Computer Diagnostics and Tuning Technical discussion on diagnostics and programming of the F-body computers

OBD1 vs OBD2 - What would happen?

Old Apr 7, 2006 | 09:39 AM
  #1  
mitchntx's Avatar
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OBD1 vs OBD2 - What would happen?

A little background ...

I have a '95 Z28 that I have built for road racing.

It has an LT1 motor and 6 speed.

The wiring harness has been completely removed and a bare bones Painless harness has been installed in it's place.

All that the car has is engine management. No trans, no fans, no EGR, no VSS ... just AIT, MAF, coil, throttle body, injectors, fuel pump ...

The car has no key ... it's on a toggle switch to apply power to the PCM, coil and injectors and a momentary toggle to enegize a starter solenoid.

So, when I say basic, I mean basic ...

My question ...

Would any LT1 sequential fire PCM work in this case, regardless of OBD1 or OBD 2?
Old Apr 9, 2006 | 07:19 AM
  #2  
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Re: OBD1 vs OBD2 - What would happen?

Surely this isn't new territory ....
Old Apr 9, 2006 | 02:30 PM
  #3  
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Re: OBD1 vs OBD2 - What would happen?

An OBDII PCM will be looking for the Crankshaft Position Sensor, which doesn't exist on the OBDI cars. Also the knock sensor is different between I and II. To make it easy, I'd suggest just using an OBDI PCM. But, doubtlessly, those 2 problems I mentioned are not insurmountable.
Old Apr 9, 2006 | 09:12 PM
  #4  
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Re: OBD1 vs OBD2 - What would happen?

Thanks for the input ...

w/o a CPS, will it just throw a code? For 96 at least, the PCM was just looking at the CPS for misfires, as I understand it. No operability issues ...

And if I install a "287" knock module, that should make all the little electrons happy, right?

The reason I'm asking is I have a shelf full of OBD2 PCMs and a single, suspect OBD 1 PCM. It went through a car fire. The wiring leading to the PCM was melted, but the connectors themselves were sooty, but not melted. There were no signs of damage external.

But who knows what happened inside that metal box. ...
Old Apr 12, 2006 | 10:42 AM
  #5  
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Re: OBD1 vs OBD2 - What would happen?

So, based upon this response ...

http://web.camaross.com/forums/showthread.php?t=444363

There should be no driveability problems. Maybe a few codes, but no engine performance issues.

Correct?
Old Apr 17, 2006 | 07:50 AM
  #6  
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Re: OBD1 vs OBD2 - What would happen?

Well, it appears to work just fine ...
Old Apr 17, 2006 | 09:53 AM
  #7  
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Re: OBD1 vs OBD2 - What would happen?

Sorry I didn't get back to you... I was away from the board for a few days. Glad to hear everything worked out for ya.
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