After reading about the injector swaps on here I am not finding anything for my 99 xj. I find 88, 98, 2001 but never 99. Please help. What injectors would I need for my 1999 XJ 4.0l 4x4 all stock engine. Any help would be great. All i need is the part numbers and the cars I might be able to find them on. Please no charts or try this page or that page. Please someone reply back that has done this swap on a stock 99 xj 4.0l. I am sorry but I read the 400 posts that are on here and am more confused now than when i started.

 

You didn't read hard enough, there's a thread on here called "more budget injector questions" or... something along those lines. I know, I'm confused too I have a stock 99 xj 4.0. A user on that thread wildbill1 or something like that has a 99 xj he put in a pair of 784's (from chrysler) and said it made little to no difference. Another user, buysellny has a 2001 (99-2001 (inclusive) has the same fuel system for injection ev6 or something like that) that he put Ford injectors into with little to no difference, he says even worse but I doubt him because he said the dealership "professionally" cleaned his injectors before he bought his cherokee from the previous user. Dealerships just put in injector cleaner as part of a deal/tune up package, I bet that's what they did, they call it cleaning throttle/fuel system. Anyway. So. you're options are, and this is just what I've found from searching, the Chrysler 784's (I think Bosch makes them, part # 0 280 155 784) or the Ford/Motomaster injectors, part number CM4956 or XR3Z-A4B but they are single hole, not four hole like the bosch's. PLEASE if you try one of these tell me some results, I can't really find good answers on how they actually work. Those two people just vaguely said "not much difference"?

 

Did the swap on my 00, same as 99 an 01. Didnt notice a difference but also have a 63mm tb, intake,free flowing exhaust. Im sure a jeep without those mods would notice it a bit more.

 

I have a 99 as well and went with the Chrysler #784's out of a 2000 Stratus with the 2.4 engine. You'll need to find two of these cars (99-02 Stratus's will have the 2.4 with #784's) in order to get all 6 injectors.

I let them soak in SeaFoam overnight, then cleaned them with a wire brush, carb cleaner, and a rag. To clean the insides, I took a 9V battery, connected speaker wire to the battery terminals, used some electrical tape to hold the wires to the battery, and then attached the wires to the injector pins. This opens the injector. Using some carb cleaner I sprayed out the inside and then used compressed air to blow out any remaining junk in each.

Did the swap and I haven't noticed a MPG increase, but my idle is MUCH smoother and throttle response is better. I'm running a little rich, but it's only because I forgot to reset the ECU when I did the swap. Resetting it today and I'll let you know if there's any MPG gain or not.

 

Thank you. That is exactly what i was asking for. I will look for the injectors this weekend and post my results when completed.

 

Don't ask me I will confuse you worse. I have the Fords in Now XR3Z.. 60 bucks for 6 new ones? Make that your biggest question on those.. Who sells brand new injectors for 10 bucks each? You can't miss my threads since Im in the middle of trying them out.. After these are tried, I am going to get 784's and rebuild them myself before installing with a rebuild kit if I can find it.. I found a boatload of those injectors locally at the junky.. After that Im going to figure out the best ones.. Ford or Boche..

But let me tell you.. I owned a BRAND NEW 2001 Jeep Cherokee Sport back in 2000.. Most people on here do not have the experience I did with a brand new 2001.. That car could smoke the tires down from a dead stop and FLY to 100mph in seconds with STOCK injectors.. It was so fast off the line your head would snap.. Unreal... Now 10 years later I bought a used one with 177K.. I can't duplicate the power of that brand new one I had.. I can understand that.. Unless I had a brand new motor I guess...

What Im trying to say is that the stock injectors are made for that truck.. They work KICK ASSSS.. This atomized spray and all this nonsense sounds great but in reality MAY do very little to nothing or make worse a truck that has excellent working condition stock injectors so long as they are in a stock truck. Im still trying to figure it out..

The first thing you should do is Seafoam and not injectors... Run it through the throttle body at a steady 1000rpm until blue smoke bellows out of the tailpipe.. Do it at your own risk lol.. Once I did that my idle was better and I had even better response with stock injectors.

SEAFOAM first! Trust me.. try that before changing stock injectors on a 99+..

 

Also keep in mind.. Stock teh truck should get 17 to 20 MPG.. Ask all the people who put in the 784's or Fords if they get better then the gas mileage stated on the sticker by chrysler.. They will all tell you NO! Most of those people MUST have had clogged crap to begin with. Why do you think some people noticed good results and others none or very little or worse.. I DID NOT HAVE CLOGGED OR PROBLEMS other then jumpy idle as my stock injectors worked great. I was looking for better performance and better MPG.. Im still evaluating but I get nothing from those fords SO FAR.. I need to run it a couplel more tanks of gas and 50 start short trips.. I am interested to see how you make out with 784's!

2000 to 2001 was a upgraded year for the throttle body and manifold correct me if Im wrong? People say 99+ but Im not sure! There was a changeover year in there mid year I think! You better look into it.. I have 2001 so no question.. Therfore the injectors must have also been upgraded!! I fear I may be going in reverse even bothering with injector swaps on a 2001.. We will see! I hope not!! I hate spending money on gas..

Does your car run like crap now? Why are you doing it?

 

I have a set of injectors from my 99' just chilling since I rolled it.
Pm me if you're interested.

 

the only upgrade to the engine for all 97+ XJ's was a redesign of the intake manifold in 2000. It allowed for better airflow and resulted in a 4hp gain over the 97-99 models. The TB and injectors were carried over from previous years though. The biggest advantage to the injector swap is not MPG, but throttle response and a smoother idle. Some people may see a slight MPG increase, or even decrease, but one thing I've learned about Jeeps is that no mod has the exact same results on any 2 XJ's.

I'm getting the same MPG as I was before, but that's also while running rich, so I won't be surprised to see a slight increase in my MPG once I get the ECU reset and it figures out the fuel trim level.

 

also, if you want the xf2e-c4b's here is a list of vehicles they can be pulled from

xf2e-c4b

FORD E-150 ECONOLINE 1999 4.2l v6
FORD E-250 ECONOLINE 1999 4.2l v6
FORD F-150 (1999 - 2002) 4.2l v6
FORD MUSTANG (2001 - 2004) 3.8l v6
FORD RANGER (2001 - 2004)
FORD RANGER EDGE (2001 - 2004)
FORD TAURUS (2001 - 2005)
FORD WINDSTAR (1999 - 2003) 3.8l v6
MAZDA B3000 (truck) (2001 - 2003)

 

Oh.. is the injector difference only the USCAR or whatever its called connector? I think the injector itself is alos diffrent in some ways.. Does 2000 and 2001 have same part number stock injectors? I doubt it.. I have no idea though.. I thought the intake manifold was upgraded so requiring more fuels flow also? I must be mistaken..

 

Sorry, I was wrong in my post. There are a couple differences in the 97+ line up.
97-98 XJ's still use the older style injector. These can be replaced with #703's from a neon 2.0.
99's received the "new" style injector. These can be replaced by #784's from a Chrysler 2.4 and the Ford C4B's.
00-01 XJ's use the same injector as 99's. However, they received a new intake manifold that allowed for smoother (not more) air flow. They also got rid of the distributor and went to a coil pack ignition system. The redesigned intake manifold and coil pack system resulted in a 4hp gain. #784's and C4B's should be used for upgrading the injectors.

On another note, I wouldn't suggest running SeaFoam through your TB. There's too high a chance of bad things happening doing it this way. Here's the safe way. Pour 2/3 of a can into your gas. Pour the other 1/3 into a cup. With the engine running, remove the main vacuum hose from the brake booster, let it soak up the Seafoam in the cup (it happens VERY quickly) and then reattach the vacuum hose. LIGHTLY rev the engine (1500 rpm) until the white smoke is done pouring from the exhaust.

When you do the injector swap, make sure to reset your ECU, or your fuel trim levels will be off. This is from Quadratec, so if anyone has a beef with this method, take it up with them. It worked well for me. With the key in the "off" position, disconnect both battery cables. Hold them together for 30 seconds. Reattach the cables and turn your ignition to the "on" position - DO NOT START YOUR JEEP. Turn your headlights on, then off. Start your XJ. Your ECU will take about 50 warm up cycles to "re-learn" what the fuel trim levels should be for the new injectors. Any time an upgrade is done to the engine (intake, TB, exhaust, injectors, etc) you should reset your ECU so that you'll get the most from your new parts.

 

Doesnt sucking it in thru a vacuum only hit the last 3 cylinders? Ive read this more than once and people say only way to get all 6 is pour it down the TB. Of course, you need to be very careful when pouring it down the tb, just little splashes at a time. Did my xj thru the TB and my dads wj via brake booster vacuum.

 

Not sure where you've heard that but I do know hits all 6. However, the method I suggested is the simplest for a SeaFoam job. There's a far more lengthy process if you want your engine to be "extensively cleaned". Some of the stuff in the "extensive clean" job goes against the "simple clean" job (when to turn it off/leave it running; how much SeaFoam to use), and it all has to do with the word "extensive". It's up to you which one you do.

Simple Clean: See my previous post.
Extensive Clean:
1. Buy 2 cans of SeaFoam and 1 can of SeaFoam Deep Creep.
2. Go fill up (all the way) with 91 octane and then add one full can of SeaFoam. Take lots of turns at speed (10-15mph) to fully mix the gasoline and SeaFoam. This cleans your injectors.
3. Go home, and add 1/2 can to your oil. Yes, sounds stupid adding a foreign substance to your oil, but remember, SeaFoam is a petroleum. Change your oil 100 miles after adding the SeaFoam. Your oil is most likely going to look like Satan's spit due to all the crud coming out of your engine. This cleans your crank and lower engine.
4. With the Jeep running, use the remaining 1/2 can of SeaFoam in your brake booster's vacuum line. Remove the line and put a skinny funnel into the line. Your engine is going to be revving like crazy due to the vacuum leak just do you know. SLOWLY pour about 1/3 of the remaining SeaFoam into the funnel. Repeat this step. Take that last little bit of SeaFoam and quickly dump it into the funnel. Your Jeep should be stall out. if it doesn't, quickly turn it off. Let your Jeep sit, NOT running, for about 15-20 minutes.
5. While it's sitting, remove the air tube from the top of the throttle body. Using the Deep Creep stuff, generously apply it to the entire TB by opening the butterfly valve. You don't need to use the full can (flooding the engine is a bad thing), but make sure the inside of the TB is coated. Hook everything back up (air tube, vacuum line, any clamps). Steps 4 and 5 clean the top end of your engine.
6. After that 15-20 minutes has passed, start your Jeep. This make take some effort as there is fluid in the upper engine, but it will start. If you need to, blip the throttle - DON'T REV IT. Let the Jeep idle for about 15 minutes.
7. Now go for a VERY spirited drive. Rev it high and floor it when accelerating. Pretty much drive it like a fat kid chasing down a Little Debbie truck (nothing mean meant by this, it's just a great analogy ). Get on the freeway and go all out. You're gonna see a nice blue smoke trail that everyone behind you is going to hate you for, but it's well worth it when it comes to your engine.

 

great writeup, another optional step would be to just take the TB off and cleaning it with a brush and the seafoam deep creep or carb cleaner. Cleaning the IAC motor can help rough idles to, and the chamber which it sits in.