SOLVED! P0017 Assistance

Brimmy

Member
As stated in my thread; "I Must Be Crazy" -- I own a 2005 GMC Envoy XL; I want to believe my trim level is the SLE. It has all kinds of bells and whistles. LOL.
4.2L I6, 4X4, 185,000 miles. But I am to the point of pulling what hair I have left out. My post may need to re-directed as I am drawing at straws at this point.
I have the dreaded P0017 and engine has been running okay. However I have emissions inspection next month & MIL is on; with P0017. I decided to get it taken care of sooner then later. I have replaced the VVS, camshaft position sensor, crankshaft position sensor, timing chain and guides and cam phaser. Engine did start. P0017 instantly came back. It did attempt the throttle body relearn procedure as it was toughly cleaned in the process. I attempted a short drive up & down my street. Stalled as I placed in gear. Would not restart unless gas pedal to the floor as a fuel flood clear. Transmission did not shift gears either. Made it back to my driveway & now it will crank & but not start. I am open to ideas as I'd like to get wife vehicle back to her. That's what I get for trying to get things taken care of before the tags expired.
 

MRRSM

Lifetime VIP Supporter
Welcome to GMT Nation...

"I have replaced the VVS, camshaft position sensor, crankshaft position sensor, timing chain and guides and cam phaser."


Did you perform the R&R of the Timing Chain Gear highlighted above... and NOT replace the Timing Chain Tensioner?

Visit THIS recent Thread ...and Watch the informative Diagnostic Video entirely to get the gist of what can go wrong and how to perform this Repair in the absence of ALSO performing an Engine Flush with 5W-30 Cheap Organic Motor Oil and a Cheap Oil Filter while substituting One Quart of Oil with Automatic Transmission Fluid and allowing the Engine to Idle for 10-15 Minutes.

Afterwards... Replace that Junk-Filled Motor Oil and Junk-Filled Oil Filter with 7 Quarts of Mobil1 5W-30 FULL Synthetic Motor Oil and either a Mobil1 or K&N Oil Filter. Afterwards, Pull the CPAS again and Clean Out the Stainless Steel Mesh Screens with Brake-Kleen Solvent and Re-Install it. Then Clear The Codes... and try again:

 
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Brimmy

Member
Is this something where I will need to get ahold of a TECH2 and do relearn procedure ?
 

MRRSM

Lifetime VIP Supporter
Changing the (CKP) Crankshaft Position Sensor will ultimately need a CASE Re-Learn using either a Tech 2 Scanner or another capable High End Scanner like your local Auto Repair Shops also carry. However... that in itself should NOT be causing the stalling condition you are presently experiencing.

What CAN cause this problem to occur is having the Timing Chain Mis-Installed and perhaps off of its Correct Alignment by even One, Single Tooth. It would help if you would answer these Key Question(s):

Did you Install the Timing Chain Hardware?
Did you also Replace the Timing Chain Tensioner?
Which Cam Phaser did you Install? (Dorman or GM OEM?)

As for the usual 'gymnastic alignment hi-jinks' necessary to ensure that the Timing Chain is not off even by One Single Tooth... THIS is the only correct arrangement of things (Black Links aligned to the Crankshaft Cog, The Intake Camshaft Sprocket and the Cam Phaser Sprocket) as per this image. Anything other than this arrangement will definitely cause Engine Ignition Timing Errors due to Failed Crankshaft-Camshaft Correlation:

GMATLASVORTEX4200TIMINGCHAIN.jpg

Take Note.... A Brand New Timing Chain Tensioner will install in the condition of having its Hydraulic Internal Plunger COMPLETELY compressed inside of the Tensioner Body as showing here within the Red Circle above. During this entire Repair... the #1 Cylinder must have been placed and kept at the TDC position on the Compression Stroke.

Also, the Two "Notches" in the back ends of the Intake and Exhaust Camshafts must also both be in their Flat, Horizontal Positions even with each other and held in place with a Special Tool in order to maintain all of these relationships. The last item is that the word "DELPHI" must appear as you see it in this Image... Horizontal and even with the Upper Engine Head.
 
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Brimmy

Member
Welcome to GMT Nation...

"I have replaced the VVS, camshaft position sensor, crankshaft position sensor, timing chain and guides and cam phaser."


Did you perform the R&R of the Timing Chain Gear highlighted above... and NOT replace the Timing Chain Tensioner?



Visit THIS recent Thread ...and Watch the informative Diagnostic Video entirely to get the gist of what can go wrong and how to perform this Repair in the absence of also performing an Engine Flush with 5W-30 Cheap Organic Motor Oil and a Cheap Oil Filter while substituting One Quart of Oil with Automatic Transmission Fluid and allowing the Engine to Idle for 10-15 Minutes. Afterwards... Replace that Junk-Filled Motor Oil and Junk-Filled Oil Filter with 7 Quarts of Mobil1 5W-30 FULL Synthetic Motor Oil and either a Mobil1 or K&N Oil Filter. Then Clear The Codes... and try again:

Yes, I replaced the tensioner as well; it was a complete kit with crank sprocket as well.
 
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Brimmy

Member
Changing the (CKP) Crankshaft Position Sensor will ultimately need a CASE Re-Learn using either a Tech 2 Scanner or another capable High End Scanner like your local Auto Repair Shops also carry. However... that in itself should NOT be causing the stalling condition you are presently experiencing.

What CAN cause this problem to occur is having the Timing Chain Mis-Installed and perhaps off of its Correct Alignment by even One, Single Tooth. It would help if you would answer these Key Question(s):

Did you Install the Timing Chain Hardware?
Did you also Replace the Timing Chain Tensioner?
Which Cam Phaser did you Install? (Dorman or GM OEM?)

As for the usual 'gymnastic alignment hi-jinks' necessary to ensure that the Timing Chain is not off even by One Single Tooth... THIS is the only correct arrangement of things (Black Links aligned to the Crankshaft Cog, The Intake Camshaft Sprocket and the Cam Phaser Sprocket) as per this image. Anything other than this arrangement will definitely cause Engine Ignition Timing Errors due to Failed Crankshaft-Camshaft Correlation:

View attachment 101670

Take Note.... A Brand New Timing Chain Tensioner will install in the condition of having its Hydraulic Internal Plunger COMPLETELY compressed inside of the Tensioner Body as showing here within the Red Circle above.
Cam Phaser was Dorman. I installed all timing chain hardware. I did replace chain tensioner.

This engine is more baffling now then my LB7 ever was.
 

MRRSM

Lifetime VIP Supporter
I concur. This "Enigma Engine" even requires that after replacing the Timing Chain Set... it is necessary to complete (14) Clockwise Rotations in order to achieve (7) 720 Degree 4-Cycle conversions with One Black Link in every (7) Links moving in time to finally arrive right back at the correct TDC position for the #1 Cylinder. And all of this just to prove that each and every one of these "Ear Marks" arrive in perfect alignment.

Crazy...huh? By the by... How did you restrain the Timing Chain in order to keep the "Black Link" from falling off of the Lower Crankshaft Cog at the 4-5 O'clock Alignment "Circle" Position?
 
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Brimmy

Member
That may have been my error. I did not rotate the crank 14 rotations to verify that everything was still in "Ear Marked" with the black links.

Just going to be hard to talk myself into tearing all that down again to see if that is what has happened.
 

MRRSM

Lifetime VIP Supporter
I agree... and so ...trying out what I covered in Post #2 first to see if those actions have any positive affect upon the entrenched P0017 Code...will be worth the effort.
 
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Brimmy

Member
I believe I am going to have to go back in. The only thing I can figure is the chain must be off a tooth on the crank pulley.
 

MRRSM

Lifetime VIP Supporter
Most of us who know what to do about the Dreaded Timing Chain Replacement comes from @Mooseman 's Thread for the Correct Step By Steps as per this Link:


However... in your present dilemma, you have 'Crossed the Rubicon' of starting with a Known Good Factory Timing Chain Orientation... and thus removing the Crankcase Oil Pan is in order and is necessary just to Remove the Front Timing Cover. THIS would be the best approach to take if you are going back into that Motor, as there is no other way to make a visual confirmation of the proper Black Link-to-Crankshaft Cog Circle Marking.

Look into watching one of our Members --> Kevin Nadeu's Youtube Multi-Part "How To" for many tips and visuals on Removing the Crankcase & Timing Cover to Clean his Oil Pump Pick-Up Tube and install a New "O" Ring on his Gerotor Oil Pump. He performs this work on his 4WD Envoy and please... pay particular attention to the serious MISTAKES he honestly shares along the way to avoid the pitfalls he encountered:

Start Here:


There ARE many other directed Threads to be found here covering this R&R so scour GMTN for most of them. You will not regret observing how other Members have fared with this epic mechanical repair.

So many additional issues can be solved at the same time while re-installing your Timing Chain Hardware Set. These Problems involve extensive shared experiences with your Brothers (and Sisters) about this issue, so 'Boning Up' before turning any Wrenches on what they have learned and shared here will turn out to be a Blessing... Not in Disguise.

@Mooseman has provided us all with True Treasure by allowing Members to have access to the Genuine GMT-360 OEM Digital Shop Manuals. Visit this Link and Download one for your particular Year, Make Model of SUV:

 
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TJBaker57

Well-Known Member
Is this a case where using a scope to view the relationship between crankshaft position and camshaft position might be able to at least have a look at where they are before disassembly? I am not a scope guy so don't know but thought I had seen it discussed somewhere.
 

MRRSM

Lifetime VIP Supporter
That would be a very logical approach for Good Diagnostics. However, the problem here is one of serious "confinement" in between the front of the Engine Block and the Inner Timing Cover. The attached images are just a few that I took that well illustrate this problem .

These images show my exploration of those tight spaces while using a Bent S/S TIG Welding Rod as the means to maneuver the Locking Tab up and down and while at the same time trying to Compress and Restrain the Strong, Spring-Loaded Timing Chain Tensioner.

The Photos well illustrate this problem of simply not having enough room in the gap in between to effectively observe or work from the top down inside of the Front Areas of the LL8 Engine:

TCTENSIONER1.jpgTCTENSIONER2.jpgTCTENSIONER3.jpgTCTENSIONER4.jpgTCTENSIONER5.jpgTCTENSIONER6.jpgTCTENSIONER7.jpg
 

TJBaker57

Well-Known Member
That would be a very logical approach for Good Diagnostics. However, the problem here is one of serious "confinement" in between the front of the Engine Block and the Inner Timing Cover.


I guess I should have used the full term, oscilloscope. Comparing the signals from the crank vs camshaft position sensor. I thought I had seen that mentioned as means of verifying proper crank vs cam correlation?
 

MRRSM

Lifetime VIP Supporter
Oh...Sorry... I thought you were referring to using a 7 to 9mm Boroscope to Check Out this Black Chain Link to Crankshaft Cog Circle Alignment...

Indeed... You can do this suggested Diagnosis by using either the Two Channel PICO-Scope Model #2204A or the 8 Channel Hantek Model #1008C along with your Laptop Computer. Don't forget to also use a pair of Hantek 20:1 Voltage Attenuators if there is ANY chance of feeding above the 20 Volts AC/DC Input Limit to EITHER of these Oscilloscopes coming from your Probes.

The Technique is to Back Probe for Channel (A) on the Signal Wire coming from the (CKP) Crankshaft Position Sensor Connector and also Back Probe for Channel (B) using the Signal Wire coming from the (CPS) Camshaft Position Sensor Connector.

The Crankshaft should provide a Single Spike (5) times with (1)"Double Spike" in the pattern on the Channel (A) portion of the Scope Screen representing TDC on the #1 Cylinder. That Pair of Spikes SHOULD align within one of the Square Wave Signals showing on Screen for the Channel (B) Signal for the Camshaft via (6) variable Square Waves rolling from right to left as either Three Wide or Three Narrow Rectangles.

With a proper on-screen Trigger set to stabilize BOTH signals in the middle of the Screen... If the "Double Spike" signals do NOT nest within or closely adjacent the Square Wave patterns at higher RPM to produce a Good Wave Form showing their correct correlation... then THIS On Screen Pattern could provide additional Visual Diagnostic Proof of the "Mechanical Crank to Camshaft Mis-Alignment" problem occurring inside of the Engine.

The Video Thomas alludes to comes to us from Paul "Scanner" Danner's brother, James where he explains all of this quite graphically and to great effect:

 
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MRRSM

Lifetime VIP Supporter
There may be a Third Player involving a recurring combination of P0014 and P0017 if the Crankshaft End Play is around 0.050" ...which would be VERY obvious if the Crank was 'gently' tested using a Pry Bar to lightly guide the Crankshaft towards the front of the Engine from behind the properly installed Harmonic Balancer while using a Digital Depth Gauge to measure this movement. The acceptable longitudinal fore and aft "Hunting" range for the Crankshaft is between 0.0044" and 0.0153".

However, if the variance is close to being only around 0.001" then just replacing the (CPS) Camshaft Position Sensor is the repair recommendation. The alternative Bad News is that the recommendation for exceeding these tolerances is to "Replace The Engine".

Be advised that the reason for this drastic approach has to do with the utter destruction of the #5 Main Thrust Bearing that can occur and the leftover Metal Detritus manages to infiltrate all of the delicate spaces inside the Motor... including the Oil Galleries and the Valve Train and can cause a whole Rat's Nest of other internal component failures.

The GM 4.2L LL8 Motors that are allowed to endure re-building at the Dealerships must be completely torn down and then have the Oil Galleries thoroughly flushed out with Soapy Water to rid the engine internals of this errant Aluminum Babbitt Thrust Bearing contamination that will simply keep doing internal damage if not otherwise removed.
 

MRRSM

Lifetime VIP Supporter
Very Glad that you managed to fix this problem before any Valve-to-Piston Clearance issues caused any damage to the Motor...

As a Footnote to emphasize the Correct Diagnostic Approach suggested by @TJBaker57 in Post #14 for "Crankshaft-Camshaft Correlation" ... These images clarify the arrangement of the (3) Large (Red Dots) and (3) Small (Blue Dots) designed "Notches" fixed into the OD of the Early Model GM Vortec 4200 Camshaft Phaser & Sprocket necessary to create the Hall Effect getting picked up by the Magnetic CPS (Camshaft Position Sensor):

BESTCAMPHASER.jpeg12563712GHENGINEHEAD.jpegACDELCOCPS_.jpg

These signals are meant to correlate the (CKP) Crankshaft Position Sensor) with the (CPS) Camshaft Position Sensor and create an acceptable "Good Wave Form" showing on the Oscilloscope Screen, with the (CKP) "Double Spike" being nested within the Rectangular "Notch" of the (CPS) as depicted below. The proper Spark and EFI Timing decided upon by the PCM is reliant upon these two signals finding this visual agreement:

GOODCKPTOCPSWAVEFORM.jpg

It is really great when such a serious mechanical issue can be solved and have such a "Happy Ending"... :>)
 
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