High Idle with slight misfire

[BRY]

I think you may have a fuel delivery problem, have you checked the fuel pressure when moving?
When was the filter/ pump last changed?
Graham had this red turbo issue and I can't remember how / if he fixed it.

[220bhp]

Thanks for your help guys, I realy do appriciate it.Dave with regards to the cats,I have taken them of an run without them now. Bry how would I check the fuel pressure when running what would I need to do this. I don;t know if the pump or filter have ever been changed before I owned the car, I have never changed them.
If you think its a possible cause then I certenly will
many thanks again Lou

[BRY]

I would do the filter if you can't find a receipt for one.

[twoqu]

Lou!

The only way you are going to get to the bottom of this is my being systematic and scientific! That means testing and eliminating components until you are left with the culprit, however unlikely.
Right we know that the fault codes for the ISV, the boost solenoid and the carbon cannister keep coming up. You have replaced the boost solenoid twice, so it is unlikely that is at fault. You have put the ISV on the S4 and it works, so there is no problem with that. So logically, it must be something to do with the wiring on the S2. As all three are fed off the same fuse, then there must be a connection. I understand that if that fuse blows, the engine goes into emergency or limp homemode. Just wondering if that is what you are experiencing.
Without the right equipment you are not going to be able to test and eliminate components. Even a 12v test light would allow you to confirm power at those components. Beg steal or borrow a multimeter for the weekend
For example you may have checked the fuse but have you tested it? A blown fuse will be open circuit. It might be the fuse is ok but there is no power to it, so you would need to probe the terminal in the fuse box to verify it has 12v. So you start at the component and work back!
The multimeter will allow you to test the components electrically through measuring their resistances. Its not difficult. We can talk you through it but you need the kit.
You should also familiarise yourself with blinking the codes yourself and indeed running the output tests as Jas has mentioned. No point in paying for someone to do that for you.
I notice that the on the second time the codes were read the knock sensor fault had disappeared. Did you replace that? If a knock sensor fails the timing is retarded on whatever cylinders it controls.
Thats not to say it isn't something else like a hose leak but if we concentrate on trying to eliminate things by testing not guessing then that must be better than randomly replacing components. Looks like you have already wasted a considerable sum on components that were ok.

[220bhp]

Thanks guys for your help, I have just ordered a fuel filter and Ipick up a multiymeter tomorrow. Many thanks Lou

[220bhp]

I have the new fuel filter, and I want to try and fit it today. Before I start ,is there anything that I should watch out for, such as fuel spurting out ect.
Also I am now in posses'stion of a multymeter and will start to test things one by one.
Has anyone had any more ideas on what might be causeing the red turbo,as I dare not use the car for fear of damage
Many thanks Lou

[Knight Rider S4]

Disconnect the fuse for the fuel pump and unbolt you will have some fuel loss as it is a pressurised system....have you disconnected the MAF and see what it runs like ?.......Red Turbo i my eyes mean boost leak or weak mixture ...Had boost leak myself and was hose under bumper needing repaced but this caused the turbo to over work to try and work through the lack of boost

Good Luck

[twoqu]

Here are some values to check. The Boost solenoid should be ok as its been replaced and the ISV seemed to function when you swopped it over. However this is just to eliminate components.
N71 ISV 7.5-8.5ohms
N75 Boost solenoid 25-35ohms
N80 Carbon solenoid 40-50ohms.
Set the multimeter to the 200ohms setting unless its autoranging. Put one probe on one pin and the other probe on the other pin. Take the reading. Simple as that!

To test for voltage you will need to select the DC 20v setting. You will need to earth one probe, usually the black one. The other probe can then be put onto whatever terminal needs checking. Personally I remove the rubber boot from the back of the connector and probe the terminal from the back. To check whether you have an earth you can use a known 12v supply.
Then its just a matter of determining the power terminal. Usually its not a wire with brown in it! I would test with the ign on and engine running. So test those three components.
The instructions for the checking the idle switch have already been posted in this thread.
See what the results are then we can make other suggestions.

[220bhp]

Twoqu I tried the multymeter on the 3 sensors you mentioned and these are the readings
N71 8.4 ohms
N75 26.7 ohms
N80 45 ohms [! valve with electrical connection at the back of the head]

I tried to read the voltage on each sensor as you suggested with the engine running, by placeing the black probe to ground ,and the other on the dissconnected supply,hear is where I stumbled, I have never used a multymeter,and the one I have is a new given to me buy a friend,but with no instructions , so i'm not sure I have set it right, IE, set it to 20v dc, the readings I got where .
N71 67-70
N75 40-45
N80 160-170 I feal this is wrong and that I have made some sort of mistake
Many tanks Lou

[twoqu]

Twoqu I tried the multymeter on the 3 sensors you mentioned and these are the readings
N71 8.4 ohms
N75 26.7 ohms
N80 45 ohms [! valve with electrical connection at the back of the head]

I tried to read the voltage on each sensor as you suggested with the engine running, by placeing the black probe to ground ,and the other on the dissconnected supply,hear is where I stumbled, I have never used a multymeter,and the one I have is a new given to me buy a friend,but with no instructions , so i'm not sure I have set it right, IE, set it to 20v dc, the readings I got where .
N71 67-70
N75 40-45
N80 160-170 I feal this is wrong and that I have made some sort of mistake
Many tanks Lou

Lou!

Well at least you have verified that those three components check out electrically from a resistance point of view. Which is what I was expecting as I don't think your problem lies with them.
Ok, basically you need to select the appropriate setting on the multimeter for DC voltage. Usually there is a big central dial you use to select the various readings. Normally there is an AC V and a DC V setting. Normally it the range is 2V, 20V, 200V etc. So for 12V you need to select the 20V range. You can then test the battery by placing the probes on either terminals. If it reads 12.5 or above, then its ok. Actually even if you used the 200V setting it would still give the correct reading. It depend on the multimeter whether you need to select the range manually or whether it selects the range itself, autoranging. You must however select manually what you are testing for. So for us it has been resistance, which is the ohms setting. For voltage, its volts DC!
You'll soon get the hang of it! As the battery is under the bonnet you can always check that you have a good earth on the one probe by putting the other probe on the + terminal. You should read battery voltage. Just practice a bit till you get the hang of it.
Before testing the components, earth the one probe and touch the other to fuse 24 where you can see the metal either side. If you can get a 12V+ reading on either side then we know power is coming into and from the fuse box to those components. If you cannnot get a reading on any or all those components then we know there is a problem in the wiring between the fuse and those components. I hope you can see the logic in this. Its like trying to find a leak!
Hope that helps!

[220bhp]

I tried to check fuse 24 for voltage,and disscovered that the hole fuse holder for that 30amp fuse is loose ,I noticed it was lower than the others ,when I touched it with the probe it went down futher ,and I had a job to retrieve it. I also noticed the holder was red in colour and the others to the left and right are white.I dont know if this is as it should be or whether it could point to it being replaced, thus sig'nifing a possible problem in the past.
As for a voltage, I tried the battery test and the digital display keeps blinking a battery sign,so I gess the multymeter needs a new one.I will replace it and try again.
Many thanks Lou

[220bhp]

New battery in the multymeter ,no change multymeter still eratic tried to relocate fuse 24 ,but it still keeps dropping down,there must be something wrong here,or is it me being stupid [dont answer that]

[twoqu]

New battery in the multymeter ,no change multymeter still eratic tried to relocate fuse 24 ,but it still keeps dropping down,there must be something wrong here,or is it me being stupid [dont answer that]

Lou!

What do you mean about erratic? If the leads are long enough its advisable to earth the one lead on a known earth point. You can then use the other probe on a known 12V source to check the reading. That way you can ensure you will get a good reading.
As you have a 3B the battery earth is handy! As long as you can see the reading it should be ok.
As fuse 24 is part of the engine management loom its not a permanent fusebox fixture. Obviously if it is moving its possible that the fuse itself isn't fully home, that partly why I was trying to get you to test for power everywhere. You need to hold the fuse holder whilst ensuring the fuse is engaged properly.
I think that this fuse receives its power from the fuel pump relay. It then goes through the fuse to those three components. So providing the S6 one is the same, you could quickly try that over the weekend.
I really think this is an electrical problem. The fact those those three share the same power supply can't be a coincidence!
Although I have been banging on about a multimeter you can use just a test light to check for voltages. Occasionally I use a nasty Gunson led one. In fact I have used this for the blink test. The terminal is a bit large but as long as it touches it will do the job! Or you could just use a bulb holder with some wires. All we are trying to verify is whether power is reaching any of those components!

[220bhp]

I have aquired another multimeter,this one is autoranging, and I have tried to retest some of the components again and do a comparision test on my s6, starting with the TPS.On the s6 reading was o.o3 to OL which I assume is Infinity. tried the 3b and got nothing,this was on the ohms setting with one probe on connecter 6 and the other on connection 4. This was assuming the top connecter as no1, I then thought what if the 3b was on the otherway round, making the bottom no1, I tested it this way,and the reading was I.O61 closed and 3.05 open I can hear the click on the s6 but not on the 3b, all this is in the rain so I will try again when it stops. LOU

[twoqu]

Lou!

Pretty sure on the 3B that 1 is uppermost. So if you are not getting closed circuit, ie nearly 0 when the throttle is shut and open circuit when the throttle is open, sometimes expressed as 1 or the same reading as if the probes aren't connected, then either the throttle is being stopped from going fully back or the throttle pot is dead!
See if you can release the throttle cable from the linkage to be sure.
If it doesen't click and you can't get the closed circuit reading then it may be dead. Does it looks as though its been touched? You could try slackening the screws and rotating the pot anticlockwise a bit to see if you can get the click or the reading.
Pretty sure that the pot also has a input to the boost control so it certaintly is a candidate for most of your problems if kaput! The idle control is activated when the throttle goes closed circuit.
Thinking about it if you bridge the rear of the connections with a piece of wire it should give the signal to the ecu to control the idle speed. Basically you are making the circuit if that makes sense. If the car then idles ok, that part of your problem sorted!