More budget injector upgrade questions
Senior Member
Joined: May 2009
Posts: 800
Likes: 3
From: The Dirty 530
Year: 1988
Model: Cherokee
Engine: 4.0 Renix I6
Ok, I see ALOT of Questions, but few answers concerning the performance gain by using the ford #19's and the better fuel pressure reg, and rail.
On years: 88-90 (91-95 already have the proper pressure @3 bar)
So.....
I went and installed the 19's. they are the volvo ones #0-280-155-746
http://www.witchhunter.com/flowdatapix/b0280155746.jpg
when the fuel rail gets here I'll put that in and the regulator and then do a
write-up on the whole thing with pic's and on my build thread too!
So far I've already noticed an improvement it does not seem so "sluggish"
More to come!
On years: 88-90 (91-95 already have the proper pressure @3 bar)
So.....
I went and installed the 19's. they are the volvo ones #0-280-155-746
http://www.witchhunter.com/flowdatapix/b0280155746.jpg
when the fuel rail gets here I'll put that in and the regulator and then do a
write-up on the whole thing with pic's and on my build thread too!
So far I've already noticed an improvement it does not seem so "sluggish"
More to come!
Oops 91-95 still need FPR according to chart
CF Veteran
Joined: Jan 2010
Posts: 5,482
Likes: 25
From: Virginia Beach by way of Michigan
I put this on another injector thread, and hopefully it will answer some, if not many, of the questions on here. I have quite a bit of experience with the swap, as do a couple others on here, and from those I've talked with, this is pretty much the feeling of all of us.
- This is for everyone - you shouldn't see any change in MPG. What you gain from the swap is a smoother idle, quicker starting, and better throttle response. Sometimes, better MPG happens, but it's not normal. However, more fuel is allowed to flow through the 703's/710's as well as the 784's/789's if you don't reset your ECU, causing you to run rich, and therefore decreasing your MPG.
- For the best results, if you have a 89-98 XJ, you need the 703 Neon injectors, or you can get the 710 Ford injectors. If you have a 99-01, you need the 784 Neon injectors, or the 789 Ford injectors.
- I prefer the 703's/784's, but the Ford 710's/789's work too. I've had better results from the 784's I have now compared to the 789's I had before. That, and from what I've heard of other experiences, is why I prefer the Chrysler ones.
- 91-95's DO NOT need the FPR. You can swap it, but it's necessary. Doing the FPR swap will give a SLIGHTLY better result, but it's not worth the extra time IMO.
Hope this helps everyone!
- This is for everyone - you shouldn't see any change in MPG. What you gain from the swap is a smoother idle, quicker starting, and better throttle response. Sometimes, better MPG happens, but it's not normal. However, more fuel is allowed to flow through the 703's/710's as well as the 784's/789's if you don't reset your ECU, causing you to run rich, and therefore decreasing your MPG.
- For the best results, if you have a 89-98 XJ, you need the 703 Neon injectors, or you can get the 710 Ford injectors. If you have a 99-01, you need the 784 Neon injectors, or the 789 Ford injectors.
- I prefer the 703's/784's, but the Ford 710's/789's work too. I've had better results from the 784's I have now compared to the 789's I had before. That, and from what I've heard of other experiences, is why I prefer the Chrysler ones.
- 91-95's DO NOT need the FPR. You can swap it, but it's necessary. Doing the FPR swap will give a SLIGHTLY better result, but it's not worth the extra time IMO.
Hope this helps everyone!
Senior Member
Joined: May 2009
Posts: 800
Likes: 3
From: The Dirty 530
Year: 1988
Model: Cherokee
Engine: 4.0 Renix I6
I'm bumping this up again because of what I just discovered.
Hopefully this will save us RENIX guys a headache
Firstly:
The 91-95 fuel rail is NOT a plug and play option for the older system!
The brackets are not the same, hell they don't even line up!
You would need to fab up some new ones (I am going to)
or do the manifold upgrade (a nightmare)
Because the newer intake manifold has a different casting/design.
Second:
I just went to check the #s on my old injectors and guess what?:
3956
They have BEEN running at the same output or lower than the ford 19's
SO:
Either coas is wrong, or those were the wrong injectors on there from the factory?
Arrgggg
I just wasted $100 on stuff I didn't need/cant use without major fab?
Coas: feel free to come back and tell me I'm wrong
Hopefully this will save us RENIX guys a headache
Firstly:
The 91-95 fuel rail is NOT a plug and play option for the older system!
The brackets are not the same, hell they don't even line up!
You would need to fab up some new ones (I am going to)
or do the manifold upgrade (a nightmare)
Because the newer intake manifold has a different casting/design.
Second:
I just went to check the #s on my old injectors and guess what?:
3956
They have BEEN running at the same output or lower than the ford 19's
SO:
Either coas is wrong, or those were the wrong injectors on there from the factory?
Arrgggg
I just wasted $100 on stuff I didn't need/cant use without major fab?
Coas: feel free to come back and tell me I'm wrong
Last edited by fallenknight308; Nov 29, 2010 at 02:33 PM.
Member
Joined: Jul 2009
Posts: 104
Likes: 0
From: Fort Collins, CO
Year: 98
Model: Grand Cherokee
Engine: 4.0
I just installed the 703's but did not disconnect the bat to reset the computer...am I confused but won't the computer relearn for the change in 50 starts anyway?
I am also confused on the point that if by using an injector that flows less fuel than the factory ones why would this decrease your gas milage as I thought I was reading earlier?
So far I am happy with the easier starting and with the smoother idol
I am also confused on the point that if by using an injector that flows less fuel than the factory ones why would this decrease your gas milage as I thought I was reading earlier?
So far I am happy with the easier starting and with the smoother idol
Junior Member
Joined: Nov 2010
Posts: 69
Likes: 0
From: Indio Desert, CA
Year: 1989
Model: Cherokee
Engine: 4.0L
Does anyone know if the 19# Ford 5.0 fuel injectors are a direct swap for my 89 4.0 L non HO Cherokee? Do I have to change the fuel rail or electrical connection or can I just plug and play????
CF Veteran
Joined: Sep 2009
Posts: 4,145
Likes: 0
Seasoned Member
Joined: May 2010
Posts: 360
Likes: 0
From: Bloomfield, MI
Year: 1992
Model: Cherokee
Engine: 4.0 HO
I just installed the 703's but did not disconnect the bat to reset the computer...am I confused but won't the computer relearn for the change in 50 starts anyway?
I am also confused on the point that if by using an injector that flows less fuel than the factory ones why would this decrease your gas milage as I thought I was reading earlier?
So far I am happy with the easier starting and with the smoother idol
I am also confused on the point that if by using an injector that flows less fuel than the factory ones why would this decrease your gas milage as I thought I was reading earlier?
So far I am happy with the easier starting and with the smoother idol
Member
Joined: Oct 2010
Posts: 204
Likes: 1
From: NY
Year: 2001
Model: Cherokee
Engine: 4.0L
The ONLy benefit might be smoother idle and better starting.. You can get that also buy buying a 28 buck rebuild kit for Siemens Deka injectors on ebay.. In facxt I have one and Im reinstalling stock injectors rebuilt once I feel like it.. in like months.. lol.. Dont bother with injector upgrade there is no real benefit unless your going to bore out the head..
Member
Joined: Oct 2010
Posts: 204
Likes: 1
From: NY
Year: 2001
Model: Cherokee
Engine: 4.0L
I get 12 mpg.. with upgrade 63mm throttle body, new exahust and XF3E for fuel injectors.. I wonder if i fouled out my plugs with seafoaming.. Not only that I have a HUGE air intake I made for it..
The truck snaps and is fast as hell.. gas is HORRIBLE!
The truck snaps and is fast as hell.. gas is HORRIBLE!
Newbie
Joined: Dec 2010
Posts: 26
Likes: 0
From: Middle Tennessee
Year: 1989 Laredo
Model: Cherokee
Engine: 4.0 ltr
1989 Cherokee Laredo
WOW! You guys are very PATIENT 
. Here is my delimma...
I have a 89 Cherokee 4.0 and all of a sudden (after a little stick up in a large mud hole) the jeep started running terrible. No power under a load, will sit and idle fine and will rev in park, with a little hesitation at 1/4 throttle then will open up. I pulled the fuel filter and replaced it...a bunch of muddy gas and debris came out...ran OK for about a week and now is back to worse than terrible. I checked all the vacuum lines and what not and drained the fuel filter again...no help. I am planning on dropping the fuel tank and cleaning it this weekend. I will also replace the new fuel filter.
My question is and why I am at this thread is do I need to replace the injectors or just clean the ones that are on there...if I need to replace the injectors which ones can I just plug in and go with...daily driver with some light wheelin.
It's funny I built the jeep but every time I drive I get stuck...so the Husband gets to drive most of the time...how's that
.
Thanks for the help, you guys helped me build this jeep jeep...and I miss driving it ready for it to be fixed!!! HELP
. Here is my delimma...I have a 89 Cherokee 4.0 and all of a sudden (after a little stick up in a large mud hole) the jeep started running terrible. No power under a load, will sit and idle fine and will rev in park, with a little hesitation at 1/4 throttle then will open up. I pulled the fuel filter and replaced it...a bunch of muddy gas and debris came out...ran OK for about a week and now is back to worse than terrible. I checked all the vacuum lines and what not and drained the fuel filter again...no help. I am planning on dropping the fuel tank and cleaning it this weekend. I will also replace the new fuel filter.
My question is and why I am at this thread is do I need to replace the injectors or just clean the ones that are on there...if I need to replace the injectors which ones can I just plug in and go with...daily driver with some light wheelin.
It's funny I built the jeep but every time I drive I get stuck...so the Husband gets to drive most of the time...how's that
. Thanks for the help, you guys helped me build this jeep jeep...and I miss driving it ready for it to be fixed!!! HELP
Member
Joined: Jul 2009
Posts: 104
Likes: 0
From: Fort Collins, CO
Year: 98
Model: Grand Cherokee
Engine: 4.0
I just installed the 703's but did not disconnect the bat to reset the computer...am I confused but won't the computer relearn for the change in 50 starts anyway?
I am also confused on the point that if by using an injector that flows less fuel than the factory ones why would this decrease your gas mileage as I thought I was reading in an earlier thread?
So far I am happy with the easier starting and with the smoother idol
I am also confused on the point that if by using an injector that flows less fuel than the factory ones why would this decrease your gas mileage as I thought I was reading in an earlier thread?
So far I am happy with the easier starting and with the smoother idol
CF Veteran
Joined: Sep 2009
Posts: 4,145
Likes: 0
I'm about to give out several explanations, but I tend to be blunt about things. Please don't get offended by what or the way I say anything, if you get butthurt after this fair warning thats on you.
Nonsense, here's why:
The newer style injectors with 4 pintle holes are markedly more effective at vaporizing gasoline than the single hole injectors.
If you know anything about the physics of burning and how fire works, the material itself isn't what fuels the fire, its the vapor that actually burns. That goes for coal, wood, gasoline, and cotton. The solid materials have to vaporize in order to burn.
The reason that 4 hole injectors are more efficient than single hole injectors is because they more effectively vaporize the fuel by spraying a finer mist with more surface area for the fuel to vaporize. That means a more efficient burn of the fuel and thus a bit more energy used per given volume of fuel.
The gas is horrible because you probably have a lead foot, that combined with a more efficient air-flow system means you're probably burning a lot more fuel. Seafoam of all things would not foul your plugs.
You shouldn't need to swap injectors if you always had a fuel filter in it.
If I had to guess, I'd say it sounds like you got water into your distributor.
It could also be fuel system related, but I doubt that.
If your goal is better gas dont bother installing anything.. it wont make aone bit of diffrence.. In fact I have brand new ones still in the truck getting worse gas..
The ONLy benefit might be smoother idle and better starting.. You can get that also buy buying a 28 buck rebuild kit for Siemens Deka injectors on ebay.. In facxt I have one and Im reinstalling stock injectors rebuilt once I feel like it.. in like months.. lol.. Dont bother with injector upgrade there is no real benefit unless your going to bore out the head..
The ONLy benefit might be smoother idle and better starting.. You can get that also buy buying a 28 buck rebuild kit for Siemens Deka injectors on ebay.. In facxt I have one and Im reinstalling stock injectors rebuilt once I feel like it.. in like months.. lol.. Dont bother with injector upgrade there is no real benefit unless your going to bore out the head..
The newer style injectors with 4 pintle holes are markedly more effective at vaporizing gasoline than the single hole injectors.
If you know anything about the physics of burning and how fire works, the material itself isn't what fuels the fire, its the vapor that actually burns. That goes for coal, wood, gasoline, and cotton. The solid materials have to vaporize in order to burn.
The reason that 4 hole injectors are more efficient than single hole injectors is because they more effectively vaporize the fuel by spraying a finer mist with more surface area for the fuel to vaporize. That means a more efficient burn of the fuel and thus a bit more energy used per given volume of fuel.
WOW! You guys are very PATIENT . Here is my delimma...
I have a 89 Cherokee 4.0 and all of a sudden (after a little stick up in a large mud hole) the jeep started running terrible. No power under a load, will sit and idle fine and will rev in park, with a little hesitation at 1/4 throttle then will open up. I pulled the fuel filter and replaced it...a bunch of muddy gas and debris came out...ran OK for about a week and now is back to worse than terrible. I checked all the vacuum lines and what not and drained the fuel filter again...no help. I am planning on dropping the fuel tank and cleaning it this weekend. I will also replace the new fuel filter.
My question is and why I am at this thread is do I need to replace the injectors or just clean the ones that are on there...if I need to replace the injectors which ones can I just plug in and go with...daily driver with some light wheelin.
It's funny I built the jeep but every time I drive I get stuck...so the Husband gets to drive most of the time...how's that.
Thanks for the help, you guys helped me build this jeep jeep...and I miss driving it ready for it to be fixed!!! HELP
. Here is my delimma...I have a 89 Cherokee 4.0 and all of a sudden (after a little stick up in a large mud hole) the jeep started running terrible. No power under a load, will sit and idle fine and will rev in park, with a little hesitation at 1/4 throttle then will open up. I pulled the fuel filter and replaced it...a bunch of muddy gas and debris came out...ran OK for about a week and now is back to worse than terrible. I checked all the vacuum lines and what not and drained the fuel filter again...no help. I am planning on dropping the fuel tank and cleaning it this weekend. I will also replace the new fuel filter.
My question is and why I am at this thread is do I need to replace the injectors or just clean the ones that are on there...if I need to replace the injectors which ones can I just plug in and go with...daily driver with some light wheelin.
It's funny I built the jeep but every time I drive I get stuck...so the Husband gets to drive most of the time...how's that
. Thanks for the help, you guys helped me build this jeep jeep...and I miss driving it ready for it to be fixed!!! HELP
If I had to guess, I'd say it sounds like you got water into your distributor.
It could also be fuel system related, but I doubt that.
Last edited by ZachsXJ; Dec 31, 2010 at 11:46 AM.
Member
Joined: Oct 2010
Posts: 204
Likes: 1
From: NY
Year: 2001
Model: Cherokee
Engine: 4.0L
I'm about to give out several explanations, but I tend to be blunt about things. Please don't get offended by what or the way I say anything, if you get butthurt after this fair warning thats on you.
Nonsense, here's why:
The newer style injectors with 4 pintle holes are markedly more effective at vaporizing gasoline than the single hole injectors.
(thats why Chrysler is still using single hole? Heres a reality check: After months of research and questioning injector rebuilders they say with Jeeps 4 hole is no better then single hole because fuel sits in ready mode in the cylander.. I guess chrysler engineers are morons?
If you know anything about the physics of burning and how fire works, the material itself isn't what fuels the fire, its the vapor that actually burns. That goes for coal, wood, gasoline, and cotton. The solid materials have to vaporize in order to burn.
(you need to ask rebuilders. I have spoken with more then 6 with a combined 100 years of rebuild experience and they all say the benifit is negligable and that teh head/manifold design of the 4.0L works fine as is and that rebuilt stock injectors will run the truck exactly like its suppose to. )
The reason that 4 hole injectors are more efficient than single hole injectors is because they more effectively vaporize the fuel by spraying a finer mist with more surface area for the fuel to vaporize. That means a more efficient burn of the fuel and thus a bit more energy used per given volume of fuel.
(really?? Comon man we already have heard this..)
The gas is horrible because you probably have a lead foot, that combined with a more efficient air-flow system means you're probably burning a lot more fuel. Seafoam of all things would not foul your plugs.
(Seafoam fouls the plugs FOR CERTIAN if done more then once.. I have a lead foot.. Either way, all i got from Brand New Injectors XF3E was better idol. Gas mileage went down.. Im reinstalling rebuilt stocks..
You shouldn't need to swap injectors if you always had a fuel filter in it.
If I had to guess, I'd say it sounds like you got water into your distributor.
It could also be fuel system related, but I doubt that.
Nonsense, here's why:
The newer style injectors with 4 pintle holes are markedly more effective at vaporizing gasoline than the single hole injectors.
(thats why Chrysler is still using single hole? Heres a reality check: After months of research and questioning injector rebuilders they say with Jeeps 4 hole is no better then single hole because fuel sits in ready mode in the cylander.. I guess chrysler engineers are morons?
If you know anything about the physics of burning and how fire works, the material itself isn't what fuels the fire, its the vapor that actually burns. That goes for coal, wood, gasoline, and cotton. The solid materials have to vaporize in order to burn.
(you need to ask rebuilders. I have spoken with more then 6 with a combined 100 years of rebuild experience and they all say the benifit is negligable and that teh head/manifold design of the 4.0L works fine as is and that rebuilt stock injectors will run the truck exactly like its suppose to. )
The reason that 4 hole injectors are more efficient than single hole injectors is because they more effectively vaporize the fuel by spraying a finer mist with more surface area for the fuel to vaporize. That means a more efficient burn of the fuel and thus a bit more energy used per given volume of fuel.
(really?? Comon man we already have heard this..)
The gas is horrible because you probably have a lead foot, that combined with a more efficient air-flow system means you're probably burning a lot more fuel. Seafoam of all things would not foul your plugs.
(Seafoam fouls the plugs FOR CERTIAN if done more then once.. I have a lead foot.. Either way, all i got from Brand New Injectors XF3E was better idol. Gas mileage went down.. Im reinstalling rebuilt stocks..
You shouldn't need to swap injectors if you always had a fuel filter in it.
If I had to guess, I'd say it sounds like you got water into your distributor.
It could also be fuel system related, but I doubt that.
