RPM smoothness variability

[Doc308]

I may have seen this addressed before in another post, but couldn't find it in the archives.

Anyway--my engine seems to run slightly roughly under 2--2.5k rpm. It feels almost like the traction control is about to kick in ( but it doesn't). As soon as the revs go above that range, it all smooths out very well. The engine is not missing , there is no power loss, and the idle seems fine (aside from a very slight roughness). Is this the way these engines run or does it sound like there is a gremlin somewhere. Is this typical of the V-Tec design?

 

[DDozier]

Well it all depends on your definition of "slightly rough". there is a rough idle spot around 1300-1400 RPM, that I have had on both my 91 & 92. I was able to reduce it by, balancing the injectors ( aprox. $180.00), cleaning the intake, and loosening the engine mounts then reving a few times then tighten everything back up. As far as anything around 2500 RPM I have not seen that on my cars, but I can tell you that I would start with the same items and see if that makes things any better. All but the injectors are easy and will cause no real down time, the injectors are harder because yours will have to be removed and sent in for cleaning, then reinstalled. Unless you know someone with a cleaned & balanced set lying around ( I have two ) then you can buy those to install the same day you remove yours, send yours in and then sell that set when you get them back. If you do the injector thing, change the fuel filter while you are at it, may not help the idle but will help on the top end of the rev range.

Dave

 

[Doc308]

Thanks, DD. Maybe you're right that something may be a bit off. The procedures you describe will be done fairly soon anyway just from a scheduled-maintenance standpoint. However, I didn't want to convey the impression that something feels wrong with the car. Maybe a better way to describe it is that it just feels " different" below approx 2-2.5k rpm and I was wondering if this is just characteristic of these cars. As noted, acceleration is smooth and powerful at any rpm range. It just feels different when driving slowly at that lower end of the rpm range.