Thermo Time Switch for '87 5ktq? [was Fuel Pressure Testing - 5ktq - where to tap?]

[Bernard Littau]

> > I have been trying to track down the cause of poor cold start problem...

Hi Ben,

I don't think fuel pressure is likely as the problem.  I had low fuel
pressure, and the car started fine -- it had problems at high load due to
low fuel pressure.  Likewise, your fuel delivery capacity is likely not the
cause -- there should be plenty of fuel to idle the car coming into the CIS.
For the fuel pressure stuff see:
http://www.sjmautotechnik.com/ficis.html#fuelp

I think the problem may still be the Cold Start Valve not squirting.  This
could be due to bad valve or bad thermo sensors.  The multifunction and the
ECU temp are possible problems, the intake air sensor is not likely.  I
don't think the intake air sensor is even used below 1800 rpm or 0.8 bar
MAP.  The fact that you get 1.4 bar makes me think your thermo sensors are
OK.  Worth checking anyway :-)
See:
http://www.sjmautotechnik.com/10vcoolt.html

Use the fuel pump relay fuse tests to cycle the Cold Start Valve and make
sure it is squirting under the control of the ECU.  See:
http://www.sjmautotechnik.com/ecuf.html#out1
specifically, test#4.

If it passes test#4, you may want to pull out the Cold Start Valve and make
sure it is squirting when the engine is cold.

Good luck,

Bernard Littau
Woodinville, WA
'88 5ktq