[V8] Idle Problem Returns to The Twilight Zone
grey_wolf_x at yahoo.com
Wed Apr 12 17:51:38 EDT 2006
I would like to get a copy of the 5spd eprom. i have a
copy of the at eprom from my 90 and a copy of a
"chipped" eprom that wont run in my at from a 5spd. i
would like to do some comparisons on them
--- urq <urq at pacbell.net> wrote:
> ... thought I'd reported it here before ...
> I can't speak to the automatic case, but I can tell
> you that a 5-speed runs
> just fine with an ECU from an automatic car. I can
> also say that an
> "automatic" engine runs fine in a five speed with
> the 5-speed brain ...
> AFAIK there are no connections between the IC and
> ECU that the 5-speed ECU
> cares about.
> It does seem a bit odd that the good whack cured the
> problem ... the only
> part that is socketed in the ECU (as I recall) is
> the EPROM itself ... even
> the board to board interconnects are hard wired.
> I have not saved the EPROM code from an automatic
> car ... but I do have a
> copy of the EPROM and can read it in if needed. I
> have soft copies of the
> contents of the 5-speed EPROM ...
> I can also speak to the IC situation ... before I
> knew any better I bought a
> car that had an automatic cluster installed ... it
> worked just fine ... just
> the PRNDL display was lit. Later I removed the back
> lights, and even though
> the LCD elements are all still visible in some
> lighting conditions, it isn't
> very noticable ... the only thing that is odd is
> that when I connected up
> the MIL wire, the incorrect indicator illuminates on
> the cluster ... not
> sure if this is due solely to the fact that this is
> an automatic cluster or
> something else. I picked up a 5-speed cluster (I'd
> almost bet these will be
> rarer than ECUs!) which had a cracked bezel. I've
> removed a bezel from an
> AT cluster and will glue it on my 5-speed IC when I
> figure out how to polish
> out the scratch I made removing it ... :-( ... The
> plan is to swap the
> speedo between clusters when I do the overall swap
> ... that way the mileage
> will not change ...
> ... final comment ... there is no "resolder fix" for
> these ICs ... I suppose
> an application of solder would definitely cure the
> interconnection problems
> ... but it would render it impossible to disassemble
> in the future (but
> then, I suppose I might never misbehave again :) ...
> the fix that I use is
> to use DeoxIt (or equiv) on the internal connections
> Steve B
> San Jose, CA (USA)
> > My WAG is that the ECUs are identical except for
> the EEPROM chip.
> > It is possible that there other electronic parts
> included/deleted based on
> > the
> > transmission type, but the circuit board is most
> likely the same.
> > That being the case, an automatic ECU should be
> just fine in a manual car
> > as
> > long as you swap the EEPROM.
> > This could be confirmed by carefull inspection of
> the circuit boards. The
> > fine
> > folks at IA would probably also know the answer to
> > btw, I wonder if anyone has saved a copy of the
> EEPROM data for both auto
> > and
> > 5-speed boxes?
> > That would be a smart thing to do so we can
> re-purpose ECUs. As time goes
> > on,
> > these things are going to get even harder to come
> >> I'm hanging onto the other ECU just in case.
> There's a chance that both
> >> computers have the same problem, but that seems
> unlikely. Because some
> >> of
> >> the signals to the Motronic come from the IC, I
> wonder if there's
> >> something
> >> going on there. Any differences between the
> 5-speed and automatic
> >> clusters,
> >> apart from the speedo constant? I'd like to have
> spare parts or at least
> >> a
> >> chance of getting them before attempting the
> resolder fix.
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