I have the the CAGS skip shift eliminator and it works great; MOST of the time! Every once in awhile, the engine will rev when upshifting from 1st to 2nd if REV match is on. It never does it when REV match is off.
I'm wondering if anyone else has experienced this?

 

I Have the skip shift and haven't experienced this.

 

I don't have CAGS eliminator and I think I know what you're talking about. If I'm cruising along and have to stop, I can put the shifter into neutral, and if it is a little off to the left, the rev match will cause the engine to rev up. This can happen on the 1-2 shift but can also occur on other shifts where I allow the lever to move to the left.
It's just the rev match engaging. Rev match is a computer controlled function. If the computer thinks you're going into first or second, it will rev up the engine as designed. I used to be concerned. Now it's just annoying if and when it does it. I have no intention of trying to address it.

 

Thanks for the replies. I thought about replacing the CAGS eliminator but it sounds like its me!

 

The CAGS just keeps second gear from being locked out.. Not sure that has anything to do with the rev match..
Also, it does not seem to make sense that the rev match would raise the RPM on an upshift since the RPM should actually be LOWER than the current gear..especially if you are skipping one or two gears.

It should blip the throttle on a down shift because the engine RPM should be higher in the lower gear to match.

I have noticed even without the CAGS eliminator, the rev match tends to HOLD the RPM when upshifting instead of letting it drop, which give the feeling that it is blipping the throttle.

 

I might try a different CAGS eliminator to see if that resolves it. I have noticed it blips the throttle if I kick the trans out of gear as I approach my a stop sign.

 

^^^
Have had a CAGS Eliminator in my 2014 Z51 and now on my Grand Sport. Never had what you are referring to. The two are NOT connected at all.

CAGS Eliminator just fools the computer into thinking the electrical pulse in sent to the solenoid in the M7 that controls a blocking pin preventing access to 2nd gear was successful. It just replaces the solenoid coil with a resistor of the same value. You'll note the 1st to 4th shift light still activates.

Rev match is much more complicated. I use rev match 99% of the time and have been able to duplicate the overreving some have experienced. In a test I was making my usual 5th to 3rd downshift. BUT while the shift lever was still in neutral I moved in just slightly too far to the left like I was going into the 1st/2nd gate. Never went to either gear BUT the computer was anticipating I was going into 2nd and revved the engine matched that speed.

Rev match uses Hall position sensors and even when you are in the neutral gate, if moving right or left of the gate where you plan to go it will confuse the computer.

On upshifts I don't feel it's working unless again i run a test. On upshifts when I take my foot off the accelerator the engine RPM slows. Rev match does nothing different. HOWEVER if I shift slowly the engine would reduce beyond the proper rpm for the next gear. Rev match will hold the proper rpm for about 2 seconds. I never shift that slow!

 

Never experienced this with my GS, but I don't use RevMatch that often. I never noticed any input from it on the upshift.

 

I agree the two are unrelated, however; I never experienced the issue prior to installing the CAGS eliminator. Maybe I’m looking at this wrong and it’s a REV match issue. I don’t feel like I do anything different anytime if shift from 1- 2. It’s sporadic but annoying

 

^^

As someone also mentioned, if you shift slowly, where the engine rpm would be expected to reduce below where it would be optimum for 2nd gear since your foot is off the throttle, rev match will hold at the ideal rpm for about 2 seconds. That could feel and sound like it revved up.

 

I’m going to try being more deliberate in my 1-2 shift. Again it’s sporadic and I didn’t think I was doing anything different. It seems to blip the throttle higher than just holding it. I have to wait for the revs to fall to complete the shift.

 

Is the need for cags skip shift eliminator a year specific device,as i have experienced being locked out of any gear yet in my 17.

 

^^^

No, but the C7 has a narrow speed range where it occurs. Trying to shift from 1st at 14 mph to 19 mph as I recall. It does not happen often and in fact I don't know how often it does with mine since I installed it early on the 2014 C7 and on day 1 with my Grand Sport. Installed it on the GS when I replaced the brake pads with ceramic the day I brought it home from the dealer! It's a few minute job when the car is jacked up.

On the 2014 I was surprised when it occurred as I had installed it in my C6 so had not experienced it al all for 6 years. I was in bumper to bumper traffic when it would not go into 2nd gear and I fumbled as I was trying to figure if it was me getting used to the shifter springs in the 7 speed!

My concern after, was with all the distracted driving if the person behind when I moved forward had followed and then got a cell phone beep and looked down to see who set a text message, they could have been in my rear! The fact that it seldom occurs could be even more of an issue!

I figure I have a wife that "helps" me drive and I don't need a computer to tell me when to shift to what gear! For under $20 an easy minor mod!

To Each Their Own.

 

thx,i appreciate that info.
I will look into adding this in the future.

 

I quit driving my 56 with it's 4-speed Muncie(non original) because it does not have a computer to keep me from shifting into 2nd gear if I'm at the wrong speed(according to what it believes is the correct speed) nor does it have a computer to operate the gas pedal when I shift gears. After all those years, I discovered that it is not possible to drive a car without computers doing the driving for you. LOL.

I started driving a stick shift in 1954(at 12 years old). I don't know how I survived all those years without a computer living my life for me.

PS- one of the first "mods' I made on my C6 Z06 was to install the CAGS eliminator. It puts me back in control of my shifting gears. I guess I just can't accept "change" like all the "techies" do.

 

^^^
I was born in 1942 as well! Have only had standard shifts as my DD since!

Love my Grand Sport but already considering when I’ll buy a C8. At our age never know how many more Vettes we’ll be able to buy!

Unfortunately looks like will have to get used to no third pedal. They will all apparently have a Tremic dual clutch, computer controlled 7 speed. At least it won’t be a GM slushbox as they are planning only one transaxle, the one from Tremic. Since they also make truck transmissions hope it’s dual dry clutches and not automatic trans type multiplate wet ones.

There goes my often used 5th to 3rd and 7th to 4th direect downshifts! Have to practice pulling on the shifter paddles quickly!

 

KIKNBAK, my '17 GS M7 with CAGS eliminator does what you describe. As others have pointed out, I don't think the 2 are related. But I have had the ARM rev up when shifting 1 - 2. I think it is because I'm lugging around in first, then when I shift to 2, it revs up unexpectedly. It always startles me and I could see it propelling the car forward if I don't pay close attention. It's really an accident waiting to happen, but not really an issues for me. ARM is one of my favorite features of the car and I always have it on.

 

Thanks Redman76; I'm glad I'm not the only one!

I love the ARM feature and HATE the CAGS. I didn't realize it was a feature of the car when I bought my car and just about took the car back. The skip shift eliminator is much appreciated.

I agree the two have nothing to do with one another. I have the the MGW shifter too and I'm just trying to figure what I'm doing wrong. It's sporadic at best and I'm going to try shifting more deliberate. One way to prevent it is to shut the ARM off at a light until I get past the 1 -2 shift.

I appreciate all of the replies. You guys are awesome and are half the fun of owning a C&!

 

This is simply a function of the rev match and has nothing to do with the CAGS eliminator. It sounds like when you're shifting (gingerly) you're letting the RPMs drop too much and the rev match is kicking them back up. It also happens in parking lots when downshifting and what not. I think it's annoying so I don't use rev match for this reason.

 

Don't know that rev match can kick it "back up" on an upshift but it will hold that rpm for several seconds. So if you shift slow, where you would normally expect the rpm to drop as your foot is off the throttle it will hold the proper match rpm. Compared to not using rev match that would appear to be over revving.

You raise an interesting place where CAGS Eliminator can be effective and this slow shift can logically occur-a parking lot. I usually park at the end of most large parking lots where there are no cars. Depending on where I enter I may be in 1st then shift to 2nd at a relatively low speed where skip shift might occur if I did not have an eliminator. Could be the same issue with shifting. Would expect for the rpm to lower below the proper match speed on what could be a slow shift with my foot off the throttle. Perhaps the issue???

If that is not the case could be something wrong with one or more of the Hall position sensors that I believe are in the trans. For the poster with the aftermarket shifter who states the same problem, wonder if the shifter alignment could be an issue? With the OEM shifter there are adjustments that affect the shifter forks and would also affect the position of the Hall sensors???