4.9 injector swap
#1
Senior Member
Thread Starter
4.9 injector swap
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.
#2
Senior Member
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..
#3
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.
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Eric Fullerton (12-15-2017)
#4
Senior Member
Thread Starter
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.
#6
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.
#7
Senior Member
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.
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..
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Eric Fullerton (12-16-2017)
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#8
Senior Member
Thread Starter
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..
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..
#9
Senior Member
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.
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
#10
Senior Member
Thread Starter
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
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
Last edited by Eric Fullerton; 12-17-2017 at 09:49 AM.