Porsche Enthusiasts Club Forum

I was going to remove my ICV and give it a soak in petrol over night to give it a good scrub clean tomorrow morning. Odd thing was that with the ignition on the ICV wasn't vibrating like it does with my Golf. I am pretty sure I have heard it vibrates with the ignition on with the Lux model, but someone in the know told me that the S2 might be running a more advanced engine management system, which means it won't necessarily vibrate as soon as the ignition is switched on. Can anyone confirm whether this is the case?

Thanks,

Dave.

Im not sure if the S2 has this ICV, but there is a good guide here on testing one.

http://www.texasblake.com/porsche/tech/icv.html

968 has one, and i've got a working spare if needed.

Thanks Nick, I will give that guide a look once I have removed the ICV. I was hoping that someone with an S2 wouldn't mind just checking their ICV (i.e. turning the ignition but not starting the engine) to see whether the ICV is vibrating when they touch it. It is located just under the full damper towards the back of the fuel rail that feeds all of the injectors. Should have two pipes running into it in an L shapre configuration.

Like I said on the Golf as soon as yout turn the ignition you can feel the ICV vibrating before starting the engine. I was kind of expecting the same on the S2 as I thought given the age the engine management system would be pretty similar, but I could be wrong.

Just don't want to be spending a lot of time trying to get a component working that is fundamentally screwed, but that guide should be useful to giving the ICV a proper diagnosis.

Cheers,

Dave.

8 valve, 16v 944 & 968 all different

I thought they might be, but I specifically wanted to know whether the ICV on the 944 S2 should be vibrating with the ignition on or not since the S2 3 litre is the specific engine that I am trying to diagnose...

Dave.

Unlike the Golf the S2 has (I think) a 3 wire icv - rather than opening/closing very quickly it makes small adjustments so it shouldn't vibrate.

Sorry to bring up an older thread, but I have been working on my ICV for the last week and it has been driving me mad!

Got the ICV out of the car, connected it to the plug so I could see what was happening inside, turned on the ignition, immobilised the car, nothing (I was expecting it to do something to prep itself in anticipation of the engine turning over).

Took out the ICV, cleaned it out with some petrol, got all the crap off the outside as well and cleaned the connectors, looks lovely, spotless inside. Cleaned the plug as well with some electrical contact cleaner.

Turned on the ignition, immobilised the car, plugged the ICV back in and it does nothing.

Ran a voltmeter across the ICV plug connected to the wire that runs down the fuel rail back to the DME, get a steady 11. something volts. Ran the voltmeter between the connector and the engine manifold and still get 11. something volts. Wires look good.

Must be the ICV. Take the ICV inside, create some jumper leads and connect it upto a 9v square battery, it snaps shut, disconnect it from the battery and it opens again. Figure 9v is less than 12 volts (I am good at maths), so figure I will do the same, but will hook it upto the 12v car battery. Hook it up to the car battery and the valve snaps shut, disconnect it and it opens again. ICV looks good.

So I definitely have 11. something volts running through the wires. The ICV definitely snaps shut when you apply 9v or 12v using a battery. So why isn't it working when I plug them together? I even connected it up via the jumper leads I made via the battery test to ensure that everything was connected and the connectors inside the plug weren't being pushed back or anything. Even tried wiggling the jumper connectors around a bit incase there was a dicky connection in the plug somewhere.

When I measure the voltage between the jumper leads not connected to the ICV, but connected to the plug I am reading 11.something volts at the end of the jumper leads, so the jumper leads look good when connected to the plug.

When I connect the ICV to the jumper leads (which are connected to the plug) I am reading 0.03 volts between the two spades at the end of the jumper leads which are connected to the ICV (I would expect 11. something). So the problem seems to occur when the plug and ICV are connected together. But I have no idea why and still no idea which is actually at fault, the ICV or the wires, since both seem to be ok when tested seperately. Can anyone with a bit more electrical knowledge shed any light on what could be going on here? I think my car is possessed.

I am also developing a dislike for car electronics.

Cheers,

Dave.



944 S2 is 2 wire, 944 Turbo is 3 wire. I am a bit of a muppet really, since I could have just figured it out in the first place by diconnecting the ICV and having a look!

And on a side not does anyone know where I can find a 12v live in the engine bay with the ignition switched on? AFM, TPS, etc are all 5v live, really want to test a full 12v through the return wire, but I am not sure whereabouts I can probe. The starter motor doesn't look accessible enough to get my probe to it. Battery is in the boot, so that is not an option either.

Cheers,

Dave.

Headlight or sidelights, I know its a switched 12v, but accessable

Post on the scuttle with the blue cap on is 12v (really there for emergency hatch opening, but will do for your purposes)

Cheers guys, used the live under the blue cap in the end.

Measured 11.xv from the positive pin on the plug to the inlet manifold.
Measured 11.xv from the 12v live under the blue cap to the negative pin on the plug.

Hooked everything up with my jumpers and then disconnected the jumper from the negative pin on the plug and touched it against the inlet manifold to act as an earth and the IVC snapped shut. So the electricity is getting through the +ve pin, going into the ICV, and then coming out of the negative pin, through the jumper and returning to the battery through the body of the car ok.

So that kind of suggests the -ve wire/connection is screwed, but that didn't seem to add up as I am getting 11.xv through the -ve wire when I hook the voltmeter up against my 12v constant live. I figured maybe it could be that the connection between the negative jumper and the plug was a bit dodgy, but I did the same check with the negative jumper plugged in and touched the multimeter probe against the 12v constant live and I was still getting 11.xv so the connection doesn't look like it is a problem either.

Spoken to a guy from an electronics company in my office building (handy) and based on what I have told him he said it sounds like it is a dodgy earth connection coming back through the -ve wire. He said that although the voltmeter reads 12v across the terminals, that voltage could well drop dramatically as soon as the ICV starts drawing current if it has a bad earth.

I did go around the car and clean all my earths a month ago (that I knew of and could find in the workshop manual diagram and that people had listed on forums), but I guess I need to trace where the -ve wire from the ICV back to wherever it is going and check the connection is ok.

If anyone knows where this -ve wire from the ICV goes to it would be much appreciated (guessing it is connected around the DME somewhere). Going to have a look through the workshop manual this evening.

Will post an update if and when I get it working to confirm whether it was the problem.

Cheers,

Dave.

Had a look and the ICV wires go into a large rubber tube along with the injector wires and then these go through the body into the passenger footwell and then to the main connector that attaches to the DME.

However, I am not sure which pins the ICV live and earth wires connect to. Does anyone know which pins these wires end up at in a 944 S2 DME plug?

Also does anyone know where the main earthing point is for the DME as a whole? It is a bit of a wire spaghetti junction behind the glove box, so it is pretty difficult to work out what is connected where.

Cheers,

Dave.

I have a Bosch Hammer which can be used for testing it on the car, on a 968 you simply listen for a click.

Your welcome to try it - will be at Donington Sunday?

Rich

Hi Rich,

That would be great if I could. Going to spend Saturday trying to sort it, but if I don't have any luck I will pop you a PM.

Going to try and figure out the pins myself if no-one knows them on Saturday using some wire between the plug connectors and my multimeter and then probing each pin of the DME connector one by one until I get a closed circuit. Think that will probably be the easiest way to figure them out unless anyone has a better suggestion?

Dave.