406oc.co.uk

Most of you will know I have had the same problems with my 406 as Landymad, ie intermittent power, for well over a year now.
I've replaced pipes, MAFs, solenoids, even the turbo
And still we have "good days" and "bad days"
Even the main stealers have found it baffling.
So yesterday it was running particularly poorly whilst out on a run to the point where it was an embarrassment to drive it, a mik float actually had more power
So I knocked the engine off at a set of lights and restarted it, which usually clears it for a bit. Firstly I noticed for the first time an odd whistle.
When I say odd I don't mean the familiar turbo whistle, I'd never heard whatever this is.
I was baffled and put it down the the window being open.
However, I got home and as the car had run pathetically I popped the bonnet a couple of minutes after switching off, mainly to see how much of a pig it was going to be to get the EGR off.
Whilst I was stood there there was what I can only describe as a funny noise like an old kettle whistling for about 5 seconds which tailed off.
The funny thing is, the car is now flying. And when I say flying, I mean keeping up with a Celica last night

Did I broked it or is there a more suitable explanation for it?

I may have mentioned this before, but I've heard of the intercooler side splitting under pressure, this makes a strange noise when it happens.

The front bumper has to come off check it.

supafrisk wrote:I popped the bonnet a couple of minutes after switching off...a funny noise like an old kettle whistling for about 5 seconds which tailed off.

So the whistling was there for a couple of minutes after stopping the engine?

Surely the charged area wouldn't be pressurised with the engine off and if it were, would discharge a lot quicker than that by blowing the turbo backwards?

I don't know diesels, but the only things that I think could whistle without the engine are the fuel tank pressure equaliser valve thing, the charged air section and air trapped in the cooling system. What if it's the first? Usually the pressure valve thing for the fuel tank (lives next to the ECU box on the V6) goes "bzzzt-tschhhh" every so often and then about a minute after stopping the car, but if it weren't working then as fuel got pumped out, there'd be a hefty vacuum building up which would reduce throughput on the fuel pump and seriously kill power?

mjb wrote:

supafrisk wrote:I popped the bonnet a couple of minutes after switching off...a funny noise like an old kettle whistling for about 5 seconds which tailed off.

So the whistling was there for a couple of minutes after stopping the engine?

Surely the charged area wouldn't be pressurised with the engine off and if it were, would discharge a lot quicker than that by blowing the turbo backwards?

I don't know diesels, but the only things that I think could whistle without the engine are the fuel tank pressure equaliser valve thing, the charged air section and air trapped in the cooling system. What if it's the first? Usually the pressure valve thing for the fuel tank (lives next to the ECU box on the V6) goes "bzzzt-tschhhh" every so often and then about a minute after stopping the car, but if it weren't working then as fuel got pumped out, there'd be a hefty vacuum building up which would reduce throughput on the fuel pump and seriously kill power?

Too technical for a bird like me

jasper5 wrote:I may have mentioned this before, but I've heard of the intercooler side splitting under pressure, this makes a strange noise when it happens.

The front bumper has to come off check it.

That's a Chris 'n' Dave job, I think

supafrisk wrote:Too technical for a bird like me

Ok you've surely noticed about a minute after killing the engine, something under the bonnet normally goes "bzzzt-tschhhh" on 406s?

Well that's a valve opening that lets air into the top of the fuel tank. Why?

Imagine a 500ml bottle of coke is your fuel tank. Put your gob over its top forming a seal and you're the fuel pump. You can drink some out, but then a vacuum forms and you have to let go and break the seal so air can get in so you can get more coke out. That's why you drink from a bottle with only your bottom lip forming a seal - you need air to get in else nothing can come out. Same with the fuel tank. If no air gets in, then the pump can't pull fuel out

That's my theory for the power loss and hissing