05-07-2015, 06:27 AM
no transmission stated or ecu part number, some cars have the wrong ecu. like my m/t had a A/T ecu. and can be tricky doing that.
yes the ECU has only one idle up pin, and a diode "or tied logic" to get more idle up inputs.
sounds like the head lamps overload the alternator ,or the ISC is messing up some way. (duty cycle not at 50 % or on the cusp of failing?)
your tachometer is very good to resolve, 50 rpm, .
lets look at that.
the wiring is very very simple. for idle up.
best is this page set... the diode block is on page 2.
the red-yellow wire (park/tail) is hot, in park and also low beams.
so is at 12v, with head lights on, (it should be, or you'd notice)
id say the ISC is overloaded by the HL. (straw that broke camels back deal, or more exactly the ISC cant open more.)
so take the idles stop, hot engine 800 rpm and open it a touch more . and now the iSC has more freeboard )
or set duty to 50% by getting DC volts on ISC pins near 7v hot idle. (1/2 x 14v)
http://www.fixkick.com/ECU/89/1990-scan-...lpages.pdf
off my bad idle 89 page.
The ECU went nuts and ISC with it? Bad inputs to the ECU can cause that:
The critical pins on the 89/90 -60Axx ECU are:
FAST IDLE COMMAND PINS: A= Y B = G , Suzuki to GM pin number changes, colors never change.
A3 = 0vdc fast idle from diode module, (fan,defrost,headlights are on, any or all)
A2 = 0v, A/C is on,
A13= 12v , if 0v your P/S is in overloaded ,fast idle feature.
A14 = 0v the TPS idle switch, if not 0 then TPS is signalling off idle ,bad TPS or maladjusted.
B12, 0v , A/T PRN switch sigs. only this signals I'm in drive if not 0v. 0 means park or neutral. This pin if at 12v, cause ecu to NUTS in PARK or Neutral, for sure. (m/T cars this is not used or 0v)
B11, 0v , of not at zero the ecu thinks you are cranking endlessly. that be real bad.
yes the ECU has only one idle up pin, and a diode "or tied logic" to get more idle up inputs.
sounds like the head lamps overload the alternator ,or the ISC is messing up some way. (duty cycle not at 50 % or on the cusp of failing?)
your tachometer is very good to resolve, 50 rpm, .
lets look at that.
the wiring is very very simple. for idle up.
best is this page set... the diode block is on page 2.
the red-yellow wire (park/tail) is hot, in park and also low beams.
so is at 12v, with head lights on, (it should be, or you'd notice)
id say the ISC is overloaded by the HL. (straw that broke camels back deal, or more exactly the ISC cant open more.)
so take the idles stop, hot engine 800 rpm and open it a touch more . and now the iSC has more freeboard )
or set duty to 50% by getting DC volts on ISC pins near 7v hot idle. (1/2 x 14v)
http://www.fixkick.com/ECU/89/1990-scan-...lpages.pdf
off my bad idle 89 page.
The ECU went nuts and ISC with it? Bad inputs to the ECU can cause that:
The critical pins on the 89/90 -60Axx ECU are:
FAST IDLE COMMAND PINS: A= Y B = G , Suzuki to GM pin number changes, colors never change.
A3 = 0vdc fast idle from diode module, (fan,defrost,headlights are on, any or all)
A2 = 0v, A/C is on,
A13= 12v , if 0v your P/S is in overloaded ,fast idle feature.
A14 = 0v the TPS idle switch, if not 0 then TPS is signalling off idle ,bad TPS or maladjusted.
B12, 0v , A/T PRN switch sigs. only this signals I'm in drive if not 0v. 0 means park or neutral. This pin if at 12v, cause ecu to NUTS in PARK or Neutral, for sure. (m/T cars this is not used or 0v)
B11, 0v , of not at zero the ecu thinks you are cranking endlessly. that be real bad.
http://www.fixkick.com