Jolting when letting off the gas

[girth]

What are you doing lugging around in 4th and 5th at 25-40? I don't think MSP's are very happy cars in the low part of the RPM band. Sounds like the engine is straining to pull that high gear at low speed and twisting itself into knots in the engine bay.

I experience a lot of lash through the drivetrain/bucking, but it pretty much can happen in any gear and it usually happens around 4k when you're into the boost and let up on the throttle quickly. The car bucks. I just figured it was a quirk, I've also attributed it to engine management. Something I can live with.

25-40 in 4th or 5th is not lugging the engine - not even close. If anything the drivetrain should act SMOOTHER at that low of a speed in that high of a gear because there will be no engine braking effect when you let off the gas. But for me, in 4th or 5th at say 35MPH, I LIGHTLY let off the gas and there's a big jolt in the drivetrain as if I was in a much lower gear - like 1st or 2nd. Only thing is, I'm not. It's a bad drivetrain, that's the only explaination why my 2 proteges both did it but no other FWD stick I've owed has done it.

 

[10lbsmocc]

i drive about 200 miles a day so i notice it also especially in 4th and 5th gear, it seems that the engine wants to go faster even though you are letting off the gas so it bucks it scared the hell out of my friend the first time it did it he thought i broke something but after months of carpooling we are used to it. my only fear is that when I modify my car that lash is going to damage something

 

[rocketspeed]

25-40 in 4th or 5th is not lugging the engine - not even close. If anything the drivetrain should act SMOOTHER at that low of a speed in that high of a gear because there will be no engine braking effect when you let off the gas. But for me, in 4th or 5th at say 35MPH, I LIGHTLY let off the gas and there's a big jolt in the drivetrain as if I was in a much lower gear - like 1st or 2nd. Only thing is, I'm not. It's a bad drivetrain, that's the only explaination why my 2 proteges both did it but no other FWD stick I've owed has done it.

My MSP is unhappy driving around at 1,500 RPMs om the higher gears. The motor really strains. The motor revs freely, so I like keeping it a little higher in the RPM range. The motor pulls along happily and I've got more power on tap. I dont' use 4th much below 40 and 5th much below 60 or so. Its all hilly and stop and go around here, though, so I don't spend much time in one gear unless its on the highway and that's pretty much all 5th. Wish we had a 6th.

I'm not saying what you're doing is wrong, just a different driving style.

I agree, though, letting off the gas gently shouldn't cause that, I thought you were quickly letting off it from your post.

 

[muohio]

I'm also experiencing a smiliar issue in 4th and 5th gear. I can be accelerating at 25% and the car will jerk heavily if I let off the gas. I've not felt anything like it in other manual 4cycl cars in the past. It's actually startling because it happens when least expected.

 

[charles]

My MSP is unhappy driving around at 1,500 RPMs om the higher gears. The motor really strains. The motor revs freely, so I like keeping it a little higher in the RPM range. The motor pulls along happily and I've got more power on tap. I dont' use 4th much below 40 and 5th much below 60 or so. Its all hilly and stop and go around here, though, so I don't spend much time in one gear unless its on the highway and that's pretty much all 5th. Wish we had a 6th.

I'm not saying what you're doing is wrong, just a different driving style.

I agree, though, letting off the gas gently shouldn't cause that, I thought you were quickly letting off it from your post.

Yes, even the WRX does this at low RPMs, and it's easy to make the car "buck" in any gear with unsmooth movements of the throttle.

In my opinion third gen motor mounts allow way too much wheel hop, but that's not really related.

 

[acidbug]

This might be pointless but im sure you all know what im talkin about.

Its really bad when your in 1st but it really happens in all gears. When you just let off the gas, or even if you are really slow, the car will jerk. 1st is by far the worst, it could be in one of those choclate mild comershals(shake stuff up)

Basially wtf causes this? fuel mangement?

This isnt a HELP ME thread, but more a open discussion..kinda like the lets kill the turkey one we had awhile back.

I have similar problems...When letting off in 1st gear..while either being hard on the gas..or light on the gas...

I changed my motor mount..The front one to be exact...It really didn't help...I'll tell ya what it helped w/...Wheel hop!

But at the cost..of my car viabratting...

My suggestiion..is while you are letting off the gas..in 1st..while in traffic..just ease the clutch..while rolling!

G/L

Chas

 

[SoniCraze]

Girth, what you described in your earler post is EXACTLY what i experence. Its totally random, one drive its ok, then the next its jerky as hell, then next its good.

dammit man i waz kinda hopeing it waz just a problem with my car.

 

[ahb11m]

and there was me thinking it was to to with gearing down!!!
like using a lower gear to hold a speed down a hill instead of frying your brakes....

 

[girth]

Girth, what you described in your earler post is EXACTLY what i experence. Its totally random, one drive its ok, then the next its jerky as hell, then next its good.

dammit man i waz kinda hopeing it waz just a problem with my car.

Yup, I'm actually glad to hear it is happening to somebody else because I couldn't believe that my luck would be so bad as to be the only 1 with the problem in BOTH of my Proteges. Both of the Proteges acted exactly the same and that's why I'm guessing it's just not the greatest drivetrain. Just to be clear for everyone else, this is not engine braking we're talking about. Of all the issues with this car this is probably the one that annoys me the most because there's not even a temporary fix for it...we're stuck with it this way.(notcool)

 

[kwiktsi]

its your motor mounts. one moment the engine is torqued back and the next its thrown forward. its normal for ANY car with soft mounts, but most notable on fwd cars because of the transverse drivetrain setup.

If you play with the throttle just right at that point, you will notice it is actually a buck- like poor tuning or something, not engine movement. My friend would pick on my car for it when he drove it and say "wtf was that, why would they even sell this thing like that?" .. He would purposely make it do it all the time just to annoy me.. The transistion in the mounts is instant, this is just a split second after with slight pressure on the accelerator.
Joe

 

[Black Majik MSP]

I've been noticing this a lot more recently. I guess motor mounts will help a little, but in the end it's just the combo of the Protege drivetrain & lack of tuning?

 

[SOSPEED]

Yes the tuning does have something to do with it and also a lot of other thing. The flash really helped with this and later down the road I plan on getting some better type of engine management. But if you get the car flashed put in mounts and run independent lines for your RBOV and actuator that bucking well be no more. Thats what I did and now I have problems keeping the tires from spinning BC theres no bucking or wheel hope. It just hooks up and goes..

 

[MrDiggler]

I'm also experiencing a smiliar issue in 4th and 5th gear. I can be accelerating at 25% and the car will jerk heavily if I let off the gas. I've not felt anything like it in other manual 4cycl cars in the past. It's actually startling because it happens when least expected.

Yep. Right there with you guys. Just hadn't gotten around to searching about the topic yet. The first few times it happened it really freaked me out. I've been driving for longer than I'd care to mention and I've never had a car that bucked like this one.

I notice it in any gear, but especially in 1st. I'm sure that it's because 1st is so much lower. I wish these cars had a taller 1st gear.

Another thing I suspect is the "tuning" of the gas pedal/throttle assembly. A lot of cars these days seem to have the throttle tuned to provide a lot of initial throttle travel with very little initial gas pedal travel. Manufacturers do this to make the car feel snappier when you tip into the throttle. My Escort GT with the 1.8 liter DOHC Mazda motor is also like this, but it's not as severe. Add some power and it gets worse.
One of the things on my "to do" list is correcting this problem and getting some nice, linear throttle travel happening on my MSP.

 

[Nextruss]

i notice easily in 2nd, just go cruising round 2500 - 3500 rpm and hit the gas and let go a few times real quick, it'll buck like the craziest bronco ever. As much as it sucks, it'll make anyone in the car laugh their @$$ off.

 

[kwiktsi]

i notice easily in 2nd, just go cruising round 2500 - 3500 rpm and hit the gas and let go a few times real quick, it'll buck like the craziest bronco ever. As much as it sucks, it'll make anyone in the car laugh their @$$ off.

Yup- that is what I was talking about. Come to think of it, it may be a "mazda" thing- I have driven several 2nd gen RX7's and they all do it also. I don't think my FD did though, but it was so far from stock, it wouldn't matter anyway .
Joe

 

[MrDiggler]

i notice easily in 2nd, just go cruising round 2500 - 3500 rpm and hit the gas and let go a few times real quick, it'll buck like the craziest bronco ever. As much as it sucks, it'll make anyone in the car laugh their @$$ off.

Ouch, that can't be good for the drivetrain!

 

[GREATG]

I would say about 75% of this went away went I put on the 3" exhaust, except for when you provoke it like below.

i notice easily in 2nd, just go cruising round 2500 - 3500 rpm and hit the gas and let go a few times real quick, it'll buck like the craziest bronco ever. As much as it sucks, it'll make anyone in the car laugh their @$$ off.