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ta1978ee 12-22-2009 03:03 PM

PCM Tuning 1999 4.0 liter WJ
I have installed a rebuilt 4.0 liter in 1999 WJ 4X4. Motor built with a Comp Cam, ported head and intake manifold, Ford 24 lb injectors. I have tried a hypertech chip with little improvement. Engine idles great. Accelerates smooth just not much much stronger than stock motor with 145,000 miles. Based on sootie tailpipe, motor is running rich or maybe retarded. When I first ran new motor, the engine light came on and the codes that came up where O2 sensors, throttle position sensor, and idle air control. I disconnected and shorted out battery cables and that cleared codes. Have a cold air intake and MagnaFlo catback with an aftermarket cat. I installed 2 new O2 sensors. Several places said I need to have PCM reflashed but I have not found anyone who can? Help!! I am in the Dallas/FW area. I have not replaced the stock exhaust manifold with a header yet. Does moving the cam position sensor have the same effect on the timing as moving a distributor did on the older motors?

robpp 12-22-2009 03:39 PM

Re: PCM Tuning 1999 4.0 liter WJ
i think superchps flashpaq works on 99 4.0

DJ BoNiOmArIo 12-22-2009 03:44 PM

Re: PCM Tuning 1999 4.0 liter WJ
well first off welcome to the garage :)

I am in the metroplex also !!!

you might want to check with Air Ram vendor here if they have a flashpaq also one of my friends he works at a firestone full service center on camp wisdom road he might be able to help flash ur system, pretty good mechanic the only one I trust out here ... and he can custom tune it

PM me if you need more details

ta1978ee 12-22-2009 04:07 PM

Re: PCM Tuning 1999 4.0 liter WJ
Thanks guys. I will follow up on your suggestions.

dreamer1213 12-22-2009 05:46 PM

Re: PCM Tuning 1999 4.0 liter WJ
You need some kind of custom tune with that work I think. Is it an aggressive cam?

Chaoul1 12-22-2009 07:29 PM

Re: PCM Tuning 1999 4.0 liter WJ
Check Air Ram with a B&G Tune. Bubba has had it with his 99 WJ 4.0L.

Chuck 12-22-2009 08:24 PM

Re: PCM Tuning 1999 4.0 liter WJ
x2 on custom tuning. Welcome to JG, any photos of the ride/engine work.

Scottina06 12-22-2009 09:48 PM

Re: PCM Tuning 1999 4.0 liter WJ
try SCT from sure if they work on the 4.0) or B&G

DJ BoNiOmArIo 12-22-2009 10:05 PM

Re: PCM Tuning 1999 4.0 liter WJ
airram is in euless which makes it easier for you to just drive over and have them check it out :)

BUBBADOG 12-22-2009 11:33 PM

Re: PCM Tuning 1999 4.0 liter WJ
Talk with Dave or at B&G he flashed my 2001 WJ with the 4.0l and it shaved off .32 off my times its a no brainer for your motor we are very limited on our choice

FlyinRyan 12-27-2009 09:33 AM

Re: PCM Tuning 1999 4.0 liter WJ
SCT is available for the 4.0 crowd. I sold my first tuner to a guy with a 4.6 stroker motor in a WJ. I referred him to Josh Bryant. I spoke with the buyer several months later, and he said his experience with Josh was nothing short of excellent. I can also recommend Sean Powell, as I have experience with both tuners. Josh is no longer the tuner for Air Ram but the new guy, Chris, is pretty smart with this stuff. I would strongly recommend going the SCT route over "mail-order flash" tuners.

Does it still throw codes or have they not come back? You should, before seeking tuning, verify that there isn't an actual sensor issue or some other mechanical shortcoming like a vacuum leak.

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