GM Volt Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
322 Posts
Discussion Starter #1
It was about 5 degrees F this morning, so I naturally pre-heated my car. I was watching it from out the window and when it came on it shook so bad that it rolled forward as far as a vehicle will roll in park. It literally looked like it got bumped from behind by another vehicle as it rocked back and forth. Now, my driveway is completely flat and my Volt was plugged in to my portable charger.
I’ve noticed before that the car runs awful when the gas engine kicks on at start-up (being in the car, not remote starting) that it’s obnoxiously loud and revs really high, but I’d never assume it was so bad that it would rock the entire car. Anyone else seen this?
 

·
Registered
Joined
·
524 Posts
Have you had recall 16055 done? Other recalls like the chuggle reprogram?
It's not unusual for any engine to be "rude" starting at 5 degrees.
How is the gasoline? Summer gasoline sitting in the car for six months could account for rough starting.
 

·
Registered
Joined
·
322 Posts
Discussion Starter #3
Have you had recall 16055 done? Other recalls like the chuggle reprogram?
It's not unusual for any engine to be "rude" starting at 5 degrees.
How is the gasoline? Summer gasoline sitting in the car for six months could account for rough starting.
Up to date on all relevant TSB's and brand new gas. Rough cold starts are normal. A start rough enough to lurch a car is not.
 

·
Registered
Joined
·
362 Posts
I haven't had it rough when starting it. The weird part I have had happen a few times now is when I park the car, engine running due to erdtt, hit the power button to turn the car off, and it shakes as if I had it in gear or something. Very weird. Wondering if it is a similar thing that happened during starting for you rather than off for me.
 

·
Moderator
Joined
·
4,851 Posts
Try to duplicate it again sometime, while you're next to it outside. Take a video of it with your phone and show your dealer. They'll hear the noise, see the lurch etc. and be able to discern if it's normal or if it needs to be investigated further.

To me that sounds excessive.
 

·
Registered
Joined
·
385 Posts
Mine was idling rough once on a cold start (somewhere in the 20 degree F area). It felt like it was missing on a cylinder, but no check engine light came on, which I would assume would happen if it were actually misfiring. But then the next several cold starts didn't act the same way. I have no explanation for it.
 

·
Registered
Joined
·
250 Posts
Mine was idling rough once on a cold start (somewhere in the 20 degree F area). It felt like it was missing on a cylinder, but no check engine light came on, which I would assume would happen if it were actually misfiring. But then the next several cold starts didn't act the same way. I have no explanation for it.
Adaptive engine learning could explain it. Startup enrichment is a hard thing to program. That is especially true when the goal is to use as little gas as possible. I am guessing GM calibration engineers went near the ragged edge for default table values and let the adaptive learning bring it into acceptance. My engine starts smoother now that it's operated in cold weather for a couple months.
 

·
Registered
Joined
·
385 Posts
Adaptive engine learning could explain it. Startup enrichment is a hard thing to program. That is especially true when the goal is to use as little gas as possible. I am guessing GM calibration engineers went near the ragged edge for default table values and let the adaptive learning bring it into acceptance. My engine starts smoother now that it's operated in cold weather for a couple months.
Sounds plausible to me. I'll run with that until proven otherwise. :D
 

·
Registered
Joined
·
354 Posts
I have observed that the warm up cycle is much louder than when after it has warmed up a bit and sounds quieter. I'm almost sure that it is part of the emissions/warm up strategy of the direct injection timing. Not only does a gas engine have variable ignition spark timing, now, direct injection engines can vary the fuel injection event timing by advancing or retarding that event. It seems to me that you are hearing the cold pistons rattle from some additional lead on the moment of fuel injection.
 

·
Registered
Joined
·
250 Posts
I have observed that the warm up cycle is much louder than when after it has warmed up a bit and sounds quieter. I'm almost sure that it is part of the emissions/warm up strategy of the direct injection timing. Not only does a gas engine have variable ignition spark timing, now, direct injection engines can vary the fuel injection event timing by advancing or retarding that event. It seems to me that you are hearing the cold pistons rattle from some additional lead on the moment of fuel injection.
There are so many variables that it astounds. That's why calibration guys are engineers in every sense of the word. As an engineer myself, I appreciate the heck out of what my car is doing. I've had my rear seat out the last few days to do some cleaning of a spill and it's neat to hear the motor controllers spinning up motors to match RPMs during engine cut-in etc.
 

·
Registered
Joined
·
322 Posts
Discussion Starter #11
Try to duplicate it again sometime, while you're next to it outside. Take a video of it with your phone and show your dealer. They'll hear the noise, see the lurch etc. and be able to discern if it's normal or if it needs to be investigated further.

To me that sounds excessive.
I've tried to replicate it (not with video), but I have it set to deferred and the one time the gas engine has kicked on, the car was parked at my work parking lot, which is sloped, which would have made any lurching difficult.
 

·
Registered
Joined
·
871 Posts
Before I had my spark plugs replaced, if the engine and ambient temperatures were both cold, accelerating at low speeds felt like I was driving on exaggerated rumble strips....extreme vibration from the engine enough to affect the transmission at low speeds.

Lurching the car forward when the engine starts doesn't sound normal on a Volt, but my old Highlander Hybrid would roll a bit if the engine started or shut off while in Park because of the way the transmission was connected.

It could have been that a clutch was a bit stuck because of the cold temperatures, so MGA was able to slightly move the part of the transmission connected to the wheels.
 

·
Registered
Joined
·
9 Posts
Our volt has started doing this as well, after sitting outside in the cold. Has done it once or twice even in the garage, but happens the most after sitting outside. Granted were having cold temps here in DC, but not uncommon for other parts of the country. The entire car shakes, feels like a broken engine mount in my old jeep. It is very audible as well. I am going to go take it for a drive see what happens. The wife just brought it to my attention the other day and tonight was the first time we could replicate it. By the time I can get it to the dealer though its going to be in the 40's so probably won't replicate. Up to date on all TSB/Recall, Early 207 model. I also spoke to my father who works at GM HQ, he couldn't find anything on record for this issue.
 
1 - 13 of 13 Posts
Top