3.0 TD Idling changes

[SSRG3]

What a great site and hello all from a newbie
Need some advise please. I have read through the threads on Idling issues but hope to get some feedback on mine;
My "well looked after" surf 1995 3.0 TD has developed the following:
1. Cold start Idles at 750rpm constant
2. During first journey at Idle speed drops to 600rpm with signs of vibration
3. Turn engine off and restart the Idle speed goes back to 750rpm.

I know some of your will say this could be normal but this only started showing the difference over the last 2 weeks with the vibrations. I read about sensor readings / faults from TPS / Water and the IAC and wonder if (no mechanic) if the IAC valve is picking up carbon build up on the throttle valve or could this be more simple in diagnosic. Anyone had the same problems and could advise me please on the first steps to investigate. Problem did raise itself one year ago with reduced rpm and my local garage moved the throttle screw by 1 revolution to raise the idle (I know this was not the answer to explain the drop in rpm then - and so did he).

Any guidance most appreciated. Andy

[charvell]

What a great site and hello all from a newbie
Need some advise please. I have read through the threads on Idling issues but hope to get some feedback on mine;
My "well looked after" surf 1995 3.0 TD has developed the following:
1. Cold start Idles at 750rpm constant
2. During first journey at Idle speed drops to 600rpm with signs of vibration
3. Turn engine off and restart the Idle speed goes back to 750rpm.

I know some of your will say this could be normal but this only started showing the difference over the last 2 weeks with the vibrations. I read about sensor readings / faults from TPS / Water and the IAC and wonder if (no mechanic) if the IAC valve is picking up carbon build up on the throttle valve or could this be more simple in diagnosic. Anyone had the same problems and could advise me please on the first steps to investigate. Problem did raise itself one year ago with reduced rpm and my local garage moved the throttle screw by 1 revolution to raise the idle (I know this was not the answer to explain the drop in rpm then - and so did he).

Any guidance most appreciated. Andy

when was it last serviced?

[Albannach]

The ECU controls the idle speed. I think it's generally accepted that this is an ECU fault, but as it's not a cheap fix, nobody has had one repaired yet.

It would be good if someone sent heir ECU to the ECU Doctor, then opened it up to see exactly what was repaired

[SSRG3]

when was it last serviced?

Hi ya thanks for the reply. . . Last serviced with new timing belt / Oil and Air filter April 2011. With past correct Oil and Air filter changes the rpm has not changed afterwards. I have read on USA sites that any car IAC's may need cleaning every 40 to 60K miles as routine but hasn't often been mentioned on hilux forums and wondered if there could be a simplier explaination. Andy

[Albannach]

What fault codes do you get? See HERE and HERE for info.

[SSRG3]

What fault codes do you get? See HERE and HERE for info.

Hello and thanks for replying. Not having done this before will see what comes up and let you know.

[SSRG3]

What fault codes do you get? See HERE and HERE for info.

Hello
The test came back with a continuous flash - so no help here!!!

[Albannach]

Most of us have idle speeds at around 500rpm.

I recall someone having their ECU fixed (which cured his idle speed problem and some other stuff), but they wouldn't open the box to see what was repaired and the Doctor doesn't tell you what he's charged you for. I think it's something to do with a Triac or a 5v something-or-another. You'll probably have to live with it, or shell out 200 beer tokens to have the ECU fixed (assuming it is actually an ECU fault).