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Cosworth ISCV

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Old Dec 6, 2006 | 06:15 AM
  #1  
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Default Cosworth ISCV

Is it possible that the ISCV can make the engine run as high as 13-1500 r/min at idle??? Sometimes constant, sometimes going to normal after af few secs or minutes

If the ISCV can not make this high revs.. it MUST be the ECU that make sit doing this.. correct?

With the ISCV unplugged it revs 600-800 cold and 850 when its getting hotter
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Old Dec 6, 2006 | 08:55 AM
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With the ICSV disconnected you are running on the throttle stop so if connected you get raised idle above normal then either the ecu is sending a signal to the ICSV (spurious) of the ICSV itself is sticking open.

Often they can become sticky caused by a build up of carbon inside.

Best thing to do is to whip it out and give it a good clean in some decarbonsing solution.

Then retry it.

Good luck.
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Old Dec 6, 2006 | 09:10 AM
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That is what I have done.. still the same.

All sensors apart from the tps and iscv is new. Just fitted after a head rebuild.
The iscv is not sticking when pushing it carefull with at screwdriver (holding it in my hand).. the piston can move very easy. But the condisitions inside the throttlebody may be different afcause.
The tps work according to my multimeter.. 42-48ohm closed to 630 ohm fully open, with NO glitches

But... CAN the ISCV cause idle in the range of 12-1500 r/min???
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Old Dec 6, 2006 | 09:25 AM
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With no load on the engine, the ISC can flow enough air to raise the revs to 1500 rpm (and above).
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Old Dec 6, 2006 | 09:29 AM
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Originally Posted by JanDK
All sensors apart from the tps and iscv is new. Just fitted after a head rebuild.
The iscv is not sticking when pushing it carefull with at screwdriver (holding it in my hand).. the piston can move very easy. But the condisitions inside the throttlebody may be different afcause.
The tps work according to my multimeter.. 42-48ohm closed to 630 ohm fully open, with NO glitches
Was it ok before the head work??? Did you remove the sensor or are they in the same position as they were before the head work???
If the ECU sends a duty cycle to the ICSV to open then it will (either a faulty signal or a load on the engine), it could be down to another sensor giving incorrect information to the Ecu.
I'd suspect the TPS.
Measure the pins at the ecu with the TPS multiplug still connected, pins 11 and 17, 0.25 to 0.3 volts DC.

Have you done a error test to ensure all sensors are ok?



But... CAN the ISCV cause idle in the range of 12-1500 r/min?
Yes it can, ive seen idle above 1500rpm all down to the ICSV.
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Old Dec 6, 2006 | 06:03 PM
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Hmm.. this will be next step then!! It have been teasing me, on and of for about 8 months now. But was not sure that it was the ISCV cause of the very high revs

Thank you guys ...
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