Fuel Injectors, the real truth? - JeepForum.com
  • 2 Post By LuthWJ77
  • 1 Post By jtec
  • 2 Post By smokeyyank
  • 1 Post By Ralph77
  • 1 Post By RobGADV
LinkBack Thread Tools
post #1 of 9 Old 06-12-2019, 02:47 PM Thread Starter
Registered User
Photoweborama's Avatar
1999 WJ 
Join Date: Feb 2015
Location: Orangevale
Posts: 528
Fuel Injectors, the real truth?

Ok, after 33 years I suddenly find myself single, and my toy car is now my only car.

Whats the scoop with four hole fuel injectors. Will it increase mileage? Its a 99 4.0. I have to squeeze everything I can out of it now...

Sent from my iPhone using Tapatalk

Photoweborama is offline  
Sponsored Links
post #2 of 9 Old 06-12-2019, 02:57 PM
Registered User
LuthWJ77's Avatar
Join Date: Feb 2018
Location: Houston
Posts: 353
Photo, sorry to hear about the single thing but probably more than a few out there are jealous of you lol!!

Search the forum you can see the different opinions on injectors but I think the overall consensus is that on the 4.0 "tractor engine" those 4 holes aren't going to do much. Probably better money spent on an intake and synthetic fluids but that engine kind of is what it is. Not ripping it I love the 4.0 for it's torque and reliability which is why it was the only option for my toy WJ. With that said, if I found myself in a situation where I was in the market for a new set, I'd probably go 4 hole version I don't think they're more $$ and if they are not by much. Can't hurt anything to try them but I wouldn't go changing them solely for hopes of MPG gains.
Photoweborama and BeetleCamry like this.
LuthWJ77 is offline  
post #3 of 9 Old 06-12-2019, 03:08 PM
Registered User
2014 JK Wrangler 
Join Date: Oct 2017
Posts: 6,271
things will get better, you are not alone.

If the injectors are OK and there is no reason to change them I would NOT - the old saying if it ain't broke....
Photoweborama likes this.

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
jtec is offline  
post #4 of 9 Old 06-12-2019, 03:16 PM
Registered User
Join Date: Feb 2019
Location: Gypsum
Posts: 156
I had 4 holes on my XJ and will it improved throttle response that was all I got. And that simply could have just been from new injectors. If you're wanting to help increase mileage...... Make sure your air pressure in tires is always where it needs to be. Run some B&G 44k through the fuel system. Make sure you got a good air filter,(doesn't need to be a K&N or anything). Replace the EGR if you haven't. Freshen up the spark plugs and wires along with cap and rotor. Really just basic stuff will go the furthest.
Photoweborama and edhammond71 like this.
smokeyyank is offline  
post #5 of 9 Old 06-13-2019, 02:21 AM
Registered User
2000 XJ Cherokee 
Join Date: Aug 2015
Posts: 1,927
When I first bought my '00 XJ there were some things I had straighten out and some neglected maintenance that needed to be done.
After that I got it in my head that I wanted to improve the MPG. Now realize I did not really care but figured I would do what I could and it would be what it would be.
4 hole injectors. Replaced all the O2 sensors. Running synthetic oil in the diffs.
Did it help? Maybe. But my logic is that if I did not replace it then it is original from the factory.
So my injectors had about 150K on them. Had to assume they were not in the best of shape.
The O2 sensors the same. Supposedly the life span on an O2 sensor is about 100K.
Diffs I just wanted to swap out the fluid to have fresh stuff in there so figured might as well switch to a synthetic.

Now you have to realize money was not an issue. Thinking might be for you. Maybe best to follow jtec's advice. LOL.
Photoweborama likes this.
Ralph77 is online now  
post #6 of 9 Old 06-13-2019, 04:15 AM
Registered User
2004 WJ 
Join Date: Oct 2018
Posts: 16
As Smokeyyank said, improved throttle response. The best thing I did to my 220,000 mile 4.0L was spark plugs, fuel filter, and air filter. I put the 4 hole injectors in around 160,000 miles so the original were probably a little tired.
0488HDFB is offline  
post #7 of 9 Old 06-16-2019, 06:26 PM
Registered User
Slattz's Avatar
1994 XJ Cherokee 
Join Date: Mar 2013
Location: Selden
Posts: 3
I just recently installed the 4 hole injectors in my 03 4.0 haven’t noticed any difference in anything. Ran good before, still runs good. I’d most likely get them again anyway because the price was not bad at all from “KSuspension”
Slattz is offline  
post #8 of 9 Old 06-16-2019, 09:27 PM
Registered User
2002 WJ 
Join Date: Mar 2018
Posts: 251
Dunno about the injectors, but I'll say this: You're better off single. Women are evil. Most of them, anyway. The few that aren't are already taken.
LuthWJ77 likes this.

'02 Grand Cherokee Overland
'05 Dodge RAM 3500 QC 4x4 6sp
'17 Dodge Charger Scat Pack
RobGADV is offline  
post #9 of 9 Old 07-01-2019, 12:38 PM Thread Starter
Registered User
Photoweborama's Avatar
1999 WJ 
Join Date: Feb 2015
Location: Orangevale
Posts: 528
Thank you all. I had a feeling the 4.0 6I was going to be just as it is... no better, no worse.

I will work on the 02 sensors and the pvc (?) valve. I just had the radiator replaced. Had to pay a shop because Im still in intensive therapy. The clutch on the fan needs to be replaced and the clock spring is bad. I think Ill fix the fan clutch and forget the air bags. Makes me nervous off road anyway...

Sent from my iPhone using Tapatalk
Photoweborama is offline  

Quick Reply

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.

Email Address:


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may post new threads
You may 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
Trackbacks are Off
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome