alpine.adrenaline

Single injector in throttle body; was wondering if anyone has found a different one that'll swap in for the stock replacement? I don't know where to find any information on them, like diameter or pressure ratings. Feel like I've combed the forums pretty well and I'm jealous of you guys throwing Mustang injectors in your 4.0's. I think my only alternative is the adjustable MAP. So... thanks for your ideas!

98 JeepJeep

if its anything like fords old TBI injection they used 2 42LB injectors to feed there V6 motors....however i am uncertain of the Renix jeeps.....

pioneer

yea the gm tb uses these same ones, there are a couple different flow rates to them, i got mine from motorman.com. if you go to 4bangerjp.com there is a thread with injector pa#s and flow rates. iirc i got mine from a gm 4.3. more gas=more power isnt true with these renix systems, cause u have no way to program the computer to compensate, your only option is to build/buy and adjustable map sensor to compensate, ive never tried it though. you could also increase the fuel pressure by taking off fuel pressure regulator housing and drill hole through bottom and tap some threads and stick a bolt through to make what ever pressure u wanna play around with, ive done that on mine. but im gonna tell ya now even then ur gonna be dissipointed, i was, ur best bet is to swap over to a carb such as a webber or something. its less mess than an mpi swap or diff engine swap. and the gain is tons better ive heard. once u go carb u could do alot of internal engine mods. if you go carb call clifford performance and talk to him about internals. u have potential to make your 115hp engine a 190hp engine. which is like having a light weight 4.0. good luck

alpine.adrenaline

Thanks, Pioneer, those are some ideas I've never heard or thought about. I couldn't find the injector specs @ 4bangerjp.com, do you know of a direct link? I've scoured that site it just doesn't seem as supported as this one. What specific injector did you use? I've already started collecting parts for the adjustable MAP sensor and I plan to install it soon but I'm certainly interested in that FPR mod. Do you know of a writeup for this? Finally, I'm hesitant to go carbuerated because I drive my XJ in elevation differences of 6,000 ft. (Denver's @ 5K, home is @ 9K). Heard that thinner air makes a carb useless.

98 JeepJeep

you can throw all the fuel at it you want...if you dont have the air to go with it..your doing more harm than good.

alpine.adrenaline

I've got the air. I'm running lean. Cold air intake in place of stock and a friend is building me a new header to make a 2.5" exhaust worthwhile (none are made for the 4 cylinder). This was the only forum on 4bangerjp.com that I could find regarding the single TBI injector: http://4bangerjp.com/forums/index.php?topic=3563.0

pioneer

dont know how to get the link, if you search 2 2.5l tbi questions ull get whole thread , but i copied and pasted, here are the #s and rates. mine was out of the 5.0L. there is not a writeup on the fpr mod, i just took tb off and took regulator off and drilled through and taped new threads and stuck bolt in with some Teflon tape around it, it works. the factory has a screw in there already, but they covered it with a pressed in piece of pot metal. if ur lucky you can carefuly drill through just enough to still be able to use factory screw, but i wasnt so lucky so i drilled through and through. and to see what pressure ur at just take out threaded plug on side of tb and use a AN fitting that matches threads to your gauge, i use one from harbor freight. and yea carb may not be for u then, different altitudes doesnt make a carb usless, just requires u to re-jet all the time. once u get use to it its no biggie.

The 7747-64 (jeep) Flows 84cc on my ASNU Machine On Test E (at) 20psi. These flow as follows on the same test:
5235203 (4.3l v6)...81cc...47lb/hr.....$34.99
5235279 (5.0l v8)...92cc...50lb/hr.....$34.99
5235206 (5.7l v8)..103cc...55lb/hr.....$39.99
17084327 ( 5.7l cop v8)...112cc...68lb/hr...$49.99 (out of stock)

pioneer

just saw u posted while i was writing, how u know ur running lean? u got a wide band a/f guage? but the header thing was a headache for me, never could keep it sealed, eventually i went back to stock after taking them on and off so much. if you have any problems keeping it sealed i have a graphite gasket i never used, supposed to be good but dont know. i used every other gasket made and still eventually leaked. some say no gasket at all...never tried it either. i got mine from clifford performance and the egr tube wouldnt fit so i cut it and used blue fuel line. keep me posted on your project, i thought i was the only one still running those old 2.5 tbi, haha.

alpine.adrenaline

Alright, so I'm going to buy the 5235279 injector and see what it does.

I took my rig to a local Jeep specialist and he checked it with a wideband (wish I had one but he's a friend who checks it for free) and said it was running a little lean, as I guess these engines do.
I've heard you can get your head and header machined to match better and reduce leaks, but I haven't had any problems yet. My other friend, Casey, is building a new exhaust manifold for me and we talked about machining my head and/or the manifold when he's finished with it.
Is the FPR the spring-loaded valve with the little orange gasket on the side of the TB (closer to the firewall, I guess)? That adjustment screw or pot metal must not be visible unless its on the underside of that thing... Thanks again for your help. Casey and I were also talking about making an aluminum spiraled spacer for the throttle body if you'd be interested. They don't do much for the 4.0 but rumor has it the 2.5 benefits from the sprialed air flow and added space underneath the injector. Trying to keep in mind the space between the throttle body and the hood...

pioneer

yea thats the fpr, but thats no gasket, thats the diaphram sandwiched between, and yea ur gonna have to pull tb to get to the fpr, and yes the plug is from bottom. i would seperate the regulator from the tb before i drilled so no shavings are left in tb. ive thought about making a spacer in the past, but that was one project never finished. i would be interested though, so let me know what ya come up with. back in the day i was gonna use the tb base gasket as a template, but i realized that the gasket is slightly larger bore size than actual tb bore size, so ur gonna have to get measurments from actual tb.