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Discussion Starter #1
Stranded the other night with 4 kids and pregnant wife after the truck started running rough and puffing white smoke with strong fuel smell. Pulled over and shut off, then couldn’t get it to start again and needed to tow home. The next morning it started up, but again with the smell, smoke and rough idle.

It seems it may be ignition or fuel injectors, but I’m not finding clear instructions on how to check these components. I’ve hooked up fuel pressure gauge on fuel rail and see 50-60 psi at start then drops to 20-30. The fuel injectors are not easily accessible to do a Noid light test, so not sure how to diagnose those without removing high pressure rails for potentially no reason.

What electrical components can I test to rule out ignition/coil/pwm issues before moving on to accessing the injectors?

Any help or suggestions appreciated!
 

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Welcome to the forum.
Might be good to inspect the physical parts of the engine before tackling the electrical. White smoke is not a good thing! It's usually an indicator of a head gasket problem. For additional diagnostic procedures, see reply 7 of this thread and download a copy of the factory service manual: Link to Owners Manual
 

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If truly white smoke my first guess would also be a failed head gasket. Would also make me think it is a mechanical issue and not an ignition issue.

My first order of business would be to pull the dipstick. Hopefully the OP sees motor oil and not what looks like a chocolate milk shake. Would also see if it smells like gas. The engine might already be pretty toasted.
 

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Discussion Starter #4
Thanks for the replies!
A bit more info: my first step was checking fluids (no sign of coolant in oil, so I’m unconvinced it’s head gasket) and visually inspecting what I easily could.

The reason I’m thinking electrical/ignition or perhaps stuck open injectors is due to the strong fuel smell in the white smoke, rather than the sweet smell of coolant. Also, all the misfires seem to be on the same bank (CEL P0300/1/3/5). I’mAlso getting indication of potential electrical issue or failed high pressure pump (P0089), and a few codes for purge flow issues (P0443, P0496). I replaced PCV and spark plugs yesterday and switched odd and even coils to see if the misfires change to even bank, but is still on odd side.

Could ECM have gone? What might cause a full bank to be misfiring that I can check before getting destructive?
 

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Could ECM have gone? What might cause a full bank to be misfiring that I can check before getting destructive?
You'd probably get some comm codes if the ECM has failed. Misfires on all cylinders of one bank could be an indication of a stuck cam phaser.
 

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Discussion Starter #8
Appreciate your help!

I read that article yesterday (and again just now), and have a few questions after doing another gauge test at the fuel rail:

Is the schrader valve location on the rail closed off from upstream effects? In other words, is a low pressure at the rail guaranteed to be caused by something toward the tank, or could there be something leaky in the combustion chamber causing it?

Low fuel pressure is a reasonable cause for misfiring (although I would expect both banks to be affected); however, does it seem reasonable to conclude that very rich smelling white smoke from the exhaust would come from low pressure from bad (tank) fuel pump or filter? It seems there’s too much fuel making it to the cat rather than too little, but the pressure on the rail doesn’t seem to indicate this should be possible at all!

This is my first time dealing with a GDI and return-less fuel system...

Is there a decent service manual for these? Thanks again
 

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Discussion Starter #10
Look at the link posted in reply #2.
Somehow I missed that the first time I looked at the link --- I thought it was just the owners manual.

I'm not finding any info on the cam phasers or how to test them, so I'll peak when I open up to check camshaft. I saw on the traverse forum someone having misfires on 1, 3, and 5 who found it to be a broken chain on the right side -- I'm going to open up the right camshaft cover and see how everything looks over there.

Do you have any idea on my previous question regarding fuel pressure?
 

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Discussion Starter #11
I just pulled the spark plugs on my way to take off the Right camshaft cover and they already have black soot on them — the engine has been on for less than a minute since these have been put in. Definitely seems like a rich mixture, low pressure on the rail
 

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Discussion Starter #12 (Edited)
I’ve searched forum and service manual for tips on getting the valve cover off, but I’m not seeing anything. I've detached the wire clip as mentioned here, and the VC is free from the seal, but I can't for the life of me get enough room. The main wire harness is still in the way, even though I've disconnected everything that I can find to get as much slack as possible. Any tips?

9009
 

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Discussion Starter #13
I managed to pull the VC off, although I have no idea how I’ll get it back in there without cutting the wiring harness. Chain is nice and tight and the cans look good. I need to get a jack to greet to t he balancer to turn the engine to see if they’re moving freely to rule out a stuck cam phaser.
The valves are covered in carbon deposits, so I’ll probably walnut blast them while it’s opened up. I’m still thinking this might be a stuck open injector.... I just don’t want the white smoke to be something worse 😭
 

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" Black Exhaust: Black exhaust smoke is an indication of a rich fuel condition. ... White/Gray Exhaust: White exhaust smoke is an indication that coolant is burning in the combustion chamber. "

You are not describing black smoke, so it is probably not a rich fuel condition.

George
 

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Let me start by saying I know nothing about cars but what I Google. Lol. The following is our recent experience with our 2011 Acadia SLT. Long story short the middle of May car was running rough. Not bad. Still had good pick up just wasn't right and check engine light on. Code was for timing chains. Went around for 3 weeks waiting on our mechanic to decide if they wanted the job. Went to another mechanic and we ended up purchasing a crate engine instead of just fixing timing chains. A few weeks later the check engine light started coming on and going off every so often. Fast forward to about 6 weeks ago. Horrible clanking noise like metal rolling around inside metal. White smoke reduced power. Bad catalytic converter bank 1 fuel to lean. Had that replaced and mechanic said the new engine was burning oil and next week they are replacing engine again. White smoke alot on startup. Rough running. Oil still looks clean but code is saying running to lean in bank 1 again. Don't know if any of this helps but good luck in getting her fixed because I love our Acadia
 

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Discussion Starter #16
" Black Exhaust: Black exhaust smoke is an indication of a rich fuel condition. ... White/Gray Exhaust: White exhaust smoke is an indication that coolant is burning in the combustion chamber.”
I’ve read this time and time again, yet the other telltale signs of coolant in the block (milky oil, sweet/coolant smell in the smoke, etc) are not present. Instead there is a strong raw fuel smell in the smoke and repeated misfires in bank 1. I hate to throw a common diagnosis at a problem when it’s not the only possible cause, although I am admittedly just a shade tree mechanic.

What do you think of the fourth reason they give here (and many other places from a quick google search): causes of white smoke?
 

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I do not know much about injectors(my fuel system knowledge pretty much ended with carburetors) but it seems reasonable. Give changing a try. My father was one of the best tuneup men in eastern NC. Once Lee Petty tried to get him go go to work for the Petty team, but Dad would not budge out of our home town. So I grew up feeling comfortable with carbs.

George
 

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Literally just had this happen on my 2010 Acadia, had it towed to the dealer. It was 2 issues but the one that caused the same problem was a faulty fuel injector. Had it replaced by them and brought it home and fixed the other issue myself(faulty O2 sensor bank 2 downstream). Hope that helps.
 

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Discussion Starter #19
Literally just had this happen on my 2010 Acadia, had it towed to the dealer. It was 2 issues but the one that caused the same problem was a faulty fuel injector. Had it replaced by them and brought it home and fixed the other issue myself(faulty O2 sensor bank 2 downstream). Hope that helps.
This gives me hope! I’m cleaning out valves while it’s all open, then I’ll move on to the fuel rail to check injectors. Is replacing injectors necessary, or can they be refurbished? With port injectors you can test them on the rail — I’m guessing with the high pressure system this can’t be done with direct injectors?
 

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Discussion Starter #20
You'd probably get some comm codes if the ECM has failed. Misfires on all cylinders of one bank could be an indication of a stuck cam phaser.
I thought I would understand this more once I got the engine manually turning with the cam covers off, but I’m realizing how in over my head I am... how exactly can I tell if a cam phaser is stuck?? The engine is turning and both air and exhaust cams are moving fine. Anything in particular I can look for to see this???

thanks!
 
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