Re: [doc] re still doesn't idle ok

[Nick Tomlinson <nickandkathryntomlinson@xxxxxxxxxxx>]

How did you check the earth connection at the ecu multi plug?
   
  Have you checked for a switched connected at the ecu multiplug from the throttle switch?
   
  Put your multimeter to volts. Connect the red cable of meter to jump start post. Use black lead to check for earth at ecu, meter should read battery voltage.
   
  Put your multimeter to volts. Connect the red cable of meter to jump start post. Use black lead to check for throttle switch input, meter should read battery voltage with throttle closed (switch operated) and no voltage with throttle open.
   
    With the ECU plugged in, check the multiplug that goes to the idle speed motor, the centre pin should have 12v on it (with key in ignition and tuned to position 2) continuously. The ecu momentarily earths the outer pins to open and close the motor.
   
  You can check for continuity using the resistance setting on the multimeter and check for wire continuity between the switched side of the coil to the ecu plug, (remove the ecu first). If there is a suppressor, temporarily disconnect it in case this has gone bad.
   
  The white lead from the distributor to the ecu is from the negatively switched side of the coil. If this was short then the car would not run at all.

   
  The Diode should be tested using diode function on the multimeter ideally not resistance.
  Reading should be between 500 and 800 with test leads one way round on the diode, and no reading (ie infinite) the other way round.
  The diode is there to stop feedback voltage going to this circuit, as the throttle microswitch operates a couple of other circuits too.
   
  I would say from your resistance tests that this diode would appear to be open circuit.
  Temporarily connect this wire to permanent earth for idle testing purposes only. Does the car idle now?? If it does then the diode will need replacing. Note which way round the diode is when you removed it and replace it with another the right way round.
   
  I am presuming that you have check for wire continuity between the idle speed motor multiplug and the idle speed ecu multiplug.
   
  Have you measured the thermister resistance?
  Do this by using your multimeter on resistance and connect to the 2 pins on the idle speed ecu multiplug. If you get no reading (open circuit) then the connector to the thermistor connector plug may have fallen off or the thermistor itself has gone bad.
  If you get no resistance, you can make some short fly leads to enable the multiplug to be connected to the ecu by 2 pins (on the 4 pin block) and the thermistor ecu inputs  to a 10 kilo ohm resistor to simulate the thermistor. If the car now idles then this is the problem.
   
  NIckT.
  

blackaddertoo <blackaddertoo@xxxxxxxxxxx> wrote:
  Hi all

an update on my idle problems
idle ecu and idle motor checked and working by martin at DMUK.
now removed motor, blocked pipes and adjusted screws...car idle ok 
at 1500 rpm.
checked power to ecu ok at plug, checked switch ok at engine but 
diode reads no resistance either polarity. (should it?) n moved for 
further testing.
checked ground connection at ecu - Ok.
put Eecu and motor back in, shorted the diode/microswitch input to 
earth...car idle 30 second then dies. exactly the same problem.
removed diode short...idle 30 secs then dies.

so i am left to check the input from the distributor (should the car 
idle if this is dead and hence the ecu does not know engine speed??)
and if the leads from the ecu to motor are OK.

if i put a test light on the connector at engine end and switch 
ignition, should there be a short positive signal on the one (to 
either close the motor or open?)

then remove the microswith...do the same and the other lead should 
go positive.

that is correct is it not, middle lead to motor is ground and the 
other run motor positive one way and positive the other to close the 
air valve??.

Thanx for reading this!! and sorry to bore you. i am determined to 
resolve this (and enjoy it really!!)






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