2010 Acadia won’t stay running

[CP]

Make

Gmc

Model

Acadia

Year

2010

Miles

100782

Engine

3.6L

Any answers out there,someone run into this before? Cranks and starts, but soon dies. Maybe runs for 5 seconds, have had it running for probably 30 seconds, and that time it ran smooth. Replaced the crank sensor, no codes will set in the amount of time it runs. Fuel pressure gauge hooked up and shows 60 plus pounds. Security light comes on with key on engine off. All the lights go out as soon as it runs. Any thoughts?
Thanks

 

[billr]

Does it die if you hold the throttle open at a "fast idle" so all the idle control stuff is by passed? Have you checked fuel pressure while it is dying? Have you checked for spark and injector pulses while it is dying? Have you used live-data to check the ECT, MAP/MAF, and TP sensors?

 

[grcauto]

When did it run for 30 seconds? What did you do to it after that? When and why did you put a cks in it?
Tell us in order and a timeline of things.

 

[CP]

When did it run for 30 seconds? What did you do to it after that? When and why did you put a cks in it?
Tell us in order and a timeline of things.

Came to me on a trailer not running. Charged up the battery as I assume the customer ran it down cranking. Found that cranking and trying to start, that it was a little interested in starting. So with some time and cranking it would run for a short time. Not long enuf to get it in gear so pulled it into my shop. Hooked up two different scanners and if I remember right there was a code p0336 for crank sensor performance. Cleared code and more cranking, same thing, would start and run for a short time, not good, somewhat missing, then suddenly dies. Must have repeated this 50 times, sometimes getting it to run a little longer, some times it would crank but not run, only act like it might. Then once today I got it to run for maybe 30 seconds, another time maybe 20 seconds. Most of the time only 3-8 seconds before it suddenly dies. Hardly enough time to run around and wiggle wires, etc. So one time today it did set the P0336 code, after I put in at new Crank sensor. Crank sensor didn’t help anything, still the same. When it is running I get counts on all 4 cam sensors. Also on crank sensor. Unhooked MAF and no different, maybe worse at starting. Fuel pressure gauge hooked up and I can see it as I crank and run it. No drop, stays at 60 or above. Checked spark at number one coil. Steady spark when running. Possibly starts cutting out but the engine dies so fast it’s hard to say if the spark actually quits before the engine. Usually cranking after it dies, it will again attempt to restart. Might not keep going or if it does it runs like the spark quits for a second and then goes again, and repeats, till in about 4 seconds it will suddenly die. That’s about the best I can describe how it acts. Thanks

 

[billr]

Check spark again, but use a timing light. It is easy to see if spark dies using the light.

How about injection pulses, did you check for that? A voltmeter can do this, but a 'noid light is easier and probably more reliable to interpret.

The CKP sensor circuit is still the most likely culprit, even though you changed the sensor. I would back-probe that signal back at the PCM/ICM connector, see if there is any obvious change there when the engine dies.

How about the ECT/MAF/TP sensors I asked about? Have you tried blocking the EGR flow path? Tried a vacuum gauge? Taken compression?

 

[grcauto]

Runs how? Good bad all cylinders hitting?
Come on man.
Is the mechanical timing good?

 

[CP]

Had a little time today to check into it farther... found the information the scanner was giving me , all looked ok. TP, MAF ,ECT all looked in a normal range.. Cam sensor counts, RPMs long term, short term etc etc. But I had to keep it above 1800 to keep it running. Then it ran ok, lower than that and it would cut out intermittently and usually die, unless you could quickly get it above 1800 again. Hooked up a timing light, not real sure about that , dies so quickly that the light flashes quickly die too?!? Checked waveform pattern of the crank sensor, nice square wave like it should be. So figured I’d pull off cam sensor connectors and see what happens. Bank 1 exhaust, start up and same thing. Run terrible ,cutting out, dying..Set a code for that connector off. On to bank 1 intake ( those are the only easy ones to get at) , started up and run like a new vehicle !! Idles, revs, restarts fine, what’s going on? Ordered a new sensor, but then took the sensor out and looks like something has been rubbing on the end of it. Not familiar with the track record of this engine 3.6. Does this happen more often, or like anything mechanical, things happen?

 

[CP]

New cam sensor went in this morning. Back to bucking and coughing at idle before it dies. Unhook sensor and runs fine, but CEL on of course... someone suggested timing chains/ kit?? Thoughts?

 

[billr]

Does the new look like it is getting rubbed? Did you check sensor wave-form back at the PCM connector?

Just guessing, but I would expect that sensor to be detecting some part of a cam gear/sprocket/shaft that is not affected by wear. I don't think changing the timing stuff is going to be the answer.

 

[grcauto]

I'd be looking at the wiring harness for rub through.

 

[CP]

This is what I found wrong
Hope it can help someone else??

Rear intake cam phaser

 

[billr]

Is it fixed now? What parts did you have to replace/repair?

 

[CP]

Its running good now and back to the customer. Replaced oil pump, timing chains, tensioner,guides,actuators,phasers,cam sensors,crank sensor,plugs, gaskets, seals,idler sprockets, the whole timing kit, I went with Cloyes. They have an installation video and tech help if you need it and lifetime warranty on the parts. Somewhat time consuming dropping the engine/transmission out the bottom, but is necessary! The power steering pulley has to come off to remove the engine cover, and the frame is in the way to get the pulley off. Oh yes and needed a radiator when I got it filled up, wet on the ground overnight, tank gasket started to leak,as I put in a new water pump and antifreeze, so someone maybe had put stop leak in and I flushed that out. So the front bumper cover had to come off and condenser....

 

[nickb2]

Dear CP, thx for this post slash thread, this is a prime example of what we love here. You took time to even post a picture of affected part in very nice detail.

Goes to show, throwing electrical parts at a car wont ever fix a mechanical problem.

Thx for your assiduousness.

 

[nickb2]

Somewhat time consuming dropping the engine/transmission out the bottom, but is necessary! The power steering pulley has to come off to remove the engine cover, and the frame is in the way to get the pulley off.

I Have done a few of these jobs, they suck large, so yeah, while your in there, if you want a keeper, might as well change the wear items invovlved, Again, great short thread,