chipped" '87 5ktqa

[Ben Swann]

[Ben (and others):

I also have a "chipped" 5ktqa. I've always assumed it's
the resistor/diode upgrade, so keep the adjustable
wastegate close to stock settings, hoping that keeps my
schrapnel-potential lower. How does one find out for
sure? My boost reads higher than the 1.4bar mentioned
when the schrapnel-knob is cranked higher, I've seen as
high as 1.7, but never kept it there for fear of
meltdown. You mention opening up the ecu, would it be
obvious? I assume a real chip would have the name of the
company on it, would the resistor/diode be obvious as
well?

steve
'86 5ktqa
'86 4kcsq
kent, wa]

Steve,

One of the simplest mods I've seen, is the grounding of the fuel pump lead
on the ECU harness pin # 21 being connected to ground.  This keeps the
computer from shutting off the fuel pump on overboost.  The problem with
this is the timing and fuel maps are not programmed into the stock chip to
account for the higher boost, although this mod will even let you read 1.8
or so on the boost indicator, if the wastegate is controlled to do so by
shrap knob or spring.  With fuel pump lead grounded, the engine may start
acting flaky at higher boost levels( over 1.5bar), and you don't get
optimal performance as you would with a proper chip, and may be damaging
the engine due to lean condition.

Look for wiring from pin 21 being connected to ground somewhere near the
ECU. If you don't see it, use an ohm meter to detect if that lead is going
to ground.  There are other ways to do this mod both inside and out of the
ECU, but why would someone go through the trouble to open the black box if
they don't need to.

An aftermarket chip doesn't need to have a label, but would not have the
MAC-11(B or C) or similar id on it.

Also, if the ECU is "properly chipped" it would control the wastegate
frequency valve so 1.8 bar is reached, unless that was disabled with the
installation of the schrap knob.

If you do open up your ECU, look for a resistor (and possibly a diode)
wired to leads on the pressure transducer.  You'll be able to tell what the
PT is because that is the thingy the vacuum port runs to.

Ben