Could it be heat soaking causing the failure? I mean, yeah, it's still early early spring, but blah blah blah reverse flow head…

I went ahead and ordered the insulator kit as insurance against that for the Utah summer: top-of-the-intake shield, fuel rail wrap, injector wraps. ~$57 on amazon.

 

“same as it ever was, same as it ever was, same as it ever was!!!!!

 

Unless your budget is really tight, I wouldn't replace just one or 2 injectors. Typically you would replace all 6. There could be build-up on the older injectors. On my '87, the 4-hole were night and day difference. Not sure on a 97 but the 2 piece design will eventually leak and then you would be left with 2 new injectors and 4 that could start leaking. Just my opinion.

 

Budget isn't that tight, but I'd rather spend $300 on a locker or winch or something

 

So you cheaped out on eBay injectors and you are paying the price.

That really isn't a 1-hole vs. 4-hole issue. I did the swap, and I noticed an immediate improvement in fuel economy and starting. Yes, I found it was worth it. YMMV.

 

I was sure hoping someone would catch that reference!!

I guess my comment oddly fit the situation even if the reference wasn't noticed. lol

 

i did the swap and didn’t notice anything. i got the kneeon injectors from the junkyard, they perform fine. my old ones were ok, as well. i only had $40 in those injectors so it’s whatever. in theory the 4 holes are superior, but i think a lot of what we can’t see determines how well the fuel atomizes. i presume the stock 1 holes spray the fuel directly into the intake valve stem to break it up. clearly that process works just fine. idk how much an engine like the 4.0 would benefit from “high performance/high efficiency” parts.

 

 

Assuming you did the "reset the ECM rain dance"?
Genuinely curious; not trolling.

On my otherwise stock '96 I noticed an immediate low-end get-up-and-go. The throttle response was sharper, too.

Took a while, but eventually the MPG normalizes. During the 50 or so warm up cycles after an ECM reset it drops...a lot. I was getting maybe 12 city.

Besides just getting my 98 back together and running, I'm curious to feel and hear what this swap will do with a less constricted header and front pipe as well.

 

yes. i did the swap several years ago and the ecm has been reset several times since, as well. mileage the same, everything the same as before. the only mod i’ve done and noticed an immediate difference is the bored throttle body. i installed a 62 mm piece and it feels like the jeep picked up 50tq down low and throttle response is quick as hell.

 

Not to argue but I don't really think what you did is really a test of 1 hole versus 4 hole. You're comparing some old stock single hole with some old 4-hole injectors from the junkyard? Really?
There's not really all that much theory involved here. More efficient atomization results in better fuel/air mixture. That's what ignites. It doesn't hit something hot first to vaporize.

 

yes, that’s my comparison. should we be comparing old 1 hole to new 4 hole? typically fuel injectors will spray up against something hard to break up and thin out the fuel to accommodate atomization. i’m not arguing that 4 holes aren’t better than one, i’m simplying saying (stock 4.0)...given the dynamics of the cyl head - there is little if anything to be gained. the jeep got 22 mpg before and after the swap. i didn’t notice a change in cold or hot starts. honestly it has ran very good in all aspects since the day i brought it home, 110k miles ago.

 

What happens if you give it a little excitement?

 

That's on the shortlist of mods for the next 1–5 years.

 

it hurt my mileage during the “driver adjustment” phase. during normal driving it now accomplishes the same rate of acceleration as before, but it only takes 1/3 the pedal. breathe on the gas pedal and it’s jumping up and going.