Burning Through Fuel Pumps (Relatively Speaking)

[DRTE30]

Greetings,

Perhaps someone has experienced this phenomenon?  I took ownership of my 318is about four years ago and some time afterwards, the original Bosch fuel pump burned out.  Within the last 3.5 years or so, I have replaced the fuel pump three times, and I am now finding myself in an oh-so-similar situation.  My car turns over and turns over, and when I'm turning it over I give the top of the fuel pump assembly a few taps with a rubber mallet and the car comes to life.  All indicative of yet another fuel pump about to give it up.

Has anyone seen a car go through fuel pumps prematurely?  Pumps are supposed to last years, and mind you I am not using OEM Bosch units as I cannot afford that, though even using a generic fuel pump shouldn't burn out this quickly.  Ideas?  Thanks for any suggestions!

[deansweet]

hrmm...
Bad ground? Motor in pump maybe due to either worn positive or negative lead?

[Darky]

The cause might be due to the increase in Pressure,
depending on modifications performed?

[SkidMark]

If you are buying aftermarket fuel pumps that could be the prob. The pumps from kragen, autozone etc. are garbage. I received one that didnt work right out of the box, and one that lasted 2 weeks. I since have replaced the fuel pump with a used oem unit from the wrecking ward (pic n pull) $10.00 and its been fine for 2 years. Just my $.02!! Skid

[colin86325]

I 'd suspect that you have something like rust or abrasive sediment in your tank.

[DRTE30]

hrmm...
Bad ground? Motor in pump maybe due to either worn positive or negative lead?

This would be a difficult one to visually test. Using a Fluke multimeter didn't show anything abnormal.  Maybe I am missing something.

The cause might be due to the increase in Pressure,
depending on modifications performed?

Mark D chip (about two years old)
Mess under the intake delete (about four years now)
Slightly larger, 4-pintel injectors from a Volvo Turbo (about four years old)

If you are buying aftermarket fuel pumps that could be the prob. The pumps from kragen, autozone etc. are garbage. I received one that didnt work right out of the box, and one that lasted 2 weeks. I since have replaced the fuel pump with a used oem unit from the wrecking ward (pic n pull) $10.00 and its been fine for 2 years. Just my $.02!! Skid

This is definitely good to know.  I have an OEM spare that I'm going to throw in this coming week.

I 'd suspect that you have something like rust or abrasive sediment in your tank.

The inside of the tank, from what I can see is with limited angle through the fuel pump hole is as clean as a whistle.  Likewise, each pump has had a filtering screen on it.

[DesktopDave]

I've only used OEM fuel pumps in other vehicles. I haven't had to replace one in an M42 yet.

If it was a BMW running dual pumps, I'd have no problem using aftermarket parts. I hate to spend that much cash on a single part, but it's a pretty important one, LOL.

If I was flipping the car, I'd consider aftermarket too. I'd note that to the buyer and specify the choice in my maintenance logs though.

[keflaman]

If I were in the market for a fuel pump I'd check out the BECK/ARNLEY Part #1520993 at http://www.rockauto.com/

[deansweet]

If I were in the market for a fuel pump I'd check out the BECK/ARNLEY Part #1520993 at http://www.rockauto.com/

And use Code: 2381694722049590 and get an additional 5% off.

"The discount takes 5% off our already-low prices. There's no limit on order size or the number of orders. Use the code for your next order, and share the code with friends, neighbors, relatives, the guy at the corner garage--anyone you know who works on cars or trucks.

This discount code expires on September 21, 2014; so don't wait!

Thanks again for buying your auto parts at RockAuto!"

Dean

[DRTE30]

You're all very nice peeps. Thanks for the rockauto stuff.

I have a doner pump from my parts car that will go in the IS. The pump is an original unit and works a-ok, so this will go in when I can pull my face away from school work.  I also noticed a split rubber fuel line right above the tank, so those will naturally get replaced too.  Thanks dudes.

[colin86325]

Another couple of ideas:  The connector to the pump might be faulty. You might be able to retension the pin sockets.
Also if you are in the habit of running your tank on empty you will prematurely wear out your pump.

[DRTE30]

I just got done putting in my spare fuel pump that I pulled from my donor 325i.  This one is a VDO unit which I recently tested and is working.  However, I am still not getting my 318is to start.

Before this swap, I could take a rubber hammer and bang on top of my cheap Autozone style fuel pump and get it to come to life with a few whacks.  Once I completed this VDO swap, I cranked the car over four, maybe five times for quite some time and nothing has happened.  I can verify that when the key is 'on' (position ii), the fuel pump does not run, and when the starter is engaged (key turned to position iii), the fuel pump whirls to life and is quite audible.

As far as I know, the VDO fuel pump is wired correctly and I checked my connections before reinstalling.  My 318is fuel pump assembly used brown/black for the wiring color and the 325i used brown/red, so I simply wired brown to brown and black to red.

Lastly, there is a brand new Bosch fuel filter and spark plugs installed.

Ideas?

[SkidMark]

Howdy,
I would check the main power relay (white) and the fuel pump relay (orange). Swap the o2 sensor relay with the fuel pump relay, easy test. If still not working, try powering up the fuel pump manually at the relay by using a jumper wire. That is as long as there is power at the relay. If no power at the fuel relay, either the main power relay is bad or the dme is bad or you have a bad crank position sensor or a bad cam position sensor or both. Scarry huh??  Heres the breakdown.. the dme needs to see signal from both the cam and crank position sensors during its initial check before it will send a trigger to the main relay to send power to both the 02 sensor heater relay and the fuel pump relay. The fuel pump relay then sends power to the fuel pump. Also do a continuity test on the fuel pump wires to the fuel pump relay from the pump to the relay to make sure they are indeed intact. Also check the fuel pump ground wire to a good ground..  if you can get the pump to run by jumpering the relay im sure all your connections and wiring are ok and the prob lies further up the system. If not bad wiring, wrong connections, bad ground, bad pump.. Hope this helps.....Skid

[DRTE30]

I wanted to make an update to this thread regarding the fuel pump issues in the event another 318is owner has a brain fart and needs guidance.  When I had wired in the VDO fuel pump and had everything put back together, I remember that the fuel pump had more of hollow noise than what I was used to.  This led me to think that rather than this pump also being bad, something wasn't exactly right.  I also remember wiring the fuel pump "the right way" in regards to the colors of the wiring (brown and red) respectively.  But I got to thinking today about this: the  VDO pump was taken out of a 325i.  I originally thought that the wiring would make no difference and was a direct transfer between models.  I was wrong- to an extent.  The fuel pump works fine and is usable cross-platform.  The issue lies in the fuel pump assembly which makes the electrical connection from the fuel pump to the exterior of the fuel tank.

If you are looking directly down at the fuel pump assembly as it sits in the tank of a 318is there is a two-prong connector.  This connector on the left side is green/purple (+12V) and brown (common).  Following the routes of these two respective wires into the fuel tank to the fuel pump, you will find that the +12V is now brown, and the common is red. WTF right?  To me, intuitively, any kind of positive lead is any color other than brown or white.  This in turn resulted in the fuel pump being wired backwards which makes all the difference in the world.  I simply swapped the leads on the fuel pump, cranked it over for about four seconds and it fired right up and the engine idled as it should.  Throttle blips were responsive as normal.  Additionally, the sound that the fuel pump made was noticeably different from when it was wired wrong.

tl;dr
Fuel pump was wired backwards.
Colors of wires in fuel pump assembly were counter-intuitive and wrong
Needed to swap leads on VDO fuel pump
Car starts and idles as it should

[SkidMark]

Good to hear you figured it out!!  ... Skid