70 replies to this topic

[podmak]

Thanks Josh for your input, i found it inspiring. And Chappp, forsheding.some light on BBOD....

Now, back to questions. Your/Our pressure difference sensor, which is mounted on drivers side, just behind the strut mount (and I think I already know the answer to this question) - how is it cabled?

I found mine having some dodgy copper running out the side, and then through the hole in a firewall near the clutch opening through to the cabin... apart from the standard factory plug - attaching pic...

Could this be the source of my lack of boost up hills? How can I test this bugger to see if it's doing what it's supposed to please...?

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[duncanm]

dunno what's going on there.. the DPS (box-shaped) just has a plug at the base and the two pressure signals on either side.  That dodgy wiring looks like its going to another aftermarket sensor sharing the same mount point. Maybe it was remnants of a boost control system?

 

I'd be removing any boost lines that go to that and making sure there's no leaks from where it was teed off the manifold pressure feed.

 

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[LukeFranky]

You have two separate parts there.

 

The first is the differential pressure sensor. The second one with the dodgy wires hanging off it is a boost gauge sensor.

 

You should check that differential pressure sensor has the correct vacuum lines attached to it and that the boost sensor install hasn't introduced a vacuum leak.

[Josh18]

When you connect the green connectors together (and black? I can't remember) do all your solenoids cycle? The big ECV duty solenoid I have found should click intermittently in this mode. Also then when you start the car does the ECV then open and close? I ask this as I reckon your code 66 which I think is a difference in pressure between the two turbos and the lack of twin mode sometimes is because the ECV is not opening for some reason. Maybe one of the solenoids that controls the ECV (there are three) is sometimes sticking causing random problems. I got to know my system a lot better by disconnecting one line at a time with the engine idling in diagnostics mode and seeing what the different lines all do and whether they blow or suck. Some of it, particularly the operation of the ECV still leaves me scratching my head but disconnecting any line always has an effect of some sort so they are all playing a part.

One thing I did notice is that the system is very sensitive to line diameter. I carried out the mod in the TT guide where you bypass the ECV duty solenoid. This didn't really work well at all so I put the lines back, but because I had cut the originals I put in some of the silicone line I had that was smaller diameter by 1mm or so. The car would now take for ever to get over the VOD. So I put the original lines back in albeit a little shorter as I had chopped them and the car was back to normal. Just something to think about if you have changed lines.

Cheers

[podmak]

Thanks everyone for their input. I haven't been able to make any progress since my last post. New DPS costs 400+ dollars to replace the one I currently have, and there is no guarantee it will solve my problem. Also I deviated from my original idle rpm fluctuation quite a bit.

I wasn't able to source any information anywhere in regards to electric values of the parts which make up the TT control system, so that I might check the resistance/voltage on individual parts and rule out any faults;

I've been disconnecting and reconnecting the boost lines (which btw Josh18 i kept the original diameter 3mm) spraying carby cleaner into the actuators in hope something would change... nothing changes, car still won't boost when I tell it to.

And now other parts are starting to fail; brake rotors are warped, handbrake shoes are gone, there is that tiny oil leak developing on the oil filter and the paint is all but dissapearing. All of that worth fixing if only that engine can turbo properly...

I am posting here hoping someone can share some of their wisdom, how to pin point the fault because I am struggling with it...

[Josh18]

That all sounds pretty painful!

Have you tried removing the lines off the waste gate(s) to see if it can actually make boost? I haven't re- read back through the thread but what about boost/ intake leaks? Could you get another DPS from a wrecker?

Keep at it.

[Chaapppppp]

I agree, keep at it you'll get there buddy.

parts from a wrecker is where i get my spares, except for hoses and other moving parts, timing belt etc

was going to get a new Idle control valve at one point but it was $600, bugger that

 

Chur

[podmak]

Just doing 1 thing at a time. Oil leak was due to loosely tightened oil filter... Oil change 101 fail... Bur now the new filter is in, the oil doesn't leak anymore, so I got that going for me, which is nice.

Next up, the BBOD shuffle dance. I intend to follow Josh18 advice and screw around with the actuators and tubes...

[Josh18]

Just make sure you label it all before you remove anything. I used paint pen and different amounts of dots for each line and where it goes. Good luck with it

[podmak]

I finally found a 2nd hand differential pressure sensor that will not cause my children to starve so you might say that things are starting to look up..

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[zanzarah]

Did you buy it?

I have a spare one.