Valve clearance -> power loss: who can figure this out?

Hi,
I have a 99 accord EX coupe, which was running fine, the engine was making a little tapping noise, so I took it to a dealer for valve adjustment.

After the adjustment, the car's power, acceleration, mileage dropped drastically. Mileage went down from 32 on the highway to 26, the car seemed sluggish on every gear.

So I took it back and the dealer claimed that 21 was the normal mileage, those F&^** can say that, but I know better.

So I went to work and redid the valve clearance myself. All the valves were out of spec by .002 to .003 inches.

The valve adjustment is exact (done by me this time), the specs I used are .009- .011 inches on the intake and .011 - .013 on the exhaust for F23A1. I cross checked that with a lambs automotive database.

The engine has grown appreciably smoother now and really quiet, but the original problem of sluggishness and low mileage still persists.

What could be the problem? The engine seems to be revving higher when I press the accelerator but the car is not accelerating..

I could easily chirp/squeal my tires on the road in 1st gear before this started, but now I cannot seem to be able to do that..

What should I try? Will the Ignition timing have to be reset, redone? Check the clutch? Check engine compression? Any suggestions?


Need some input on this problem.

Thanks

Rao

Did you do the valve adjustment with the engine cold?

Yes I did it when it was perfectly cold.

How about spark plugs, plug wires, cap/rotor, fuel filter, air filter, *O2 sensor

If you haven't replaced your clutch than I would believe that this is your main problem (disc is worn down). If your revving higher and not really going anywhere then your clutch disc is worn down therefore not transfering engine power to the trans. Hope this help[s

If you haven't replaced your clutch than I would believe that this is your main problem (disc is worn down). If your revving higher and not really going anywhere then your clutch disc is worn down therefore not transfering engine power to the trans. Hope this help[s


I dont think it is the clutch.. Something else is wrong, the car is burning a rich mixture..

One possibility is that the o2 sensor is bad, but how did that happen during the valve adjustment?

Also, the mechanic cleaned the engine compartment with water after the service, could that have shorted some sensors??

I dont think it is the clutch.. Something else is wrong, the car is burning a rich mixture..

One possibility is that the o2 sensor is bad, but how did that happen during the valve adjustment?

Also, the mechanic cleaned the engine compartment with water after the service, could that have shorted some sensors??

I would try replacing the dizzy cap and rotor and plugs too while you are at it. If you run the car rich enough you will foul the plugs and it will continue to run rich even if you have corrected the oringinal problem.

There could be many things that can give you poor performance. Most important check your ignition system (cap/rotor, plugs, timing, plug wires) and then your fuel system (listen for injectors using a long screwdriver, check fuelpump and fuel pressure). It is true that your O2 sensor can give you problems but I believe the cpu should give you a code. Also you might want to check the EGR valve.

Hi,
I have a 99 accord EX coupe, which was running fine, the engine was making a little tapping noise, so I took it to a dealer for valve adjustment.

After the adjustment, the car's power, acceleration, mileage dropped drastically. Mileage went down from 32 on the highway to 26, the car seemed sluggish on every gear.

So I took it back and the dealer claimed that 21 was the normal mileage, those F&^** can say that, but I know better.

So I went to work and redid the valve clearance myself. All the valves were out of spec by .002 to .003 inches.

The valve adjustment is exact (done by me this time), the specs I used are .009- .011 inches on the intake and .011 - .013 on the exhaust for F23A1. I cross checked that with a lambs automotive database.

The engine has grown appreciably smoother now and really quiet, but the original problem of sluggishness and low mileage still persists.

What could be the problem? The engine seems to be revving higher when I press the accelerator but the car is not accelerating..

I could easily chirp/squeal my tires on the road in 1st gear before this started, but now I cannot seem to be able to do that..

What should I try? Will the Ignition timing have to be reset, redone? Check the clutch? Check engine compression? Any suggestions?


Need some input on this problem.

Thanks

Rao





i have exactly same problem as you on my 2002 Accord
did u find out what was causing major power loss?
please let me know

I've been away a while but now that I think about it; it sounds like you might have a problem with either your mechanical or ignition timing. If any one of these are a little off you will definitly experience poor gas milage and loss of power. I experienced this myself after I rebuilt my engine two years ago. When I reasymbled my engine one of my timing marks (front balance shaft) was off by two knotches of the timing belt. When I started the car it sounded ok but driving down I-95 I realize my car was topping out at 110 mhp. To make a long story short I fixed the mechanical timing issue and still noticed that I was lacking power and had poor gas milage. A friend of mine bought over his timing light and we found at the engine ignition was 10 degrees out of time. Once the timing was fix I regained the lost power and the milage went up from the lousy 19 mpg to 26mpg.