Tuning a 4.6

Hey everyone,
So i just got my 4.6 back from the machine shop and everything is assembled. I am almost ready to put the engine back into the jeep but now I have some questions about tuning it. The stroker recipe is as follows for referance

1998 block
clearwater cylinder heads 0331 head
258 crank and rods (reconditioned)
bored .030
new factory cam
new bearings all around
new oil pump
new timing set
block was decked to allow running of pump gas

Im under the assumption i am going to need to adjust the map on it and tune it. however it is a california emissions jeep with the pre cats and 4 o2 sensors in the exhaust manifold. If there is anyone that can shed some light on the best way to go about this or anyone that may be able to help id really appreciate it. I am just not sure how to do the tune myself without a little guidance.

Most will say go for an adjustable map or 24# injectors.I installed my 4.6 stroker with the crane cam and and 0620 head...I got the 24# injectors and they are way to large I don't see how most go this route.I simply put in the bosh neon 784 injectors-uscar connector running on the renix set up they are just about right.Even when you use an adjustable map sensor or a piggie back system all that matters is what the factory ecu sees from o2 reading and adjusts correctly,just try your set up first and use a ceaper o2 air/fuel gauge tied into the stock o2 sensor and adjust injector size accordingly.I see you have the pre-cats..tie it into the upstream ones

Personally, I would go with an AEM F/ID and a set of larger injectors. The F/IC allows you to "dial back" the larger injectors when it is in open loop. I also recommend that a wide band O2 senfor along with an AFR gauge be installed. I use all AEM components.
Just be adived that the F/IC8 is the better of the two choices. More money but, more capabilities as well.

There are two F/IC6. One is for non-Chryco vehicles and the other is specifically for Chrycos. Chrylser decided to use a "nonindustry" standard for detecting injector misfires. The only difference between the two model F/IC6s are the loading resistors that produce the drive current the PCM reads.

There are a goodly number of threads here on the F/ICs.

No reason to mess with the MAP sensor when it can all be done with the appropriate PCM piggyback.

Your best bet would be to have chris at christuned.com build a stroker cal and flash your ecu with it. No excess wiring or added complication to deal with.

Don't get me wrong, the fic would work, but why mess with it when your stock ecu will do everything you need? Plus Chris can add timing to your cal to take full advantage of your new stroker, which is something you can't do with a fic.

sidewaysstarion said:

Your best bet would be to have chris at christuned.com build a stroker cal and flash your ecu with it. No excess wiring or added complication to deal with.

Don't get me wrong, the fic would work, but why mess with it when your stock ecu will do everything you need? Plus Chris can add timing to your cal to take full advantage of your new stroker, which is something you can't do with a fic.

Click to expand...

That is indeed what i am attempting to do. I spoke with him shortly the other day and hopefully he can get my stroker tuned in so i can run it this year!

I'm in Pa too.... east, near Doylestown.
My '01 with 4.6 ran okay with the stock injectors. Then I bumped up to a slightly larger Ford injector (23.5 lb), but they're still on the small side..... runs rough (lean) at start up for the first minute, runs well after that but it's adding about 20% to the fuel trims to get 14.7 ratio. Gonna try some larger Neon injectors next, hopefully within a week.

I read the MAP mod won't work with the later OB2 system.... it'll ignore it and still adjust to a 14.7 ratio. Can anyone confirm this?

I hear the Chris tune is the way to go for the optimal setup.

Retlaw01XJ said:

I'm in Pa too.... east, near Doylestown.
My '01 with 4.6 ran okay with the stock injectors. Then I bumped up to a slightly larger Ford injector (23.5 lb), but they're still on the small side..... runs rough (lean) at start up for the first minute, runs well after that but it's adding about 20% to the fuel trims to get 14.7 ratio. Gonna try some larger Neon injectors next, hopefully within a week.

I read the MAP mod won't work with the later OB2 system.... it'll ignore it and still adjust to a 14.7 ratio. Can anyone confirm this?

I hear the Chris tune is the way to go for the optimal setup.

Click to expand...

If you ever get over towards York/Lancaster let me know I'd like to go wheeling if i ever get my xj back together. When I spoke with Chris it seemed the best way to go for a sure tune was with his set up. I am looking into the map mod and it just seems like its not even worth it for the 200+ you pay for a wideband and air fuel gauge you can get Chris to tune it and probably get a better tune as well

my old jeep required no tuning and threw no codes AND ran great. 4.6 with 26lb injectors. maybe I got lucky.

What was your AFR at WOT?