In the beginning there was confusion:
Some people seem to think the 2.5L and the 4.0L used the same injectors. They don't. Here's the scoop. From 1991-1995 the 2.5L used the Siemens
53007232. The 4.0L, on the other hand used
33007127 till 1993. Then in 1994 they switched to
53030343. The XJ seems to go along with the YJ Wrangler (the 4.0L Renix used
53003956). To confuse things even more, the 1993 ZJ uses the same injectors (
53030343) till 1995.
In 1996, some weird things started to happen. Chrysler decided to use the
53030778 universally in both the 2.5L and the 4.0L engines for the XJ Cherokee. The 2.5L TJ, the 4.0L and 5.2L ZJ also used these injectors. The 4.0L on the other hand used
4854181. Then to make things even more complicated in 1997 the XJ and the ZJ switched to
4854181 as well.
- 1987 -1990 - 4.0L – 53003956 *Cherokee
- 1991 -1995 - 2.5L - 53007232
- 1991 -1993 - 4.0L - 33007127 *Wrangler & Cherokee
- 1993 -1995 - 4.0L – 53030343 *Grand Cherokee
- 1994 -1995 - 4.0L - 53030343
*source: http://www.crownautomotive.net/catalog/fuel/fuel_injectors.htmlNow those parts number only help you find the OE part and to see which vehicles used with injectors. What we really need to know is the rate of flow. This seems to be a bit harder to find and isn't listed in the Factory Service Manual. According to some people at
http://www.dodgedakotas.com/ and
http://www.moparchat.com/ these are the flow rates.
- 1991-1995 (53007232) - 17.4psi/hr @ 39 psi
- 1991-1995 (33007127 & *53030343) - 21.4psi/hr @ 39 psi
- 1996-2003 (53030778) - 23.2psi/hr @ 43.5 psi
*needs confirmation but looks right
**source http://www.moparchat.com/ and http://www.dodgedakotas.com/A thing or two about Injectors:
There are a lot of different things to consider when choosing a different injector. First off there is the flow rate. Unless you have calculated your required flow rate you will want to stay near stock. Add too much fuel and you will run rich. Run too small of an injector and you'll run lean. A wide-band O2 sensor with a air/fuel gauge is a good idea when you need to experiment. Several members have noted that when running at higher RPM's the Computer (ECM) leans out fuel. This is really noticeable on a YJ around 4000RPMs. The engine does not want to rev much higher without effort. More on this later.
The other consideration when choosing a fuel injector is the spray pattern. The stock fuel injectors have a single jet. This is the hole where the fuel is sprayed out. Some fuel injectors have 2 or more jets to help produce better atomization. You want the fuel to be mixed into the air evenly so a mist be better then a stream.
Lets take a look at some Ford Fuel Injectors since those are the popular ones. The one everyone touts is the Ford Design II 'Yellow' 19lbs Fuel Injector. The Injector is a Bosch/Delco and is rated at 19psi/hr. The color helps make a quick ID. Each of Fords fuel injectors are color coded. The Design II's have a plastic upper housing with a metal lower housing. They have a slot on neat the top that holds the retaining clip which holds it to the fuel rail. The Design II Yellows can be found on several different cars but the most common is the Mustang 5.0L. There is a Design III Yellows that is used on Ford Explorers. These are easily spotted by the all plastic design. They do not use a retainer clip and are held in place by the fuel rail itself.
It is also worth noting that the plugs for the Jeeps are known as EV-1's. It seems the the Explorer Design III's are one of the few with the older EV-1plug on the newer injector. There are adapters available to use the EV-1 plug on a EV-6 Injector. Both the Yellow Design II and the Design III's use 4 jets. The Design III's are supposed to have better atomization then the Design II's.
Getting dirty:
Tools required:- 11mm Socket
- 13mm Long Socket
- Ratchet
- Ratchet Extension
- Standard Screwdriver
- Jar
- Rags
- Tape
- Pen
Swapping out the fuel injectors isn't too difficult but can get messy. Start off by disconnecting the negative battery terminal. Make sure there is enough room above the fuel rail. So if the air hose is in the way, remove it. Unclip the throttle cables form the top of the valve cover. Next you will want to disconnect the plugs from the top of the fuel injectors. These are be easy or hard. The trick is to pull straight up. If you pull at an angle they will not release and you risk breaking them. Put some masking tape on them and make where they go if you do not have a Factory Service Manual handy. If there is a pressure regulator on the rail (YJ) disconnect the vacuum line. Next unclip the throttle cable(s).
Now that everything is disconnected you can get to work. Start off with the 11mm socket. There are two bolts and a nut that hold the throttle cable bracket on. Move the bracket out of the way. On the other side near the firewall, there is another nut that holds a plug in place. Remove the nut and lift the plug off the stud.
Now there are two ways to go about this. One is to remove the fuel rail as one or disconnect the injectors from the rail with it still connected. Both are easy but I think it's easier to take the whole rail off. This gives you enough room to clean the sockets and the rest of the intake if you want. If you decide to take the whole fuel rail off you will want to get a jar ready and place it under the fuel and return connectors at the front of the fuel rail. On the top of the rail is a gray cap. Remove the cap and there is a schrader valve (same used for the tires). This will release the fuel pressure in the rail. It will also leak some fuel. You might want to wrap a rag around it before releasing the pressure.
To disconnect the fuel lines you will need a standard screwdriver. There is a white plastic clip that needs to be pulled out while pulling the fuel line in the opposite direction. Once the line comes off, gas will flow out. There is about ¼- ½ cup of gas in there. The injectors are next. Near the top there is a metal clip which holds it to the fuel rail. You'll need a screwdriver to unhook the clip and wiggle the injector out. It won't be easy. The injectors are held in place by the O-rings. If you pull too hard, the O-ring might be lift behind. This is not a problem.
Wiggle the injectors out and inspect them. It's probably a good idea to keep track of which injector goes where, in case you ever need to replace them.
Now, that all of the injectors are out, it's time to put the new ones in.
Before installing the new injectors make sure all of the O-rings are intact. If you're in doubt, replace them. This is not the place to cheap out. To get the injectors in easier, lubricate the O-ring in some gasoline. Don't use too much force otherwise, you risk tearing the O-ring. Once they're in, reverse the steps and you're done. If you can bolt down the fuel rail and it's against the tabs then the injectors are probably seated OK.
Once it's all together, it's time to reconnect the battery and try to start it up. Turn the key to ON and wait a second or two. This allows the fuel pump t pressurize the system. It will probably take a second or two to start. If the engine idles fine then you're good. If it seems to be a little rough, you might have a fouled or damaged injector. Check all of the plugs to make sure you haven't forgotten anything.
After thoughts:
Well according to all of the information above, the 19lbs Fuel Injectors will probably work well on a YJ with some mods. (Test vehicle: 4.0L TB, TBS, Hi-Flow cat, cat-back exhaust, PD Ignition). Otherwise, it might be good to try out the 17lbsDesign III injectors. If you have a TJ, you will probably want to use the 24lbs Injectors.
Now on a YJ, I quickly noticed a difference in the exhaust. It sounded a bit more throaty. Around town driving didn't really change. What I did notice was when rev'ing the engine over 4000RPM. With the stock injectors, the engine would feel like there wasn't anymore to give. With the new injectors the engine will easily rev over 5000RPM. This is a clear indication that the ECM leans out the fuel at the higher RPM's.
Overall, it was a simple conversion and fairly inexpensive with used injectors.
