Aftermarket Fuel Injectors

[X E Ryder]

Another thin to improve has milage is to bore out the TB. I have your same mods plus the 60 mm TB. Gas milage is hovering right around 16mpg. Until now, I have never been able to get into the 15 range. Putting some Ford 700 injectors next week.

True that! I bought a new BBK 62mm TB, slapped it on, pulled my posi batt cable and shorted to the neg and wow it woke up things up and improved my MPG too. If I behave myself I'm getting up to 17mpg and that's mountain/rural driving.

The intake manifold has a 62mm hole in it (when you pull your stock TB you can flip it over to see the carbon ring from the larger intake manifold opening), and the OEM TB venturi's the size down - these bored or oversize TB's let the air flow in the same size passage all the way in. We are port injected anyway, so I can't see the gain of a venturi there; nothing to mix!

Anyway, with the other bolt-ons I did and the 703 injectors my XJ hauls A$$ now. It's not the one mod you do, but the way the sum of the mods work together.
:cheers:

 

[sixty7ss]

I have access to a metal machine shop. Is boring out the TB something I could do myself?

 

[Talyn]

Only the bottom really. You would need a larger throttle blade (which is not just a circle) to go out any further. If you don't want to spend a ridiculous amount on something like the BBK check out Leigh Performance. http://www.strokedjeep.com/

Also, there is no guarantee that the intake hole is 62mm. I had to open mine up a bit for the 62mm throttle body. And a bit more for the 63mm I am now running.

 

[XJCasper]

When I was looking, and am too cheap to buy the available 63 mm TB, I passed. But did eventually find guy on CF that will bore out your factory TB to 60 mm. Much less expensive. That is the direction I chose.

 

[sjkimmel99]

installed a set of 703's from two Neons this weekend.

A couple of screen shots of obdcom output. The first one is to capture the steady state behavior of the fuel trim during a period of 40-50mph. The second has a short acceleration segment.

for comparison added a screen print with data on fuel trim on the original injectors, just steady state driving.

1996 XJ.

second page

.
.
original(stock) injector data

 

[CobraMarty]

It looks like over time it was learning from the short and long term trims.

 

[Cottontail]

A handful of times on this post there was a generic reference to the "4.0 Jeep engine." Is it a safe assumption that these mods will work in other brand models?

I have a 96 ZJ, and 01 XJ, and an 04 WJ that I would eventually like to do this upgrade to. Will the same Dodge JY injectors (703 for the 96 and 784 for the 01 and 04) qualify for these vehicles?

 

[AmnDay]

I think I would use Talyns advice, seems to me he is the only one with actual proof of what he is talking about, at the same time its yours do as you wish. I come here to learn from people with the tools and brains to test and verify data not word of mouth claims or my friends uncles girlfriends brother.

 

[X E Ryder]

installed a set of 703's from two Neons this weekend.

A couple of screen shots of obdcom output. The first one is to capture the steady state behavior of the fuel trim during a period of 40-50mph. The second has a short acceleration segment.

for comparison added a screen print with data on fuel trim on the original injectors, just steady state driving.

1996 XJ. second page original(stock) injector data

Nice datadump! Which scan tool did you use to create the data? This would be outstanding for me to see the results of my tuning efforts. Thanks for posting.

 

[sjkimmel99]

It's called OBDCom (http://www.obdtool.com/software-obd.htm) goes for around $90 including the obdII cable. It's OK but doesn't save settings (like the showing the gauges after a restart) and a few other quirky things but better than a plain code reader/wiper. Only runs on Windows OS, an Android or iOS tablet version would be cool. There are other ones around (OBDScan) Worth doing a little research before buying.

I'd add that the XJ doesn't have all that many parameters (as far as this tool can tell) so you'll still want something like an AFR meter and/or EGT (has anyone installed one of these?)

 

[sjkimmel99]

It looks like over time it was learning from the short and long term trims.

I think the main thing I take away from it is that the trim numbers are not running at -10 or -12 as predicted earlier in this thread. My interpretation is that the computer is able to control the mixture without shutting down the injectors (shortening the pulse width?) too much. It's definitely pulling more fuel out than with the stock injectors.

There are a few places where a -13, -14 or -11 show up in the ST trim but those were when I let off the gas so presumably the computer needs to shut down the injector in a very short time to compensate for the lack of incoming air.

If the computer can control the injectors, maintain an acceptable mixture as far as the O2 sensors are concerned and not throw a code (because it isn't wandering outside the acceptable range) then not sure why this isn't an idea with at least neutral impact. Whether it's a good one (better mileage for me) remains to be proven.

As far as WOT (or opening the throttle enough to put it in open loop mode?) I almost never drive it there anyway so if the default is too rich not sure I care that much. Looking at the LT trim during those periods of open loop (when ST is 0) it's only -.8 anyway. Even on cold startup open loop the LT trim is +3.9 (which could be a lot, can't tell without an AFR gauge.)
On cold startup it takes between 1 and 2 minutes to go into closed loop mode so it's not squirting fuel that long.

In general the performance seems smoother but can't really discern a great difference. I'm hoping the improvement really shows up at the gas pump.

 

[rstarch345]

I'm a little out of my league here, but I do have a question or two about these Ford YR3E-A4A and XF2E-C4B injectors.

1) What vehicle used these injectors/what would they look like (colour?) I know it's been said that Junkyard parts are risky, but if I can't find them elsewhere for a good price this will be the route I'd go.

2) My Jeep is a bone stock 97 XJ with the 4.0 I6 and automatic. I plan on installing electric fans, cowl-mounted CAI, and eventually a cat-back exhaust system. It may be lack of sleep, but IIRC stock injectors flow 23 lbs, and if that's so, would the YR3E be the best choice?

Thanks y'all for the help, I just keep seeing so much info and opinions thrown back and forth, it's really confusing. I'd just like some injectors that'll spray better/atomize the fuel most efficiently. So many say 703's, others say... Well so many other types. IMHO the injector that sprays the closest amount to stock, but with a better spray pattern is what I want.

Paul, let me know how this works out for you. I installed the xx703s in my '98 and the XF2Es in my '00. The '98 performance dropped and the only benefit I found for the '00 was it ran cooler. I went back to OEM and am happier with them. If you don't catch me here, catch me on MyUnibody.

 

[BuckeyeBullet]

Just got a new set of X2FE's and went to put them on my fuel rail. The O-rings seem way oversized for the rail and the intake. Is that because the Ford parts they are designed for are different and I need Jeep O-rings, or do I just need to work them in with a little more effort and/or some kind of lube? I've never worked on a fuel injected vehicle before...don't know much about the systems.

 

[Talyn]

More effort and you need some kind of lube. Lube is not optional.

 

[clean4drxj]

So will the 703's work for my 96 XJ with newer intake/header/borla catback swap, cai, upgreade screamin demond coil/firepower wires and DIY tb bore ?

 

[Talyn]

I wouldn't. None of the mods need an increase in fuel to use an injector that large. Especially that "upgraded" coil. lol.

 

[BuckeyeBullet]

Oh yeah, more spark means you need more fuel! LOL just kidding...

What kind of lube do you suggest for those injector O-rings? Motor oil, light coating of grease, something else?

 

[Talyn]

I use motor oil myself, but some suggest Vaseline. I don't see a problem with oil as it the o-ring will be exposed to fuel, crankcase vapors and oil.

 

[X E Ryder]

What kind of lube do you suggest for those injector O-rings? Motor oil, light coating of grease, something else?

I use a little Marvel mystery oil - things go back together nicely with it and it smells good enough to drink! :thumbup:

 

[my2monkeys]

Do these alternative injectors solve the issue with the OEM Renix era 2 piece body injectors that start leaking atthe body seam?

I had a few of my original Bosch injectors that needed replacing at different times with whatever Autozone had at the time(years ago can't remember the brand).

Picked up a jy set from a donor that were new looking, at least all the same maker.

But they were still the stock style, no "yellow top" for example.

Do you think they will leak eventually?

Old missed match leaky injectors