Tombags

Hello I have a 1992 with the standard 6 speed manual transmission. Sometime (around 2 out of 10 times) when shifting from 1st gear to second, it fights you and won't go into second. If you double clutch it, it will shift smooth. All of the rest of the time it shifts from 1st to second like cutting butter. Any ideas what this is??????
Thanks
Tom

truggiero19

It is the 1st-4th skip shift, fuel economy feature that is not letting you into second. If you are in between a certain speed range and below a certain throttle percentage. The car tries to get you to shift from 1st into 4th. You can go on almost any Vette parts website that sells C4 parts and buy a "Skip shift eliminator." It is just a plug that plugs into both ends of a wire next to the transmission after you disconnect the wire. Makes it so that disconnecting the was does not through any codes.

Tombags

Thanks truggiero19 that makes sense. I appreciate your help

Tom

65GGvert

You'll notice that it happens when you are just putting along, not when accelerating. You may also notice that when it does it, a light will come on on the instr panel that says "1-4 shift". Rev it up a little higher in first and you won't notice either of those things. After you put the skip shift plug on it, you'll still get the light, but it will not interfere with the shifting.

RollaMo-LT4

It can be a nuisance some times, but is very easy to defeat.
Just stay in first gear a little longer before shifting, and you'll notice the light go back out.

truggiero19

The light is quite dim and almost impossible to notice in the day time though if you are not looking for it. The 1-4 really confused me when I first got the car until I looked it up online. I would just buy the eliminator. Its like a $12 part from Corvette Central and takes 10 mins to install. Just jack up the car unplug the original wire and plug the wires with the new part.

MikeT 90 C4sixer

It is a pain, i like toshift gears when i want to, not when the ECM tells me! I plan on taking it out of the chip programming, very soon!

RollaMo-LT4

Well, the ECM isn't telling you "when" to shift.

It just prevents you from shifting into 2nd within a very narrow set of parameters.

Coolant temp needs to be above 170 degrees
Speed between 15mph-19mph
And throttle position is 21% or less

Anything outside of those parameters, and it won't bother you.
I very rarely shift out of 1st below 19mph, so it never bothers me.

Watch your dash light sometime when you take off from a stop sign.
As you move away slowly at about 15 mph with light throttle you should see the "One To Four" light come on.
But if you continue accelerating, you'll see the light go back out.

You really almost have to drive like grandma for this to be a real issue.

Not trying to talk anybody out of the skip shift eliminator though.
Just wanted to point out the narrow parameters where it would actually bother you.

LT4 F45

I bought and installed the eliminator, works great... Dont worry the 1 to 4 light will still illuminate but the feature in the transmission will not.

truggiero19

When you shift sometimes varies though with traffic and how loud of an exhaust you have on the car. I found that when I was in traffic I would want to be shifting into second right in the middle the 1-4 range almost every time because I didn't want to drag out first gear and make a bunch of ruckus while not going anywhere. Now I understand how much fun it is to just make a bunch of noise from time to time but I don't like having to do it every time I take off from a light.

barney c4

3 000 rpm

helphos

My Vette came with the override plug already installed. But when I drove my son's Z28 (same vintage), it caught me by surprise!

It's only bad when you're in heavy stop and go traffic. Then the skip shift will drive you crazy.

I can't imagine that it ever saved any gas. Just a trick to make EPA happy.

MikeT 90 C4sixer

Well in my ECM, the enable temp was 50C, which is 122F. Not sure about the speeds or TPS, that must be in the programming. So if you drive it like grandma, the light comes on, goto 4th, and the motor bogs down. I have wound it out in 1st, and the light goes out, so you can goto 2nd. Just dont feel the need to wind it out everytime. With some of my other 5-speed cars, i usually go 3rd-5th sometimes, and skip 4th. I just want to be able to shift it when i want to. The $$ i saved for the eliminator plug paid for my ECM definition file, and i have so many other things i can do in the ECM.
Good stuff!