. Today coming in to work, the same thing happened again. It started to lose power, then sputtered out. It cranks hard, but does'nt engage. I'm thinking fuel pump? Any suggestions? TIA

get the diagnostic tool on the car
look for what the engine temperature is
check the sparkplugs for wetness after she dies

Fuel filter, FPR's.
Fuel pump will either work or it will not work. What you have described sounds like a progressive "build-up" of a problem. Check vacuum lines while you are at it.

Grazie, wilco

wilco ???

la prego di fami avere il risultato :)

???

la prego di fami avere il risultato :)

Roger, wilco on that too...

???

la prego di fami avere il risultato :)

Anche Io :). Gonna try and check the regulators, fuses and relays today along with the pump.

Fuel filter, FPR's.
Fuel pump will either work or it will not work. What you have described sounds like a progressive "build-up" of a problem. Check vacuum lines while you are at it.

Noob question #2,302: What is the procedure to check the vacuum lines?

Anche Io :). Gonna try and check the regulators, fuses and relays today along with the pump.



Noob question #2,302: What is the procedure to check the vacuum lines?

visual - look for cracks or rips. Hose should be soft, not hard and brittle...

Like Tx said, the pump either works or doesn't, no in between. If you pull the passenger rear seat bottom to expose the pump access plate and even remove that, you should be able to hear the pump working, and that would be part of your hose inspection as well as it of course starts there to go to the filters. If your pump ever does go south it isn't a hard fix but it's expensive. BMW or aftermarket suppliers only sell the right side as a complete unit with the housing, float, sending unit, etc. @ $500+. Personally I refused to pay that on a recent fix and simply replaced the actual Pierberg pump portion with similar from the 540/740. I tossed all the simpler plastic surrounding it and retrofitted into the E31 (840) housing. The later M73 pumps are the same, the early pumps are dual, as a referrence for used parts.

it can be that the pump stops working if it doesn't get full 12v.
ed told me that. so that is why in the morning with full batteries the car can run fine.
but then starts to act up. but it just means that a fuel pump on the last limp will go out soon.
i keep saying it and i will say it again. get some proper testing equipment ,
if you want to work on your car yourself. you will save yourself a lot of money and speculation.

it can be that the pump stops working if it doesn't get full 12v.
ed told me that. so that is why in the morning with full batteries the car can run fine.
but then starts to act up. but it just means that a fuel pump on the last limp will go out soon.
i keep saying it and i will say it again. get some proper testing equipment ,
if you want to work on your car yourself. you will save yourself a lot of money and speculation.


...car runs on the alternator as soon as it is running. Pump either works or does not.

Well, maybe your alternator is crapping out and causing the fuel pumps to act up (unlikely).

...car runs on the alternator as soon as it is running. Pump either works or does not.

Well, maybe your alternator is crapping out and causing the fuel pumps to act up (unlikely).

i see... well, i was going from what ed told me

Thanks all for the directions and info. Gonna try and get into the shop today, but work is way to hectic lately.

Quick question: On one of my O2 sensors, the wire is chewed up pretty bad. I'm guessing it was hitting the driveshaft and got shredded. Could this cause the sputtering out?

yes, it can be part of it. Remember that the O2 sensor tells the engine if that side is running "rich" or "lean" and since it is not saying anything anymore - you have a problem.

it would cause the car to run crappy. and fuel consumption to be sky high.
what you want to get is a diagnostic tool on that obd port.
that way you can see what the engine temp does when the car is hot.
it's a common failure and it will cause what you describe.
three sensors are 60 bucks at autohaus AZ.
but, i can't tell you anything online as it can be so many different causes for this
you could end up changing out pretty much every maintenance part , if you listen to
suggestions from here

yes, it can be part of it. Remember that the O2 sensor tells the engine if that side is running "rich" or "lean" and since it is not saying anything anymore - you have a problem.

partially right, for the first few seconds before engine temp rises the O2 are not looped in. therefore the car always starts with out values from the o2 sensor.
once the coolant reaches a certain temp they will get impulse from the engine management

Cool... Gettin, closer

I'm 80% certain that my problem is the fuel pump. Replaced the fuel filters 2 month ago, and just replaced the cam ps & crank ps. Still a strong crank, just won't catch. I found the (?) fuel relay (almost certain it's the orange one, but replacing the blue and white one also for good measure, can't hurt). I checked the pump connection with a test light and it seemed to me there was no juice going to the pump. I'll know by tomorrow if i'll be the proud owner of a new fuel pump purchase...

the orange one is for the o2 sensor
the two blue ones are for the fuel pump.
the white ones are for the engine management.
how do your sparkplugs look? are they wet ?
and what happens if you start the car without fuel pump relays?


at the fuel pump. the dme will only turn on the fuel pump for the first 3 seconds.
if the car won't run by then , the management will shut the whole shebang down.
as a safety precaution.

how to test the fuel pump with a test light
connect the light to the connectors at the pump
set the tester on top of the hump in the middle facing forward
so that you can see it when you turn the key.
there ough to be 12 v for the first 3 seconds.
if not check the fuses #23 and #24

one more thing... you have to jump the fuel pump relay, if you want to test for continuity
it is jumper #37 and #80 at the relay
doublecheck the two to make sure you know what is what.
(but make yourself a little jumper wire and don't just
poke a piece of stripped wire in there).
http://i376.photobucket.com/albums/oo208/bmdoublesyou/jumperwire.jpg
this is a pic of the wires, i made up
and when you connect it. connect the #80 port first, that is minus and then to #37
if you do it the other way around and touch any of the surounding metal you'll see a few surprises.

jumping your fuel pump relay is your last test you wanna do and just for a few minutes to test things
that is why i wrote it at the end.


and i am 80% sure your problem is not the fuel pump

I wrote down what you sent verbatim, will try tomorrow. I didn't check the plugs, just changed them out last week before the drama (they were all dry, then...), but will check tomorrow nevertheless. I would love for it not to be the fuel pump. BTW, I only have 1 blue, 1 white and 1 orange relay, 4 short and all...:)

ohh man i just saw you got an 840... geeeeeees well
all will apply minus the second blue relay and white relay, you just have one of each

No worries, look at all the money I save buying less :)

a nice way of looking at it:)

I did the checks, I'm 90% certain now it's the fuel pump. I'm getting a second pair of eyes to double check for me, but I'm almost certain (90%) that the problem is the fuel pump. The car has a little over 230,000 kms, so I supoose it's to be expected. I just wish they were'nt that damn expensive...

the fuel pump will go out with a bang...
have you tried running the fuel pump by supplying 12v straight from a battery pack?

Yessir, Nothing to report. Unless there was something else contributing and by coincidence the pump crapped out the second time. Stranger things have happened. I disconnected the batteries, topped them off with distilled water and had them charged fully. I figure tomorrow i'll hook everything up, go through each step again just to be sure. Does anyone know the Bosch part number for just the fuel pump, sans the entire assembly?

so just to make sure.
you pulled the plug by the fuel pump and connected a battery back to it and and nothing happened?

if so... i think randy played a bit with the fuel pump of a different bmw i think there are some that fit

so just to make sure.
you pulled the plug by the fuel pump and connected a battery back to it and and nothing happened?

Roger. I am a firm believer of check and recheck. Maybe I messed up somewhere, that is why had the batteries recharged and will walk through the steps again. With the way work has been, I have to run in at different times and knockout one thing at a time. Patience and a second car is a virtue.