shift/one to four

[flyin ryan]

i recently purchased a 1990 ZR-1 ( 1706 ) with a little over 18,000 miles. the car is basically untouched, still has the original windshield & tire's.i'm the second owner. i've hardly driven the car, maybe 20 miles. i was doing some reading & it was talking about the one to four light on the dash. the car has done the one to four shift a handful of times & i got to thinking i don't remember any light come on? so i looked in the owners manual to see where the light is located then i found it in the car. now, i've never seen the shift light come on either but i've never had the power key. here's the deal, the light's don't come on at all when i turn the key. i mean they should right? i can't imagine the 68 year old gentleman who owned the car went through all the trouble to pull the bulb's out & i don't want to rip the dash apart just to check unless it's a last resort. so is there another way to disable those light's that i don't know about or what should i be looking for? i just want to make the car right, you know. thanks alot guys.:)

[guinnessdood]

i recently purchased a 1990 ZR-1 ( 1706 ) with a little over 18,000 miles. the car is basically untouched, still has the original windshield & tire's.i'm the second owner. i've hardly driven the car, maybe 20 miles. i was doing some reading & it was talking about the one to four light on the dash. the car has done the one to four shift a handful of times & i got to thinking i don't remember any light come on? so i looked in the owners manual to see where the light is located then i found it in the car. now, i've never seen the shift light come on either but i've never had the power key. here's the deal, the light's don't come on at all when i turn the key. i mean they should right? i can't imagine the 68 year old gentleman who owned the car went through all the trouble to pull the bulb's out & i don't want to rip the dash apart just to check unless it's a last resort. so is there another way to disable those light's that i don't know about or what should i be looking for? i just want to make the car right, you know. thanks alot guys.:)
You're mixing apples and oranges...The power key and the shift light are not related. The power key is a blank ignition key and can be obtained most anyplace. The 1-4 Shift also known as CAGS is best utilized by eliminating it. If yu search some of the prior forum posts or even within the ZR1NetRegistry website you'll find how to diasble it....nevermind...here it is...

Tip #9: Defeating the 1 to 4 shifting

There are a few ways to defeat the 1 to 4 shifting.

1. Disconnect the molex connector under the ZR-1 next to the transmission on the drivers side.
2. Look at Service Manual 8A-201-25 figure 52; then unplug "2nd and 3rd gear blockout relay" (CAGS relay). The relay is behind the battery.
3. Most of the after market performance chips with disconnect this feature.


If you don't have a power key (turned on) and you don't have the "Full Power" ....you have a 250 horsepower C4...get the key...get THE POWER! Things will never be the same...

Uly

[tomtom72]

I think the shift light comes on at about 6900 to 7K rpm's...with the valet key in the full power position. The "1 to 4" light will come on if you "egg foot" the gas...saves mpg's....like Uly said.

I don't notice them much anymore...I've had my 90 for about 2 yrs & 10K miles now....sometimes the wheel could be in the way & block your view...the shift light is positioned high on the left so it is more visable but you need to be in the full power mode or the motor will not get much past 5K rpm's.:mrgreen:

:thumbsup:
Tom

If you can't find a power key post up someone should be able to help...I have two & I can try a locksmith to find a blank that fits & so on but I think any chevy dealer still can get them(???). Let me know.:thumbsup:

[flyin ryan]

i actually drove the car a little last night & the shift light came on like it is supposed to cruising in 5th to go to 6th. then with the power key on the shift light came on around maybe 6900-7000 rpm like you guys said. so the shift light works good like it's supposed to. but the one to four light dosen't come on at all. the CAGS works fine, but the light dosen't come on. i don't want to dissable the CAGS, i want to get the light to come on with it. so do you guys think the bulb got pulled out or burnt out or is there a way to dissable the one to four light without pulling the dash apart that the guy before me might have done that i can put back the way it's supposed to be from the factory? thank's guys Flyin.

[tomtom72]

Flyin,Maybe the previous owner had a custom chip made for the car? Usually the CAGS light & process is eliminated...along with getting the fans to come on at more reasonable temps. Marc Haibeck has some good explainations on his site as to the why & how of making a custom EPROM, it is interesting reading. Well for me it was as I never had a computer managed hot rod till my Z!;)

You could flip the ECM and take off the PROM cover & look to see what's in there. Seems strange that the light would be dead of natural causes...I would think they last longer than the use you have on your car??:icon_scra

:cheers:
Tom

[flyin ryan]

that give's me a place to start anyway's. thank's alot Tom:thumbsup: .
in my first post i should have been specific as to what keys, ignition or power, i was refering to. after reading the comment's i went back & read my post again & seen where the confusion started. i'm not a 90 word a minute kind of guy so i'm always trying to condense my sentances. sorry about that. thanks guys. Flyin

[tomtom72]

Ryan,

No need to say anything....I'm a hunt & peck type myself, more like 4.2 wpm!:sign10:

We all try to help out each other because that is the way it is with us brothers of the beast.....that's what makes these cars so special....we stick together like musk oxen in a siberian winter storm... isn't anything thicker than our brother hood!
:thumbsup:
Tom

[tpepmeie]

Speaking of the upshift light, there are two different conditions which it can be illuminated. First, the upshift light is enabled at revs above 1400 (& at least 45mph). The exact lighting is subject to throttle position. At the lower revs, the light is illuminated at <20% throttle. Remember, this is a fuel economy-driven upshift light. Above say, 2400 rpm, the light should illuminate at anything less than 50% throttle.

Second condition, is at higher RPMs, when the shift light is "forced" on, regardless of throttle angle. This is the lighting that most people would look for on an acceleration run. On most stock calibrations, this is set for about 5800 revs. It is easily adjusted to a higher limit, but there is a slight trick if you need to go higher than 6375 rpm.

It should be noted, that GM disabled the lighting of the shift light on most of the service calibrations. For example, on the latest '91 calibration, the enable temp is set to 151C. Clearly, you will (hopefully) never see the light if that is the case.

Finally, for 1-4 shift (Computer Aided Ratio Selection) the light and solenoid are energized simultaneously in the program. So if you are not seeing the 1-4 light, yet the gate lockout is functional, I would suspect a faulty bulb. Most aftermarket calibrations will defeat the CARS via either the enable speed or temp thresholds.

Hope this helps,
Todd
91 1145

[flyin ryan]

thank's Todd
see my understanding was that the shift light function was for economy with the power key in the off position & for performance ( upper rpm ) when the power key is turned on. sounds like you have it figured out:thumbsup: . i was driving home late last night & when i got into the city to some stop lights, i pulled away normally & hey what's that, one to four, :icon_scra so i tried to get it to come on again & it did no problem. so now i either have an intermitent light problem( not likely ) or i was on crack cocaine before( not an everyday occurance ). i wouldn't have started this thread if i absolutly hadn't seen those light's originally. ya i know what you're all saying:blahblah: . still seems kinda strange that those two light's don't come on when you turn on the ignition key & every other one on the dash does? maybe it's just me. later guy's. Flyin

[guinnessdood]

or i was on crack cocaine before( not an everyday occurance ). Flyin

Every other day? It might be wise to not be drivin the Z on those days! :-) LoL