Hey all, as i've been reading on the net,for cheap/junkyard swaps that fits the xj with no or minor adjustments, found that some replaced the xj's injectors (1 hole) with ones for 5.0L mustang or dodge neon..that both have 4 holes...some say they noticed better fuel efficency...some say they gained power at acceleration and better response......sooooo, did anyone tried it or have another opinion due to this experience?? Any advice ? Thanks.

 

I saw better throttle response. Smoother idle. Seems to get a little better mpg from what I can tell, not incredible.

As for power gains, I did not notice any at all. If anything it feels like it may have lost power.

If you do it right and reset the computer so it builds its adaptive memory based off the new injectors, you will have **** MPG and the jeep will probably run very rich until it relearns the new injectors and your driving habits. This could take anywhere from 50-200 miles from what I noticed.

The good: better throttle response, smoother idle. Maybe a little better MPG, but not really noticeable.

The bad: loss of power? Need to reset computer, and ****ty MPG while it tunes your jeep based of the adaptive memory it creates after reset. This takes a bit of driving around.

Just my 2¢...

 

I installed the neon 4 holers in my 99' XJ (273,00 miles) and gained some throttle response, smoother idle and acceleration. I am running 33' tires with 4.56 gears and have not seen any fuel economy gain what so ever. Not sure I believe everyone who claims to have instantly gained gas mileage just by changing injectors. I believe it is worth the swap but not for fuel economy gains.

 

I would think that most gains of any kind are probably a result of squeaky clean injectors. Replacing injectors after a few hundred thousand miles is probably a good idea anyway.

 

First 2 posts are right on and what I saw after a "784" swap into my 99, a worthwhile upgrade in my opinion.

 

My 784's should be coming in any day now. My input is not valid though because I'm one of those guys that feels an increase in torque and hp after changing the thermostat. There's no telling what I'll feel after upgrading injectors!

 

I did the 4 hole injector upgrade (with a new fuel rail) in my '00, Jeep had about 150K on her, and do not doubt the statement above. At the same time though I swapped out my front and rear diff fluid with synthetic, swapped out all 4 O2 sensors, cleaned my throttle body, my IAC, did the valve cover gasket just cause I was half way there already, and had put brand new Cooper Discovery HT's in a 225 75 15 on her just a little before all that above. Now this is just a DD and all stock. Was getting about 13 MPG before. Getting 16 sometimes 17 MPG around town now. That is also taking it easy on the skinny peddle though.

 

that small gas mileage increase was the new tires LOL... gotta love new tires...

 

Don't doubt it. I am guessing all the those things contributed a little to the total. I needed new tires. I was not getting any CELs but just figured all my O2 sensors were original, had a 150K on them, and just needed to go. Figured the same with the diff fluid. What BrawnyDog said about the fuel injectors makes perfect sense. Nothing to do with 4 hole injectors but the fact that the Jeep has new clean ones in there.

 

Here is a link i found ( https://thexjguys.wordpress.com/2012...injector-swap/ ) that shows ur right guys.. the gain in power is due to cleaner new injectors...anyways..i need to change my injectors coz its still the factory ones hahaha.. as long as there is no harm in swapping to 4 holes ill do it.. any recomendations?any Particular brand? Serial number? Need to upgrade the injectors

 

There is all sorts of info about boneyard swaps. Dodge Neon, I want to say Dodge Caravans too. Think I have seen people talk about Mustang swaps. Guys in the forums are always selling cleaned injectors. People have mentioned buying Bosch ones. Looks like you have a '91? You are just going to want to make sure the injectors have the right connectors. All the info you need is in that link. I have a '00 and went a different route. We have an engine builder in my town who I believe to be one of the premier engine builders in the country. His son just so happens to have an '00 too. They tweaked the engine a bit but on their advice bought my injectors from a place called Marren Fuel Injectors. They assured me that they would be fine in a stock 4.0. They happen to be local. Pricey. $320. Funny thing is even with my discount in the auto parts store I work at would have spent $230 for new stock ones. You will be able to do so much better online. Thing is these are people who when the talk you need to listen. I also figured cause Marren is local to me any problems could be resolved in person. Do not regret spending all that money one bit.

 

Correct, that is what I use in my '96. #403 injectors. Has mist pattern rather than squirt pattern of stock injectors.

 

I doubt the "Always" part, for the reason you will have a better atomization of fuel with the newer 4 hole injectors over the single, due to improvements in design.

 

Are any of the rebuilt Neon injectors that are all over ebay and Amazon any good, or should I insist on new ones?

 

I swapped with some old neon injectors and it's too early to tell about any fuel economy increase. But I got the same as everyone else. smoother idle and throttle response. Worth it? I think yes. It's easy to do and well worth it especially if your current ones are due for replacement.