Extended crank times with Buick Enclave
I have a 2012 Enclave that we purchased 8 months ago. We really like the car except for one problem-random extended crank time ~ 15% of the time. I have had it in (2) dealerships 5 times in the last 6 months plus I brought it to a private mechanic. This vehicle is still under warranty and the dealerships cannot repeat the problem and send me on my way. The private mechanic said the high pressure fuel pump was getting ready to go out as it would leak down during his pressure test. The last dealer said if I could video the condition he would be able to possibly perform a leakdown test- but because it never throws any codes it's indicating that everything is fine.
I have actually narrowed down that after you drive the vehicle (I drive around the block and park back in garage) and wait for 1 to 2 hours you can duplicate this extended crank every time. If you only let it rest for 30 minutes it starts fine and the same for if you let it sit for maore than 2.5 hours. My hypothesis is that driving it pressures up the fuel system (time or distance doesn't matter) and it takes time for the injectors to leak by and (1) allow fuel to accumulate in the cylinder and (2) bleeds pressure from the rail. So after you have an extended start the engine runs "rich" (rough idle, surge)for a few seconds to burn out the extra fuel. After 2.5-3 hours it must evaporate the fuel? I have tried speaking with GM customer service and have been playing phone tag for (3) days- the last dealership has the video and they have finally said that I am not crazy and that it does have an extended start but they are not sure what they can do but they will speak with their technitions. No call back as of yet. I posted a compiled video of the extended crank condition as both dealerships and GM directly are acting like this is the first time they have ever heard of this and I call [non-permissible content removed]. Has anyone else had this problem? Also I had the top end "cleaned" about 1000 miles ago and it didn't help anything, made the car run worse for a while but no improvements. The car only has ~38k miles and we purchased it with ~23k miles.
https://www.youtube.com/watch?v=d_irqmqtKuw&feature=em-upload_owner
If you have had the same issue I would love to hear about it.
I know it was long winded, but I thank you for your time.
I have actually narrowed down that after you drive the vehicle (I drive around the block and park back in garage) and wait for 1 to 2 hours you can duplicate this extended crank every time. If you only let it rest for 30 minutes it starts fine and the same for if you let it sit for maore than 2.5 hours. My hypothesis is that driving it pressures up the fuel system (time or distance doesn't matter) and it takes time for the injectors to leak by and (1) allow fuel to accumulate in the cylinder and (2) bleeds pressure from the rail. So after you have an extended start the engine runs "rich" (rough idle, surge)for a few seconds to burn out the extra fuel. After 2.5-3 hours it must evaporate the fuel? I have tried speaking with GM customer service and have been playing phone tag for (3) days- the last dealership has the video and they have finally said that I am not crazy and that it does have an extended start but they are not sure what they can do but they will speak with their technitions. No call back as of yet. I posted a compiled video of the extended crank condition as both dealerships and GM directly are acting like this is the first time they have ever heard of this and I call [non-permissible content removed]. Has anyone else had this problem? Also I had the top end "cleaned" about 1000 miles ago and it didn't help anything, made the car run worse for a while but no improvements. The car only has ~38k miles and we purchased it with ~23k miles.
https://www.youtube.com/watch?v=d_irqmqtKuw&feature=em-upload_ownerIf you have had the same issue I would love to hear about it.
I know it was long winded, but I thank you for your time.
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Comments
so I just got a response from the second dealership and they want to do multiple leak down tests on it and they will need all week. This dealership is 50 miles out of town but at least they say they will do the leak down test, I don't trust the dealer that is closest to me to do anything. I'll have to see if they fix it or if it's still "in spec" when I pick it up. They want me to drop it off and let it sit at the dealership until they can get to it. Extremely frustrating situation.
But I think you're on the right track here, that pressure is being bled off and the fuel pump needs more time to re-energize the fuel rail.
It's typical that many problems don't throw a code. Onboard diagnostics aren't as astute as we might think.
Maybe the other dealer will give you a loaner at least?
When you dropped the car off, were you specific about needing to drive the vehicle, let it sit for the period of time that is required and then attempt to re-start as you have here?
Getting to recreate the conditions that the symptom occurs under efficiently is really important. The techs get paid .3 hours (eighteen minutes) under warranty one time to try and analyze an issue. They don't get paid for additional visits no matter how much time they have to invest.
As far as the fuel rail bleeding down, it should take about two hours for the rail pressure to drop after shutting the car down. The fuel normally will be making its way back to the low side of the system and that should still retain some pressure. It's common for GDI to turn the pump on to pre-charge the system when the door is opened and the dome light comes on. (Port fuel injected engines waited until the key was turned to prime the system.)
As far as the pressure bleeding off, the low side of the system can be monitored with both a gage and with an appropriate scan tool. The high side (rail) can only be monitored with a scan tool. I suspect you may see some bleed-off, but it cannot be significant because that would impact the cold starts even more than the warm restarts. When I listened to the recording, I could tell that you had no cylinders firing, then some random combustion events just short of starting and then it fully started up. The first thought when I experience that is excess fuel vapors making the engine too rich to start, essentially its flooded. With the injectors in the cylinder and not in the intake, a leaking injector would cause a single cylinder misfire, and not load up the entire engine except for the random occurrence at shut-down when the engine stops turning and leaves that cylinder's intake valve open.
While nothing is ruled in or out yet, its far more likely that you could be getting fuel into the intake from another source such as a stuck open purge valve. There could be a fuel injector command issue causing an incorrect fuel delivery during warm crank. You might even not be getting proper spark or injector command. Someone is going to have to take the time and confirm what is working and what is not during the three seconds worth of extended cranking that is occurring. That takes planning and discipline and the tech who has learned to do this usually doesn't event get paid for the effort.
i was specific in my previous visits that it needed to sit for an hour to 1 1/2 before trying to crank. The purge valve was the first thing I had replaced, no change in condition.
i have not tried to step on gas while cranking yet but I will- what am I looking for with that operation?
i figured that warranty work doesn't pay and suspect I was being pushed out the door without any thought put into the diagnosis, then I showed them the first set of videos and because a error code didn't pop up I was told there was nothing to fix.
i am not against the dealer having my car for a week to fix it, but I get the feeling it's just sitting there and then I get a call that they can't repeat the problem and it's working just fine- come and pick it up.
i just find it hard to believe that with all of the enclaves, traverse, Acadia, etc. running around that I am the only one with this issue and everyone acts totally shocked that this car does that.
that it really is defective. "IF" its flooded, you will see it start quicker because the PCM recognizes that as a command to clear a flood and it shuts the injectors off. That leans out the mixture and it will fire quicker. If it is not flooded, then it will make it harder to start and maybe not start at all. You'll have to cycle the key and attempt a restart without stepping on the throttle. Without being there and knowing who you were talking to, what his/her technical education is if they were just a service advisor, let alone what kind of communication took place between the advisors and the techs in regards to the symptom and any attempts to recreate it, it's easy to expect that we are missing details here. You probably do have to leave this for an extended time. Even if the symptom is replicated, they have about three seconds per test event to narrow down the focus on the issue, and then they have to wait for the approximate amount of time to get another chance to advance towards a solution. This is difficult work for any technician and you really need a top gun who is very patient and disciplined in his/her approach. This may take a dozen events to genuinely make real progress, and by your description that could take a couple days to accomplish. This is where the common misconception is. Even if someone has had a car present with a similar symptom, that means nothing when it comes to dealing with the next one. (In this case yours) Each and every car has to be analyzed on its own. Assuming what fixed another car will work this time is how someone ends up throwing that purge valve at it blindly. The catch 22 here is if that would have worked, the techs get insults tossed their direction because you fixed it yourself as if that portrayed competence. As you see when that approach doesn't work if that is someone's technical limits, they are overwhelmed and don't know how to proceed and that's the real competence showing.
When tossing a part like that works for a shop/tech nothing is really learned and the lesson and experience come later when they have a car that it doesn't work. Now the job is upside down and everyone loses.
Why didn't you stay with the independent technician and just let him/her solve the problem?
It's clear in your posts that you are or have been a "service technician" and I applaud you for that- I 'm just a guy trying to figure out how to fix my car because the ones that are supposed to have all of the knowledge of fixing it either don't want to, won't get paid to or can't. As you stated above- they only have 18 minutes to diagnose warranty work, after that they don't get paid for it. As a service company that is a poor procedure, unless the intent is to wait until the warranty expires and then magically find the problem and present me with an overinflated (twice the cost of an independent shop) bill.
I think its sad that I have to diagnose the problems for the "technicians" because they won't get paid enough to do it correctly the first time or they don't care. At the end of the day I am the one left driving this car and if I have to fix it I will- but again, I shouldn't have to because it's under warranty.
And from my recollection I do remember stepping on the throttle during one of these extended cranks and it caused it to crank even longer and run very rough for a longer time period than if I wouldn't have stepped on it. I know I said earlier that I didn't do this but it's been 8 months of dealing with this and after thinking it through I remember doing that, just like we would in an older vehicle if it was flooded.
FYI- I haven't reached my technical competence level as of yet, I posted on this forum to give me ideas of other things I can possible do instead of bringing it to the dealer because multiple dealers have already said there isn't anything wrong with the car a half dozen times- so I am not sure whos competence level is being called out here. And correct me if I am wrong but isn't a shop technician one that needs the scanning tool to tell him what part to replace? A true mechanic should be able to diagnose a problem or at least narrow it down without a scanner.
I welcome all other opinions besides the cardoc3.....thanks again for reminding me why I should never purchase another GM product...ever.
http://forums.edmunds.com/discussion/40553/gmc/acadia/2014-acadia-gmc-starter-issues#latest
Until testing is done, there is a lot more in play and it would be very easy to narrow down where the issue actually is with that one because it's dead and staying that way.