power steering sensor needed? O2 sensor?

Zorm · 01-15-2008, 02:18 PM

Ok, doing the 92 engine swap in to the 89 and I had to buy a new presure power steering hose. Well the YJ I got the engine from was hit on the drivers side front so the sensor that is on the power steering pressure line right benind the pump is broken. Do I really need that sensor connected? I can just plug where is screws into right?

Also, the exhaust is from the 89 engine that did not have the O2 sensor, do I really need to connect that for the 92 engine/ecm? Won't I just run rich maybe?

I swaped out the complete engine and in cab wire harness from the 92 also, so all the wires, ecm and engine are 92 (2.5L)

**Big-n-Broke-YJ** · 01-15-2008, 04:43 PM

the ps pressure switch should bump up the idle when needed.....

the o2 sensor isn't NEEDED but the engine will run rich and aside from smelling like raw fuel, running crappy, and ruining your already crappy gas mileage, you will eventually cause internal engine problems from fuel wash on the cylinder walls.... not immediatly... but eventually.... an o2 sensor bung is a buck or two on summit racing's site, and o2 sensor is $25 or so.... weld it yourself if you have a welder... if not, just go to a small local muffler shop or performance shop and tell them you need an o2 bung welded into your header.... no biggie at all....

-Erik

Zorm · 01-15-2008, 05:59 PM

cool, thanks, I know I may need the O2 sensor, just did not know about the ps pressure switch.
I need the first part of the exhaust pipe anyway, where it bolts to the manifold, that flange thing is almost rusted off, bad thing is the PO welded the whole wxhaust pipe from front to back.

KrwlinYJ · 01-15-2008, 06:15 PM

the pwer steering pump pressure switch is used only to turn off your ac compressor, when you are turning your jeep.. It is used to help with engine power so that when the ac is running and you turn, you dont drop the rpm of the motor too low and possibly stall the motor.. So if you are not running ac in your jeep then you dont need it, otherwise if you are , then it would be a good idea to put it in... I hope this helps..

**Big-n-Broke-YJ** · 01-16-2008, 05:24 PM

Quote:

Originally Posted by ALLDATA

This switch senses the pressure of the power steering system and works in conjunction with the ECU to adjust the engine rpm when the engine load is high and the rpm are low (i.e. when the vehicle is being parked).

When the power steering system pressure exceeds 1896 kPa +/- 172 kPa (275 psi +/- 25 psi) the ECU will increase the idle rpm via the Idle Speed Actuator (ISA) Motor so that the engine will not stall.

The power steering pressure switch and A/C control output lines are routed together to the ECU. This means that the idle speed will be raised, via the ECU and ISA motor, if the A/C is turned on and/or if the power steering system pressure exceeds 1896 kPa +/- 172 kPa (275 psi +/- 25 psi).

that was for my old TBI 2.5 engine..... which makes perfect sense b/c that jeep didn't come with a/c and still had the switch... and the idle was definatly effected when dry steering..... ALLDATA doesn't give a description of operation for the 92 4.0 like they did for the 89 2.5 for some reason, but i can't help but think it would be exactly the same....

-Erik

pat8942 · 01-16-2008, 06:50 PM

I could be wrong but I don't think the 4.0 was equipped with the P/S pressure switch
I checked the wiring diagram and no P/S switch for the 4.0

Quote:

Originally Posted by Big-n-Broke-YJ

that was for my old TBI 2.5 engine..... which makes perfect sense b/c that jeep didn't come with a/c and still had the switch... and the idle was definatly effected when dry steering..... ALLDATA doesn't give a description of operation for the 92 4.0 like they did for the 89 2.5 for some reason, but i can't help but think it would be exactly the same....

-Erik

**Mr.B** · 01-16-2008, 10:13 PM

Quote:

Originally Posted by pat8942

I could be wrong but I don't think the 4.0 was equipped with the P/S pressure switch
I checked the wiring diagram and no P/S switch for the 4.0

X2

I don't have a 4.0, but I remember reading that.

Zorm I'm sure you don't need to plug it in.

mdo817 · 01-17-2008, 12:34 AM

I changed a 2.5 to a 4.0. I still have the switch but there is nothing in the 4.0 harness to hook to it.

Zorm · 01-17-2008, 08:06 AM

mdo87, want to sell that switch?

Thanks for all the input, sad thing is, since this is going to be the wife's ride, she wants A/C, heck I told her to just take the top off (not hers) and drive like that. She still wants A/C. I was going to put in an old system I got out of one of my mustang projects (66 coupe) and just use the Jeep compresor, but after the info on the idle, ps, and A/C, I might need to find a Jeep 2.5 A/C system? Maybe I can still talk her out of it, depending on the price.

thanks again gentlemen!