Fuel pressure goes to zero with key off RENIX
#1
Member
Thread Starter
Join Date: Jun 2009
Posts: 132
Likes: 0
Received 0 Likes
on
0 Posts
Year: 2001
Model: Cherokee
Engine: 4.0L
Fuel pressure goes to zero with key off RENIX
I have an '87 Comanche with the 4.0L, well it's a renix electrical, 2000 intake, 96 block and head and new 24lb/hr injectors. Every time I prime the fuel system with the key it promptly goes right to zero. It doesn't even get to 40psi, it gets to around 20 and stops.
I have a Hesco adjustable fuel pressure regulator and a return system via the renix. Should I replace the fuel pump? Is the check valve in the pump for sure? I thought it was my old Ford injectors so I bought some 4 hole re manufactured ones on the bay that were flow tested etc.
Please give me some advice and a part number for the pump would be fantastic!!! I have heard horror stories about how hard it is to find a pump.
I have a Hesco adjustable fuel pressure regulator and a return system via the renix. Should I replace the fuel pump? Is the check valve in the pump for sure? I thought it was my old Ford injectors so I bought some 4 hole re manufactured ones on the bay that were flow tested etc.
Please give me some advice and a part number for the pump would be fantastic!!! I have heard horror stories about how hard it is to find a pump.
#4
Senior Member
Join Date: Nov 2014
Location: Los Angeles, CA
Posts: 766
Likes: 0
Received 5 Likes
on
4 Posts
Year: 1989 Limited
Model: Cherokee(XJ)
Engine: I-6 4.0L AMC Renix
Originally Posted by knever3
No, fuel pressure. I have a gauge connected to the schrader valve on the rail.
#5
Member
Thread Starter
Join Date: Jun 2009
Posts: 132
Likes: 0
Received 0 Likes
on
0 Posts
Year: 2001
Model: Cherokee
Engine: 4.0L
So an update, installed a Carter replacement pump to the Bosch and now I get zero pressure period. The needle doesn't move at all! The one the parts store ordered was wrong when I compared my pump to theirs. They had the cross in stock, but I installed it and it makes noise but no pressure. Awesome worse than when I started...
#6
Member
Thread Starter
Join Date: Jun 2009
Posts: 132
Likes: 0
Received 0 Likes
on
0 Posts
Year: 2001
Model: Cherokee
Engine: 4.0L
Back up again, Replaced Carter pump with a Bosch from Amazon. I can prime the system with the key probably 4 times before I get 20psi on the fuel rail. It takes probably 6 seconds of cranking to start. I can hear the pressure bleeding off through the return at the Hesco adjustable fuel pressure regulator. This leads me to believe the fuel is just getting by the regulator back to the return instead of draining back through the pump.
So I have changed the o-rings on the regulator, replaced the fuel pump twice. I can't use a stock fuel pressure regulator, but I have one from a '95 I could try to see if the fuel rail holds pressure. I really don't like the chance that the new Bosch pump is bad out of the box.
Thoughts? The one thing I haven't done is pinch the lines to see which way the fuel is leaking back.
So I have changed the o-rings on the regulator, replaced the fuel pump twice. I can't use a stock fuel pressure regulator, but I have one from a '95 I could try to see if the fuel rail holds pressure. I really don't like the chance that the new Bosch pump is bad out of the box.
Thoughts? The one thing I haven't done is pinch the lines to see which way the fuel is leaking back.
#7
Member
Thread Starter
Join Date: Jun 2009
Posts: 132
Likes: 0
Received 0 Likes
on
0 Posts
Year: 2001
Model: Cherokee
Engine: 4.0L
Update way to late...
It was indeed the Hesco adjustable fuel pressure regulator. The check valve failed in it so I bought 21lb/hr injectors and used a '95 stock regulator. Problem fixed.
It was indeed the Hesco adjustable fuel pressure regulator. The check valve failed in it so I bought 21lb/hr injectors and used a '95 stock regulator. Problem fixed.
Trending Topics
#8
::CF Moderator::
Join Date: Aug 2011
Location: Prescott, Az
Posts: 43,863
Received 1,524 Likes
on
1,236 Posts
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Thread
Thread Starter
Forum
Replies
Last Post
moonltgmblr
Introductions
3
01-26-2016 12:48 PM
srivera
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
2
01-24-2016 02:15 PM
clmanaa@att.net
Stock Grand Cherokee Tech. All ZJ/WJ/WK Non-modified/stock questions go here!
0
01-24-2016 12:44 PM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)