Cadillac Owners Forum banner
  • Hey everyone! Enter your ride HERE to be a part of MAY's Ride of the Month Challenge!

21 - 36 of 36 Posts

Registered
Go ahead, blame me. Everybody does 馃檮
Joined
12,082 Posts
He'll be back.
 

Registered
'14 CTS-V LongRoof; '16 ATS-V Sedan,' 04 Trailblazer 4x4; '10 CTS LongRoof gone but never forgotten
Joined
16,741 Posts
I mean, WTF? A little stressed, are we?
 
  • Like
Reactions: Nonsmiley

Registered
Go ahead, blame me. Everybody does 馃檮
Joined
12,082 Posts
I mean, WTF? A little stressed, are we?
Don't you remember his other posts?


Apologies to the OP for sidetracking the thread.
 

Registered
'14 CTS-V LongRoof; '16 ATS-V Sedan,' 04 Trailblazer 4x4; '10 CTS LongRoof gone but never forgotten
Joined
16,741 Posts
Never mind, thankyouverymuch.

Now, back to our regularly scheduled programming already in progress.
 

Registered
2010 CTS4 sedan
Joined
1,440 Posts
I checked the hoses are tight fitting on the connectors - nothing loose or leaking.
there really isn鈥檛 a PCV valve, it鈥檚 more of just an elbow. But I did remove it and there鈥檚 no blockage and it鈥檚 really not oily either. (Hose goes from air intake to pcv elbow and is good.)
Air filter was replaced about 7000 miles ago.
Hmmm. All those spikes - and no real misfires. Makes me suspect a tank of really bad gas or a failing sensor or a failing connection to a sensor - but which one could cause your LTFT to jump around like that? And on both banks? Hmmmm.

What spark plugs did you use and what are they gapped at?
 

Registered
**2014 CTS4 Sport Wagon-Luxury**
Joined
2,634 Posts
I sign in whenever I am on here and sometimes it requires the Captcha ("click on pics with bicycles in them") before I can fully sign in...just a few seconds more and it doesn't always show up to sign in...

curious to find out what is causing OP's woes...so...back to that...

Bill
 

Registered
Joined
11 Posts
Discussion Starter · #28 ·
Hmmm. All those spikes - and no real misfires. Makes me suspect a tank of really bad gas or a failing sensor or a failing connection to a sensor - but which one could cause your LTFT to jump around like that? And on both banks? Hmmmm.

What spark plugs did you use and what are they gapped at?
The $8 iridium spark plugs. They were pregapped around 45 (which is correct for the 3.0 engine) so I didn鈥檛 adjust the gap.

I鈥檝e tried a new tank of gas. No change.
Tried adding some Berrymans 鈥淚talian tune up鈥 weeks ago when I first noticed it (thinking misfire or injector)... Also no change.
 

Registered
Joined
11 Posts
Discussion Starter · #30 ·
Need to run a "mode $06" and check for misfires, would expect some in history.
I posted the pic of the misfire history. In a 15 min drive with a few WOT, maybe 2 misfires.
Not enough to trigger a CEL
 

Registered
2010 CTS4 sedan
Joined
1,440 Posts
I posted the pic of the misfire history. In a 15 min drive with a few WOT, maybe 2 misfires.
Not enough to trigger a CEL
Yup. Misfires don't seem to be the problem. It seems to be fuel delivery. But why?
 

Registered
Joined
11 Posts
Discussion Starter · #32 ·
Yup. Misfires don't seem to be the problem. It seems to be fuel delivery. But why?
I鈥檓 guessing the fuel filter isn鈥檛 along the line under the car?
I still feel like it鈥檚 more 鈥渂ehind the engine鈥 related, I wonder if a tranny mount or the flex discs that attach the shaft are causing the bucking...
And I鈥檓 assuming without a lift I can鈥檛 check the tranny fluid to see if it鈥檚 fowl or low.
 

Registered
Go ahead, blame me. Everybody does 馃檮
Joined
12,082 Posts
I鈥檓 guessing the fuel filter isn鈥檛 along the line under the car?
I still feel like it鈥檚 more 鈥渂ehind the engine鈥 related, I wonder if a tranny mount or the flex discs that attach the shaft are causing the bucking...
And I鈥檓 assuming without a lift I can鈥檛 check the tranny fluid to see if it鈥檚 fowl or low.
No "in-line" fuel filter on these cars.
Tranny fluid needs to be checked with the vehicle raised on a horizontal plane.

Does the gear shifter move when you feel this surging?
 

Registered
Joined
11 Posts
Discussion Starter · #34 ·
No "in-line" fuel filter on these cars.
Tranny fluid needs to be checked with the vehicle raised on a horizontal plane.

Does the gear shifter move when you feel this surging?
Shifter doesn鈥檛 shake or move during the stutter.
 

Registered
2010 CTS4 sedan
Joined
1,440 Posts
Well, the stutter shows in the fuel trims levels, fuel rail pressure, and a host of other things. I am out of my depth on this but I do wonder if there's a problem with either the high pressure fuel pump or a sensor that manages the signals to it. Those swings in critical numbers are very abrupt - I just can't see them being caused by the transmission. Maybe the throttle position sensor??

If it is the TPS, it's easily tested. But if there was a problem, you'd think there'd be a CEL and a code.

What are you seeing in throttle position and fuel rail pressure at a steady idle and at a steady 1500 rpm?
 

Registered
Joined
11 Posts
Discussion Starter · #36 ·
Well, the stutter shows in the fuel trims levels, fuel rail pressure, and a host of other things. I am out of my depth on this but I do wonder if there's a problem with either the high pressure fuel pump or a sensor that manages the signals to it. Those swings in critical numbers are very abrupt - I just can't see them being caused by the transmission. Maybe the throttle position sensor??

If it is the TPS, it's easily tested. But if there was a problem, you'd think there'd be a CEL and a code.

What are you seeing in throttle position and fuel rail pressure at a steady idle and at a steady 1500 rpm?
ok, here鈥檚 the car at idle in the driveway for 5 mins from a cold start.

599001
599002
599003
599004
599005
 
21 - 36 of 36 Posts
Top