injector help
There's probably something on here telling me this. But here goes. Got an 89 Cherokee wondering if some injectors out of a 95 would work in it. I know there are differences but would it still swap out.
CF Veteran
Joined: Feb 2012
Posts: 1,249
Likes: 12
From: Hamburg AR
Year: 1995
Model: Cherokee
Engine: 4.0 HO
it would work but not correctly. the older jeeps have different fuel pressure ratings. If he used 703 injectors he would cause his jeep to run Rich. They would work but there are better options.
Op: You would be better suited to using Ford injectors
4.0L
'96-'98 #53030778 23.2lb/hr @ 49psi
'99-'04 #4854181 22.5lb/hr @ 49psi
2.4L
'96-'02 #53030778 23.2lb/hr @ 49psi
'96-'98, ........53030778, ...Grey, .........49psi, .................23.2lb/hr
'99-'04, .........4854181, ...Blue tip, .....49psi, .................22.5lb/hr
Replacement:
Ford Motorsport 19.0lb/hr @ 39psi (Part no. FMS-M9593-C302)
Ford Motorsport 24.0lb/hr @ 39psi (Part no. FMS-M9593-A302)
Ford Motorsport 30.0lb/hr @ 39psi (Part no. FMS-M9593-B302)
Pre 96 the fuel pressure is lower at 39 PSI.
'91-'93 #33007127 21.0lb/hr @ 39psi
'91-'93, ........33007127, ...Brown, .......39psi, .................21.0lb/hr
The Ford injectors are rated at the same pressure, so yes, you can do this as well..... By using:
Ford Motorsport 24.0lb/hr @ 39psi (Part no. FMS-M9593-A302)
'86-'90, ........53003956, ...Black, ........39psi, .................18.6lb/hr
Op: You would be better suited to using Ford injectors
4.0L
'96-'98 #53030778 23.2lb/hr @ 49psi
'99-'04 #4854181 22.5lb/hr @ 49psi
2.4L
'96-'02 #53030778 23.2lb/hr @ 49psi
'96-'98, ........53030778, ...Grey, .........49psi, .................23.2lb/hr
'99-'04, .........4854181, ...Blue tip, .....49psi, .................22.5lb/hr
Replacement:
Ford Motorsport 19.0lb/hr @ 39psi (Part no. FMS-M9593-C302)
Ford Motorsport 24.0lb/hr @ 39psi (Part no. FMS-M9593-A302)
Ford Motorsport 30.0lb/hr @ 39psi (Part no. FMS-M9593-B302)
Pre 96 the fuel pressure is lower at 39 PSI.
'91-'93 #33007127 21.0lb/hr @ 39psi
'91-'93, ........33007127, ...Brown, .......39psi, .................21.0lb/hr
The Ford injectors are rated at the same pressure, so yes, you can do this as well..... By using:
Ford Motorsport 24.0lb/hr @ 39psi (Part no. FMS-M9593-A302)
'86-'90, ........53003956, ...Black, ........39psi, .................18.6lb/hr
CF Veteran
Joined: Oct 2011
Posts: 4,440
Likes: 3
From: Seal Beach, CA
Year: 1996
Model: Cherokee
Engine: 4.0 HO Straight Six
I think what they're saying is you can. BUT. It may run a little rich (as in use a little more gasoline than it usually would) but it would work.
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CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
I've taken a little time to try to figure some of this out. The puter and sensors control the Pulse Width, how long the injector stays open. In the same engine a higher flow injector will get a shorter pulse, relative to a lower flow rate injector. The puter can figure this out based on info from the 02 sensor. Gotta be within parameters though. Your 87 may well use 18.6 LB/hr injectors, so with a higher flow rate you won't ever be too lean. In "open loop", while it's cold and running on a "default pulse width" it will be rich, and being rich won't help it heat up. That said at least a couple pretty smart guys here think it goes into closed loop pretty darn quick.
The 21# from the 95 should be OK, I think.
On a tip from Programbo, I tried the 4 hole Volvo injectors, (and sold my 703's a bit later). So that's below. Below that is some info on rates and pressure and stuff. I'm learning here! So there's that!
https://www.cherokeeforum.com/f2/199...r-swap-163105/
http://www.jeep4.0performance.4mg.com/tech_specs.html
V- I liked my 703's too!- V A great improvement over stock.
The 21# from the 95 should be OK, I think.
On a tip from Programbo, I tried the 4 hole Volvo injectors, (and sold my 703's a bit later). So that's below. Below that is some info on rates and pressure and stuff. I'm learning here! So there's that!
https://www.cherokeeforum.com/f2/199...r-swap-163105/
http://www.jeep4.0performance.4mg.com/tech_specs.html
V- I liked my 703's too!- V A great improvement over stock.
Last edited by DFlintstone; Apr 5, 2013 at 11:46 PM.
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