...next time LEARN how to properly reply.

I don't know if you're talking about current chrysler vehicles rolling off of the assembly line, but I HIGHLY doubt that they are still using single hole injectors. Heck Dodge Neons are Chrysler vehicles and most if not all of the injectors used on Neons were of the 4 hole type.

Your argument as to why the 4 hole injectors aren't more efficient makes zero sense. You're right, stock injectors in good condition will definitely work just fine for a Jeep, however as I'm sure we've all experienced at some point, the stock parts used on a vehicle doesn't in any way mean that they are the best parts for that application. Most of the time you can find different than stock parts that perform better than stock parts.

As to seafoam fouling your plugs...did you pull your plugs out and check them? It takes about 2 minutes to remove, check and replace a spark plug.
I've used seafoam multiple times and each time the throttle response is better and the idle is smoother, which suggests quite the opposite of fouled plugs. I have no idea what XF3E is, and google doesn't bring anything up.


The bottom line is this: Physics shows that a 4 pintle hole injector is more efficient at vaporizing a given volume of fuel than a single pintle hole injector. Due to this, they can increase your gas milage by helping the engine to more completely burn all of the fuel injected in to the cylinder.

 

Can anyone confirm any documented improvement in fuel economy with any of these injector swaps?

 

As late as 2004 single hole were still being used. I am not sure whats going on now but anything must be better then whats in my 2001 Cherokee. Anyway, this is a good discussion. I am mearly posting what I found out with phone interviews and in person interviews with injector rebuilders. Here is why the argument that atomized spray patter in these jeeps make no big diffrence according to people who deal with fuel injection ona daily basis.

1. People are removing dirty, worn and intermittent spraying stock injectors and then installing 4 hole flushed and or rebuilt injectors and getting great results. If you rebuild the stock injectors FIRST they will work as good or BETTER and not create unkown conditions insidide the combustion chamber. Did you ever consider why chrysler did not put Neon injectors in the Jeeps to begin with back in the early 2000's?? I guess the army of engineers that work for chrysler during that time did not bother testing the injectors or comparing results with 4 hole vs single hole? You must consider what I am saying.. In 1999 Chrysler was using neon injector 4 hole and single hole in Jeeps for a reason. Wouldn't it be cheaper by MILLIONS of dollars for chrysler to use one style injector thats plug and play while improving MPG and preformance such ans the 784's or 703's in Jeeps?? Why not then?? Think about it and give me a reason that makes sense on that fact. And it's a fact.

2. I was told by more then one source that the style of intake manifold and the firing pattern Siemens Deka uses is made to preform BEST for the Jeep setup. Mine is a 2001.. The upgraded the intake manifold on these yet kept the same injectors. I was told by several sources who do injection for a living that the fuel inside these manifolds sits in some ready pattern and that the design and firing mechanizim will not benefit from atomized spray. In fact, I was told atomized spray will more then likely result in rich running Jeeps due to spray going places its not suppose to inside the chambering design. In other words its desgined to spray directly into the chamber for a reason.

3. I am running these recommneded in an aussie post. This is my thread on the results. I bought the best ones recommnded for my year XR3E sorry for typo.. See my post

https://www.cherokeeforum.com/f2/sin...-4-hole-62398/

4. Seafoaming the plugs: Seafoaming was teh best thinng I ever did to teh truck.. that and the 63mm throttle body and CAI. I was told by an ASE tech that they do this decarbonization procedure then change plugs for fouling. Ask a dealer if they change the plugs for decarbinazation.. Who knows.. I never changed them.. Mine dont take minute to remove.. I have a coil pack and its a bit of a process.. I have a 2001 which is a diffrent setup.. I have seen posts on here saying seafoaming fouls the plugs a bit..

5. Atomizing the spray will cause the chambering to leave some unburnt fuel. The trucks will run rich.. I got worse gas with brand new injectors.. Nearly everyone who changed injectors feels they run rich.. How do you find out? I wish I could figure it out.. I have my stock injectors rebuilt now and ready to go.. Turns out I needed two new ones for intermitent spraying. The Siemens Deka injectors are VERY bad with dirt according to more then a few injector rebuilders who say teh little pin wears on them as well and if dirt gets in at all the injectors fail.. They are good if kept clean, and real clean.. Also no shop i sent my stock injecotrs to would do a inionization cleaning.. they said it ruins the inectors??

 

...no because I never wrote it down. However I did check my gas milage using the only truly accurate method(i'll explain in a second) and saw a 2 mpg improvement along with a smoother idle and quicker throttle response.

Here's the method I used to check my gas milage:

Pick my regular gas station, fill all the way up, don't top-off and reset the trip meter. Then drive until the gas light comes on. Return to the same exact station and same exact pump and refill again without topping off. Then divide miles driven by gallons used, and account for the difference between 29s(stock) and 31s. I went from about 17mpg to 19mpg


I don't see how futher atomizing the fuel would cause a vehicle to run rich...or less efficiently.

In my mind the more atomization the better, and same amount of fuel.

I gained 2mpg over what I had. I swapped in used Ford Mustang 5.0 Yellow injectors for my used stock injectors and saw that gain.

 

Sorry this was in the wrong thread.

 

I have read every post on this thread and it has been a real education for me, and I'm sure for others as well. There are several people on here that have posted a lot of great information, and I would like to thank them for spending thier time to do that for us.

I think I have this figured out, but in the 28-29 pages here I couldn't find an exact answer for my exact application or situation so I need to ask a couple of questions before I jump into doing this upgrade to my XJ.

This upgrade will be done on a (rebuilt) stock 1991 XJ, 4.0L. from what I have read I plan on using the 703 injectors. I will also be installing an intake manifold from a 99 XJ, Edelbrock (EO legal) header, and a cold air intake. My main gole is to improve throttle response and fuel economy.

Here are my questions:

1) Will the 703 injectors be compatable with the stock 91 fuel rail and the 99 intake manifold, or will I need to get a fuel rail for the 99 intake?

2) Is it correct that I should stick with the stock FPR?

3) Will the 91 ECM be able to fine tune things with this combination?

4) As far as actual exaust emissions (sniffer test), do you think I will run into any problems when it comes to passing CA. emissions test after making this upgrade? CA. smog test can be a PITA!

5) Any other suggestion's?

I think was it.
Thanks again for all of the information!
Dennis

 

The 99 manifold will require the 99 PS bracket as well. Others that have completed this mod are split as to any real advantage. Some claim that it has little effect on power, as others have seen the opposite.

I installed a reman set of Bosch Gen III injectors from FIC with an increase of 1-2 MPG. Power/throttle response is better.

My 92 has been gone through countless times to ensure all the sensors are running/calibrated correctly. Checked and rechecked FP, MAP, timing, etc.

I'm considering swapping up to a later model ECM/PCM from a 95/6. Haven't seen many who have tried the swap.

No one has come forward with ECM tunes or tunable PROMS as yet.

As basic as the 4.0 is, its hard to imagine it failing "smog" if all is in decent running order.

Living in a CARB 1 (Yosemite) zone has its perks as we only test when the vehicle is sold.

cheers!

 

im an ase certified master tech and if i told you that if you put cream and sugar in your gas tank only ice cream will come out of the exhaust would u believe me?
"storing" fuel in a ready state in the intake is the stupidest thing i have ever heard. since the intake sits above the exhaust any fuel sitting will be heated up and would cause vapor lock. from my years in auto work of all kinds i have found that when a person specialize in a certain part of a car thats all they know is the injector them self's not the motor, not the intake, valves ect...reading this crap makes my head hurt... no car has ever had a problem with atomized fuel. my 703 injectors where 10% better then the new rebuilt oem ones i had.

 

ok so my ? is this I have a somewhat high modified tranny and engine to produce more torque. Ok so ? which injectors should I use the 19 or 24, and also which throttle body will fit my 89 xj 4.0 I6 I would like to fit a bigger one than the stock. If you can answer ASAP PM or post PLEASEEEEE!!!!!! HELP!!!!!!!!!!!!!

 

depends how highly modified the engine is.

If you're still running the RENIX ECM your throttle body options are very limited from my understanding.

 

great stuff guys. i have a buddy that bought some alternate style of injectors and went back to stock. had issues with them and alot of this info helps to understand why. mods this should be a sticky.

 

I just wanted to point out something on the 1 hole/4 hole debate in the last few pages. Its been a common argument on many modifications across the forums that "if it was better they would have done it OEM" with various ways of saying that (engineers, etc).

The problem with this line of reasoning is twofold: "better" for us wasn't always "better" for the manufacturer. The company's goals were not just moderatly good mileage for sales, but also something that would pass emmisions of the time, other government regulations, and still be cost effective to turn the biggest profit they can. Point with this part is that the reasoning for a person buying an SUV or jeep isn't for gas mileage, just that it works and gets the job done.

The other half of statements like "the engineers know best" is along the same lines of "if we were meant to fly we would have wings". If everything was done the best of the best at teh factory we'd not have much to talk about on these forums, other than "Man, these jeeps are cool! don't have to do a thing to them!"

I think there must have been some reason that during the same manufacturing time period they used 4 hole injectors on Neons and singles on XJs, and this reasoning probibly goes into some improvement on something we don't see, either profits, emissions, or some other company related issue. It would make more sense to me to have a single injector for all suitable products company wide to save costs, but since they didn't, there's a reason they did it, but not necessarily just because the engine wouldn't run better or get better mileage. If that were so they wouldn't have used them in Neons. Keep in mind that the high CR of the I6 makes emmissions a greater issue than a small four banger in a passenger car, and a company has to deal with percentages of tolerances.

That's a thought... perhaps the company found that with 4 hole injectors they got like 2-3% of the jeeps that wouldn't pass emissions in CA. That would be enough to kick the injectors if 99.999% passed with single hole. After all, that's one of the things that killed the production of the I6 as far as I understand. They won't try different combinations of parts on each jeep to figure out what works best for us, they're just trying to make as much money as they can with the least amount of work.

Another thought as to why different people are getting different results with different upgrades (intakes, injectors, throttle body spacers, "cold air" intakes, etc) besides the fact that no one's doing exactly the same thing or measuring the results the same way every time: our jeeps were not all created equal. They are close enough to have interchangable parts, but some were made in canada, some in mexico, some in america, some in austrailia.... So even of the same year you have different block castings (this is why you have to blueprint your block when you try for a 5L stroker). On top of that, most jeeps these days have had a number of owners with different amounts of care taken to the maintenance of them, wearing the valves and cams differently, different ages of sensors, different fuels, plugged filters that still function but don't flow right.... each difference changes the outcome with these engines since they are some of the highest allowable compression engines around. Just a slightly overheated set of piston rings could vary your chamber pressure by a significant percentage and change your horsepower dramatically.

Personally, I've decided to gather as much good info about an upgrade, try it on my own jeep and see if it works.... but I'm gonna have a backup plan and my old parts in case it goes south!

 

You gained two miles per gallon because your ORIGINAL injectors were shot.. JUST LIKE EVERYONE ELSE WITH CLAIMS OF MPG GAINS. Or once again we can argue all day that "Why did chrysler not go ahead and do that same thing you did off the factory line" Surely they would have sold more vehicles right? Imagine if in 2001 you could buy a Jeep Cherokee sport with a sticker that says," 18mpg city and 24mpg highway! Simply because Chrylser decided to use NEON injectors.. AND just imagine if they showed a 2mpg gain in gas consumption ALONG with more power and better idle"

I guess you want us to think what? Chrylser engineers guess like we all do on here? LOL.. comon..

Guess what.. THEY ARE STILL USING SINGLE HOLE TODAY! Better chambering..

Your don't have to be genius to figure that one out.. There is NO WAY IN HELL you got better gas mileage from Stock Injectors to some other type of injecotrs leaving all other stock items unchanged.. It's irrational thinking and wishful at best..

You can buy a rebuild kit for Seiemens Deka, have them PROFESSIONALLY cleaned and tested all for around 60 bucks.. Drop those in there and you will get the same results..

THE HEAD AND INTAKE MANIFOLD DESIGN IS SUPPOSE TO USE SINGLE PISSING TYPE INJECTION.. Your going to go by what some guys tested on here or said is better over the engineers at chrylser? They changed the manifold in 2001 but not the injectors on Cherokee's.. Why is that you have to wonder? How much tooling did it take to change the manifld to an UGRADED one yet not change the injectors? I'm not convinced at all by any claims on here for 10 year or more old trucks who's owners changed injectors and saw wonders.. Clean the old ones and put em back in..

 

You continue to ignore the physics, facts and post an illogical argument.

I'll believe that they're still using singe hole fuel injectors when you post the part numbers and cars their used in. Diesel and Direct injection engines don't count because they use significantly fuel injection systems.

Why did Jeep just leave the fuel injection system the same instead of changing thing to improve gas milage? Because it wouldn't have been feasible, throughout all of its model years the XJ sold extremely well. Why would Chrysler even think of fixing something that wasn't "broken", especially during the middle of the SUV boom? They wouldn't because there was no reason to.

Believe it or not, there are numerous people who agree that changing to 4 hole injectors from stock single hole injectors will improve gas milage. Plus its more economical to swap injectors than it is to have stock injectors "rebuilt".

A couple comments: You can't "rebuild" fuel injectors, they're sealed units and really are so simple they don't have any parts to break. The most common problem with them is fuel varnish building up, which can very easily be cleaned even at home.

The other thing is, what in the world is "Chambering"? I've never heard that term used when talking about anything on a vehicle.

 

It would be fruitful for you to view the videos on this link. http://forums.corvetteforum.com/c4-t...questions.html

Not that I'm attempting to change your mind, more so to give you a better visual of how the efficiency of the the new generation injectors have true performance advantages.



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