10% MPG Improvement + Better Drivability
CF Veteran
Joined: Jan 2009
Posts: 1,964
Likes: 6
From: Baltimore, Maryland
Year: 1994 1993
Model: Cherokee
Engine: 4.0
This is very helpful information.
I upgraded to 784 injectors on my '00 4.0 and reset the ECU, and noticed an immediate drop in fuel mileage. Not a huge one, but it's there.
On subsequent fuel ups, my mileage calculation showed that it's improving, if only slightly. I haven't quite done 50 start up cycles yet, so we'll see.
I upgraded to 784 injectors on my '00 4.0 and reset the ECU, and noticed an immediate drop in fuel mileage. Not a huge one, but it's there.
On subsequent fuel ups, my mileage calculation showed that it's improving, if only slightly. I haven't quite done 50 start up cycles yet, so we'll see.
Anyway..NoTop..What is your take on these as far as an "upgrade" compared to the 784's? 0280156007
Seasoned Member
Joined: Sep 2009
Posts: 299
Likes: 12
From: Whittier, Ca
Year: 1989
Model: Cherokee
Engine: 4.0L
Hello,
I re-read the post which compared the stock XJ and Liberty injectors, which indicated only 1lb of difference. I would think that 1lb would be a slight difference and not so noticeable, and that my increased fuel usage may not simply be the injectors themselves.
I was looking over my stock injectors and they have corrosion on the electrodes which means there is corrosion on the connectors. Would that be enough to adversely affect the signal/operation of the new Liberty injectors? I am using the EV1/USCAR adapter as well. What if I spliced in new USCAR connectors?
I appreciate any thoughts.
I re-read the post which compared the stock XJ and Liberty injectors, which indicated only 1lb of difference. I would think that 1lb would be a slight difference and not so noticeable, and that my increased fuel usage may not simply be the injectors themselves.
I was looking over my stock injectors and they have corrosion on the electrodes which means there is corrosion on the connectors. Would that be enough to adversely affect the signal/operation of the new Liberty injectors? I am using the EV1/USCAR adapter as well. What if I spliced in new USCAR connectors?
I appreciate any thoughts.
Thread Starter
Seasoned Member
Joined: Jun 2010
Posts: 448
Likes: 0
From: Charleston, SC
Year: 1990 - 2000
Model: Cherokee
Engine: 4.0
[quote=Anyway..NoTop..What is your take on these as far as an "upgrade" compared to the 784's? 0280156007[/QUOTE]
The 007 is in between the 784s and the 021 Libertys The wide open flow is only 0.8 lb/hr more than the liberty, but the dynamic flow rate is smack between 784s and 021s.
I would clean the connectors on the harness and run the adaptors. Splicing in was not fun, and is not reversable.
The 007 is in between the 784s and the 021 Libertys The wide open flow is only 0.8 lb/hr more than the liberty, but the dynamic flow rate is smack between 784s and 021s.
Hello,
I re-read the post which compared the stock XJ and Liberty injectors, which indicated only 1lb of difference. I would think that 1lb would be a slight difference and not so noticeable, and that my increased fuel usage may not simply be the injectors themselves.
I was looking over my stock injectors and they have corrosion on the electrodes which means there is corrosion on the connectors. Would that be enough to adversely affect the signal/operation of the new Liberty injectors? I am using the EV1/USCAR adapter as well. What if I spliced in new USCAR connectors?
I appreciate any thoughts.
I re-read the post which compared the stock XJ and Liberty injectors, which indicated only 1lb of difference. I would think that 1lb would be a slight difference and not so noticeable, and that my increased fuel usage may not simply be the injectors themselves.
I was looking over my stock injectors and they have corrosion on the electrodes which means there is corrosion on the connectors. Would that be enough to adversely affect the signal/operation of the new Liberty injectors? I am using the EV1/USCAR adapter as well. What if I spliced in new USCAR connectors?
I appreciate any thoughts.
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
The Neons flow closer to 20% higher flow rate than stock injectors. I flow tested both of them at the same time on the same setup (12 volts, 3 bar pressure, full on for 30 seconds) and the stock injectors averaged 77.7 grams and the Neons averaged 93.0 grams. There was less than 1% measurement variability between the stock injectors.
Purely in the name of science a few tanks after the switch I left my Bat disconnected for 24 hrs. No change after a few more tanks.
It DOES hold pressure now though. I'll probably post the ebay listing for 8, (6 tested) 703's, if that's OK with the guy's upstairs ^, and put that dough toward a set from Precision Injectors. (or not?)
I'm looking at an adjustable MAP, thought maybe it might even help with this stuff we are getting out of the pump, but it looks like maybe it only comes into play in open loop. (starting a thread on that in a minute).
http://go.jeep-xj.info/HowtoMAPsensor.htm
NIX on the new thread ^. I'm going to rule out any problem with the 02 sensor next.
Last edited by DFlintstone; Apr 10, 2012 at 02:11 PM.
CF Veteran
Joined: Jun 2011
Posts: 2,858
Likes: 1
From: Nor-Cal
Year: 1990
Model: Cherokee
Engine: The venerable 4.0
Adjustable map comes into play at wot. I built one. If you get an adjustable fpr you pretty much have full control of your mixture. One of the beautys of renix.
Last edited by Slick761; Apr 10, 2012 at 03:56 PM.
Seasoned Member
Joined: Dec 2011
Posts: 319
Likes: 0
From: Wenatchee, WA
Year: 1990
Model: Cherokee
Engine: 4.0L Renix
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
So is it true? Really? The Map only comes into play at Wide Open Throttle, (70-80%), and any other open loop condition? I thought it filled in for a MAF, dealt with altitude and air density....
Guess I'll unplug mine when it's warm some time, see what I see.
CF Veteran
Joined: Jan 2009
Posts: 1,964
Likes: 6
From: Baltimore, Maryland
Year: 1994 1993
Model: Cherokee
Engine: 4.0
CF Veteran
Joined: Aug 2011
Posts: 1,090
Likes: 0
From: Lehigh Valley, Pennsylvania
Year: 1999
Model: Cherokee
Engine: 4.0 stroked to 4.6, Thanks to Teasdale'sMachine!
Originally Posted by Programbo
Wide Open Throttle. And of course Fuel Pressure Regulator
As far as MPG, can't tell, doesn't use a drop while on the trailer.
Seasoned Member
Joined: Dec 2011
Posts: 319
Likes: 0
From: Wenatchee, WA
Year: 1990
Model: Cherokee
Engine: 4.0L Renix
Huh! No kidding, an adjustable Fuel Pressure Regulator? Looking into that.
So is it true? Really? The Map only comes into play at Wide Open Throttle, (70-80%), and any other open loop condition? I thought it filled in for a MAF, dealt with altitude and air density....
Guess I'll unplug mine when it's warm some time, see what I see.
So is it true? Really? The Map only comes into play at Wide Open Throttle, (70-80%), and any other open loop condition? I thought it filled in for a MAF, dealt with altitude and air density....
Guess I'll unplug mine when it's warm some time, see what I see.
CF Veteran
Joined: Nov 2011
Posts: 2,322
Likes: 1
From: Edmonton
Year: 1990
Model: Cherokee
Engine: 4.0
low voltage at high vacuum, high voltage at low vacuum. so do you adjust that higher voltage for a longer injector pulse width? how?
CF Veteran
Joined: Jun 2011
Posts: 2,858
Likes: 1
From: Nor-Cal
Year: 1990
Model: Cherokee
Engine: The venerable 4.0
Originally Posted by DFlintstone
Huh! No kidding, an adjustable Fuel Pressure Regulator? Looking into that.
So is it true? Really? The Map only comes into play at Wide Open Throttle, (70-80%), and any other open loop condition? I thought it filled in for a MAF, dealt with altitude and air density....
Guess I'll unplug mine when it's warm some time, see what I see.
CF Veteran
Joined: Jun 2011
Posts: 2,858
Likes: 1
From: Nor-Cal
Year: 1990
Model: Cherokee
Engine: The venerable 4.0