I have a working upshift light on my '86 4-speed, and I was wondering if anyone has rewired it so it lights up when its actually time to shift? At like 5200 or 5500 or 6000 rpms? I think it'd be neat, the thing is definetly noticeable when it comes on, and it could help people who like to autocross their car and stuff not overrev their car.
Hmmm my 86 4 speed has one of those too.... It just tells you when to shift to drive your car regular. I seen a pickup truck that had one too... You have a good idea there tho to make it like a factory racing shift light... I have no idea how to do it tho. My bikes shiftlight is programable which is cool.
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05:23 PM
thismanyfieros Member
Posts: 3468 From: Red Deer, alberta,canada Registered: Dec 2002
I have a working upshift light on my '86 4-speed, and I was wondering if anyone has rewired it so it lights up when its actually time to shift? At like 5200 or 5500 or 6000 rpms? I think it'd be neat, the thing is definetly noticeable when it comes on, and it could help people who like to autocross their car and stuff not overrev their car.
Isn't 6000 rpms borderline overreving for a stock 2.8?
I have a 94 S10 4 banger stick. If you shift when the light tells you to you'll be in 5th gear at 20 MPH. The truck will buck and lug and barely run.
Isn't 6000 rpms borderline overreving for a stock 2.8?
I have a 94 S10 4 banger stick. If you shift when the light tells you to you'll be in 5th gear at 20 MPH. The truck will buck and lug and barely run.
Tim
Exactly. The stupid light wants you to lug the engine. I was thinking of finding a way to turn that little light into a racing shift light, it'll come on at like 5200 rpms or so.
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07:02 PM
beken Member
Posts: 158 From: Delta, BC, Canada Registered: Jan 2004
If I'm sort of lugging it, the shift light comes on to provide fuel economy. However, if I'm booting it, the light comes on at a much higher rpm. It's programmed to predict what you are doing based on throttle position or movement or the throttle and engine load. I have been able to have my shift light come on above 5500rpm. So I know it works this way.
If you car is telling you to upshift way too early no matter how hard you're driving, there might be a problem. I'm not sure how the sensors pick up information. If it's through some vaccuum line somewhere, it is possible that after 20 something years, it's clogged and does not get into high performance mode
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07:21 PM
Fastback 86 Member
Posts: 7849 From: Los Angeles, CA Registered: Sep 2003
There is no rewiring to do, the Shift light is controlled by the computer. Its actually a fairly impressive program GM came up with to calculate when to shift for best gas milage, based on the limited sensors the computer has to read from. Suffice to say, it would be a PITA to reprogram it, if you even have the equipment to do so.
**Edit - to emphasize that the program doesn't just say "turn on shift light at XXXX RPMs," it actually calculates when to turn the light based on RPMs, throttle position, speed, and at least one other sensor reading I'm forgetting.
[This message has been edited by Fastback 86 (edited 08-04-2006).]
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08:30 PM
CoolBlue87GT Member
Posts: 8489 From: Punta Gorda, Florida, USA Registered: Apr 2001
SCCA FIERO, Tell us about your tach. Is that a boost gauge ?
I don't think I've ever seen that gauge on a Fiero.
It's from an 86 Sunbird turbo. The gauge is in a few boosted Fieros. Skitime has one, TK had one and a few others. Not too hard to do and almost looks stock.
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12:29 AM
Fastback 86 Member
Posts: 7849 From: Los Angeles, CA Registered: Sep 2003
As some have said I also have a dual purpose shift light. It comes on at around 3k rpms and around 5.5k rpms i willdouble check, but because I couldn't focus on the light when racing on the street I installed an external shift light that runs off the stock tach.
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01:19 AM
cliffw Member
Posts: 37599 From: Bandera, Texas, USA Registered: Jun 2003
How does it work ? I remember some cars having an "Econometer" for fuel consumption. It was basically a vacume guage. I also like the way it looks. I would put one in my Fiero if I could make it somehow functional.
There is no rewiring to do, the Shift light is controlled by the computer. Its actually a fairly impressive program GM came up with to calculate when to shift for best gas milage, based on the limited sensors the computer has to read from. Suffice to say, it would be a PITA to reprogram it, if you even have the equipment to do so.
**Edit - to emphasize that the program doesn't just say "turn on shift light at XXXX RPMs," it actually calculates when to turn the light based on RPMs, throttle position, speed, and at least one other sensor reading I'm forgetting.
It should be easy to reprogram, its just a standard EPROM.. ( getting the setting right wouldnt be as easy, but the mechanics of doing it should be ) I bet an EEPROM would work too.
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10:08 AM
PFF
System Bot
jscott1 Member
Posts: 21676 From: Houston, TX , USA Registered: Dec 2001
Originally posted by beken: If I'm sort of lugging it, the shift light comes on to provide fuel economy. However, if I'm booting it, the light comes on at a much higher rpm. It's programmed to predict what you are doing based on throttle position or movement or the throttle and engine load. I have been able to have my shift light come on above 5500rpm.
Yes the same here, it seems to vary to your throttle/load response. However the driver still decides when to shift
It should be easy to reprogram, its just a standard EPROM.. ( getting the setting right wouldnt be as easy, but the mechanics of doing it should be ) I bet an EEPROM would work too.
Its not different than reprogramming the chip for another reason. The catch is that these old style PROMs require a UV eraser, and you have to wipe the entire memory and upload a whole new program. So in addition to the PROM reader, you need the eraser, too. Not to mention the software and program to upload. And again, you'd still have to do something with that complex Shift light program in the first place.
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03:21 PM
Formula88 Member
Posts: 53788 From: Raleigh NC Registered: Jan 2001
I thought I read somewhere that they disabled the light in 88? The bulb in my 84 could be burned out.
quote
Originally posted by partsman:
Our 88 has a working shift light.
Is your 88 a 4 cylinder or 6? Every 88 V6 5-speed I've seen has not had a working shift light. The blank is there, but unused, AFAIK. On my Formula there isn't a bulb in it, so I'll pop a bulb in it and see if anything happens.
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03:31 PM
Lambo nut Member
Posts: 4442 From: Centralia,Missouri. USA Registered: Sep 2003
Both my 84 SE, and my 84 Indy four speeds, have the shift lights. The Indy, I drive, does not come on at any set speed/RPM. Varies from how much I am getting on it. Does seem to come on early for me though, so I don't pay much attention to it. If you ignore it, it will go away! I shift at about 2500 to 3000 regardless.
Someone grab a bulb and connect it between +12V and ALDL F and see if it lights up cruising around on light throttle. If so, they removed the power to the Upshift light (or just the bulb) or they removed the wire from ECM A7 to ALDL F or they remove the wire from ECM A7 to the dash.
I looked at the calibrations and it doesn't look like they zero'd out the upshift light tables so it should work. They might have turned off a flag that I didn't look for but on fist glance, it should work on the 88.
You could always toss an 86 chip in and see if that works (even a 4 speed chip would at least flash the light). If so , then something else is changed.
[This message has been edited by TK (edited 08-06-2006).]
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11:15 PM
Aug 7th, 2006
jscott1 Member
Posts: 21676 From: Houston, TX , USA Registered: Dec 2001
Someone grab a bulb and connect it between +12V and ALDL F and see if it lights up cruising around on light throttle. If so, they removed the power to the Upshift light (or just the bulb) or they removed the wire from ECM A7 to ALDL F or they remove the wire from ECM A7 to the dash.
One of these days when I'm really bored I'm going to do this test. My guess is that they removed ECM A7 to the dash. I didn't bother to implement the "Up Shift" on my firebird cluster since I never saw it work in the first place.
This light is controlled by the vacuum to the motor. If the light comes on and you don't like it, push the gas harder.
[edit] AFAIK, all manual Fieros have the upshift light.
What he says........cars that had them stock like cuda back in the 60s called them economy meters. Its just a vacum gauge. I even remember seeing one that had MPG markings to show what you were getting....
My 85 se has one and it seemed to work pretty good on the spin i took it for, it gives me 2 shift options, depending on how fast i accel. the economy light and the perf. light so mine works
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02:00 AM
D B Cooper Member
Posts: 3141 From: East Detroit, MI Registered: Jul 2005
I wondered about that awhile back. My 84SE had a shift light, but the 87GT does not. I forgot to check the bulb when I had the cluster out to swap trip odometers though; so I still son't know if it's just the bulb or not. I almost wonder if they omitted the shift light on all getrags ? Not like it matters, I'm just curious.
