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Old 07-18-2010, 04:20 AM   #11
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Originally Posted by add|ct View Post
At other times, while using engine breaking, I'm going from 5th to 2nd(1 gear at a time if I can help it) and eventually making a right turn onto my street at about 10-15 MPH in 2nd gear. While doing this I get this awkward 'pop' like sound when I go back in on the clutch to shift into 'N'.
Where does the pop come from?

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Is DFCO with engine breaking considered a 'Lean Burn' mode
Lean burn is lean air-fuel ratio, but still burning fuel. DFCO is complete fuel cut off, no burn at all. They are different effects and are used differently.

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or is the car just 'bucking' from fuel cut off then to resuming?
There is a small jerk when going between DFCO and normal.
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Old 07-18-2010, 04:31 AM   #12
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Originally Posted by fobx530 View Post
I don't believe I do this.
You should definitely try double-clutching. Usually, difficulty getting into gear is because you're asking the synchronizer to do a lot of work.

You can do the work for the synchro instead.
1. Shift normally to neutral.
2. Clutch pedal up.
3. Rev-match. Jab the gas pedal to bring RPM up to whatever it's going to be once you're in gear. You may want to overshoot it a little.
4. Clutch pedal down.
5. Shift to 1st.
6. Continue as normal.

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BUT transitioning from first to second gear below 5mph SHOULD NOT do this right?
It's normal to be difficult to get into 1st gear while moving...doubly so with a clutch that's not fully disengaging.

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I don't want to force it into any gear it doesn't want to go in to, but I can't help it when I'm in traffic or freeway. Weird situation when it's traffic, I let the car into neutral to slow down, then when it gets to ie. 3mph, I put into 2nd gear (goes in easily) BUT it shakes violently THUS I have to nudge it into 1st gear. When I finally get it into first gear, yes it jerks a bit, but works fine.
It sounds like you're putting it in 2nd at too low of a speed. The workaround is to slip the clutch. I call it a "rolling 2nd launch"; it's like starting from a stop in 1st, except you're starting from a roll in 2nd.

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What is a grabby clutch?
That's a clutch that is difficult to slip, where a slight foot movement results in it going from completely disengaged to completely engaged. It seems to suddenly "grab".
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Old 07-18-2010, 10:15 AM   #13
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Originally Posted by theholycow View Post
You should definitely try double-clutching. Usually, difficulty getting into gear is because you're asking the synchronizer to do a lot of work.

You can do the work for the synchro instead.
1. Shift normally to neutral.
2. Clutch pedal up.
3. Rev-match. Jab the gas pedal to bring RPM up to whatever it's going to be once you're in gear. You may want to overshoot it a little.
4. Clutch pedal down.
5. Shift to 1st.
6. Continue as normal.


It's normal to be difficult to get into 1st gear while moving...doubly so with a clutch that's not fully disengaging.



It sounds like you're putting it in 2nd at too low of a speed. The workaround is to slip the clutch. I call it a "rolling 2nd launch"; it's like starting from a stop in 1st, except you're starting from a roll in 2nd.

.

For double-clutching, I just rev before dropping the clutch on gear 2 right? Doesn't this eat up the clutch or burn it?

Can you explain your "rolling 2nd launch" technique?
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Old 07-18-2010, 12:02 PM   #14
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Originally Posted by fobx530 View Post
For double-clutching, I just rev before dropping the clutch on gear 2 right? Doesn't this eat up the clutch or burn it?

Can you explain your "rolling 2nd launch" technique?
I think he means throttling slightly above the RPMs usually called for under 'normal' acceleration, kind've like when you first get the car moving from a stop in 1st gear.

In a VX, 1500-1600 RPMs seems to be a solid RPM if you're wanting to shift into 2nd at anywhere from 5-10 MPH, specifically below 10 MPH; especially while your speed is already in the process of slowing some, in order to not not have the engine lugging behind(5 MPH and the RPMs falling to 1000 or so) by the time you shift into 2nd. You don't want to wear out your first gear by going into 1st when you can blip the throttle and shift into 2nd(with clutch of course) just before/as the RPMs of the engine first feel like they are going back to idle from your 'blip' of the throttle. That way, you get the car ready to move when you shift into 2nd while slowing.

By pushing the RPMs slightly to 1500(slightly overcompensating to 1600 is acceptable), clutching in and shifting to 2nd you may thus be able to cut down on the lugging effect you get when it feels like being in 1st would've been the better 'choice'. Now, if you are shifting into 2nd at around 15MPH under normal acceleration and you get these lugging symptoms some other things could be amiss.

HC may be suggesting use without the clutch, but I'm not sure. It can be done that way, but your previous gear I believe is important in that scenario. Otherwise, simply going from any gear to N, then throttling up the RPMs just before clutching and proceeding to your next gear; in this case 2nd instead of 1st, can be done safely without needing to line up the syncros and shifting without the clutch.
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Old 07-18-2010, 12:10 PM   #15
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Originally Posted by theholycow View Post
Where does the pop come from?
Seems to be from clutch/tranny side of engine bay, but I'd have to roll down the windows next time. Definitely has me questioning whether I'm asking the clutch to do too much?

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Originally Posted by theholycow View Post
Lean burn is lean air-fuel ratio, but still burning fuel. DFCO is complete fuel cut off, no burn at all. They are different effects and are used differently.

There is a small jerk when going between DFCO and normal.
That's right. Its supposed to cut fuel off, not lean the mixture.

Sometimes, though, it seems like it wants more fuel or throttle than it should when its under normal driving conditions. Like it wants me to drive as though its spooled up to VTEC-e mode and stuck that way, instead of going lean, the RPMs dropping down to the 1500-1800 range. Though, I've heard some cars take longer than others once VTEC has been engaged to going out of that mode, even though 2500 RPMs was tripped a while back, so to speak.

I'm curious to know what the replacement LAF sensor will do for me in relation to this. If anything.

ADDED: For the record, the VX is my first manual and I'm still a newbie to say the least myself.
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Old 07-18-2010, 01:27 PM   #16
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Quote:
Originally Posted by fobx530 View Post
For double-clutching, I just rev before dropping the clutch on gear 2 right? Doesn't this eat up the clutch or burn it?

Can you explain your "rolling 2nd launch" technique?
On double clutching: If the clutch pedal is pressed down while you rev you are single clutch rev matching. If your foot is off the clutch pedal while you rev (or if you've revved and you bring the clutch up for just a moment while RPM is higher), you are double clutching.

Single clutch rev matching saves wear on your clutch and reduces jerking when you engage the clutch.

Double clutch rev matching does all that, plus it also saves wear on your synchronizers and allows you to get into gear faster, without waiting for your synchronizers to do their job.

On the rolling 2nd launch: Your feet do the same thing they do when you're in 1st gear starting from a stop, but instead you're in 2nd and already moving. You don't just immediately engage the clutch. Instead, you slip the clutch until you're going faster, and you give it a little gas while you do it.
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Old 07-18-2010, 01:28 PM   #17
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Sometimes, though, it seems like it wants more fuel or throttle than it should when its under normal driving conditions.
I've never driven a VX but I think that's usually described as normal for lean burn. The whole point is that it allows more throttle to get more air but doesn't inject more fuel.
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Old 07-18-2010, 01:46 PM   #18
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I've never driven a VX but I think that's usually described as normal for lean burn. The whole point is that it allows more throttle to get more air but doesn't inject more fuel.
I was thinking that perhaps it had something to do with the lean burn, but after all of the recent electrical work being ruled out I wasn't sure. Really, just if anything else was going on in connection with the LAF sensor throwing a CEL every trip these days.
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