NAXJA Forums -::- North American XJ Association  

Go Back   NAXJA Forums -::- North American XJ Association > NAXJA Unibody Jeep Technical Forums > Jeep Cherokee XJ (1984 - 2001) > OEM Tech Discussion
HOME Member FAQ Sponsor Info Rules Bylaws E-Mail

OEM Tech Discussion Forum for OEM (Original Equipment) or stock XJs and MJs.

Reply
 
Thread Tools Display Modes
  #1  
Old November 24th, 2022, 01:01
Jethrodaredneck's Avatar
Jethrodaredneck Jethrodaredneck is offline
NAXJA Forum User
 
Join Date: Oct 2020
Location: Okla
Posts: 17
Renix fuel issues maybe?

I have a 89 4.0 aw4 that's been sitting last two minutes months cause of case problems, but that's a story for another time. Tried to start the jeep today and it didn't have no fuel pressure at the rail. And yes I had a gauge hooked to it in case y'all are wondering. Thought maybe cause the battery was dead and charging it might not have nuff juice to pull fuel up. Skip ahead like two hours and still no pressure, she'd hiccup and that would be it. So I poured a little fuel into the throttle body and after a couple revolutions she fired up and ran like garbage. Still wasn't showing pressure so I cracked the throttle body open a hair and sure as the sun sits in the east sge started to get pressure albeit it was only 20# I was thrilled. Tapped the throttle a couple times and she has factory specs concerning fuel pressure then all a sudden she'd start losing it and stumbling. Shut her off and pulled the filter and blew through it. Went and turned the key on......no pressure once again. So I "primed" the throttle body once more and same results as last time. Figured I'd check the injectors by pulling harness's while she was idling #1 #2 #3 didn't make any difference plugged in or not. So I'm thinking there might be a slight obstruction some where and the suspect injectors are also clogged, my question is how do I go bout back flushing the fuel system and being as my pump has the funky power ground where it can be reversed could I get say a container with fuel in it and back flush the pump like that. Taking the pump out isn't an option for me atm.
Sorry this was such a long thread for those two simple questions.
Reply With Quote
  #2  
Old November 24th, 2022, 06:12
cruiser54's Avatar
cruiser54 cruiser54 is offline
NAXJA Forum User
 
Join Date: Nov 2009
Location: Prescott, Az
Posts: 7,048
Re: Renix fuel issues maybe?

All roads lead to fuel pump/pressure issue.
Reply With Quote
  #3  
Old November 24th, 2022, 09:19
lawsoncl lawsoncl is offline
NAXJA Forum User
 
Join Date: Jan 2006
Location: North Idaho
Posts: 5,868
Re: Renix fuel issues maybe?

While cranking, the fuel pump will run at full voltage. With the key in run position, if the computer doesn't see the engine turning, it will turn off the fuel pump. So you need to watch the pressure while cranking.

When the key is in the run position, the fuel pump circuit runs through a ballast resistor to drop the voltage. That was Jeep's fix for complaints about the pump being noisy. The resistor is the ceramic thing on the drivers fender near the airbox. See https://cruiser54.com/?p=35 and https://cruiser54.com/?p=249. Actually, go through all of his tips, but especially the one on improving the grounds. Check the connections to the resistor, and try bypassing it with a wire jumper and see if that helps. You can leave it permanently bypassed. That's also a handy place to stick a meter and see if you've got voltage and how much current the pump is drawing.
Reply With Quote
  #4  
Old December 5th, 2022, 17:07
90xj06's Avatar
90xj06 90xj06 is offline
NAXJA Forum User
 
Join Date: Aug 2006
Location: Peabody, MA
Posts: 1,758
Re: Renix fuel issues maybe?

Pump should prime for a few seconds at key on. Normally you can hear it.

Also I have to do it. Does it have gas?
Reply With Quote
  #5  
Old December 10th, 2022, 13:15
Jethrodaredneck's Avatar
Jethrodaredneck Jethrodaredneck is offline
NAXJA Forum User
 
Join Date: Oct 2020
Location: Okla
Posts: 17
Re: Renix fuel issues maybe?

The gauge says a quarter tank but I crawled under it yesterday and knocked on it and she sounded hollow so I'm throw some in tomorrow when the weather clears up.
Reply With Quote
  #6  
Old December 20th, 2022, 08:51
90xj06's Avatar
90xj06 90xj06 is offline
NAXJA Forum User
 
Join Date: Aug 2006
Location: Peabody, MA
Posts: 1,758
Re: Renix fuel issues maybe?

how did you make out?
Reply With Quote
  #7  
Old December 22nd, 2022, 11:36
Jethrodaredneck's Avatar
Jethrodaredneck Jethrodaredneck is offline
NAXJA Forum User
 
Join Date: Oct 2020
Location: Okla
Posts: 17
Re: Renix fuel issues maybe?

Been dealing with a t case dilemma atm but being as it's snowing out and I don't plan on climbing under her I'll try today.
Reply With Quote
Reply


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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
87 Renix No Fuel at Rail + Low Fuel Pump Voltage Pokey_87 OEM Tech Discussion 6 February 8th, 2021 15:52
Renix issues the_shotty OEM Tech Discussion 23 December 20th, 2015 22:11
Renix fuel lines to 91-95 fuel rail? AIbandit Modified Tech Discussion 5 June 17th, 2014 17:53
YJ fuel pump used in cell fuel delivery issues barillms Modified Tech Discussion 4 June 15th, 2013 19:19
RENIX Issues (Hesitation, high idle, poor fuel economy) maalox OEM Tech Discussion 7 November 12th, 2007 14:00


All times are GMT -7. The time now is 03:34.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2023, vBulletin Solutions, Inc.
NAXJA and NAXJA logo's Copyright NAXJA. All content/images Copyright NAXJA 1999-2014