118TSi - CAVD to CTHD conversion, wiring harness Q? HELP!

[Mk R]

Where did you tap the manifold for your gauge? I had one for a while but never got it installed properly. I've still got the AutoPolar FIS+ but don't have it installed currently although I keep thinking of putting it back in.

Hi Hawk,

I took one look at that boost piping system and went straight to my mechanic before i made a dogs breakfast out of it. I'd be happy to to post some photos and ask them for you though. I recall even they had issues capturing the + and - boost readings properly.

My gauge now shows negative and positive readings on idle and boost respectively. Interestingly on start up when it runs like it has smokers cough for the first 30 seconds the pressure goes to zero before settling into -20.

On a side note, had my N75 replaced today after seeing the failure on the boost gauge at the 3500RPM switchover and boy does she boost hard on turbo again!

[The_Hawk]

The Polar FIS never showed a negative number for boost, from what I understand this can be normal and if a limitation of what the systems actually read/measure. I like the idea of a mechanical gauge, had the Podi one for a while but it blocked part of the display which bothered me and it wasn’t hooked up correctly and I had the AutoPolar unit so I sold it on. (I never really looked too closely at getting it installed properly). (I have installed a few pods into GTI/R Golfs which are very very easy to do correctly.

I keep meaning to drag out the VCDS cable and check for errors since I haven’t don’t that since first installing the GFB DV+. I’ll have to remember to have a look at the N75 too, although I have no reason to question it at the moment.

[Mk R]

The Polar FIS never showed a negative number for boost, from what I understand this can be normal and if a limitation of what the systems actually read/measure. I like the idea of a mechanical gauge, had the Podi one for a while but it blocked part of the display which bothered me and it wasn’t hooked up correctly and I had the AutoPolar unit so I sold it on. (I never really looked too closely at getting it installed properly). (I have installed a few pods into GTI/R Golfs which are very very easy to do correctly.

I keep meaning to drag out the VCDS cable and check for errors since I haven’t don’t that since first installing the GFB DV+. I’ll have to remember to have a look at the N75 too, although I have no reason to question it at the moment.

I have the GFB DV+ installed too and it hasn't thrown up any errors yet, definitely holds some boost between 2nd and 3rd on a quick change.

Here's some picture of where on the air system the Podi gauge is hooked up, you can see its line trail off with the inline filter towards the connection into the cabin. Mine is quite noisy now on idle making a mechanical scratching noise as it hovers but I only notice it on start up. I don't mind the way it blocks that part of the dash. IMHO there's really no need to easily see that deep into the redline around 8,000 RPM or keep an eye on the odometer. Might be an issue if you use cruise control a lot. The overlapping gauge circles look kinda cool to me.

[The_Hawk]

Well that's a hell of a lot easier than I was led to believe! That's not buried deep within but right on top!

[Mk R]

Yeah, i know! I told them what the forums were saying about the hook up point and they ended up experimenting when it wouldn't work and ended up with this.

[Mk R]

Being a little further away it may have a bit of delay in the reading but when you really put the boot in at 3,000 RPM+ the needle shoots up to 15-20 PSI quick smart.

I have the dial and needle set on red and it flashes to white at 22 PSI so you can see the boost peak without taking your eyes off the road.

[highflyer1]

Hi Hawk,

I took one look at that boost piping system and went straight to my mechanic before i made a dogs breakfast out of it. I'd be happy to to post some photos and ask them for you though. I recall even they had issues capturing the + and - boost readings properly.

My gauge now shows negative and positive readings on idle and boost respectively. Interestingly on start up when it runs like it has smokers cough for the first 30 seconds the pressure goes to zero before settling into -20.

On a side note, had my N75 replaced today after seeing the failure on the boost gauge at the 3500RPM switchover and boy does she boost hard on turbo again!

A few days back on the road and engine warning light is on. Checked codes and it is overboosting. With WOT it struggles past 4k, and every now and then it goes into limp mode until I restart. if I apply throttle gently, it holds boost OK but it's not a smooth boost "curve". Kinda jerks a little. I might get the GFB DV+, and a new N75 valve. In the mean time I will have to drive it like I'm driving Miss Daisy around....

Once these issues are ironed out it's straight to the shop for an APR tune and the podi you mentioned!

Other than that - she's purrrrrrrrrring along nicely

[Mk R]

A few days back on the road and engine warning light is on. Checked codes and it is overboosting. With WOT it struggles past 4k, and every now and then it goes into limp mode until I restart. if I apply throttle gently, it holds boost OK but it's not a smooth boost "curve". Kinda jerks a little. I might get the GFB DV+, and a new N75 valve. In the mean time I will have to drive it like I'm driving Miss Daisy around....

Once these issues are ironed out it's straight to the shop for an APR tune and the podi you mentioned!

Other than that - she's purrrrrrrrrring along nicely

Maybe have a good look at the turbo and see if everything's working ok. There seems to be a ton of stories out there about actuator issues and turbine vane damage causing that sort of thing, mostly in diesels though.

[highflyer1]

Yep, definitely crossed my mind to check the actuator and vanes. The turbo came with the engine as a complete unit with 9k on the clock. To think that it could be sticking with such low millage is a concern, albeit the engine was pulled out for a good 25 weeks or so....

One question tho...

The pipe coming out of the intake circled in the pic... where does this go to? What does it do? It wasn't in the original engine (CAVD) but is on the new one. I was getting an intake leak error code until I swapped out the intake pipe to delete the said pipe...

[Mk R]

Yep, definitely crossed my mind to check the actuator and vanes. The turbo came with the engine as a complete unit with 9k on the clock. To think that it could be sticking with such low millage is a concern, albeit the engine was pulled out for a good 25 weeks or so....

One question tho...

The pipe coming out of the intake circled in the pic... where does this go to? What does it do? It wasn't in the original engine (CAVD) but is on the new one. I was getting an intake leak error code until I swapped out the intake pipe to delete the said pipe...

No idea. Partsbase.org might have some answers for you...