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Vtec honda

Hello
I have had my civic honda 2002 taken cared of by a well-known car care chain shop since I acquired it. Lately it would start convulsing whenever I accelerate usually from around 50 to 60 or 70. The convulsions go away after I settle at a speed of 70 or more, however, it comes back when I slow down or pick up speed again. My lifelong car repair shop changed the spark plugs and the convulsions stopped occurring but only for 2 weeks and the problem remained so this time I brought the car to the dealer who recommended valve adjustment vtec solenoid (codes provided, misfiring found in the system).
Instead of having it fixed by the dealer, I brought the car to a third car care shop recommended by my friend, and informed him of the dealer’s findings. I asked what was wrong hoping to understand( I really don’t, honestly) and he spoke about changing coils, etc. I’m lost. Can you please tell me what is wrong and what needs to be done? Thank you.

Why did you bail out on the Honda dealer? Vtec is a system that changes valve action depending on rpm of the motor. The dealer seemed to be recommending repairs to the system that adjusts the valve action. The 3rd garage has no clue and is just recommending replacing ignition parts that can be tested and hope for the best. Pretty much the same for your regular chain shop.

Sometimes the expertise of the dealer is worth paying a bit more for the service. I’d pull the car out of garage #3 and take it back to the Honda dealership. By the way I have an '03 Honda Civic EX with the Vtec motor and it were my car I’d be taking this problem to the Honda dealership. I do use a local independent shop for many repairs (including a new timing belt) but the shops you are using aren’t very knowledgeable about this particular motor.

@Lita I agree with @UncleTurbo

If you wait too long on your valve adjustments, you might have burned valves. And you’ll be crying when you find out how much that’s going to cost you.

Yep, agree too. Back to the dealer.

"Can you please tell me what is wrong and what needs to be done?"
To give anyone here a fighting chance to answer, you should provide the code numbers.

3 different shops? Why? You bailed on your “lifelong” without giving them a 2nd shot, that’s not fair. Any decent shop gives a guarantee, so the fact that their 1st attempt didn’t fix it should have entitled you to some free diagnostics. Then you wasted a dealers, and a 3rd shops, time. Next place you try, hopefully your 1st shop, go on a road test with the technician so you are both trying to fix the same thing.

To help you understand. Your valves are driven by what used to be referred to as solid lifters. Engines have either solid lifters or hydraulic lifters. In your engine, the cam shaft, which is a long shaft with bumps (called lobes) on it that rotates, and as it rotates, the lobes hit the rocker arms (which act as the lifters in your case) and open the valves as needed.

A timing chain or timing belt connects the camshaft to the crankshaft through a couple of sprockets to keep the valves opening in sync with the rotation of the engine. This is referred to a valve timing

There has to be a cushion between the cam and the valve, this can be a gap called valve lash, or it can be a cushion of oil as in the case of hydraulic lifters. If this gap, which is only in the area of the cam where the bump is not opening the valve, closes up, then the valve may not fully close. This will cause the engine to misfire and will burn the valve, causing permanent damage to it.

The V-tec is a special rocker arm. It ride on two separate cam lobes, each lobe is designed to give the engine special characteristics. All cam lobes have a profile that determines the engine characteristics. All cam profiles are a compromise between horse power, low end torque and fuel economy. The V-tec design allows the engine to have two profiles that are optimized for the load at that time. One profile is optimized for low end torque and good fuel economy and the other is optimized for high end horse power.

The selection of which cam profile the engine will use is done by the computer and the computer controls the rocker arm through a V-tec valve. The V-tec valve directs oil pressure into the rocker arms to change which cam lobe the rockers will follow. The V-tec valve is operated by a coil called a solenoid.

I don’t think the third shop was talking about this coil though. I believe your engine has what is called a coil on plug ignition, that is there is one coil on top of each plug that fires that plug. I think that is what they are looking at, but it appears that the Honda dealer already ruled that out. And I agree with the dealer on this.

Valve lash inspection/adjustment is part of the recommended maintenance on your Honda. If you have not had this done, you should get it done. The 2002 Civic still has a timing belt so if this hasn’t been changed, it is way overdue. It should have been changed in 2009. Your lifelong chain shop may not have been aware of this. It is a very expensive maintenance so you would remember it, around $700 to $1000.

If you have not had the timing belt/water pump service and valve lash inspection done, I suggest that you get a quote from the dealer. Honda dealers usually have a special on this service that is often less expensive than the independent shops and quite a bit lower than the chain shops. Their mechanics are more experienced with the Honda engine as well. get all this done.

I think the Honda dealer is thinking that the problem is in one of the rocker arms. On rocker arm is not switching over to the higher profile causing a mismatch between the cylinders. This will cause the engine to vibrate badly. That cylinder may actually start to misfire under acceleration, causing it to appear that the coil or spark plug is bad.

One last thing, the operation of the V-tec rockers is sensitive to the oil used. You must make sure that only the specified oil is used. It doesn’t have to be the Honda brand, but it must match the Honda specs.

If you haven’t had the transmission fluid changed, you might also have the dealer do that for you. It does require the Honda brand ATF. It only take three quarts so a simple drain and refill should not cost too much. Do not allow them to flush the transmission though, just a simple drain and refill. The dealer should know that Honda specifically recommends against flushing the transmission, but some dealers do it anyway because they make more money that way.