Driver side motor mount - how much movement is too much

[nayborbob]

How much should this mount allow the engine to move? Mine seems excessive and I think it might be causing intermittent electrical issues in a wiring harness, leading to a bunch of electrical faults that seem to occur when engine acceleration causes the engine to move.

2013 Yukon SLT 5.3 TEXAS edition

 

[Charlie207]

Doubtful it's causeing any electrical issues, unless the entire engine is moving 12" off the mount, and smashing through the hood. There's plenty of slack in all the cables that matter.

Have you put eyes-on the mount to look for leaking fluid?

Have you slowly revved the throttle in Drive, with your foot pressing firmly on the brake pedal, and watched the engine move? (Use a buddy or just look under the gap of the raised hood.)

(What is Texas Edition? Does it break down when the temps drop too low?)

 

[mikez71]

How much should this mount allow the engine to move? Mine seems excessive and I think it might be causing intermittent electrical issues in a wiring harness, leading to a bunch of electrical faults that seem to occur when engine acceleration causes the engine to move.

If you can see upward movement on the motor, it's probably too much movement.
Especially since the mounts are known to fail, and the driver side goes first.

This is too much.. and if you watch the video long enough, he does reverse which looks about normal.

Broken Motor Mount Test?

Had my Yukon in gear sitting still with my left foot on the brake and gave it some gas with the right foot. Felt like the left side of the vehicle jerked upward when hitting the gas. My wife is too afraid to do this while I look under the hood so I am not positive.

www.tahoeyukonforum.com

What kind of electrical issues are happening? Maybe corroded battery cables?

 

[nayborbob]

If you can see upward movement on the motor, it's probably too much movement.
Especially since the mounts are known to fail, and the driver side goes first.

This is too much.. and if you watch the video long enough, he does reverse which looks about normal.

Broken Motor Mount Test?

Had my Yukon in gear sitting still with my left foot on the brake and gave it some gas with the right foot. Felt like the left side of the vehicle jerked upward when hitting the gas. My wife is too afraid to do this while I look under the hood so I am not positive.

www.tahoeyukonforum.com

What kind of electrical issues are happening? Maybe corroded battery cables?

The engine was moving 2+ inches acceling in drive with foot on the brake. No such movement in reverse. Removed drivers mount last night (PIA!), confirmed the mount failed. Will update effect on electrical issues after I drive it a while. Fault codes were b2555 passenger compartment lamp control circuit short to battery, c0900 device 1 voltage high, c0253 centering error , b3782 air flow control 10 feedback circuit short to ground, b0413 temperature control 1 feedback circuit open. I think every time stuff happens it's on engine acceleration...we will see

 

[mikez71]

Check your battery cables for tightness and corrosion!

All codes cleared and all come back?

 

[nayborbob]

3 hrs driving after replacing motor mount, including 2hrs pulling my boat, and seems the problem is solved. Thanks to the AutoZone sales person for the tip!

 

[Doubeleive]

I would suspect if the motor movement from a bad mount was causing a electrical fault then it is just a matter of time before it comes back even with a new mount
like bending a small piece of metal with your hand back-n-forth until it breaks in half. unless you fixed the connection otherwise.

 

[mikez71]

3 hrs driving after replacing motor mount, including 2hrs pulling my boat, and seems the problem is solved. Thanks to the AutoZone sales person for the tip!

... unless you fixed the connection otherwise.

Did you happen to remove and re-install the battery cables?

 

[nayborbob]

Did you happen to remove and re-install the battery cables?

I did not. Battery was new AGM in 2024 and I cleaned contacts then. There is a wire harness on the bottom of the engine that runs close to drivers motor mount and it did look a little contorted. I will have vehicle on a lift at the end of the month to replace shocks and struts, and will look at it more closely then

 

[nayborbob]

I would suspect if the motor movement from a bad mount was causing a electrical fault then it is just a matter of time before it comes back even with a new mount
like bending a small piece of metal with your hand back-n-forth until it breaks in half. unless you fixed the connection otherwise.

I was worried that maybe damage is done and that fault might return... Fingers crossed, but I will look at it next time I get it on a lift..I will post pic of the wire near the mount if I remember how do I turn on notifications when someone replies or comments on my thread?

 

[PG01]

I was worried that maybe damage is done and that fault might return... Fingers crossed, but I will look at it next time I get it on a lift..I will post pic of the wire near the mount if I remember how do I turn on notifications when someone replies or comments on my thread?

On phone or computer? On my phone i can click on my profile pic and i can see everything about me…look for preferences and set what you want

 

[Doubeleive]

I was worried that maybe damage is done and that fault might return... Fingers crossed, but I will look at it next time I get it on a lift..I will post pic of the wire near the mount if I remember how do I turn on notifications when someone replies or comments on my thread?

in the top right hand corner of your thread title, there are a couple buttons that you can choose to watch/watch and get a notification, unwatch, etc
if you want to tag someone it is the same process as basically anywhere @ followed by the usename @Doubeleive

 

[Fless]

I was worried that maybe damage is done and that fault might return... Fingers crossed, but I will look at it next time I get it on a lift..I will post pic of the wire near the mount if I remember how do I turn on notifications when someone replies or comments on my thread?

In addition to the selections in your account Preferences, you can watch any thread (as indicated by @Doubeleive). To watch a thread, open it and go to the top of the thread page and click on the Watch link, then make your selection:

 

[nayborbob]

I would suspect if the motor movement from a bad mount was causing a electrical fault then it is just a matter of time before it comes back even with a new mount
like bending a small piece of metal with your hand back-n-forth until it breaks in half. unless you fixed the connection otherwise.

Well, I'm afraid you were right. It came back again pulling the boat last weekend. This time the door locks all toggled lock-unlock continuously for a minute, the gages all swept back and forth, the transmission bucked...I pulled over and shut the vehicle off. After a minute I restarted it and it was fine the rest of the way home. Pics below are the wires I think got stretched? I guess I need to look at them more closely, figure out what they are and if I should replace them...dang!

 

[Doubeleive]

Well, I'm afraid you were right. It came back again pulling the boat last weekend. This time the door locks all toggled lock-unlock continuously for a minute, the gages all swept back and forth, the transmission bucked...I pulled over and shut the vehicle off. After a minute I restarted it and it was fine the rest of the way home. Pics below are the wires I think got stretched? I guess I need to look at them more closely, figure out what they are and if I should replace them...dang!

I would check for any wires that have been sitting on or rubbing against any surface feel along the bottom edges. Check the whole engine compartment and under the engine area

 

[mikez71]

There is a tsb about pinched/chafed wires..

https://static.nhtsa.gov/odi/tsbs/2015/MC-10113715-9999.pdf

 

[Hoeston]

(What is Texas Edition? Does it break down when the temps drop too low?)

Lol

 

[nayborbob]

Lol

It's got chrome side mirrors, non standard suspension

Lol

Chrome details on side mirrors, grill, tail pipe; towing package, suspension upgrade, 20" polished aluminum wheels

 

[nayborbob]

I would check for any wires that have been sitting on or rubbing against any surface feel along the bottom edges. Check the whole engine compartment and under the engine area

Can I run a sister wire alongside wires at sections that were stretched instead of replacing a whole harness (if it's $$$)?

 

[Doubeleive]

Can I run a sister wire alongside wires at sections that were stretched instead of replacing a whole harness (if it's $$$)?

well, that's a lot of work
the thing is it might only be a wire or two that broke internally or it could be a hidden rubbed wire, or it's possible it might even be something else entirely.
finding it might be tedious, it might require a oscilloscope.
best thing to do is to start a visual inspection, use your hands and a flashlight or a worklight when you are looking down in the engine bay or up from underneath a light helps
a rubbed wire might just look like a shadow or grease spot in low light.
a problem like this can be a real rabbit hole