LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Help VSS now

Old 04-10-2019, 12:11 PM
  #1  
LT5
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Help VSS now

Ok so as some of you know ive had a ton of problems with my 1994 camaro z28, i have fixed alot of wiring, got rid of alot of fake codes, been working on her alot lately to get this car back on the road ext. So i had 4 codes did a wiring fix on the tps, and the idle air control valve and everything is looking good. I drive 80 miles one day and at the end of my shift a light comes on again....im like ****, so then it turns off and i ignore it. Well the next day the light is off and bam car shuts off again. I have new coil icm, wires and opti were replaced 2 years ago (msd stuff). I have 1 code now out of 4 because i fixed all that wiring which was causing faulty ses lights. But the code 24 still is showing, the car will not start if i turn it off and try to start it right away, but let it sit and it starts. The mph does not work either, i did replace the VSS before but maybe that one was bad or i need to clean in inside of the tranny where it sits because the thing came out dirty as hell. Anyways i was wondering if a VSS can cause these kinds of problems as i have been having them all day and i need this car for work ( my only car) lol. Any suggestions would be helpful for now im going to try to get under there and take a look at whats really going on.
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Old 04-10-2019, 05:13 PM
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Re: Help VSS now

The VSS code will not shut the engine down, nor will it prevent the engine from starting.

On the other hand, when the throttle is open and the car is moving, the PCM opens the idle air control valve, to prevent stalling when the throttle blades suddenly close. As speed increases, the PCM raises the IAC counts. If the PCM doesn't know how fast the car is moving, it has no way to tell how far to open the IAC. It that the way the car stalled - on sudden decel?

The VSS is a permanent magnet generator. It generates electrical pulses as the teeth on the reluctor gear on the trans output shaft pass by it. If there is a heavy coating of steel particles (which are naturally attracted to the magnet) it could prevent the sensor from working. If you have that much sludge/iron particles in your T56, and it repeats after replacing the sensor once, you may have a problem with excessive wear of transmission components.

The factory service manual also mentions that failure of the circuit could be due to a PCM problem.

Hard starting when hot can indicate a problem with heat soak of the ICM or the optical module in the Opti..
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Old 04-11-2019, 02:56 PM
  #3  
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Re: Help VSS now

Ok so here's the deal, i repaired a ton of wiring she has been running good, But for some reason does not want to start, will start up when it wants to, i put my 300 dollar bosch snanner on it and did all the data....i crank the engine and the RPM do not move at all, to me this indicates a bad opti right off the bat, but im going to follow shbox's site now and go ahead and do the opti test. Because the coil and icm are relativly new and i mean it doesn't matter, the scanner should have sensed that there was some kind of engine movement, and there was nothing it just sits at 50. Any more ideas would be great as i have to use this car for my new job and im over here worried as hell now cause the problem keeps getting worse....
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