So, just curious: the NA (port injection) injectors on the 4.2 are four port. Some injectors on the X100 seem to be 12 port.

Why the difference?

And assuming it's possible, is there any merit in using a 12 port in place of a 4 port?

Wouldn't it cause better atomization? And would the ECU stoichiometry loop adapt to a 12 port injector?

Thanks!

 

Some research came up with this. 4 on the left, 12 on the right.

 

That's a massive difference!

 

I've never seen 4 hole injectors for the xk100 4.2 (aj33) they should be 12port 21cc and they also come in the aj41.

The later 4.2 (aj34) also came with 12port however a higher flow being 25cc.

 

Well, I replaced the port injectors on my '07 4.2 NA (naturally aspirated) with 80K mi. Used remans from Injector Planet, which turns out to be a small business near me, in Pompano Beach FL.

Kind of an unfriendly website (clunky), but seems to be a good product. This model number is Denso 0480. Also FoMoCo 6R83-AD. Injector Planet say they only use original OEM remans, never knockoffs.

And I don't know what they do with Direct Injection products. Anyway, their product appeared well rebuilt, and works like new in the X150.

Injectors cost me $38 each after a $10 credit for the old cores. Reman means they take them apart and flush them, clean ultrasonically and flowtest. Of course, new gaskets, pintle cap and filter.

Here's what five of the originals looked like. My guess is that the PO used some really crappy gas, or perhaps that's what Denso's look like after this mileage. Don't have anything to compare it to.

Idle went from slightly rough to absolutely smooth. Very noticeable. Painless to do, detailed in https://www.jaguarforums.com/forum/x...4-2-na-245778/ Remember that Direct Injection injectors are much more complex to replace than these port injectors.

These were NA injectors. I don't know if the 4.2 SC uses similar. But, 4 port all the way across, which is what JLM used on the Naturally Aspirated 07-09 X150.

I'll keep the forum posted if I run into any problems on the reman units.

 

EDIT: Figured out the 4 vs. 12 port, at least on Naturally Aspirated X150.

So, could likely get a 12 port for the SC and put it in a NA, but no clue on what it would do.

From Injector Planet's site (note core credit of $10)

Supercharged: 12 port.


and NA, 4 port:

 

OK, my last observation in this thread.

Over 70K miles, and if you DIY, it's probably worthwhile to pull your injectors and have them professionally cleaned and remanufactured.

There are quite a few places that'll do them for you for a very reasonable price ($35-40 per). Very common in the marine and diesel area.

It's convinced me that, while Techron (etc) is helpful, the only way to really get them clean is to have them redone.

Again, I don't know about the 5.0, but the 4.2 is exactly like the manual. The NA was easy (about a half-hour to remove, 60 min to reinstall, because I DIY very carefully).

According to the Manual, the SC is considerably harder because you have to remove the coolant manifold, Throttle body elbow, supercharger and charge cooler.

Anyway, hope this helps some of you.

Panthera

 

Well, port injectors need about 50 psi while GDI injectors need 2000 psi or more. Yeah, they a bit different.

 

Kind of interesting that the 4.2 XKR used only a port injection system. And as far as I can find, it used the same fuel pump at 55 psi operating. Only difference seemed to be the 12 port. Still got 390 hp out of it, though.

Of course, the 5.0 used GDI etc.

 

How bizarre they reverted back to the 4 port injector for the aj34 when the aj33 was a 12 port .

I didn't even bother to check how many holes were in my injectors when I had my engine apart I just presumed 12 port well nevertheless they do flow more 25cc vs 21cc then then first series (aj33) of 4.2 and the (aj41) 4.4

Good pick up panthera

 

What do you think would be the effect of installing the 12 port in the current engine? Appears to be physically identical.

 

We can't put the aj33 12port in as they flow 20% less and can't see the ecu compensating (without a tune) for the drop in cc.

However if you could find 25lbs in 12port that would work

Whilst I can't see a huge increase in power if any at W.O.T I could definite see a improved idle, greater smoothness through the entire rev range , lower emissions and better fuel mileage all due better atomization .