What are these connector for!?

[Steven Leece]

I have a new loom and I have connected everything up but I still have these two connectors spare. I did think they were for the anti perc fan turbo heat shield sensor, but the connector is metal and wires them together and therefore the perc fan would run if this was plugged in to this holder??



I joined the connectors which I had put to the carb base switch together and the perc fan fired up so I know that works.

Also on a separate note I started the rebuilt engine in my car yesterday and that's the first time I've heard it running since 2009! Hopefully not long till it's back on the road but I need a full respray first!! Started like it had never been off the road!! Have had a big grin on my face all day!!

Just wanted to say thanks to the club as I have obtained a lot of knowledge and help from reading over the years, but I'm not really one for posting much!

Steve

[Alex]

I agree, they look like perc fan related to me, probably for the sensor in the heat shield. Well done on getting the car going!

[rabbitstew]

Definitely for a perc fan sensor. Mine has 2. One in the heatshield and another in the base of the carb.

[Steven Leece]

Thanks for the replies.

Maybe I am wrong but with them wired together shouldn't the perc fan run?

Keep meaning to get a project going think I will start getting some pics up now I feel like I've got somewhere!

Cheers

Steve

[rabbitstew]

Thanks for the replies.

Maybe I am wrong but with them wired together shouldn't the perc fan run?

I would have thought so. Like you said, if you short the ones to the carb base then the perc fan runs, which is how I wired a dash switch up to mine. But ive never tried shorting the heatshield wires.

[Matt_S]

From my limited knowledge, they should fire the perc fan when touched together. The perc fan sensor at the turbo end is a thermistor. If it literally sat on the turbo, the fan would be on all the time.

[Steven Leece]

Thanks for the replies

It's strange that it doesn't do anything when they are joined together or apart! Must be missing something or I've done something else wrong!?

Cheers

Steve

[Trevhib]

We could do with seeing a pic from further out

[Steven Leece]

Not sure if these help much Trev? They do point to perc fan but do don't much ha ha

Thanks Steve

[Trevhib]

You can see in this picture (from this thread here: https://www.rtoc.org/boards/showthread.php?t=38043), that those wires go to the green resistor for the perc fan (towards the right hand side), yours seems to be missing:

[Steven Leece]

Mine doesn't have that green thing or the bracket for it, what's it do?

Also I don't have wiring for the turbo sensor then!?

Thanks

Steve

[Trevhib]

You do have the bracket, it's the same one that your TCD sensor attaches to. You just don't have the big green perc fan resistor bolted to it.

See post #12:
https://www.rtoc.org/boards/showthrea...c+fan+resistor

[Trevhib]

I can't see your wiring for the carb base or turbo heat-shield sensor. You don't have the resistor and the purple wires aren't bridged. Does your perc fan ever come on?! Maybe you do have the carb sensor and I just can't see it.

Either way, I'd remove the whole thing anyway. Especially if it's sat there redundant!

[Steven Leece]

Hi Trev

I badly phrased that, my bracket doesn't have the green thing not does it have the connectors or area to bolt the green thing. I know this as I bought the bracket with the green thing on and it's different to that on mine. Try get pics later.

The perc fan works when I bridge the wires on that go to the carb sensor. Therefore as it works and renault put it there for a reason and I like the standard look I am going to keep it.

I suppose the key question would therefore now be in terms of the green thing, what does it do? Am I going to miss it as my car didn't come with it anyway? Should I put the working perc fan wires to the turbo heat shield or the carb base?

Thanks for your replies.

Cheers

Steve

[Trevhib]

No worries.

Yeah, Renault put it there for a reason but that reason seems not to be apparent in a lot of GTT's and the Perc fan has been the cause of many an engine fire over the years, so the risk v reward ratio is not so great, hence why many removed the job lot.

If using OE as the reason to keep the fan however, then ideally a turbo heatshield, sensor and wiring would be in order. So you have more than just 1 of the 3 triggers implemented. Did you know that it's the original heat-shield design that caused heat to run along to the carb base, requiring the perc fan in the first place! It went like this:

• Early Ph1 - no heat shield originally
• Later Ph1 - heat shield added due to external regulations
• Ph1 - develop hot start problems due to heat shield
• Perc fan added to combat this
• GTT owners remove heatshield (and things like bonnet carpet)
• No need for perc fan, especially since it seizes and causes engine fires

I don't know how the resistor fits in with the wiring description in that last thread. Maybe someone here knows, or perhaps flick through the bountiful number of perc fan threads that come up in the search

[Russ B]

If my memory serves me right........ (also applying a little logic here as well )
When the perc fan comes on, the solenoid on the bulkhead then opens so that the "cool" air is also blown into the main boost hose yes...

If the perc fan is on & you are driving the car, then the last thing you want is the solenoid open as its a rather large boost leak yes...

So the resistor is there to reduce the current/voltage to the solenoid (much like the dim dip resistor). Its then not held open with any strength....boost will shut it/close it & hence no leaked boost.

[Steven Leece]

Thank you for info gents, very much appreciated.

I have a heat shield and the heat shield sensor but not put on yet as only just finishing putting everything together and was easier to leave off for access and checking for issues etc.

Cheers

Steve

[Trevhib]

Keep us updated Steven.

[Charlie]

Hi, the two purple wires go on the green resistor thing, the blue and orange wires are for the heat shield sensor which is linked to the carb base sensor but carb base sensor is not needed for the perc fan to work.

[Goobie]

As said, it's for the green thingy and also as said, Perc fan is a fire hazard.

[Brigsy]

Did you know that it's the original heat-shield design that caused heat to run along to the carb base, requiring the perc fan in the first place!

Not true..the heatshield makes feck all difference to hot start. Hot starts are poor without the heatshield. If only it was as simple as removing the heatshield to cure it the perc fan does a half decent job considering its a lash together. You will never get a fire if a - the perc fan is in good nick & the most important part b - the fuse is fitted inline to the perc fan wiring as per the recall.

[Steven Leece]

Pics as promised,

The bracket on my car:


A bracket with the green thing attached:


As you can see my bracket doesn't have the point where this mounts, nor did the original wiring loom have anything which was not attached?

And this is the wiring ice put to the carb base/inlet manifold (when joined together the fan runs):


I also have the fuse fitted to the perc fan wiring.

Cheers

Steve