Quick Chip Question; Can I go back to stock chip?

[Swoboda]

I'm not looking to stir the hornet's nest about whether chips are good or bad.

I just have a question about switiching back to a stock chip after modifying my DME from a 2k to a 4k by moving the jumper.

I have a 1985 Carrera with the earlier 2k DME. Steve Wong's site says that I should modify my DME by moving a jumper.

If I make that modification from 2k to 4k, can I reinstall my stock chip without any ill effects?

I posed the same question to Steve Wong and am awaiting a response. (He's always very prompt so I expect a reply in short order.) I want to know if anyone has done this and if there are any issues I should worry about.

Thanks in advance.

[DRACO A5OG]

Yes, I have for Smog Checks

[Swoboda]

Thanks, Draco.

Also, to just follow-up: Steve Wong responded to my email (very quickly) and confirmed that the chip cn be reinstalle without issus.

Now to fret about damaging my DME by doing the soldering for the modification....

[DRACO A5OG]

How did you damage it?

[Lorenfb]

"I just have a question about switiching back to a stock chip after modifying my DME from a 2k to a 4k by moving the jumper. If I make that modification from 2k to 4k, can I reinstall my stock chip without any ill effects?"

The answer is mostly no, i.e. If the board was modified by changing jumpers to use
the 4K chip, then to re-use the 2K chip one needs to revert to the original
jumper configuration. If the 2K & the 4K were totally interchangeable, then
there wouldn't have been a need to change the jumper in the first place.
There are some later 2K chips, e.g. Euro, that may work, but the majority
of 2K chips require the original 2K jumper configuration.

"Yes, I have for Smog Checks"

Guessing not allowed! Then both were 2Ks or both were 4Ks,
or the 2K may have been the later 2K.
Again, that's why there's a jumper change!

Bottom line: The first responses posted on a forum are NOT always correct!

[Joe Bob]

I just flip a switch on mine.....

[Swoboda]

The jumper change is a fair rationale for the 2k and 4k chips not being a simple plug-and-play option.

I was thinking that there could be a backward compatibility between a newer 4k chip and a 2k chip.

Oh, well. If the jumpers need to be redone to original 2k specs to reuse the original chip, then that's the way to do it.

Draco, I didn't damage anything. I was just curious.

Thanks.

[DRACO A5OG]

Oh OK,

As far as my 4K setup, I have a chip with OEM programming that fits into the 4K mod.

[Lorenfb]

"As far as my 4K setup, I have a chip with OEM programming that fits into the 4K mod."

You need to peel part of the OEM sticker and read the chip manufacturer's part number,
e.g. MM27XXD, TMS27XXD, etc. That will determine the chip type. It's not only the fit.
A picture would be helpful.

[DRACO A5OG]

It was copied from my OEM chip.

With OEM Cat, the Brown wire connected, it's allowed me to pass SMOG and runs like it has an elephant in the back. SLOOOOOOW