Eric Fullerton

Has anyone ever changed the injectors on a 4.9 with the upper intake in place? I was looking today and it looks possible, not sure though.

justintendo

considering the effort involved just removing the upper intake..it would likely be easier to just remove it and have a much easier time. dont forget a lil vaseline on the new injector orings..

DPDISXR4Ti

I've done an injector swap on a 4.9 with the intake left in place. I'm not sure I saved any time as it was slow and tedious. Perhaps now that I've removed all the A.I.R. stuff it might be a little more feasible and avoid any risk of hurting the gaskets.

Eric Fullerton

What I had in mind, was a test of sorts; I have a set of 19lb 4 hole injectors, I'm thinking they are more likely to work in closed loop than the older 1 hole type, since they react quicker, and more accurately. We have tried this on the V-6 Super Coupe, which has a fuel / air ratio gauge, and in a week it was back to 14ish, the computer had learned them. It is about the same vintage, so likely the '96 4,9 would do so as well. However, if that isn't the case, they will have to be changed back, or another fix applied. My 4.9 is somewhat modded; cam, porting 3" exhaust, and in my opinion it runs a little lean on the highway, it just sounds like a lean flutter. It runs fine, will run 75 smooth as glass. When it is in open loop it seems to have considerably more power, once it goes closed loop it runs okay, but a little weaker.

Chris_1

iTrader: (1)

Once you pull the upper intake once, subsequent times will be a snap.
Just for the sake of being able to get the injectors in properly, I would move the intake.
You'd just need one gasket I think; leave stuff hooked up and just fold it out of the way.

DPDISXR4Ti

19's are a big jump up from stock. I've run 14 pph 4-hole injectors out of a '93 2.3 Mustang and even they ran a little rich. I recently dropped in a set pulled from a '95 4.9 and I'm happy with them.

justintendo

i see..i will be interested in your result. have you tried turning the fuel pressure up some on the stock injectors? i know they are about maxed as it is but may be helpful with different ones as well.
i have the kirban unit...much nicer quality than the junk holley regulator.
the last 4.9 truck have a 2 hole bolt pattern, instead of the older 3 bolt. i ordered the "newer" ford regulator from kirban, having 2 holes. bolts right up. i believe this is the bolt pattern the 4.6 uses..

Eric Fullerton

I doubt you can turn it up much on the 4.9, the expected pressure has to be just about the capability of the pump. You could however, turn down the 19s to somewhere a little north of the stock injectors. That would make the whole thing work. Good info on the newer regulator, the only thing I could find was a write up on putting the 5.0 regulator on the 4.9, and that looked shady at best. So thank you. Don't look for instant action, I'm still planning all this, and it is freezing cold out there.

justintendo

according to my gauge the pump will turn up to 75 psi easy..probably higher..
i have mine set 5 psi or higher than stock spec..hitting 65 with vacuum drop..seems to like a tad extra fuel on stock internal engine. i wanted to get the regulator as at some point my head will be ported with some type of cam in my 96

Eric Fullerton

The cam in my 96 is a Crower 19212, it seems like a good choice, though it never worked properly till I got the proper springs, so the kit is the way to go if budget allows. It was already in there when I bought the truck, part of a fresh rebuild, so I don't know if it is advanced, straight up or what. It has never failed an state OBD2 check, so that's a plus.