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94 trans am no start!


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#21 boredguy1187

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  • Year: 1994
  • Make: Pontiac
  • Model: Trans Am
  • Engine: 5.7l
  • Transmission: auto

Posted 11 June 2012 - 10:27 AM

ok terminology was incorrect but i did the tests as they were stated in shoebox and on the video from the thread the dealership near me is selling remanufactured only is it possible the cap and rotor could be bad not the optical part of it? thats what im hoping for he threw the fuel pump at it blindly thinking thats why it wasnt starting only part i have thrown at it was the coil after doing those tests im still stuck tho so opening it up and taking a look at the cap and rotor doesnt sound like a bad idea if its corroded and making a garbage connection that could very well be my issue

#22 boredguy1187

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  • Transmission: auto

Posted 11 June 2012 - 10:34 AM

i had 12v ac at c+b key on engine off, had a reading that jumped to 5v and then bounced between .6-1.6 on crank at d, and no reading at a or d key on engine off for dc when it said i should have had 10dc there

#23 Injuneer

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Posted 11 June 2012 - 12:56 PM

The Opti has two major sub-components -the optical cam position sensor (back 1/2) and the cap/rotor (front 1/2). Either one can go bad all by itself. The optical cam position sensor is an electronic module. It can break down, heat soak, the optical emitters and receptors can get dirty of go bad, the optical shutter wheel can be damaged or dirty. If that happens, you get DTC codes.

The cap/rotor is no different than any other conventional distributor - the rotor tip and terminals can be burned up from high voltage discharge, the tip of the rotor can come loose, the rotor can come loose from the shaft, the cap can crack, the dielectric properties separating the routing wires in the cap can break down, there can be moisture buildup or there can be carbon tracking causing the spark to travel to the wrong terminal, or not at all.

The big problem with the non-vented Opti (93/94) is that the high voltage discharge in the cap creates ozone, and the ozone corrodes the metal internals. At 60K miles, mine was giving me intermittent codes and sudden stutters. The entire inside was full of rust, and the rust particles were blinding the tiny LED emitters and the receptors. The vented version was supposed to vent the ozone from the case. The seem to last longer. When I built the stroker, I converted to a vented unit.

On top of all that, the bearing is a cheap friction bearing, and it wears out. Oil from the timing cover can also flood into the case due to a bad seal. The rubber seal in the tower for the harness connector rots and leaks (it's right under the water pump weep hole). The ozone will then corrode the harness connector. And like any distributor, corrosion can build up in the contact terminals where the plug wires and coil wires attach.

1994 FIREBIRD FORMULA
FRED

 
381ci all-forged stroker (Callies Stealth, Oliver billet rods, BME 2618-T61 nitrous pistons) - 10.8:1 - CNC LT4 heads/intake - Comp Cams solid roller - MoTeC M48 Pro engine management - 8 LS1 coils - 58mm TB - 74#/HR injectors - 300-shot dry nitrous - TH400 - Gear Vendors 0.78:1 O/D - Strange 12-bolt - 4.11 Pro-Street gears - AS&M headers - true duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP / 800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117 MPH straight motor
 
https://www.firebird...9_698_32777.jpg

 


#24 boredguy1187

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Posted 11 June 2012 - 01:02 PM

his is the unvented one and everywhere I go has the vented ones...what kind of a nightmare am I running into replacing it with that or am I just running into parts people that are looking up the wrong stuff...which I believe could happen at an autozone or an advance or something but the dealership was even showing me pics of vented :-/

#25 Injuneer

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  • Model: Firebird Formula
  • Engine: 381ci LT1 stroker
  • Transmission: TH400 + GV O/D

Posted 11 June 2012 - 01:22 PM

i had 12v ac at c+b key on engine off, had a reading that jumped to 5v and then bounced between .6-1.6 on crank at d, and no reading at a or d key on engine off for dc when it said i should have had 10dc there


There is no way you can have 12V AC anywhere in the car, unless the rectifier in your alternator has died. Pin "B" on the ICM is the pulsed signal from the PCM that tells the ICM to fire the coil. Per the factory manual, key on/engine off you should have no voltage at all on pin "B". Then you indicated that you did have a variable AC voltage on the white wire (pin "B"). That would indicate you have an output signal from the Opti cam position sensor, but the AC voltage on the white wire is on the low side.

Then you indicate you have 0 volts on pin "D". Did you have the meter set to V-AC or V-DC? Did you check the ignition fuse?

1994 FIREBIRD FORMULA
FRED

 
381ci all-forged stroker (Callies Stealth, Oliver billet rods, BME 2618-T61 nitrous pistons) - 10.8:1 - CNC LT4 heads/intake - Comp Cams solid roller - MoTeC M48 Pro engine management - 8 LS1 coils - 58mm TB - 74#/HR injectors - 300-shot dry nitrous - TH400 - Gear Vendors 0.78:1 O/D - Strange 12-bolt - 4.11 Pro-Street gears - AS&M headers - true duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP / 800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117 MPH straight motor
 
https://www.firebird...9_698_32777.jpg

 


#26 boredguy1187

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  • Engine: 5.7l
  • Transmission: auto

Posted 11 June 2012 - 01:28 PM

I did switch it over to v dc and got no reading and the ignition fuse is good

as in the fuse isnt broken should test at the fuse make sure there isn't a hairline fracture that I can't see and could be causing me all this grief for a 15cent part...I think I will when I get home anyway




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