XJ6 & XJ12 Series I, II & III 1968-1992

1986 series 3 xj6 fuel pump 4.2

 
  #1  
Old 07-06-2016, 10:59 PM
Senior Member
Thread Starter
Join Date: Apr 2013
Posts: 167
Received 34 Likes on 30 Posts
Default 1986 series 3 xj6 fuel pump 4.2

when your car is idling do you hear your fuel pump buzzing? eratically?
Does your pump get power when the ignition is on[engine not running] or only when cranking?
Just had to tow the xj6 home as would only run on aerosol starting fluid, there is fuel at the rail but im doubting the pressure, as i was driving the revs were dropping as if being starved for fuel until it would only run at idle then not at all.
Richard
 
  #2  
Old 07-06-2016, 11:17 PM
Senior Member
Join Date: Feb 2013
Location: Waco, TX
Posts: 224
Received 52 Likes on 29 Posts
Default

To my ear, my correctly working fuel pump has a very consistent hum. Not quite a buzz or rattle but it definitely makes noise and if its very quiet you can hear it from inside the cabin with key in II position and car transmission in 'D'. The noises should not be erratic when idling whatsoever and I would imagine erratic-ism could have two causes: improper electric signal controlling delivery OR internal failure of the fuel pump itself.

Pump should get power with the key in the II position and the car transmission in 'D'.

I'm not sure but I don't believe that the pump gets power with key in III position with transmission in 'P' prior to crank but I would imagine so.

If you can, fit a fuel pressure gauge to the rail so you can get clear readings to identify the source of the fuel delivery failure. This certainly sounds like a bad/failing fuel pump to my ears from your description but I'm sure others with more experience will chime in and ask the right questions. Perhaps consider fuel pressure regulator at the front-side of the rail as well.
 
The following users liked this post:
hooter (07-06-2016)
  #3  
Old 07-07-2016, 12:16 AM
Veteran Member
Join Date: Mar 2008
Location: Pacific Northwest USA
Posts: 20,151
Received 6,557 Likes on 4,863 Posts
Default

Originally Posted by john_cook12 View Post
To my ear, my correctly working fuel pump has a very consistent hum. Not quite a buzz or rattle but it definitely makes noise and if its very quiet you can hear it from inside the cabin with key in II position and car transmission in 'D'. The noises should not be erratic when idling whatsoever and I would imagine erratic-ism could have two causes: improper electric signal controlling delivery OR internal failure of the fuel pump itself.

I agree


Pump should get power with the key in the II position and the car transmission in 'D'.

I'm not sure but I don't believe that the pump gets power with key in III position with transmission in 'P' prior to crank but I would imagine so.

I'm a bit confused by position II and III designations.

On a 6 cylinder Series III the fuel pump will not power-up until the key is turned fully to the 'start' position (is that what you mean by "III"?).

Simply turning the key 'on' will not power-up the pump


If you can, fit a fuel pressure gauge to the rail so you can get clear readings to identify the source of the fuel delivery failure. This certainly sounds like a bad/failing fuel pump to my ears from your description but I'm sure others with more experience will chime in and ask the right questions. Perhaps consider fuel pressure regulator at the front-side of the rail as well.
Agreed again !

Cheers
DD
 
The following users liked this post:
hooter (07-07-2016)
  #4  
Old 07-08-2016, 06:49 PM
Senior Member
Thread Starter
Join Date: Apr 2013
Posts: 167
Received 34 Likes on 30 Posts
Default

Update, the problem was the fuel change over solinoid deciding not to work so a full tank of fuel was not getting through while the pump was sucking from a dry tank, for now i have fitted a brass t piece with a ball valve on each side so i will have to open the boot to change over
 
  #5  
Old 07-08-2016, 08:41 PM
Senior Member
Join Date: Jun 2012
Location: SW Ga. Home of grits and gnats!
Posts: 381
Received 52 Likes on 46 Posts
Default

Originally Posted by hooter View Post
Update, the problem was the fuel change over solinoid deciding not to work so a full tank of fuel was not getting through while the pump was sucking from a dry tank, for now i have fitted a brass t piece with a ball valve on each side so i will have to open the boot to change over

Don't forget to select the same side tank on the dash switch or you'll pump all the fuel into the wrong tank thru the return!
 
The following users liked this post:
hooter (07-08-2016)
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
dinop
XJ6 & XJ12 Series I, II & III
4
06-14-2016 02:48 PM
frostee
XJ6 & XJ12 Series I, II & III
15
04-21-2016 08:50 PM
tigger
XJ XJ8 / XJR ( X308 )
9
04-02-2016 08:56 PM
Rabidfox
XF and XFR ( X250 )
3
03-29-2016 08:55 AM
badmojo
S-Type / S type R Supercharged V8 ( X200 )
4
01-06-2007 03:37 PM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 

Thread Tools
Search this Thread
Quick Reply: 1986 series 3 xj6 fuel pump 4.2


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: