Solkanar60

Just put a set of 784s in my 2001 Cherokee. Having some trouble at low idle. Rpm gauge bounces up and down and will almost shut off. When you give it gas it seems fine. Any suggestions on what it may be?

DocOrng XJ

did you "reset" your computer after you installed the new injectors?

Programbo

Sometimes it takes them awhile to settle in. As mentioned reset the computer and even then it sometimes takes a number of starts before things run smoothly. Make sure there is no minor leak anywhere. Or maybe just a less than clean injector slipped by.

no rdplz

1. Did you reset your ECU when you did the swap? If not, check the injector write up in my signature for how to do it.
2. If you did, make sure the negative terminal on the battery is tight. Mine was doing the same all because that terminal was loose.
3. Did you make sure all the injectors worked before installing them? You can easily test them with some carb cleaner, a syringe, small hose, speaker wire, a 9V battery, and an ev6 electrical connector.
a) Attach the hose to the syringe and the "top" of the injector (filter end - does not have the 4 port holes).
b) Put some Carb cleaner in the syringe and slightly depress the plunger so it creates a vacuum.
c) Connect the speaker wire to the EV6 connector and then attach that to the injector.
d) Touch the speaker wires against the 9V terminals.

If the injector is working correctly, it'll spray fluid from the ports. Do this to each injector to make sure they are all functioning properly.

Solkanar60

I did reset the ecu. I think I may have the wrong pintle cap. I think the hole is too small to get the right fuel spray.

Solkanar60

The one I have looks like this



I think I need something more like this.



Am I right?

no rdplz

You are correct. The small opening caps are the wrong ones.

CharlesS

Did you ensure that you cleaned the intake manifold pockets thoroughly where the O rings seat.... There is a chance of a small vacuum leak....

Solkanar60

I cleaned it out really well. Could the wrong caps cause the issue I am having?

Programbo

Hello. Yes if you are using EV-1 pintle caps on an EV-6 injector you are blocking some of the ports.

19cherokee96

How much did you have in the injectors and do you have cold air intake to get the fuel/air ratio you need to run smooth? And increase in power any effect on mpg? Im going to start doing some mods to get more power out of my 4.0

Solkanar60

I have about $50 in the injectors and $15 in a rebuild kit for them. I also have cold air intake.

19cherokee96

Could I have my stock injectors rebuilt to be bigger I know you can with diesels but not sure about these

Programbo

What do you mean "rebuilt to be bigger"? More flow?

19cherokee96

Yeah more flow like for an example on diesels you could take a stock injector and have them custom made to say 20% over stock