What's causing this then?

CarreraMonkey · 2 Dec 2016

Ok, so I had to have a new pse actuator fitted last week as the original one was toast and was leaking.

However my pse still is sent working.
:dont know:

The vacuum is definitely working, so the actuators are closed, but they won't open at 4000 rpm. They don't open even if I disconnect the brown plug.

Obviously if i pull the vacuum pipes they open.

So what's failed? Is there a solenoid that needs replacing?

Slightly miffed that after spending a few hundred quid on a new lambda sensor and actuator, i still have an outstanding issue with the pse.

deMort · 2 Dec 2016

Vacum valve solinoid in the picture is a common failure .. i would tend to take both vacum pipes off and join together .. you can make it switch on off by joining and unjoining the vacum pipes , that proves its valve or switching .

If the valve is not being switched at all then thats a little more unusual .. i would start with checking the codeing .. if its lost the codeing then it wont activate .. i would start with the valve though .. valve is a common one to fail on many systems so much so that i have spares at work i can just fit to check one.

CarreraMonkey · 2 Dec 2016

Thanks dermot, will investigate.

CarreraMonkey · 3 Dec 2016

The solenoid seems to be a cheap fix, so ordered one anyway.

Looks a bar steward to get at on an x51 engine though, :roll:

deMort · 3 Dec 2016

just a little query but your garage replaced a pse valve because of a leak which was obviously stopping it working but then didnt test to see if it was working .. or was it that it was working but has stopped since you got the car back ?

Lambda sensor was for something else i take it ?

Not sure off hand the location of the valve on X51 but i think its n/s of the engine.

CarreraMonkey · 3 Dec 2016

Demort said:
just a little query but your garage replaced a pse valve because of a leak which was obviously stopping it working but then didnt test to see if it was working .. or was it that it was working but has stopped since you got the car back ?

Lambda sensor was for something else i take it ?

Not sure off hand the location of the valve on X51 but i think its n/s of the engine.

Dermot-
Lambda sensor was foobarred after being swapped out from the original cats to the 200s. 1 of the 4 didn't like being moved and threw an error.

I rushed my indie as I was running late and had to get to twickers on Saturday morning and by his own admission he didn't test it properly. Hence, we had a better look at it on Friday when I moaned that it didn't seem to be operating correctly...

James will stick the new solenoid on, no big deal, but we will also check that there's a current going to it when the switch is on for sure.

deMort · 4 Dec 2016

Aghhh ok cheers

Exhausts and lambdas being swopped can often kill them .. happens with stud replacement as well .. fair bit of hammering going on close to them.

CarreraMonkey · 5 Dec 2016

Dermot - quick question if I may please?

When testing if there is a current at the plug (when the switch is on) should I expect there to be a permanent 12 volts at tick over, which then drops when the speed hits 30 mph? Or is it the other way round?

I can do the test myself whilst waiting for the solenoid to come, but want to make sure I understand how the switch works.

Thanks for your assistance.

Monkey

EDIT:
James called me this morning to say that he'd had a new solenoid delivered, so I popped in at lunchtime to get it fitted.

Before we tried it for the first time we checked the voltage at the plug. it was reading about 14.5 volts with sport off and 8.4 with sport on. We put the plug on and tried it and it worked. Turned it on and off a few times - all good.

Only when we tried it for a 3rd time, it didn't work. So we tested the voltage at the plug again and it was 10.8 volts with sport on, which is obviously not low enough to switch the solenoid. We disconnected the battery to reset the ecu as well, just in case my switching on and off had triggered something, but it didn't help.

Can you confirm what you'd expect the on and off voltage to be at the plug please?

Any ideas on what the issue could be? Seems an odd one to me! :dont know:

deMort · 5 Dec 2016

Sigh .. another interesting job and no where near me .. i swear god hates me and just wants me to do servicing for the rest of my life !!

Ive not got a lot of info at home but from what ive just looked at on a basic wireing diagram .. the sports valve ( grey ) will have a 12 volt feed to it .. this comes from fuse D F5 , theres quite a few other items that are also fed from this fuse , i saw 2 splice joints as it takes the feed off for other items .

so in essence the valve will have a 12 volt feed to it , when switched the DME will give the valve an earth ( C14 dme pin ) .

Unplugged and you should have a good 12v feed to the RD/BU wire , needs a load test so either a power probe or a small bulb down to earth to prove its a good 12volts ..

A volt meter might show 12volts but if the wireing is high resistance then when the item trys to draw current it cant draw enough to power the item .. think of a tap turned on so a trickle of water comes out .. a meter will say yup theres water there .. try to fill a pint glass and your there forever !!

The dme earth switch is the GY/GN wire which goes to C14 on the dme .. this again could have a resistance , it goes through the main engine plug .

I take it its still inop with the new valve fitted ?

Im not quite sure of how you checked it .. did you unplug the valve and with meter on both wires turn on and off the sports .. if so i would expect 12volts and then nothing as the dme would stop supplying the earth ..

If your getting 12volts or a highish voltage with sports switched on and off then it sounds like a short circuit to earth to me .

just to point out ive used a wiring diagram that may not be specific for your car .. but they are normally pretty much the same accross the board .

Disconnecting a battery will not reset anything as such , sometimes usefull if like a computer you need to turn it off and on again though. .. a tester will clear codes or adaption values but thats not applicable here.

Not sure off hand if theres a drive link for it on a tester in the dme section .. worth looking though.

Phil 997 · 5 Dec 2016

Another dam interesting thread ,

opcorn:

opcorn: good luck getting it sorted Monkey.

deMort · 5 Dec 2016

Id just like to point out there are several other things it could be .. an over current draw on one of the other fed items being what im thinking but we need to check the wireing to this valve first before we get onto other more unlikely faults .

Hey welcome Phil .. i thought this was a 2 horse thread :grin:

Phil 997 · 5 Dec 2016

Demort said:
Id just like to point out there are several other things it could be .. an over current draw on one of the other fed items being what im thinking but we need to check the wireing to this valve first before we get onto other more unlikely faults .

Hey welcome Phil .. i thought this was a 2 horse thread :grin:

:floor: Hi Iain , No I was just quietly watching (I know unlike me lol) as I didn't have any knowledge on the subject ,but was interested in what both You and Monkey were finding and trying. :grin:

CarreraMonkey · 5 Dec 2016

Yeah we put a voltmeter directly to the plug terminals and measured the voltage with the switch on and off. We expected the voltage to be on or off, so we were pretty surprised to see such high readings across the terminals when there shouldn't be any.
:?

The old solenoid was definitely goosed, we checked it after we'd swapped it out and initially the new one worked, but it did seem that initially the current at the terminal was lower. Howver it seems that there shouldn't have been a current at all..

If we can work out a few tests that I can do tomorrow, I'll have a fettle with it tomorrow morning and report back. But some guidance on what those test should be would be greatly appreciated.

deMort · 5 Dec 2016

Valve unplugged , meter on the 2 wires and check to see if voltage is switched on / off when activateing the switch .. as i understand it you have voltage both times ?

The 12v is a permanent feed with ign on but the earth should be switched .. if you are getting a voltage reading then the earth is not being switched but is permanent .

this would need a continuity check from the dme to the valve to see if the wire is shorted to earth .. if its not and all is as above then you have a dme fault .. this is getting pretty dam rare though .

It would be worth checking the correct wireing diagram for the car . i have a general LHD version which might not be correct .. but if it is and the wire colours match up then from what ive read so far an earth short is the most obvious.

When checking dme wireing the correct meter connection ( probe ) must be used .. to big and it will damage the connection .

A job i would far rather look at in the workshop than here .. here is not easy to explain im afraid !

CarreraMonkey · 5 Dec 2016

Demort said:
Valve unplugged , meter on the 2 wires and check to see if voltage is switched on / off when activateing the switch .. as i understand it you have voltage both times ?

The 12v is a permanent feed with ign on but the earth should be switched .. if you are getting a voltage reading then the earth is not being switched but is permanent .

this would need a continuity check from the dme to the valve to see if the wire is shorted to earth .. if its not and all is as above then you have a dme fault .. this is getting pretty dam rare though .

It would be worth checking the correct wireing diagram for the car . i have a general LHD version which might not be correct .. but if it is and the wire colours match up then from what ive read so far an earth short is the most obvious.

When checking dme wireing the correct meter connection ( probe ) must be used .. to big and it will damage the connection .

A job i would far rather look at in the workshop than here .. here is not easy to explain im afraid !

Yes, 14.5 volts when there's meant to be a current, but 10.4 when there's not meant to be a current. Interestingly, when the ignition is turned off there is still a current (wtf?) although it does gradually drop away.

Where can we get a wiring diagram for a rhd 2007 c4s?

Where is the dme located? What would be the best way to do acontinuity check between the dme and the valve plug?

What's causing this then?

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