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How is my check engine light on with no ECM?

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Old Nov 29, 2005 | 10:57 PM
  #1  
84z28350's Avatar
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From: Yellowknife, NWT, Canada
Car: 84 Z28
Engine: 357
Transmission: TH-350C
Axle/Gears: 3.43
How is my check engine light on with no ECM?

Well i finally got around to starting up my second 84 camaro i just picked up recently. To my surprise the beast fired right up, not a bad deal for $300!

Well anyways, this thing has no ECM in it and the damn check engine light is on...

I see the normal ALDL connector under the dash but how the heck does it have a code in the first place?

The choke is pootched on it, would that cause it? i would imagine just the choke light would come on...
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Old Nov 29, 2005 | 11:14 PM
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From: lowry crossing, texas
Car: 1984 Z/28 Camaro
Engine: 350ci
Transmission: T-56
Axle/Gears: 9" 3.73 spool
remove code by removing light bulb for check enginge light...
i also have a 84 z28, also with a 350, also with no computer, also my check engine light is on, go figure, all i need to do is remove the buld and never worry about it, i have thought about making it a shift light, that might be fun
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Old Nov 30, 2005 | 12:36 AM
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84z28350's Avatar
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From: Yellowknife, NWT, Canada
Car: 84 Z28
Engine: 357
Transmission: TH-350C
Axle/Gears: 3.43
This isnt on my 350 swap 84 this is on my other stock 305 84...

My 350 swap has the removed lightbulb

So anyway this car in question being bone stock AFAIK, with all the EGR and all the other good junk. How the heck does this thing have a functional (or lack thereof) check engine light?

Last edited by 84z28350; Nov 30, 2005 at 12:40 AM.
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Old Nov 30, 2005 | 10:50 AM
  #4  
Vader's Avatar
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Does it turn off when you depress ther brake pedal? Depending upon how you rigged the TCC relay, it may be back-feeding through that circuit.
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Old Nov 30, 2005 | 11:20 AM
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From: Browns Town
Car: 86 Monte SS (730,$8D,G3,AP,4K,S_V4)
Engine: 406 Hyd Roller 236/242
Transmission: 700R4 HomeBrew, 2.4K stall
Axle/Gears: 3:73 Posi, 7.5 Soon to break
IIRC the "light driver module" located above the glovebox uder the dash operates in reverse.
Remove the little circuit board from the case and the light will go out forever
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Old Nov 30, 2005 | 11:39 AM
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From: Yellowknife, NWT, Canada
Car: 84 Z28
Engine: 357
Transmission: TH-350C
Axle/Gears: 3.43
I didnt do any "rigging" to this car light stays on with brake pressed.

Its all like it was from the factory w/ 700R4 and craptacular LG4.

I was told that stupid little black plastic box was for the cruise control...
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Old Nov 30, 2005 | 01:04 PM
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If you have the TH-700R4, you'll want to provide some means of locking the TCC if you can. Running without lockup can have several disadvantages, not just in fuel mileage.

The NAND gate module on the early ECMs also controlled the MC solenoid, EGR and EVAP, IIRC.
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Old Nov 30, 2005 | 01:22 PM
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From: Mercedes Norte, Heredia, Costa Rica
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Originally posted by Vader
If you have the TH-700R4, you'll want to provide some means of locking the TCC if you can. Running without lockup can have several disadvantages, not just in fuel mileage.

The NAND gate module on the early ECMs also controlled the MC solenoid, EGR and EVAP, IIRC.
He more than likely has a factory non-computer car, in which case none of the above applies.
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Old Nov 30, 2005 | 07:09 PM
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From: Yellowknife, NWT, Canada
Car: 84 Z28
Engine: 357
Transmission: TH-350C
Axle/Gears: 3.43
Exactly...

Being a Canaduck this is a non cc car, the TCC is operated on a vacuume switch.

Enough about the damn trans though, anyone know wtf is up?
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Old Nov 30, 2005 | 07:15 PM
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From: Mercedes Norte, Heredia, Costa Rica
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Take the bulb out and don't worry about it.

It has a choke light, but it just doesn't turn on?
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Old Nov 30, 2005 | 10:24 PM
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From: Yellowknife, NWT, Canada
Car: 84 Z28
Engine: 357
Transmission: TH-350C
Axle/Gears: 3.43
Well i figured out why the choke didnt work and the choke light wasnt on, the damn fuse was gone. Now the chokes functioning correctly and the choke light works.

The check engine light still stays on though
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Old Dec 1, 2005 | 07:29 PM
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From: WI,USA
Car: 89 FORMULA 350, 91 Z28 Convertible
Engine: ls1, LB9
Transmission: t56, Auto
Axle/Gears: S60/ 3.73
you need a schematic. if I remember right it has a two way feed of some sort (sorry no book next to me) anyway when one is lost it lights the bulb.
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Old Dec 2, 2005 | 12:09 AM
  #13  
84z28350's Avatar
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From: Yellowknife, NWT, Canada
Car: 84 Z28
Engine: 357
Transmission: TH-350C
Axle/Gears: 3.43
Well i think this cars ready to burn down from an electrical fire lol

The engine light is off now!

One thing that really got me going was the damn seatbelt light and the buzzer started going while i was half way down the road. At first it scared the hell outta me because thats one awful sounding buzzer and i wasnt expecting it, then i looked and saw the seatbelt light come on then it went off finally about 30sec later!

WTF?? lol
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