Dear All,
I just bought an Accord 99 LX 5-speed MT.
At normal engine temp (this is not happen if the engine still cold ) , if I change the gear, the RPM will rev up a little for awhile then down (just like you still push the gas paddle then push the clutch). The sequence is I put my foot off from the gas paddle then push the clutch, usualy it very quick (RPM drop). I drive alot of manual trans cars ( I don't like AT ) for years. And I still drive my other cars (94 Camry MT and 94 626 V6 MT).
If I just release the gas paddle and push the clutch...it seem the RPM just stay there for half second before drop. Looks like vacuum leaks ?
Other problem, the engine temp gauge does not have grade, when start from cold...in 2 second it move to middle very fast and stay there. I dont think its right because the RPM still in warm-up mode (above 1000) and the RPM will drop to normal after warm-up (usualy take a couple minute).

Thank's[/align]

 

This sounds normal to me. I will check my car at lunch but I think it is normal for the rpm's to "float" there for about half a second when you depress the clutch.
And the temp guage sounds to me typical of how Honda temp gauges behave.

 

My '98 temperature gauge doesn't act like that. Start it cold, it'll take aminute or 2before the gauge begins to register anything as the engine actually warms up.

If the engine is already warm (say I park for 5 minutes) then the gauge rises to the temperature very quickly. I guess it depends exactly whatyou meant...

 

I was thinking it was the same as what happens on mine: I crank the car &let it warm up for a few minutes. As soon as the car starts to get warm, the temp needle progressively travels from the bottom to the middle with little or no pause in between. Both of my Honda's warm up like this.
Of course, if that is not what he is talking about, maybe it's not normal[&:]

 

I might be a little bit paranoid with the car because I have it with a very good deal (a price of Camry..!).
Anyway...I don't think the is RPM right, Every time I change the gear It will rev up a little before drop unless after I release the gas wait for a while before push the clutch. I think the RPM is floating too long ( It's only happen when the engine is already warm).
Well, I am going to clean up the throttle body, check the PCV this weekend soo.....hope fix the prblm.
The temp gauge behaves like that even when the car is started from overnight cold, My wive's car (98 LX AT) does not behave like that.

Thank's[/align]

 

Oh...maybe something is amiss then. Any check engine light? I think I was wrong about my RPM's as well. I have been watching them and they really don't "float" like I thought they did. As soon as I let off the gas and press the clutch, they start to fall.

 

I think that a vacuum leak would cause your idle to run high all of the time. A sticking air control valve or throttle plate could cause your idle problems. When you take yourfoot off the gas, there would be too much air entering for a second till the throttle plate seats or the air control valve closes a bit. Cleaning out the throttle body is a good start. I know that the idle control valve is different on 98+ Accords, so I'm not sure how you could clean that out. Maybe spray a bit of throttle body cleaner in the hole in the throttle body to clear out any deposits. Seafoam might be a good option for you too.

As for the engine temperature, replacing the thermostat is a cheap maintenance item. Buy the thermostat from a Honda Dealership (~$12), because aftermarket ones open at a differnt coolant temperature and can cause problems. The only other problem that I could think of is an erratic engine coolant temperature sending unit. If the resistance jumps from cold to hot then you might want to replace that. The resistance should change gradually. Make sure to ground the cable that plugs into it, because the temp gauge needle will move to H when the circuit is open and the needle could get damaged.

 

I put of and cleaned the throttle body. Adjust the idle air. The rev up is not as bad as before.
But I feel the engine still not right. It almost no engine brake. Not like my other cars. Its weird because this car is my lowest miles car that I ever have, it only around 80 K miles.
I'll run compression test tomorrow and vacuum test after that. Hope not the piston ring.
But it is most likely the piston ring because the oil slightly decrease and gets dirty earlier ( compare to the 98 accord ).
Now I need your opinion about this:
If it the piston ring ( not valve ), I probably just replace the engine instead fixing it.
I have 2 engine options:
1. from 2002 accord lx coupe (4Cyl) LEV with a good history known miles.
2. from 1999 accord lx (4Cyl) ULEV no history (I have to run the compression test my self).
My car is LEV.
So..which one ???

Thanks

 

I would go with option 1. But don't go replacing that engine just yet! Do some diagnosis first! Post any results here. Let us know how the compression test and vacuum test goes.

 

Rev up the car in neutral with the clutch pushed in. How long does it take the idle to return to normal when you let off the gas? Rev it up in Neutral with the clutch engaged (foot off) -- any change? What's the base idle in neutral with the engine warmed up? Check the throttle cable and cruise (if equipped) cable for binding at the TB.

Engine braking is a function of compression. I think the others are right on the money in recommending a compression test.

I'm assuming the flywheel is stock and not a lightened or aftermarket piece.

BTW -- some modern cars "hold" the revs in this manner as an emissions control/fuel economy helper, but that's usually on modern electronic throttle systems.