ALFAGTV6.COM

x-rad · Post by **x-rad** » Sun Aug 12, 2007 2:10 pm

OK: here is what I have found...

In a Bosch 0 280 001 134 3.0 box, you can change the value of a resistor to increase rev limit. Decreasing resistance increases rev limit.

Resistor is #R704 located on the underside of the NON connector board.

1. Remove ECU
2. Remove two case bottom screws
2.5. Remove guts
3. Carefully remove two spring clips
4. Carefully remove THREE retaining screws. This is the board you want to work on.
5. open plastic wire cover(it just pops open)
6. GENTLY flip board over

In top left quadrant, you will see three elevated resistors. SEE PICS. The BIG FAT resistor is the NEW one. It is ~4700 ohms by color bands ( better to use at least 1/2 watt , and this is Gold quality..not that that matters too much..it's probably the best resistor on the board)

http://www.radioshack.com/product/index ... age=family

Anyway, OLD resistor is ~6200 ohms using color bands.

As a double check, NEW resistor is 4600ohms measured resistance (on board) ...

I checked both boards closely and this was the only change I could find. And , this makes sense as only one resistor should be needed to effect peak rev waveform....this allows "overvoltage or over-rev" to occur and does not shut off injectors. I have no other electrical mods to Bosch stuff and can rev to at least 7500rpm...

WARNIG: mod done on 3.0L ECU, although similar, I am not familiar w/2.5's. Also, overrevs can kill your engine..do this at your own risk!!

gtwheee · Post by **gtwheee** » Mon Aug 13, 2007 9:17 am

nice info

where did you get the modified ECU from? (if I read it correctly you acquired the ECU already modded?)

brookstroutr · Post by **brookstroutr** » Mon Aug 13, 2007 9:43 am

x-rad,

Are these fotos of 2 different ECU boards? I see other components that are different, albeit similar.

I think my Verde 3.0ltr came with a ZAT modded ECU. I may open it up and see if they changed like you did. I'll try to post a foto of this as well.

x-rad · Post by **x-rad** » Mon Aug 13, 2007 3:11 pm

TWO different 3.0 boards..one has slightly older components but they are the same thing in a different package..both run my car very well with O2 at stoich and everything else being the same except for rev limit

Yes . the board was modified when I got it. Done by a guy back East near Philadelphia whose name I have written down somewhere but can't find....he also modified the 2.5 wiring harness to work with 3.0. stuff

x-rad · Post by **x-rad** » Mon Aug 13, 2007 3:13 pm

brooks: yeah..lets see the pics...

brookstroutr · Post by **brookstroutr** » Mon Aug 13, 2007 11:19 pm

Here's the best pics of my 3.0 ltr ECU & Spark Box. There is a piece of tape with markings of "modified version #1" in both. I guess this is a 'Pandora's Box' as they say. My ECU has the fat resistor.

x-rad · Post by **x-rad** » Tue Aug 14, 2007 10:06 am

did you measure the resistance of the changed resistor?

Did you ever hit rev limit?

x-rad · Post by **x-rad** » Tue Aug 14, 2007 5:27 pm

Brooks: Under the tape should be the chip number...probably common manufacture as these are likely not programmable.

brookstroutr · Post by **brookstroutr** » Tue Aug 21, 2007 1:37 pm

xrad,

These are re-programmable. I cannot remember how they used to do this. This was back in the early 80's that I'm familiar with the L-Jets on BMWs.

I haven't checked anything on this one. This set up came with my Verde motor. I think it's the modified "pandora's box". I do not have the specifics other than the rev limit was raised. I'm not too concerned as I will go stand alone and elimenate this antiquated system and get my GTV6 into the 21st Century. I'm leaning towards Gotech right now.

x-rad · Post by **x-rad** » Tue Aug 21, 2007 2:44 pm

well if you are able to reprogram these chips, you will need the correct chip socket and a computer capable of reading and writing eprom chips..if that is what it is....OR somebody who has the hardware and software from the 1990's...

INCREASING REV LIMIT