NEED HELP Runs drives fine cold warms up and stalls no restart

Gogo5o

Original poster
Member
Nov 5, 2019
8
Louisiana
So this is my fathers 05 trailblazer. He brought it to local Goodyear shop and they told him he needed a radiator cause it had a crack and cam sensor. $1100+ to fix.

So went to the local Napa picked up the cam sensor, vvt sensor, and radiator.
Yes it did have the codes for both sensors.

Changed it all and ran beautifully. Noticed the bolt for the ground post was bad so I drove it to napa with a 8mm wrench and bolt the new post bolt and changed it in the parking lot. Drove perfectly home. Called my father to tell him it's all done and he came to pick it up and started up and was misfiring. So told him to leave it and I will continue to look at it. So after finding a misfire on #2 & #3 I read coils could possibly go bad. I asked him if the spark plugs have ever been changed and he told me he didn't think so. So took the airbox off and saw that #6 coil was definitely has been changed. So did a little more digging they changed #6 spark plug and coil. So I swapped all 6 plugs with the proper AC delco plugs and replaced the 2 coils. Ran beautifully until you turned the A/C on and it would stall and die.
So grabbed some throttle body cleaner and cleaned it as well. (Was told there is a relearning that the computer had to do)
Anyway truck has been running great now for 3-4 weeks and now it dies after warm up and will not restart.
Weird thing is the abs and brake light on the dash comes on along with the speedometer jumping before it stalls.
It now shows code P0013.
But I just changed the vvt sensor.

Any help with this would be great.

Sorry it has 279xxx miles.

 
Last edited:

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
The CEL flashing like it does is very strange and unusual. Even during a misfire it would flash regularly. It's as if power to the PCM is getting cut off. Check the connectors and fuses. Wiggle them a bit to see if they are loose or the contact is not good. When it quits like that, try to read the codes to confirm you still have communication to it.

What about the ignition switch? It can be the cause of electrical gremlins like this.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
If the contacts in the switch are arcing, it could fail intermittently. That's maybe why when you repeatedly try to start it, it does but quits. It's the PCM that sends the signal to the relay so if it loses power, so will the starter. It's a cheap enough part and easy to replace.
 

TJBaker57

Member
Aug 16, 2015
2,897
Colorado
That is a harness connector. Somewhere in there you have one or more bad connections. You can try wigging the separate wires to see if you can isolate the bad one(s). You can also disconnect it to inspect for corrosion inside. There are 2 "buttons" you squeeze to release the locking mechanism. One you can see on top and there is another just like it on the bottom. Squeeze them together and then rotate the lock/release lever for a look inside.

IMG_20191105_135651.jpgIMG_20191105_135704.jpgIMG_20191105_135437.jpg
 

Gogo5o

Original poster
Member
Nov 5, 2019
8
Louisiana
Well started shaking more wires and thinking it could be the pcm middle plug wires cause now it wont start at all
TjBaker57 I did take it off and inspected the pins to see if any one of them were burnt. They all looked good.
 

seanpooh

Member
Jan 24, 2012
461
You replaced the bolt on the negative cable that connects to the battery? You didn't strip the threads in the lead of the battery did you? Did you double check that point to make sure it's tight & good contact? I didn't see any mention of checking there, might be worth a look-see.
 

Gogo5o

Original poster
Member
Nov 5, 2019
8
Louisiana
You replaced the bolt on the negative cable that connects to the battery? You didn't strip the threads in the lead of the battery did you? Did you double check that point to make sure it's tight & good contact? I didn't see any mention of checking there, might be worth a look-see.
Yes it wouldn't tighten before with the old bolt but it does now.
 

mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,641
Tampa Bay Area
Suggestion: Examine the Wiring Harness of the CPAS for signs of Oil Invasion and the likelihood of it Shorting Out. If the CPAS Electrical Connector of the CPAS Body is Filled With Engine Oil... or has broken or Torn Wires... Replace the CPAS Pigtail (Available on Amazon) or if not... Replace just the CPAS (Solenoid) with a Delphi or ACDelco Brand ONLY.

Trailblazer P0013 Diagnosis and Information:


In a Worst Case Scenario... Bear in mind, your Dad's GM Atlas 4.2L Engine has VERY High Mileage that points towards the likelihood of:

(1) Excessive Timing Chain Stretch.
(2) Fully Extended Timing Chain Tensioner.
(3) Deeply Grooved Timing Chain Guides.

All of these events can conspire to change the delicate alignment relationship between the Crankshaft, the Intake and the Exhaust Camshaft Positions during Engine Rotation. Sensor Mis-Readings can cause the PCM to become unable to know precisely When to Fire the (6) Spark Plugs during the proper BTDC locations for ALL Six Compression Strokes.

This can happen when the PCM, CPAS, CPS and the CKP Sensors ALL fail to agree with the Cams vs. Crankshaft positioning. Replacing the Entire Timing Chain Components as a Full Set may be the only way to sort out such an Aging Engine with almost 300,000 Miles in its RVM.
 
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Gogo5o

Original poster
Member
Nov 5, 2019
8
Louisiana
Ok found a donor for 700 with a running rod knock motor. It is a LT compared to my fathers LS. My question is, is the harness the same.
 

TJBaker57

Member
Aug 16, 2015
2,897
Colorado
What is that part that I'm wiggling


With the engine off, wiggle that connector and find & identify the part that is making the clicking sound we hear in the video. It is not the harness connector clicking, there is nothing to click in there. It is a relay in the fuseblock or a solenoid somewhere on an engine control. You should be able to feel the device clicking with your free hand while you wiggle the connector like you do in the video. Once you find the device making the clicking look at the wiring diagram and identify the color of the wire going to or from it. It likely goes through that connector.

There is NO WAY I would try replacing any multi-wire harness connector for the sake of a single bad connection that may or may not be in said harness connector.
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Time to get the meter out, grab the schematics (manuals in my signature) and start checking continuity, concentrating on power and ground wires first.

Did you check your ground wires??? Especially the ones on the block. Those can also cause a lot of electrical weirdness when bad.
 
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mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,641
Tampa Bay Area
Re: Post #5 and Post #14...

...and after isolating the the involved Clicking Relay using the 'Touch Technique' suggested by @TJBaker57 wiggle the Suspect Relay and see if there is NO Resistance when you Pull it Out of the Power Distribution Center. But... prior to performing a Schematic Broken Wire-Connector Trace and before tearing into that Harness and Connector, use some "Canned Air" first with a Red Tube attached to blow all of the accumulated Sand and Dirt contamination from inside and around that whole area. Then liberally spray everything down, inside and out with THIS Stuff, which CAN be sprayed on LIVE ELECTRICAL CIRCUITS and not short out things or start a fire:

CRCLECTRAMOTIVE.jpg

@TJBaker57 once suggested 'gently bending the metal tines of an Errant Relay' to make better electrical contact inside of the Power Distribution Center if any of those innards have spread open wide enough to get loose and ARC or break contact enough to cause the engine to Stall. As an educated guess... I'd "start" with The Fuel Pump Relay and then trace that Wiring Circuit Diagram using @Mooseman 's suggested GM OEM "Bible" Service Manual into the Connector and Wire Bundle ...but only after cleaning out all of the dirt and reduce the confusion obscuring the Wire Binary Coloring for Pin Probing with a Lighted Pin-Probe or a DMM set to Continuity.
 

Maverick6587

Member
Dec 16, 2018
730
Sterling Heights, Michigan
There is NO WAY I would try replacing any multi-wire harness connector for the sake of a single bad connection that may or may not be in said harness connector.
I agree with TJBaker57!

Start back probing (T-pins work great, but be careful not to shove them all the way in the back of the wires) the wires on each side of the two connectors (in post #6) to see where the power/ground is lost. Make sure that you review the wiring diagrams so that you know which wires are power and which are ground. No need to probe polarity incorrectly and burn out a module or the PCM.

Have you checked for 5v reference anywhere? That would probably be my starting point for a no start issue. Does it at least crank now, or no crank, no start?
 

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