Welcome to Bimmerfest -- The #1 Online Community for BMW related information! Please enjoy the discussion forums below and share your experiences with the 200,000 current, new and past BMW owners. The forums are broken out by car model and into other special interest sections such as BMW European Delivery and a special forum to voice your questions to the many BMW dealers on the site to assist our members!

Please follow the links below to help get you started!

Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 5 Series > E34 (1989 - 1995)

E34 (1989 - 1995)

Reply
 
Thread Tools Display Modes
  #1  
Old 12-12-2012, 04:25 AM
robhely robhely is offline
Registered User
Location: Australia
 
Join Date: Dec 2012
Posts: 3
Mein Auto: 525i
New member fuel pump fuse issue on 1989 525i

After blowing the 7.5amp fuel pump fuse and discovering that it was drawing 16a instead of about 4.5, I concluded that the problem was most likely the fuel pump. I'm not particularly mechanical and didn't know how to test the pump, but after removing it and seeing that it was the original model, I thought it would be wise to replace it (and the fuel filter) anyway. After installing the correct (and genuine) part at much expense, I started the car up, drove it down the street and the fuse blew again.

Given that it's not the pump or clogged filters, I assume it must be a short in the wiring somewhere between the engine bay and the tank. How might one go about diagnosing this kind of problem and has anyone else had the same issue?

Thanks
Reply With Quote
Advertisement
  #2  
Old 12-12-2012, 04:50 AM
robertobaggio20 robertobaggio20 is offline
Banned
Location: earth
 
Join Date: Oct 2009
Posts: 3,403
Mein Auto: car
The short is likely to be in the wire harness's section which runs between the fp's connector and your battery/ area under the rear seat. Chaffing of the wires while the car jostles on the road leads to this deterioration. Why not simply use new wires for live and return for that section and splice them into the harness at both points ? It may not be diagnosis but odds are you will have to do that anyway. The bentley manual will help you determine which wires to splice. Please search for it here.

Dont feel bad about the new pump. You did a wise thing - fp failure is a common no start issue for our car at around this age. Next thing you must kill would be the fp's relay and crank sensor and you are pretty much safe.
Reply With Quote
  #3  
Old 12-12-2012, 12:17 PM
robhely robhely is offline
Registered User
Location: Australia
 
Join Date: Dec 2012
Posts: 3
Mein Auto: 525i
Thanks for the reply. The battery in this model is in the engine bay, not under the seat. There is a fuse box under the seat, is this where you mean the wiring harness is?

Where do I find the fuel pump relay and crank sensor - is it worth replacing these before looking for a wire short?
Reply With Quote
  #4  
Old 12-12-2012, 03:38 PM
robertobaggio20 robertobaggio20 is offline
Banned
Location: earth
 
Join Date: Oct 2009
Posts: 3,403
Mein Auto: car
The short is unrelated to the relay and crank sensor. These two need to be done but fixing the short first would be a better idea. However you need to do these too they ought to be next on the list (oem parts only for these).

It does not matter where the battery is. The harness section i refer to is in the same place. I could be wrong but most likely, thats where the problem is. Yes there are some fuses in the back seat to. The harness section i refer to runs BETWEEN the back seat cavity and the pump in the trunk.

Please search for and download the e34 bentley manual, relay positions will be listed there.
Reply With Quote
  #5  
Old 12-14-2012, 04:10 AM
robhely robhely is offline
Registered User
Location: Australia
 
Join Date: Dec 2012
Posts: 3
Mein Auto: 525i
Great thanks, I will download the manuel and have a good hunt around the wiring tomorrow, in an attempt to locate the short.
Reply With Quote
  #6  
Old 12-14-2012, 10:19 PM
My525iT My525iT is offline
Officially Welcomed to the 'Fest
Location: Florida
 
Join Date: Aug 2011
Posts: 127
Mein Auto: 92 525iT Wagon M50
If I am not mistaken. And I am not since I can read . The 89 5series has an 80 amp fusible link used between the battery and FP. I would start there. It is all in the Bentley including some other FP tests so you can get the proper electrical readings.
Reply With Quote
Reply

Bookmarks


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 5 Series > E34 (1989 - 1995)
Today's Posts Search
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On



Forum Jump


All times are GMT -7. The time now is 05:08 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
© 2001-2011 performanceIX, Inc. All Rights Reserved .: guidelines .:. privacy .:. terms