James Whisenhunt

So I got my xj 2 months ago and decided to do the injector swap.
I should add that at 280k miles anything but what I had would be an upgrade. That said I scrounge over a couple junkyards, 50+ cherokee and every Chrysler that had 703s from factory with no luck but after looking at all facts on swapped injectors found that since the upgrade has 4 hole for better atomization figured 210 cc from the stock 230 is questionable on an obd1 cherokee. However if I upgrade regulator I get around 220 which wouldn't necessarily make me run lean with better atomization so I decided to swap. In Colorado I searched over 100 cars for 703s and unless I had ev6 connectors (so many cars had this equivalent in ev6 connector, obd1 is lucky!) I think all the hype has ppl pulling them all and ebay selling that stuff
Now I realize even is not the connection type as more of injector style but it's a good guideline and most jeep owners understand it this way.
So a grand marquis is where I found ford yellow 710s and rebuilt and swapped them. Very simple and easy and made a tad bit of difference. My injectors were old but I rebuilt prior to this and flow tested to make sure it's not a placebo affect. I'm only at 210cc of flow since I'm not running higher fuel pressure so up to 3500 rpm is an improvement on torque but if I full throttle it I'm not as impessed as I can tell fuel is slightly lacking and higher velocity. I feel if you do 710 on obd1 run the bigger fpr as people suggested. I feel the obd1 shouldn't have this problem due to the different fuel set up and better intake flow allowing even better higher rpm velocity. My gas mileage is ever so slightly better due to the fact I'm not on the throttle as much. It feels as if the car bogs less at idle and pulls more efficiently. I have no data to back it up so test for your self. If you can't yet 703s do these. If you want better fuel do 710 as 703s I can bet you'll be a tad rich which is fine for most but will lead to other premature wear (don't bash me on this with the "o the ECU will compensate" ) because these cars were designed to be run rich. They were designed to run lean.
703's will make more of a difference but I didn't car as I wanted better efficiency not a quicker xj. This injector does that and after the fpr regulator I'll be as close to stock injection cc wise as I can go. I believe the 703s will put you at 240? Can't remember.
Also the retaining clips are unnecessary as they don't hold crap in but really just hold injectors as the rail is pulled. If you SEAT the injectors properly with new o rings you'll be fine. And since I was a dumb *** make sure you put the injectors on the rail then match to the intake, and with a rag, rubber and mallet lightly tap the injectors to seat. I relied on bolts to help seat and striped the last fuel rail bolt. Alot of how to videos didn't explain properly or missed this part and it was a pain for me to fix this, luckily the intake is aluminum and I now have higher grade bolts on the rail.
I want to hear others experiences with injectors and what's worked.
No bashing as keep in mind we have the same cars but everyone's engine runs differently due to millions of factors.
I want easily compiled injector info here as well since everyone breaks it up and crouds it with small talk.
Unless you have experiences to share or facts don't post. There's three threads most info I found came from but had over 5 pages of "will this work" or where can I find them. We can easily find where to get all these injectors. I want them all compared
Happy injector hunting!

odgreen

Proof read please...... a lot of misspelled words and contradictions. I'll erase this once you fix it.

thatXJguy

My opinion is that fuel injector swaps do nothing. Now I will prepare to argue my case:

The 4.0L is too simple of an engine for a spray pattern to make any difference. All the fuel will pool on the piston before it detonates whether it's sprayed as a stream or as a mist. There are other engines on the market where the placement of the fuel injector and detonation timing will make a difference, but the 4.0L is far from one of these performance engines.

Moreover, the flow rates are exactly the same as the factory injectors, so you're getting the same amount of fuel per detonation as you were before switching the injectors. The only way you might see a difference in any kind of performance at all is with a fuel injector with a different flow rate, but even then, the fuel rail has a set OEM capacity and can only get sent to it what the fuel pump is willing to send over to it.

Overall, I did every fuel injector upgrade mentioned across these forums. Tried Ford Orange Tops, 784s, and others. Nothing increased/decreased my gas mileage or made the Jeep any faster with throttle response. Nothing except for 4.56 diff gears did anything.

My stock fuel injectors were always clean. It would seem that the only people who really get any gains from a fuel injector swap are those who just need to clean their original ones.

cruiser54

Probably correct.

I advocate changing the injectors on the Renix Jeeps because they are prone to leaking at the injector body seam.

XJwonders

I do the same to 97-01 too because those bodies are also prone to cracking due to rusting internally.

cruiser54

So, I can't bolt on some different injectors and get an instant 500 horsepower increase?

James Whisenhunt

Stock yes but that's with ANY stock car. Fueling is usually addressed later after intake header exhaust and camshaft etc but these cars are designed lean from the factory and unless you do a stand alone there is no way to take advantage of that. All this is simply stating, albeit maybe explained horribly, that the better spray pattern helped my start ups and lower throttle response due to it not being chugged out.
Best explanation is look at a carb compared to efi. Almost always carbs you can bog down by jumping and releasing the throttle and you feel the hesitation but efi doesn't have that depending on the systems efficiency. My xj had that bog and didn't shut down too smooth as if it still momentarily was fuel run on

James Whisenhunt

My apologies I should have proof read. Sometimes my mind thinks faster than I type. Was also in a rush to work, so alot of run on sentences. What's the contradictory info? I'm no mechanic so I'm sure I have ALOT of misinformation but I've only had an xj for a few months so still learning it.
Mainly just didn't want people to stray from 710s because so many say not to when it runs good in my opinion. I feel it lacks up top still compared to my stock.
Also how do I edit my post. I'm mobile so maybe I can't remember edit? I'll structure it tomorrow morning

Rogue4x4

syncview

installing higher flow injectors will only make it harder for the ECM to control fuel trims, if trims get out of range it will pop up a CEL.

Higher flow injectors can only be beneficial when using a piggyback or aftermarket management system, mostly in stroked or forced induction motors or maybe if you have a high lift cam installed in the 4.0 :P

odgreen

"They where made to run richer. They where made to run lean"
That's a contradiction. Lol