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Motor Swap Question

9

96xjeeper

NAXJA Forum User
Location
Fort Leonardwood, MO
OK Guys my XJ is a 1992 and it has the original motor in it. Well it is pushing 150,000 miles and is running horribly. Well anyway I just got my hands on a 1998 XJ motor that had 80,000 miles on it when pulled and it ran fine. So question is will a 98 motor be a direct swap into a 92?

My plan is to pull my motor and put both motors side by side. Then simply pull whatever parts I need off my motor and put them on the new motor.
 
Shouldn't be anything wrong with that.

Question? Have you tested the engine to determine what the problem is? At 150k a 4.0 is still considered virginal.
 
Not quite virginal(that's less than 100K)--more like middle aged. It'll work just fine--the 98's sensors have different connectors, either use your current tb, distro and sensors(could be why yours is running bad), or chop off the 98's connectors from donor and solder them into yours(after you cut off the 92's except the o2, refer to both fsms to be sure, but wires should be in the same config). The 98 won't have the coolant port in the back of the head to feed your dash temp gauge(really the only issue I see). Use new motor mounts, now's the time to do a new header(or make sure the old one has no cracks) and/or 99+ intake swap, clutch job and pilot bearing(if ax15).
 
Last edited:
I think mine has a bad injector or fule pressure sensor but it has a horrible miss and POURS gas into the oil. When this started I changed a few things out and then changed the oil and the oil was watered down with raw fuel to the viscosity of water.
 
The vintage of the long block itself doesn't really matter although some accessory mounts are different. Instead the real difference is in the computers and the parts they talk to, and sometimes fuel plumbing matters too. Fastest way out is to just unplug the sensors and fuel rail from the existing engine, swap them onto the donor engine, and drive away happy. Try to use the power steering and belt tensioner setup from the 98 since it is superior to the 92 setup and will make it easier to swap in a 99+ intake manifold later if you want.
 
96xjeeper said:
I think mine has a bad injector or fule pressure sensor but it has a horrible miss and POURS gas into the oil. When this started I changed a few things out and then changed the oil and the oil was watered down with raw fuel to the viscosity of water.
Click to expand...

Why not swap in some used Ford orange-top injectors ($20 at the salvage yard) and see if you really need an engine?

What you are describing was a common problem with Bosch CIS fuel injection systems in the days of Yore--the fuel distributor would go bad and one or more injectors would become a fuel dumping HOSE into the engine.

Try some injectors, put some el cheapo Wal-Mart oil in it and fire it up.

If it fixes the problem, change the oil a couple times with el cheapo, then put good oil in it and drive it another 5-10 years.
 
Forgot about the fuel rail difference(92 has return, 98 doesnt). Keep your fuel rail, but use the 98 injectors(esp since you stated fuel in oil from the 92s) w/ new o-rings. 92 has map on firewall, 98 has it on the TB. It'll be easier for you to use the 92 TB--just take out the IAC and clean the whole TB.
 
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joe_peters said:
Why not swap in some used Ford orange-top injectors ($20 at the salvage yard) and see if you really need an engine?

What you are describing was a common problem with Bosch CIS fuel injection systems in the days of Yore--the fuel distributor would go bad and one or more injectors would become a fuel dumping HOSE into the engine.

Try some injectors, put some el cheapo Wal-Mart oil in it and fire it up.

If it fixes the problem, change the oil a couple times with el cheapo, then put good oil in it and drive it another 5-10 years.
Click to expand...

What injectors would I put in it? are the a direct swap? I can get 6 stock replacement injectors for $100 but if your saying $20 for 6 thats worth a shot.

Also could it be the fuel pressure regulator?
 
ehall said:
98 injectors will not work correctly with 92 ECM
Click to expand...

Correct. While they might plug in and it might run, it be delivering a wrong amount of fuel and would be running pig rich. The 92 uses 39psi and 21lb injectors while the 98 has 49psi 23.2lb injectors. The injectors need to match the electronics being used in order for A/F ratio to be correct. You will need to use the original injectors or new ones that are the same. (Ford 21ish lb injectors if you wish to go that way) As stated the fuel rail is different so you need to use the original rail which may or may not fit without modification. I don't know anything about any MAP differences, but all the original sensors must be used, AFAIK the TBs are the same 91 and up so the map hose should work. Use all the 92 sensors from the intake (MAP, MAT) and elsewhere.

I suppose you could swap the head and intake from the 92 over to the 98 and not have to worry about anything intake/fuel rail related. The 91-95 head is supposed to be the best one anyway. There is a series of potential problems that doing this would avoid, including the temp sensor in the head which went away at some point over the years(dunno when).
 
joe_peters said:
Why not swap in some used Ford orange-top injectors ($20 at the salvage yard) and see if you really need an engine?

What you are describing was a common problem with Bosch CIS fuel injection systems in the days of Yore--the fuel distributor would go bad and one or more injectors would become a fuel dumping HOSE into the engine.

Try some injectors, put some el cheapo Wal-Mart oil in it and fire it up.

If it fixes the problem, change the oil a couple times with el cheapo, then put good oil in it and drive it another 5-10 years.
Click to expand...

OK I concide. I swapped in injectors today and jeep is running like a champ
 
Glad you got it running.
 
Glad you got it working. The 98 23.2#@49psi injectors used on a 92 39psi rail will flow 20.7#(the pcm would have to add a little to compensate compared to the stock 21#, so no it won't be a pig). I've used my 96s 23.2s in the 95 I just sold and it was fine.
 
This is an old list of Ford injectors, so it may not be complete:

Lbs - Color

12's - Gold top
14's - Blue Top - E3EE-BA ( Low Impedance )
14's - Gray top -
16's - Blue - E43E-AC ( Low Impedance )
17's - Creme/white top ( Low Impedance )
19's - White - E6EE-AB ( Low Impedance )
19's - Orange/Yellow top -
19's - Gold
19's - Yellow/Black
21's - Lavender - ( EV6 )
22's - Pink top ( EV6 )
23's - Black - E4EX-BA ( Low Impedance )
24's - Light bluish/gray top -
25's - Blue/Green -
25's - Light blue ( EV6 )
30's - Dark Red top -
30's - Green - E3ZE-BA ( Low Impedance )
35's - Brown top ( Low Impedance ) -
36's - Cobalt blue top ( sometimes silver )
37's - Green- E3VE-A1A ( Low Impedance )
39's - Blue ( EV6 ) ( thin style ) -
42's - Lime Green top -
46's - Blue - EOSE-A1A ( Low Impedance )
52's - Gray - E43E-AC ( Low Impedance )
56's - Blue - E43E-AC ( Low Impedance )
64's - Green - E53E-AB ( Low Impedance )
150's - Bright Orange top ( Low Impedance )
 
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