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Upgrade 96 to 99+ Intake. Upgrade injectors, too?

BigG

NAXJA Forum User
Location
Michigan
I have searched on this, but have found nothing diffinitive. I am about to undertake a upgrade of my jeep replacing the intake manifold, exhaust manifold, air cleaner, throttle body, and muffler. I currently have a stock 96 XJ. I will be putting in:

99+ Intake manifold
99+ Bored throttle body
APN Exhaust manifold
Donaldson FPG07 air Cleaner
Flowmaster Extreme Offroad Muffler

I have read several threads that mention that the injectors from the two eras of Jeep fire at different pressures. My current injectors are still running great. The whole engine is running fine except for the cracked exhaust manifold.

Do I need to replace my injectors with the 99 model, or will my original ones work fine?

If they need to be replaced, where's a cheap place to get them?
 
OK, after a little more searching, I found this:
This is from Dr. Dyno's site:


Quote:
The following is a list of the injectors used on the 4.0L since 1987 along with their rated static flow:

Model Year, ...Part #, ......Colour, .....Fuel Pressure, ...Static Flow,
'87-'90, ........53003956, ...Dark Tan, ..39psi, .................18.6lb/hr
'91-'93, ........33007127, ...Brown, .......39psi, .................21.0lb/hr
'94-'95, ........53030343, ...Tan, ...........39psi, .................21.0lb/hr
'96-'99, ........53030778, ...Grey, .........49psi, .................23.2lb/hr
'99-'01, ........04854181, ...Blue tip, .....49psi, .................22.5lb/hr

So I have the 23.2lb/hr now. I shouldn't have to worry about replacing them right? Just make sure their clean and replace the o-rings I disturb in transfering the fuel rail?
 
I did pretty much exactly what you are planning to my 96
only difference was i used rustys air tube and a K&N

i swapped th 99 injectors in and it ran like a dog

put the 96 injectors back in and it purrs :dunno:

so you might save some cash and reuse

just replace the o rings
 
Yup. o-rings are on my list. Thanks!
 
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