I am wondering if I can alter the mileage on my 84 berlinetta. I am putting a 350 engine and trans in it and don't want the car showing 150,000 miles when I go to sell it. I would like to change the mileage if that is possible. If so, what can I do? thanks a lot.

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1984 camaro berlinetta, in the process of being restored. Here is my car the day I brought it home. http://www.infopop.com/my documents/84 camaro pictures/car on trailer/bringin the ride home.jpeg

 

The short answer to your question is no you can't change the mileage. It is illegal to do so. It may be considered fraud in your state. This would make it a felony. Just because you put in a new engine does not make the car have less wear. Things like the suspension and the rear end also have 150000 miles on them. You should be honest about the mileage and show reciepts on the work performed to the engine, transmision and other things that you replaced. Most buyers will pay more than the 150000 mile price for a car with a newer engine and transmission. All buyers will be angry when they try to transfer the title only to find that the state refuses because there are less miles on the car than their records show. All states keep track of the mileage at title transfers. Also all states with inspections keep track of mileage on a yearly basis. Altering the odometer is a very bad idea.

John

 

The mileage in the 3rd gen digital clusters is stored in a 256 bit EEPROM, using an encrypted code. Unfortunately, I do not know the encryption algorithm that GM used, so simply clearing all of the memory locations in the EEPROM to zero will not result in the display showing zero, but the message "error", instead. I have swapped EEPROMS between Berlinetta clusters (the EEPROMS are a socketed 8 pin DIP device), when swapping clusters (the V6 & V8 tach red lines are different & I wanted the higher V6 red line for my V8), and I have programmed EEPROMS with a known "good" data word for a specific milage, but I don't know how to arrive at a correct data word for a specific mileage reading. If you really wanted a pseudo zero reading, one possibility would be to connect a signal generator to the VSS input to the cluster & quickly run the mileage up to the next hundred K mile reading, like 100,000, or 200,000 miles, manually.

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Tim

1992 Z28, 305 TPI 5 speed, 12.1 sec @ 114.7 mph

1984 Berlinetta 305 TPI Auto, 13.8 sec @ 99.7 mph

 

Thanks for the info, i am aware that it is illegal and do not plan on doing it, even if i could. I was just wondering if it could be done. I realize that people would buy it for what it is no matter what, so the miles won't matter that much. Thanks again.

 

Hey Tim -


I understand the tach on the V-6 Has a higher yellow-line / redline than the V-8 ,..... but how did you manage to get the V-6 Tach to read the correct V-8 RPM's ????

(I may have already asked Ya' this question !)

John in RI

 

A pulse mask circuit - one pulse out of four needs to be masked to use a V6 tach on a V8. A V6 outputs 3 pulses per revolution of the crankshaft, while a V8 outputs 4 pulses per revolution of the crankshaft.

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Tim

1992 Z28, 305 TPI 5 speed, 12.1 sec @ 114.7 mph

1984 Berlinetta 305 TPI Auto, 13.8 sec @ 99.7 mph

 

Makes sense,........ I always thought the reading was abourt 22% off when using a V-6 tach in the V-8 car. I guess the Tach will really be 25" off !

One more question - Is this "pulse mask circuit " installed in the dash,..... or on the wiring between the tach filter and the Dash cluster ??

Thanx !


John in RI

 

John, when using a V6 tach on a V8, the error is actually (3 + 1) / 3 = 1.33, or 33% high. The circuit would go between the distributor module output (or, in my case, the MSD6AL tach output) and the cluster - cut the white tach wire at the cluster connector & install the circuit in line there.

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Tim

1992 Z28, 305 TPI 5 speed, 12.1 sec @ 114.7 mph

1984 Berlinetta 305 TPI Auto, 13.8 sec @ 99.7 mph

 

Ok, a related question. I intend to swap out my busted 2.8 for a newer v8, and then a digital dash as well. If I understand the posts correctly, my just-under 82K miles should still show after the work, right?

 

You could always take the output from the EEPROM and then manipulate the milage with a simple circuit that converts the 7-segment LED driver signals to a numeric number, subtracts a certain amount, then drives the LEDs with the new signal.

But only for legal purposes of course.

I'm trying to learn this myself because I'm planning on swapping a GTA dash into my IROC, and I want my proper IROC milage displayed on the dash, along with "CAMARO" instead of "PONTIAC" displayed, although that should be easier.

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The IROC Homepage
<A HREF="http://www.rit.edu/~jli4307/camaro" TARGET=_blank>
View the restoration of an 85 IROC</A>
Custom Thirdgen Subwoofer Enclosures
"I didn't know a bored out Ford could go so slow" -Shenandoah

 

Jim,

I don't think that that would be possible with the GM digital clusters used in the third gen F-bodies. The cluster microcontroller writes data (speed, rpm, milage, etc.) to the display module, so it would not be as simple as interfacing to a multiplexed seven segment display, since the display is part of a module. You would have to write new code for the microcontroller on the cluster, and then replace the one time programmable microcontroller.

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Tim

1992 Z28, 305 TPI 5 speed, 12.1 sec @ 114.7 mph

1984 Berlinetta 305 TPI Auto, 13.8 sec @ 99.7 mph