Very detailed. Thank you!. FYI - Petroleum jelly will degrade rubber over time causing it to harden and crack, a silicon grease is a better option for lubricating o-rings
Just bought a 98 about 6 months ago. About to tackle this, replacing exhaust manifold and head gasket this weekend. Super high quality video, please keep them coming. I'm subbed.
I used k suspension 12 ports.. I sea foamed before hand did a tune up then changed them out post ecu reset and relearn I got about 14 to 16 mpg on 3 inch lift with 31s and a roof rack and trunk full of tools after adding a BBK throttle body and cold air I got about 17 running cruise control I’m happy with it mpg changes all the time so this was under best conditions
nice video - well, several opinions about 4 hole injectors - fuel pressure and pulse width are given values - change in fuel economy and performance are not really noticeable.
I get 13-14mpg on worn 33's with 4.88 gears towing a trailer. Stock injectors. The roof rack and lights must be really killing your mpg. I see others suggesting ideas to improve mpg. One not talked about a lot would be to install locking hubs. Allows you to diconnect the wheels from the drive train so the front drive train doesnt move when going down the rd in 2 wheel drive.
@@JeepinJimmythe 4.88 to 1 gearset has a really skinny pinion gear skinny to the point it becomes weak. 33in and 4.56 to 1 is known to be a great combination for power and efficiency and the pinion gear is still a massive chunk of metal
One issue you haven't addressed is your fuel filter. I've got a '93 ZJ with 123K and changed mine out at approx. 120K. The amount of black silt that poured out of the old filter was scary - I can only imagine the residue left in the tank itself. As everyone is probably already aware - • If your fuel filter gets clogged, it can reduce the flow and weaken performance as the engine has difficulties drawing fuel. • With a clogged filter, the fuel pump works much harder and you may have problems starting the car or notice poor acceleration or stalling... Because of its abrasive action, dirt and contaminants in the fuel can speed up wear and tear, damage expensive parts and even cause the fuel pump and injector to fail. • For most cases, the fuel filter needs to be replaced every 20,000 to 30,000 miles. • A clogged fuel filter can cause decreased fuel economy. I went from an average of 13-14mpg to 16-17mpg, just by changing the filter - even though I've been driving it a little bit more aggressively on the freeway. They're less than $20 for the 4.0 liter Jeep vehicles - some are less than 10 bucks. So, if you haven't changed yours yet, it may make a big difference in all around performance and fuel mileage. Thanks for sharing this content with us. - I Subscribed to your channel. 👊
I also have a 93 ZJ and did the 12 hole K-Suspension Injector upgrade about 1 1/2 years ago , I used the little adapters Instead of directly wiring in the new pigtail clips. Last week I ordered the new pigtail adapters and wired those into the harness , A night and day difference in how my little jeep runs now. Those adapters always were loose so I'm sure my injectors were misfiring Off and on at times. I also changed my fuel filter, which is an external filter on the drivers side by the rear tire above the axle, mounted to the chassis area. I have 127526.5 Miles on the little in-line six and she runs like a dream. But unfortunately my torque converter failed and ended up burning the transmission so I'm now replacing it as I write this comment, I certainly do love my little Jeep and can't wait to get her back on the road. Anyway, you're right about the fuel filter needing to be changed and diligently monitored, with today's fuels and all the additives and re-formulations of ethanol It's almost like the industry is quietly sabotaging gasoline engines all together. Stay safe brother and thank you for posting. Danny in Texas.
Man buddy you were doing such a awesome job right up to the point you used “Butt” connectors for the new wires🤷🏻♂️. Ya gotta know you are supposed to solder those wires and use heat shrink to protect the connection. But hey to each his own👍
Solder is actually known to get brittle over time and is less flexible than the original bundle of wire, in most automotive applications it's recommended you use crimped connectors with heat shrink that has glue inside it, especially in tight areas that experience high heat.
I’d shy away from soldering. High dollar heat shrink crimp connections with at least one or two layers of heat shrink tubing. It was probably my own idiocy trying to solder FI ends on, but I fried the ECU. I know I jacked up the soldering… but I wanted to use crimps and got talked into soldering …. Anyhoo. Peace
I don't solder those wires. I crimp connect, then paint with liquid electrical tape, then heat shrink. Same with my boat trailers. Unless the wire harness is subject to motion, like the harness that runs into the drivers door for the master window/lock panel, it'll never break.
You can lightly coat them using a qtip but I wouldn't recommend it. Jelly will start to liquefy on skin Lnn so anything above 98 F (like in a motor compartment) will end up dripping everywhere.
Hmm my 96 gets 16.5mpg (18.2 hwy) and it's 236k mi, only thing done was the accel tune up kit. I keep going back and forth on doing the 4 hole injectors. But might finally do it, chasing the 18/20mpg.
Thanks for the video, I was surprised you only got a half mile improvement, I was expecting a lot more than that and 12-13 MPG with a 6cyl isn't very good, I thought those Jeeps got about 16-18 avg.
You mentioned heat soak at the end of the video, and it appears you do not have any type of intake manifold/injector heat shield. A company (Design Engineering) sells a heat shield kit for the Jeep 4.0L engine that protects manifold, fuel rail, and injectors from heat. For later TJs/XJs there is also a Mopar intake manifold heat shield (but to my knowledge no Mopar, fuel rail, nor injector heat shields). Also, please, what purpose do the cables running from your roof rack to your hood corners serve? Thx.
Should have got new pins and connectors. Those butt connectors are the worst. Atleast get the non insulated type crimp them with an actual pair of crimpers and heat shrink it...
The Chinese Bosch injectors are junk! I tried a set on my 2001 XJ and one was bad when I put it in. Withing days another failed. I pulled them all and put in a set of OEM injectors. The Chinese Bosch fuel pumps are also trash. "Botch" has never been a good brand in my experience. I didn't name then "Botch". That was an accepted description way back in the Sixties.
Im assuming you're using stock gears? If you have a larger tire than stock nothing and i mean nothing will improve power and economy more drastically than regearing the differentials. 4.10 for 31in tires 4.27 for 33in tires 4.56 for 35in tires....to compensate for the extra rolling resistance and leverage of the lager tire one could decide to go a little more aggressive ie 4.27 for 31in, 4.56 for 33in, 4.88 for 35in. Btw according to the xj forums 33in with a 4.56:1 gearset seems to be the magical combo netting somewhere usually above 20mpg. Nice jeep👍
