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Foc'd off

Member Since 06 Apr 2013
Offline Last Active Aug 10 2013 07:11 PM
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Posts I've Made

In Topic: Sorry To Ask, Another Idle Problem!!

07 April 2013 - 01:56 PM

Well I'm no nearer to a solution than before.

 

First I measured the IACV, that comes back as 9.7 ohms, the plug on the loom shows one pin at 12.8v and the other appears to be earth. I was wondering why bother to have an earth wire to the IACV when it could easily be done through the chassis ground?

 

Anyway, I removed the ECU and stripped it to find masses of metal filings inside, some were on the legs of a rather large processor looking chip. I removed all the dust etc and rebuilt it. Still no difference, the IACV holds fully open no matter what.

 

Whilst I'm thinking about this, does anyone know the travel of the IACV piston? Mine only moves about 3mm from shut to fully open!


In Topic: Sorry To Ask, Another Idle Problem!!

07 April 2013 - 10:08 AM

iac isnt the easiest to test without an oscilloscope..
you can do a basic resistence/supply test of iac

disconnect wiring, test at iac

should have approx 9.5 ohms between terminals 1 and 2

disconnect wiring, ignition on, test at harness plug

11-14 volts between terminal 1 and earth
 

 

 

I'll go out and check these now and report back, I'll also be taking a more thorough look at the condition of the wiring for frayed/earthing wires corrosion etc.

 

Thanks all for your comments!


In Topic: Sorry To Ask, Another Idle Problem!!

06 April 2013 - 08:47 PM

Let's not get into an argument over this. All I really want to know is why my IACV is holding open at any temp or rev setting.

 

My bets is a damaged ECU/PCM module but I would still appreciate any feedback on this!


In Topic: Sorry To Ask, Another Idle Problem!!

06 April 2013 - 07:01 PM

iac isnt the easiest to test without an oscilloscope..
you can do a basic resistence/supply test of iac

disconnect wiring, test at iac

should have approx 9.5 ohms between terminals 1 and 2

disconnect wiring, ignition on, test at harness plug

11-14 volts between terminal 1 and earth

beyond that you need to test at pcm iac signal with oscilloscope...should have a switching voltage of approx 3v, with hot engine at idle, the speed of that switching would be way to fast for a voltmeter to cope with

im inclined to agree with you in that chances are its pcm/wiring, unfortunately been a long time since ive tested one, autodata doesnt give anymore than above info.....best bet, if resistence/supply is ok, get a scanner that can read live data, chances are that will show what the pcm is doing

Thank you for your reply, i may also suspect it's the PCM since I found it was damaged due to a previous accident. I will drag the ECU/PCM out and see what's going on. I have access to a scope but in all honesty I can't be asked when the only problem is a low idle when cold!! With the IACV disconnected it's fine when warmed up.


In Topic: Sorry To Ask, Another Idle Problem!!

06 April 2013 - 06:53 PM

I have no idea what you guys are talking about so many acronyms I'm going to declare myself out lol.

Let me enlighten you.

 

PCM = Power Control Module

TPS = Throttle Position Sensor

TMAP = Thermal Manifold Absolute Pressure Sensor

PCV = Positive Crankcase Ventilation

ECU = Electronic Control Unit

IACV = Idle Air Control Valve