Vibration and loss of MPG after Timing belt change (99 Honda CRV)


#1

My dad changed the timing belt on my 99 CR-V in August and he had some trouble getting it in time (he had to tear down and put it back together 3 times!). Sometime after the timing belt/water pump/spark plug change, I noticed a vibration in the steering wheel while at a stop and a loss of MPG (went from getting 24 mpg to 22.7).

It did not happen immediately after the timing belt change (or at least i dont think it did) so i thought the mpg loss might be due to the changing weather and the vibration coming from a motor mount that i knew was broken, but I got the motor mount fixed and it did not do anything. I think that the vibration has gotten worse, but it seems to be at its worst when the car is really cold. (this morning the temp. was 9 degrees and it vibrated harder than it ever has).

The vibration only happens when the car is in park or at a stop, and it goes away when i accelerate, even if I only accelerate a little bit. I have not noticed a loss in power, or any sluggishness in acceleration. I have tried to research this, and I read something about the drive belt being out of time, but I’m not savvy with cars so I just don’t know.

What could be the cause, do I HAVE to get it fixed, and what do you think a reasonable cost to repair is? Thanks in advance for taking the time to respond!!


#2

More than likely the timing belt is off a tooth or 2. You can pull the covers and check to make sure the timing marks still line up. It will not kill the car, but it’s not running properly and I would get it fixed.


#3

Agree with knfenimore and the engine must be turned over after installing the timing belt. If you button up the engine before doing this…9 times out of 10 the timing marks will not be aligned when you check them.


#4
It did not happen immediately after the timing belt change (or at least i dont think it did)

This, plus no loss in power, suggests to me a vacuum leak or throttle body or EGR issue.
Is the check engine light on?


#5

I have not noticed a loss in power, or any sluggishness in acceleration.

Based on my limited experience, this is not consistent with a timing belt even 1 tooth off
.


#6

no check engine light, and the car seems to run fine!


#7

There’s a variety of things that could cause this symptom, including an improperly installed timing belt. Some engines are considerably easier than others to install a timing belt. The hard ones are usually the kind where you have to route and align the belt over two separate camshaft pulleys, in addition to the crank pulley. Just one crank pulley and one camshaft pulley like my 4afe Corolla has is easier.

And if the job involved removing the engine mount, that has to be done in a way not to damage anything, b/c the engine has to be supported properly. And in many cases there are other mounts that must be loosened first, to allow for the necessary play for access. So that’s another potential cause, like if the exhaust system got damaged in the process.

Finally, another source could be just that some wire or sensor didn’t get re-connected. Timing belt jobs often require a lot of stuff be removed, and it all has to be reinstalled like it was. It’s easy for a diy’er to forget something in the process.

What I’d do if this happened to my Corolla, first I’d read out all the diagnostic codes and address those. There can be stored diagnostic codes with no check engine light. Next I’d remove the timing belt covers and check the belt tension and static alignment marks, then use a timing light to check all the sprockets are aligned like they should when the engine is running. While I was at it, I’d do a visual inspection on all the engine mounts and check the exhaust system for leaks and re-check all the connections to the sensors and other electrical and vacuum connectors.

Still a no-go? If all the routine maintenance is up to date, you’ll probably either need to live w/ it, or to take the car to a mechanic.


#8

If I make the assumption that the timing marks are correctly lined up then the first thing I would suggest checking the valve lash. This should be done every 30k miles but that is also something that is seldom ever done by anyone with a mechanical lifter engine.

This can manifest itself as a rough idle due to lowered compression because of a valve being too tight; usually an exhaust valve. Elevated RPMs has a tendecy to make low compression on a cylinder.

If an exhaust valve is tight then adjusting it to specs may get rid of this problem. (Assuming it is lash related)
The problem is that an exhaust valve can be damaged quickly if the lash is too tight and any correction may be short lived. Hope that helps.


#9

I just wanted to ask the experts here. knfenimore suggested that the timing belt might be off a tooth or 2. I am of the opinion that being off even a single tooth causes dramatic engine idling and running issues - to the point where it would be immediately noticeable.

Am I wrong on this?


#10

When I did the TB on my 99 Camry 4cyl. I got the exhaust cam off by 2 teeth and it was noticeable both in idle quality and acceleration. Not very noticeable, but having driven this car for the previous 50k miles I could tell it.


#11
I am of the opinion that being off even a single tooth causes dramatic engine idling and running issues

Depends on the vehicle. It could just cause the engine to knock excessively. May not effect idle at all. 2 teeth on a small 4-cylinder engine…it probably won’t run.