Picartman

Hello everyone, I've been having an issue with my Civic for a long time. Hopefully someone can give me a hand and help me figure out what's going on.

Whenever my civic's IMA battery power drops too low, in order to recharge the battery, it refuses to auto-stop the engine when I'm completely still. At this point, the engine continues to run, and on the dashboard it shows that the battery is recharging.

The issue is when I accelerate from stop when it's recharging. If I release the brake and press the gas without waiting at least 1 second, the car makes a nasty thump. I feel it coming from the center/center-front.
If I release the brake, let the RPM's jump from 1,000 to 1,250, drop back down to 1,000, and then press the gas, then there's no issue. Basically, I have to wait 2 seconds to accelerate or else the thump happens.

In order to better illustrate the issue, I have recorded a video. In this short video, you will see in the first clip I release the brake and press the gas quickly, and it makes the thump. In the second clip, notice how the RPM's jump up and back down, and then the car accelerates slowly with no thump. Please note I always press the gas very gently, and regardless, it would still make the thump. Video: https://www.youtube.com/watch?v=gWnt...ature=youtu.be

The dealer didn't see anything when they claimed they drove it around and tested it, so hopefully someone here has a better idea. Looking forward to any responses, thanks for looking.

ezone

I can speculate that your feeling has to do with the battery charging and what the system has to do to the engine in order to charge the IMA battery.

If you take it to your dealer, you REALLY need to demonstrate your issues to the technician or advisor. That's about the only way to get everyone on the same page. By all means take them for a test drive but keep it brief like 5 minutes or so (time is money!)
Trust me, you can try to describe a problem to the advisor until you are blue in the face, and 95% of the time everything you said is ignored.


Also, has your IMA battery been replaced yet?

Picartman

I would love to show this issue to the dealer, but it's impossible to get the timing down right. The IMA battery needs to be recharging, and that happens once every 80 or so miles. The best I could do was record it. Before I go and show them the video though, I wanted to ask on these forums. To be honest, I don't really trust my dealership.

Around 80,000 miles I kept complaining about sluggish power and the IMA battery always draining on my Civic. After going back and forth many times, they finally checked the battery, and saw that it was almost depleted. I had it exchanged free of charge, but it was still irritating to have to convince them that the car wasn't functioning properly.

Also another thing, a "transmission mount" (as they called it) was replaced at around 100,000 miles. The car has 122,000 miles on it now. Perhaps the thumping noise has something to do with the mounts?

ezone

I can tell you (as a Honda tech) the video does not show much worthwhile. All you really show in the clip is the tach, and I could not hear anything of value through my laptop, it sounds like you are putting the shifter into gear.. Not much to go on there at all.
It's very difficult to record a feeling.


I don't know that what you described would concern me much if I felt it either. Like I said, I speculate this may be due to battery charging routine/strategy with elevated idle RPM combined with the start clutch engagement upon takeoff. The RPM probably needs a second to drop down after you release the brake pedal before it engages the start clutch, and your feeling might have to do with trying to take off (start clutch applies) while the RPM is still elevated.
(I have no idea if this matches what I see in your video!)

I speculate this solely because you indicate the only time this happens is when it's in an IMA battery charging routine.

We really are supposed to wait until the battery causes certain fault code(s) before replacement, we can't just slap a $2500 battery repair (I don't know the real price) on a car without just cause, proof, -- and authorization.
A factory rep would likely need to be involved to authorize the job, that can be a hassle by itself.


I can't answer that from where I sit. Anything is possible, I guess.


HTH

Picartman

Thanks for the in-depth response. If you turn up the volume, you can hear a distinct loud thump in the first clip.

I can feel the thumping noise coming from the center of the car, but I feel the force of it throughout the entire car. It does not seem like normal behavior, especially since it started happening only a few months ago. I just never looked into it because I would purposely accelerate slowly, which would prevent the issue. However, since I'm convinced that it's not a normal thump, and that it started happening after 100,000 miles, it concerns me. I'm asking here because I have no way to show the dealership techs, and this video is all I have. I don't know any other way I could film it in a more explanatory manner.

I'm assuming that the start clutch is being applied and the car is shifting into gear, like you said. In fact it does seem to match with what is happening in the video. I couldn't film my feet and the dashboard at the same time though, which is why I tried to explain the situation as best as I could through words I just feel as though this thump is way too loud, and perhaps it had something to do with the transmission. It's just a guess though, I don't know what else it could be.

ezone

What I heard sounded like the shifter being moved.
I'm using a laptop though. This thing is not known for quality sound reproduction.

Could your complaint be a metallic clunk-- as in maybe loose mount hardware or a bad mount?

Is the hood prop rod clipped securely into its resting spot, or is that clip broken? (I saw one of those make a surprisingly loud bang LOL)



Allow me to wonder this for a minute:
How are you managing to get the IMA battery run down so far that it disables auto-stop and has to charge at stops?

With a good IMA battery and conservative driving habits it seems like this should be a very rare occurrence.

Picartman

I always had the hunch that it is a loose mount and something is smacking something inside the car when the thump happens. It's not a metallic thump though. Imagine shifting a manual car into 1st gear, but not letting the gears engage all the way and the car stutters forward and makes a thumping noise. I'm willing to assume its either a shifting/gear issue (which I don't know if an automatic hybrid can even have that issue) or a mount issue. I just checked the hood and its latched on properly, good suggestion nonetheless.

The 2007 and 2008 Hybrid models are known to have this issue. Back in June of either 2010 or 2011, there was a system reflash that changed the way the car handled the IMA recharge. Everyone was complaining that their batteries were reaching 0% and not assisting, or that their batteries were failing. The reflash made it so that the battery could not drop below 20%, and that the car would not auto-stop when recharging it. This made the batteries last longer. However, many people now experience sluggish response times when driving the car when it's recharging. People would say that when accelerating, the car is extremely slow to respond, and it feels like it's driving through quick sand. I drive this car like a grandma, never passing 1,900 rpm, coasting as much as possible, and avoiding the usage of the AC. I'm getting 42mpg driving 95% city, which is good, but my battery dips to 20% and recharges every 50-60 miles of driving.

Google "2008 Honda IMA battery issues", "2008 Honda sluggish acceleration", and "2008 Honda IMA battery reflash" and you'll see how bad it is.

Picartman

Bump

ezone

I just drove an 08 that does exactly the same thing you described.
It has a weak IMA battery too.

Picartman

Yeah I wish Honda would just admit that there was some sort of issue. Instead, they just slapped a reflash on the system and gave the owners a driving experience they didn't pay for.

ezone

This 2008 I drove does not have a trans (CVT) problem at all.

The thump I felt is not a complaint. It has everything to do with the elevated idle RPM for charging the IMA battery.


Not sure if this car makes noises upon takeoff, this car looks like someone has been living in it LOL