Strange idle connected exhaust vibration

[twoqu]

Running out of ideas!
I noticed that Greg S was testing his ISV and said the following:
I was trying to check the voltage on the ISV when engine running and varies with throttle opening between 5.2v and 5.8v which finger in the air is probably OK for approx 40 to 60% duty cycle.
So perhaps you could do the same with the MM set to volts on the the two pins of the ISV. If we get a voltage then at least we know something is happening. We know we have power, but despite the resting we have not really verified that the ISV is being controlled. Try that and post the result.

[newsh]

Mmm, seems like we have no shorts on those 3 sensors anyway.

I just checked the symptoms on mine again. Engine warm.

When I unplug just the ISV there's a clicking from the WGFV, the idle goes high and is slightly unsteady but when I try to open the throttle just slightly the revs rise and fall as though I'm blipping it.

If I unplug just the TPS nothing much happens but the idle speed rises a little.

If I unplug the WGFV there's series of short sucking noises from the ISV pipework and a short rise in idle speed, then it settles back down to normal.

[220bhp]

Things are getting worse.My multimeter for some unkown reason has decided to stop reading voltage,no digital display,only continuity alarm.Changed the batteries but no go.so I am of to Halfords to buy another.

[newsh]

Multimeter will have fuses inside which can sometimes blow if you connect on the wrong range or too much voltage..

Lou, I just spoke to Pete Berry. He said to check that the wires to the white temp switch on the back of the cylinder head are good, pull back the rubber boot and visually inspect for breakage and shorting. (I have a feeling you've fitted a new one of these but not sure if you've looked at the wiring.) Unplug the sensor and see if symptoms change.


Also check the wiring on the TPS in the same way, visually by pulling the rubber boot back.

[twoqu]

Hope it died before you did what I suggested!
What with John's experimentation, it is still pointing towards the ISV. The symptoms are just too similiar to be a coincidence. We know we have power, so it points to the ecu grounding somehow.
From that MG thread it implues that the ISV is activated even after the throttle switch is open. I guess that is where it closes the bypass channel. As I mentioned previously, that should be visible on an electrically connected ISV, leaving the other connected up for the air.

Not sure what Halfords sell (*****!) but it might be worth searching for something more automotive related. A decent MM is a worthwhile investment.

[220bhp]

Right,strange indead,I just started the car with no throttle,and it stumbled a little but slowly went up to a steady 850,first time it has done that for a while,gave the throttle a few blips,and it settled at 900,but when I presss the throttle to 1450 it occilates. so it occilates both hot and cold.
I then disconnected the g62 from the back of the headas John suggested,and there was no change.I let it warm up,and it was grumbling again at 2000revs.
Odd thing I noticed yesterday,when this happens you can se the gear stick moveing back and forth when you lift of the gass in gear,you do not realy notice it on the rev counter as I think its happening to quick,which is odd,but it is stil enough to make the gear stick move.

[twoqu]

Another possibility is that the wire back to the ecu from the ISV is broken but makes contact without the engine running but the engine movement is sufficent to break it. That way we would get continuity when testing it removed from the ecu, but not when its connected and running. Thats why it would be ideal to verify some activity (duty cycle/voltage at the ISV with the engine running) by some method. We have only confirmed it is powered.
Its tricky but you could remove the cover from the ecu connector and use a length of wire to connect from ecu pin 4 to ISV pin 2.

[Greg_S]

Take a look at my project thread and using the procedure from the SJM site try doing the output tests and you can check if the ISV is operating as it should be

http://www.s2forum.com/forum/showthread.php?p=655126#post655126

[newsh]

Output test!

Yes, I was just about to post the same thing, I've just been out and checked that this works on the 3B and its really easy to do.

Make yourself a jumper with a piece of bent paperclip. Jumper the ODB plugs as per the diagram below, ignore the LED unless you want to read the blink codes, on my car the plugs are in the fusebox so it looks like the one on the right, if I remember right on your car they're under the dash.. Anyway its the same in both cases, the black plug looks like an A (or a house) and the white (or brown) looks like a D in both cases you connect the bottom of the "letter" so bottom of the "A" and the bottom of the "D"

Switch on the ignition but do not start.

After at least 4 seconds remove the jumper.

Now under the bonnet. With your fingers on injector #1 (so you can feel it) open and close the throttle, the injector will click 5 times
With your fingers on injector #2 open and close the throttle, the injector will click 5 times
With your fingers on injector #4 open and close the throttle, the injector will click 5 times
With your fingers on injector #5 open and close the throttle, the injector will click 5 times
With your fingers on injector #3 open and close the throttle, the injector will click 5 times

The test should then switch to the ISV which should click on and off.

Put the jumper back in for 4 seconds then remove it, the test should switch to the Carbon Can Valve which should click on and off

Put the jumper back in for 4 seconds then remove it, the test should switch to the WGFV which should click on and off.

If you want to.. Put the jumper back in for 4 seconds then remove it, this clears the codes. If you want to do the test again then run the engine for 20 seconds then switch off and start again.


Finally Lou. You didn't say.
Have you ever fitted a new G62?
When you disconnected the white G62 temp sensor did you inspect the wiring under the rubber boot?
Have you inspected the wiring under the rubber boot on the TPS?

[220bhp]

Getting out of my depth now Robin,but I will try anything at the moment.
Talking about the moment.My wife has just returned from Halfords with a multimeter.Not the one I saw on line,but some all singing all danceing thing that is impossible to understand,with symbols, that are so small a mouse could not read them,and a screen so big that you need to stand back. It was just sorry mam,we have run out of stock,this is the only one we have. Do you want it or not,at 54.99. The one on line was 39.99 .which was to much.What they did not tell her was that there was one in stock a mile away.So my poor wife,dessperate to please me, as always,came back after being,basicly, robbed buy some salesmen on commission,with this bloody monster.Bellieve me I am not a vindictive man,but I will never ever shop at Halfords Again.I think this a rip of,and that people should vote with there feet,or finger as it is to day.Rant over.
I will be out with the new mutimeter tomorrow,when I have calmed down,and have spent some time trying to understand it,as it is completely dfiferent from they one that has just packed up

[twoqu]

Lou,

Just hook up your spare ISV to the connector and follow John's instructions. That way you can see it working rather than just hear it. You should see it revolve to expose the valve part.
Of course if it does work with the ign on that means the wiring is ok. It will not prove its working when the engine is running! Still it would be progress.
I was just trying to point out that if for some reason the wire or come to think of it the connector was not making contact, by running a length of wire directly from the ecu to the ISV you would bypass the loom wire. If the car idled correctly we would know its the loom.
When you look at the ISV connector are both terminals in the same place? Sometimes the terminal can get pushed out of its holder which would mean its not seated when connected.
Tell us the MM you have. Maybe it has some settings that are useful to us. Might be a blessing in disguise. Agreed, I hate people who sell you what they have rather than what you want!

[220bhp]

I have just connected my origanal ISV,by taking the connector of the one in situe,and it move open a little then shut almost,but you could see it moving to and fro,by no more than a Mil,a very small amount,but its quite obvious that it is working to some degree,But i have no idea if it is right,only that it is being controlled to some degree,at idle.

[twoqu]

To me that doesen't sound right. If you orientate the spare ISV so that the angled port, the one with the arrow on is facing you, you should see the bypass slot on top in the unpowered position. Thats what passes the air to allow the high idle speed if the ISV fails. The ISV when operated should (I think) close that opening by rotating the rotary valve so that the opening appears in the bottom. We are unsure what exactly happens but I am guess the ISV is actived to close both the bypass and the rotary valve after its idle functions are finished.
You can see what I mean by carefully rotating the valve with a cotton bud through the port with the arrow on it, pushing from the bottom to the top.
You can try that again perhaps with a torch on the other port to see if its closing that bypass port off. Its difficult to tell, but I would think it would need to move more than that, say 5mm or more.
Obviously if you do the output test you can see for your self how much it moves, assuming it works!

[newsh]

Lou, try the output tests I've described above, its really easy.

[twoqu]

Lou,
Not sure what MM you have got from Halfords but if its not what you want take it back! If its one of those new fangled long/slim ones (rather than a short fat one) they are about £10 on eBay! To be honest you will be able to turn up a much better quality one than what Halfords has (Gunsons?) for that kind of money if you are patient!