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Discussion Starter · #1 ·
So I was told my PCM is done in my 94 Roadmaster, I changed out the spark plugs, wires, coil, regulators, fuel pump, fuel filter cleaned the MAF sensor with that spray and the service engine light is still on (even disconnecting the battery and then reconnecting it doesn't reset it) I am still getting the same codes (4) I did before I listed them somewhere on here needless to say they all trace back to the PCM malfunctioning. So here is my question what now? the book says I have to pull the chip that's in there and erase it and reprogram it ??? but then backyard mechanics are telling me all I have to do is find one with matching numbers?? I am not able to spend another $500.00 or more on this car I'm at a loss and frustrated to say the least any help would be appreciated
 

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These cars don't have "chips". Just change out the PCM with another with the right numbers. Someone here on the forum will be able to come up with one for you. It won't be $500. You might make an inquiry in the PCM section. Good luck.
 

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So I was told my PCM is done in my 94 Roadmaster, I changed out the spark plugs, wires, coil, regulators, fuel pump, fuel filter cleaned the MAF sensor with that spray and the service engine light is still on (even disconnecting the battery and then reconnecting it doesn't reset it) I am still getting the same codes (4) I did before I listed them somewhere on here needless to say they all trace back to the PCM malfunctioning. So here is my question what now? the book says I have to pull the chip that's in there and erase it and reprogram it ??? but then backyard mechanics are telling me all I have to do is find one with matching numbers?? I am not able to spend another $500.00 or more on this car I'm at a loss and frustrated to say the least any help would be appreciated
Do you have any salvage yards near you? If so, you should be able to get another one for under $80. Your cheapest route would be to get a pcm from a 94-95 Roadmaster. Be sure to get one from a car that matches your gear ratio (2.56 or 2.93).

You can get one from any 94-95 B-body, D-body, LT1 F-body and Corvette. However, if it's not from a matching Roadmaster, it will need to be reprogrammed. They are super easy to swap out. Most salvage yards have warranties so, if it doesn't work (which is rare), you could return it for another one. Try car-part.com.
 

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Discussion Starter · #4 ·
thanks guys! ... sorry this has been a frustrating couple of months with nuthin' but problems with her, yeah the book I have said the 94's had chips but if I can get the brain at a salvage yard or now know where to go for the PCM a little bit of a relief ... gotta understand I love my Roadie ...

and I'm glad I found this site with people who know Roadies
 

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You can normally find a PCM for less than $100. It's under the air box, and takes about 5 minutes to change. I do it so often on my cars, I don't bother to disconnect the battery.
 

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When you get a PCM from a salvage make sure it is from a Roady with the same options, shift points will be different as well as speedo scales within the tune that is in the PCM, sure any OBD1 PCM will work just fine, but just make sure that it is for a Roady, the base tunes are very different from let's say a Caprice 9C1.

What was this code that you were throwing?
 

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There are great yards here in so cal. PCM's are $49. Today is half price day at the yard in San Bernardino. they usually have some B Bodies out there.

But first, what codes are you getting??

Who told you the pcm is done?
 

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I found your other post about the codes that you are throwing, but these codes would lead me to believe that either the grounding location (G104) on the drivers side front head is screwing up or the Opti or Opti harness is bad. I highly doubt it is the PCM, they are pretty hearty units and it takes something pretty severe to blow them up.

For others from his other post DTC's set are 42,36,48,55

I really don't think that it is a PCM, but you can buy one and put it in and see if it is doing the same thing to prove me wrong :)

By the way throw out the book that you are looking at :) It is obvious it isn't an FSM :)
 

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I found your other post about the codes that you are throwing, but these codes would lead me to believe that either the grounding location (G104) on the drivers side front head is screwing up or the Opti or Opti harness is bad. I highly doubt it is the PCM, they are pretty hearty units and it takes something pretty severe to blow them up.

For others from his other post DTC's set are 42,36,48,55

I really don't think that it is a PCM, but you can buy one and put it in and see if it is doing the same thing to prove me wrong :)

By the way throw out the book that you are looking at :) It is obvious it isn't an FSM :)
42 & 36 sounds like and optical sensor 48 sounds like a W/P temp sensor 55 maybe an o2? When I had a bad ground at the coil it said bad PCM or something like that. Start with the free stuff like checking redoing the grounds at the coil first. Is the car running correctly and making correct power or missing and so on?

Edit: I was thinking 48 was map so disregard that.
 

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42 & 36 sounds like and optical sensor 48 sounds like a W/P temp sensor 55 maybe an o2? When I had a bad ground at the coil it said bad PCM or something like that. Start with the free stuff like checking redoing the grounds at the coil first. Is the car running correctly and making correct power or missing and so on?

Edit: I was thinking 48 was map so disregard that.
Correct! with 42 and 36 in there as well as 48 this would lead me to believe the ground is a p.o.s. 55 I would think that he fixed as it is generally fuel pressure, fuel filter related. Still this should be checked i.e. fuel pressure to rule that out.

This write up is very good and it should be followed as it consolidates everything into one single post to check, very good information http://www.mainstreamtopics.com/forums/index.php?showtopic=78
 
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