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Electronic Variable Orfice power steering

A

Acesneights1

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I apparently have this on my Burb. I'll ask that a mod move GM Guys explanation of it to this thread from my motor mount thread so we can discuss it more. My old 2000 had a recall on the power steering Pump. I notice the PS pump on my burb has been replaced as well and looks like the dealer did it but it appears to be leaking from the EVO. Also I notice my brakes feel spongy at times particularly first few miles in the a.m. I wonder if this is why ? How can it be eliminated ? It looks like I would need a different fitting on the back of the PS pump and a different line. Has anybody taken theirs apart ? Mine is leaking. It ruined my motor mount, a job I do not wish to do again.
I'm gonna call the Chevy dealer. If it was dealer recall they would have been the ones to most likely fix it. Anybody know how to check for recalls online ?
 
Last edited by a moderator:
aces, that weird deal is the EVO system. Electronic Variable Orfice. 98 was the first year of it. most rebuilt pumps leave it off, but I checked at the local GM dealer, and they sell a brand new (presumably, as the system didnt say reman, rebuilt, etc) pump with the EVO installed for under 200. I dont think the EVO can be bought seperately.

I am getting educated on the EVO, as that is why I dont have shit for brakes at times. I think AK dieseldriver was the one that said unplugging it at the steering shaft sensor (in the cab) will disable the whole thing and make it work like any other PS system.

I think the whole purpose of it is to reduce steering effort at slow speeds, and firm it up at road speed. one more thing we could have done without IMHO, along with passlock.
 
Acesneights1 said:
Yeah, I'm not sure why they replaced the PS pump on my 2000, but it was free...:D
Click to expand...

gotta love free. The EVO started in i believe 97. my 96 doesn't have that crap. I can steer just fine, although the original PS pump does whine due to the Lucas I put in there. The entire system leaks enough to make the pump and steering box wet but nothing on the ground. I've just dealt with it since i bought it.

Leaks much less with the Lucas, and the steering is super smooth. So smooth in fact that i added a little bit of the Lucas stuff to the K-5s steering long ago. Again, nice, smooth, effortless steering.

Wonder what idiot came up with the EVO idea at GM? It sounds like a disaster waiting to happen to me.
 
His thread didn't specify if I could just swap a different pump on. he swapped the pump and box if I read it correctly. So if I put an older pump on it weird stuff may happen to the steering box ?? Ugghh. There should not be electronics on steering period. Might send this one off the Craigslist soon too. Has anybody actually taken an EVO off the pump ? Mine is leaking and I don't know if that means it's bad or just needs someking of seal. At a glance it looks like it's held on by a snap ring and can rotate ?? What stupidity.
 
Kenny the EVO is probably sealed by an O-ring. Odds are it's just dried out and cracked after all these years.
 
I don;'t want to take it apart until I know what's in there and if I can get it...:D
I'll swing by GM tomorrow and see if they have a pic.
 
the power steering box is the same as other years only diff Simon and I could find/figure was the pump and the sensor at the bottom of the column. We dissassembled the box that came out of his 98 and couldn't find anything out of the ordinary. It was all mechanical with hyd assist so the only thing the pump could do is vary pressure/volume. The wiring is all controlled in the passlock box
 
Did he take the EVO apart ? What is in there that could be leaking ? It ruined my motor mount and is making a mess under there.
 
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