MichaelSuch

Hey everyone, this problem just started 2 days ago. While holding the pedal at a constant angle, usually around 25% in 6th and cruising it felt like it was having a very slight missfire. I started a HP Tuners log to see what was going on and the TPS would bounce from ~20-28% for a few seconds then go back to 25%, then start bouncing around and go back to 25% again. At idle the issue doesn't happen, it's always at 18% and idles at 850. It doesn't seem to happen at WOT either, it's always at a constant 99%. Does the TB motor need cleaned? Or maybe just the throttle body? Or does it need re-learned?

NIKDSC5

iTrader: (10)

This is typical. That is exactly how a TPS goes bad, the sweep sensor on it wears out where the throttle spends the most time. which for most is just like you said at cruise down the highway. Just change it and move on!

Edit: or drive faster and avoid that area of the throttle

MichaelSuch

Where can I buy a new TPS? I searched GM Parts Direct, google and came up empty. Does GM call it something else?

ryridesmotox

Rockauto ACDelco P/N 17113566

http://www.rockauto.com/catalog/more...400&cc=1432726

They do have other cheaper ones. Just search through their dropdown lists. I think the ACDelco was $70+... A Delphi one was $45

MichaelSuch

After a little more research I could not find the TPS on my car. That sensor is for 5.7L cars, which is why Rockauto wasn't showing it under 2006 CTS-Vs. It's built it to the throttle body actuator on LS2 cars. I'm starting to wonder if that is the problem or if its the APP Sensor sending false data.

NIKDSC5

iTrader: (10)

ahhh, yeah that changes the game on an ls2 car.

ryridesmotox

Dam, sorry dude, I am on mobile, didn't see you had a 06 until I looked at it on the website

DMM

TPS still resides in the throttle body, it is an internal component of the TAC module. The APP sends the request, the TAC operates the throttle blade, and the TPS registers the throttle blade position.

I would check ALL of your grounds, esp the two grounds at the rear of the passenger side head. You can also try to make a quick ground cable and use one of the throttle body bolts to attach it and run it straight to the NEG terminal of the battery. Make sure you have clean connections.

If grounds do not fix anything, try a new battery. Crazy, but you'll have to trust me. Batteries can develop high internal resistance to ground and signal circuits suffer in this manner.

If none of that changes anything, you're looking at a $500 throttle body. The LS3 will NOT/NOT work for your application.

NIKDSC5

iTrader: (10)

Scoggin Dickey has new/remaned ls2 throttle bodies for 225$

MichaelSuch

I just replaced the battery 2 weeks ago with a new EverStart from Wal-Mart and the problem definitely wasn't noticeable before then, I still had the original AC Delco in the car and it was very very weak. I will definitely check the grounds and report back. If I'm forced to buy a new throttle body I'd rather not go with an OE unit. I'd rather pay the extra and get something like a NW.

DMM

Some of the NW units are LS3 based so do your homework before you buy.

2007V

iTrader: (2)

dang, mine just started doing the same thing.

Any luck with testing the grounds?

MichaelSuch

Honestly I haven't had time to touch it and it's been super super cold since this started happening. This started happening right after I put in a brand new battery, so I did check the negative cable on it and it was MAYBE 1/4 turn loose. After that I really haven't noticed a problem with it doing this. But I did look at the grounds on the heads and they didn't look that pretty so I definitely will be cleaning them up as soon as it warms up.

2007V

iTrader: (2)

Thanks, I'll take a good look at the grounds and see if that is the issue.

2007V

iTrader: (2)

Update: My fluctuation went away with a new tune. The maf was scaled by 1/2 and I changed it to 3/4 to gain some resolution back. The fluctuation is now gone. That was the only change.

2007V

iTrader: (2)

shortly after all of this my coolant temp sensor failed. Replaced it and it failed again. Replaced the battery now as it only tested to 65% charged (optima model red78). If I don't post again then it was the battery.

dub.ya.es.SICK

iTrader: (3)

2007V - are you sure it is the coolant temp sensor? I just chased this problem for over a month. 6 months ago I changed the temp sensor, so I was wondering if it was a temp sensor.

Anyways check this thread at another forum I created, it has all the diagnostic and information on the coolant temp sensor and cooling system.

Mine ended up being the o-ring on the thermostat jammed up into the thermostat keeping it slightly open all the time.

just an FYI, it might be some good information for you on your troubleshooting

2007V

iTrader: (2)

Thanks dub.ya.es.SICK

I changed the coolant temp sensor when it stopped indicating. Didn't do any diagnosis, just changed it. I had a 165 thermostat laying around so I did it at the same time. I saw one ground strap when changing it and it looked great. If there is a bad ground then it is in a more burried location.

After changing it, everything was fine for a few days then it stopped indicating again. So between that and the throttle position moving on me I was really suspecting the grounds or battery. Also, driving into work today the voltage was showing 13.3 which I thought was pretty low. Don't these run at 14.4 when the alt is charging?

Anyway, since the grounds that I saw looked pretty clean I took the car to Oriellys and they tested the battery and alternator. Both were good but the battery was only 65% charged. They ended up warranteing the battery since it was only 2.5 years old give or take.

The sensor was reading on the ride home so that's all I know right now. Maybe it will come back soon but I'm crossing my fingers. I hate electrical problems like I'm sure how many others feel.

dub.ya.es.SICK, is your other thread on caddillacownersforums?