Throttle Body problem?
I recently became the happy new owner of a gas sipping 1993 Honda Civic VX (49 state version) It has a 1.5 liter VTEC-E engine and 5 speed manual transmission. The speedo/odometer don't work all the time so it has *at least* 175,000 miles.....
There's quite a few problems with the car so far but the biggest issue is with how it drives. A few things regarding this.
First,
when shifting at lower speeds (mainly going from first gear to second and second gear to third) the tach does not drop down to 1000RPMs immediately *like it should when the clutch is depressed between shifts*. I'm at 2000RPMs, I put in the clutch, but the tach just hangs out at 2000RPM for a second or three before slowly dropping down to 1000. I usually shift at around 1800-2000RPM when in first or second gear, and 1400-1600 rpm from 3rd to 4th, and 4th to 5th. This car likes to operate at low RPMs. The problem does not go away when the car is warmed up. The problem doesn't seem as noticeable going to 4th and 5th gear (but that could just be because I shift at lower RPMs for these gears)
Second,
When cruising at highway speed (60-65mph, I'm trying to get a bazillion miles per gallon here), and the gas pedal is depressed at a steady constant to maintain a constant speed, there will be a sudden, but subtle, loss of power, and the car will start slowing down, then there will be a sudden, but subtle, surge of power and the car will start accelerating again or at least maintaining speed--the power surge and power loss are very subtle. It actually happens at just about all speeds except maybe below 25mph. It's almost as if it is slacking on the job, and then realizes it and tries to correct itself. The person who sold me the car said that that was the car entering into the lean burn mode. But I am skeptical. Especially when you consider the third part of this problem of which all three parts I'm assuming are related.
Third,
When accelerating at lower speeds, especially at low RPMs (say 1200, no really, the car likes low RPMs!) sometimes in addition to lagging, it stutters, and for a brief moment, sometimes, I think the car is going to die on me. But then it pulls itself together and pulls forward. It doesn't always do this so I don't think it is a lugging problem. When a car lugs, it makes an unhappy but fairly even noise that screams 'Up shift! Up shift! For Godsakes Up shift!". There is no noise out of the ordinary, and it seems to me the jerky stutter is too erratic to be a traditional lugging of the engine.
Might there be something wrong with the lean burn aspect of the VTEC-E engine?
Here are some of the things I've been told might correct the problem, or that I thought in my own limited understanding of cars might correct the problem: (these are quotes from car forums)
"VX and CX engines are both finely tuned engines and require valve adjustments every 15,000 miles I believe."
"the varrying throttle in my expearince is the o2 sensor, but going thru and doing a tune up might make it go away as well, make sure your EGR valve is working properly too, as I was told by the dealer mecanice that if that is not working right that it can sometimes have the same affect, to check that simply pull the vaccum hose off the EGR valve and plug it with a pencel." [sic]--dyslexia maybe, or English not his native tongue
I'm car-DIY-aphobic so I haven't messed with anything on the engine myself. I've left that to my friend who works at Jiffy Lube (who was the one to do the tune up). Oh, the guy who sold me the car said the rising RPM problem could be fixed with a throttle body cleaning? or something with the throttle body--not exactly sure, the car lingo kinda goes in one ear and then gets stuck on some ear wax before it ever gets a chance to actually penetrate any gray matter let alone make its way over to my other ear.
It did have some other throttle issues, but they *were* mostly improved by tune up. For example it stalled once on the 45 mile drive home from where I bought it but hasn't stalled since the tune up. But the engine still rises to 2000RPMs sometimes inexplicably when I put the shifter in neutral (the temperature gauge indicates the engine is warm, but this will continue to happen up to ten minutes after the temp gauge has stopped rising-or even after a long drive [not all the time, but sometimes, when it feels like it. Sometimes it'll stay motionless at 1000RPM like a good tach, and other times it will bob up and down between 500 and 1100-but then sometimes it'll sorta just wander up to 2000 and hang out there. This seems to happen more while putting along in congested traffic in town])
Just so I'm really clear. What I *want* the car to do is to idle normally . That is stay at 1000RPM at all times when not in gear (I don't really mind the bouncing tach at low RPM). If it wants to warm the engine up at 2000RPM, then it should do it for the first five minutes, not at random intervals throughout the day. And I want it to have even and smooth acceleration and to maintain even throttle response when I have the throttle depressed at an even, constant pressure.
__________________
three stripes the charm!
Car mods are overrated. Just gotta adjust that nut behind the wheel for best mpg.
Forget about World Peace...Visualize using your turn signal.
|