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Discussion Starter #1
Picked up my car from the dealer Friday after the blower replacement and trans service with overfill was done and immediately noticed that it drove different. After cruising at pretty much any speed and you let off of gas it doesn't slow down like it used too but instead hold more speed as it decels (hope that makes since). When you are stopped and release brake the car will slowly accelerate to about 1000-1200 rpms or so. Now when brake is held or in Park it idles perfectly. Wondering is the bypass being set too tight and holding the blade open would do this? I did back off the BP valve to have a little clearance but since I'm at work I can't test drive yet. Checked all the connections and everything else looks good so no noticeable vacuum leaks that I can see. Anyone else seen this??

Thanks;

Paul
 

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Sounds like you're getting too much airflow - your symptoms are classic of this. The reason? Can't say - but could be several things, the bypass being one of them.
 

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Discussion Starter #3
My thoughts exactly but if that was the case shouldn't I see the symptoms is Park as well?
 

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Wondering is the bypass being set too tight and holding the blade open would do this?
No. Under the driving conditions you described, the bypass valve is already wide open. Check the intake tube connections downstream of the MAF for air leaks. Do you have logging capability? If so, check to see if your short term fuel trims are trending high positive.
 

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Discussion Starter #5
No. Under the driving conditions you described, the bypass valve is already wide open. Check the intake tube connections downstream of the MAF for air leaks. Do you have logging capability? If so, check to see if your short term fuel trims are trending high positive.
Good info. I have a checked the connection from my CIA at the TB and all looks good.
 

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You could spray around everything with carb cleaner or something and listen for a change in the idle. A vacuum leak would suck it in and be pretty obvious where the leak is located.
 
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Discussion Starter #7
You could spray around everything with carb cleaner or something and listen for a change in the idle. A vacuum leak would suck it in and be pretty obvious where the leak is located.
Yep I'm going to do this tomorrow. I'd like to track this down before I pull the blower off to do the pulley and other things next weekend.
 

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My thoughts exactly but if that was the case shouldn't I see the symptoms is Park as well?
Not really - there individual idle airflow adjustments for every gear (1-6) plus settings for park, neutral, and reverse. You can literally set each of them differently - and there are valid reasons you want to do so. On top of that there are adjustments for transitions between those options (as you move the selector in an auto, for example) that keep idle rpm smooth when changing the loads that shifting can bring. And they are more adjustments for things like AC compressor turning on and off. Lots and lots and lots of stuff, all of which can change individually.

And as someone else noted - the bypass valve might be open or partially so under different conditions.

As someone who's been digging around with his idle settings, I can tell you it's VERY sophisticated (or you could say "complicated"?) - offering countless adjustments for OEM's so they can get the car dialed in just perfect. To me its the beauty of computer control.
 

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Discussion Starter #9 (Edited)
Not really - there individual idle airflow adjustments for every gear (1-6) plus settings for park, neutral, and reverse. You can literally set each of them differently - and there are valid reasons you want to do so. On top of that there are adjustments for transitions between those options (as you move the selector in an auto, for example) that keep idle rpm smooth when changing the loads that shifting can bring. And they are more adjustments for things like AC compressor turning on and off. Lots and lots and lots of stuff, all of which can change individually.

And as someone else noted - the bypass valve might be open or partially so under different conditions.

As someone who's been digging around with his idle settings, I can tell you it's VERY sophisticated (or you could say "complicated"?) - offering countless adjustments for OEM's so they can get the car dialed in just perfect. To me its the beauty of computer control.
Gotcha. Way over my head!!! I like nuts, bolts and wrenches. LOL Thanks though.


Paul
 

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Discussion Starter #10
Looks like problem solved!!! It was the adjustment of the bypass valve. I backed it off earlier today and on the drive home this evening all feels normal again. It's only a 7 miles trip but I'll drive it a good bit tomorrow so I'll know for sure. Thanks all for the advise.

Paul


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Discussion Starter #11
Drove around a good bit this morning and all is 100% back to normal. Definitely was the adjustment on the bypass valve. It looks new so I'm guessing it came installed on the new blower that way and the tech didn't adjust it. Now next weekend I'll pull the blower back off for the 2.45" pulley and new injectors with all of the other goodies!!!

Paul
 
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