Steering difference between 2 1999 Suburbans pretty drastic

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redfishsc

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I have 2 1999 Subs, both are the same truck except one is a RWD and the other is an Autotrac 4wd.

Both are 1500's, 5.7 with 4l60e, with 215k/231k miles.

Front suspension on both are bone stock.

The C1500 is ridiculously overboosted in its steering. Steers easier than my old 85 Riviera. At highway speed, that's freaky. Not twitchy. Just constant overboosted

The K1500 is just right. Feels tight and responsive in turns.

The only difference is that the K1500 has a new PS pump (O'Reilly brand with the EVO bypass hose). The C1500 has the old EVO still intact.

Both have new ps fluid.

Is that EVO bypass really the thing making the difference?
 

98chevy2500SS

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Now this is getting me interested as mine is very easy to turn, like your C1500 Burb. I would like it to be like your K1500 Burb as you mentioned.
 

Cokeman95

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The Evo is likely your issue here. My 99 K1500 Suburban was incredibly twitchy at highway speeds until I bypassed the Evo.

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redfishsc

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Did it make the steering firmer (more feel of the road) or just remove the twitch?

My C1500 doesnt really twitch any, just has no feel of the road. Overboosted and numb.
 

someotherguy

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Is that EVO bypass really the thing making the difference?
Yes, but because the EVO is not working correctly on the other truck. It's going full boost when it should not. EVO is only supposed to increase boost at low speeds to help maneuvering like during parking. A feature inspired by soccer moms that were bitching about steering being difficult trying to cram a Suburban into a space...IMO, anyway. Go ahead and delete that crap.

Richard
 

df2x4

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It's the EVO sensor on the steering column. It's gone out in both of my trucks at least once. Causes exactly the symptoms you're describing. Overboosted steering that feels borderline unsafe above 40-50mph. If you want a cheap fix that will last a while you can just replace that sensor.

Thanks for posting this though as it confirms a theory I've had for a long time. I had a conversation with someone on here who was of the belief that the EVO bypass had the exact same effect on steering as just unplugging that sensor. I couldn't see how that would be the case, and I'm glad it's not! Now I'm interested in the EVO bypass for both of my trucks.

EDIT - Here's the sensor I'm talking about. Not sure why they're so expensive on Amazon right now, but that's the correct ACDelco part number. 26064468.

https://www.amazon.com/dp/B00GV8PRNK
 
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Bear 77

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It's the EVO sensor on the steering column. It's gone out in both of my trucks at least once. Causes exactly the symptoms you're describing. Overboosted steering that feels borderline unsafe above 40-50mph. If you want a cheap fix that will last a while you can just replace that sensor.

Thanks for posting this though as it confirms a theory I've had for a long time. I had a conversation with someone on here who was of the belief that the EVO bypass had the exact same effect on steering as just unplugging that sensor. I couldn't see how that would be the case, and I'm glad it's not! Now I'm interested in the EVO bypass for both of my trucks.

EDIT - Here's the sensor I'm talking about. Not sure why they're so expensive on Amazon right now, but that's the correct ACDelco part number. 26064468.

https://www.amazon.com/dp/B00GV8PRNK
Glad you pointed that part out, thought was the piece on the rear of the power steering pump.


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someotherguy

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When I bought the '98 C3500 crew wrecker with the Frito 19.5's (8 lug direct-bolt) and some seriously bald tires, and stupid bad ball joints, I had to drive it home 400+ miles. What I didn't know was that the wires to the back of the pump had really messed-up insulation and had shorted against each other. That was the most white-knuckle trip I've had in recent memory. I held the steering wheel with literally the tip of my index finger and thumb; the slightest input to the steering would have me switching lanes or aiming for the ditch.

Once I got it home and started cleaning up the disaster of a wiring harness, I noticed those particular wires and repaired them, which made a big improvement. Front end wear was obviously still a huge problem but at least the truck was no longer literally dangerous to drive.

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What a POS that truck was...but it served its purpose!

Richard
 
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