Head Gasket can of worms??? - Now chasing Boost Leaks!!!

[Fat Audi 80]

Thanks, I will ping Alex - Cheers!

[Greg_S]

I''ll add the injector wiring to my list of jobs as I occasionally get a lumpy idle. Its nice to see both motors up and running and on your drive

[Fat Audi 80]

Thanks Greg!

On a side note, I am now chasing boost leaks as the old girl is not as spritely as I remember.

One found on the short cam cover breathe hose, but it is still not holding boost. I can hear it coming out around the entry to the intercooler....

I will get there in the end!

[newsh]

Thanks Greg!

On a side note, I am now chasing boost leaks as the old girl is not as spritely as I remember.

One found on the short cam cover breathe hose, but it is still not holding boost. I can hear it coming out around the entry to the intercooler....

I will get there in the end!

If you haven’t already done so take the headlight out.
DV is tee’d in down there, and DV to MAF hose.
Then there’s the nipple on the turbo going to the N75.
Turbo outlet can be tricky to tighten and is often oily and rotten but as you’ve had the head off I guess you’ve gone silicone hose?

[Fat Audi 80]

If you haven’t already done so take the headlight out.
DV is tee’d in down there, and DV to MAF hose.
Then there’s the nipple on the turbo going to the N75.
Turbo outlet can be tricky to tighten and is often oily and rotten but as you’ve had the head off I guess you’ve gone silicone hose?

Hi John, yes replaced all the hoses and clips down there. I am going to re-run the boost leak test at the weekend to see if I can find it.

It is boosting more now, but it still tailing off under high load....

Stay tuned!

[K Simmonds]

I had to replace all of the pink inserts on my injector connectors after constantly chasing random misfires and a lumpy idle, like John I used second hand ones from old connectors I'd cut of old looms prior to scrapping them, they're not just used for the injectors I managed to find five from bit's of various VAG looms. This was on my old 3B, the one's on my RS2 still seem to be fine, though that car has covered half the miles.

[Fat Audi 80]

I had to replace all of the pink inserts on my injector connectors after constantly chasing random misfires and a lumpy idle, like John I used second hand ones from old connectors I'd cut of old looms prior to scrapping them, they're not just used for the injectors I managed to find five from bit's of various VAG looms. This was on my old 3B, the one's on my RS2 still seem to be fine, though that car has covered half the miles.

I have some ordered new inserts from Alex (Error404) so will get this done soon.

Thanks

Steve

[Greg_S]

It is also worth checking your PCV for leaks Steve, that has caught me a few times in the past

[Fat Audi 80]

Second leak found. Right in the middle of the intercooler. Has anyone any experience of trying to fix this with JBWeld or equivalent?!

(I have already had a dig around the fins to try and find it and white stuff is washing up liquid!)

Thoughts?

Intercooler small.jpg

[newsh]

Second leak found. Right in the middle of the intercooler. Has anyone any experience of trying to fix this with JBWeld or equivalent?!

(I have already had a dig around the fins to try and find it and white stuff is washing up liquid!)

Thoughts?

Intercooler small.jpg

******!

Yes.

Clear away the crinkly stuff around the leak, make sure you’ve definitely found the leak.
Clean it really well, rough it up with coarse wet&dry, clean again with alcohol or brake cleaner and stick a blob of JB Weld on it. Should last for years.

[Fat Audi 80]

Thanks John, that was my thought process. Nothing to lose really.

[Fat Audi 80]

Once I get the boost leaks fixed it will be mega. I think it has had some leaks for a number of years, started to feel "flatter" about 4 years ago!

[Fat Audi 80]

Well I spent most of Saturday chasing more boost leaks! The intercooler one appears to have been successfully patched up.
I then found another one on the ISV, this was successfully sealed with clear epoxy.

My compressor will now pressurise to approx 6 psi (it was 3 psi before) so there is some progress, but I cannot get it to go any higher. Air is escaping somewhere and I cannot see or hear it!

To cut a long story short I have taken off and visually checked every single rubber hose in the intake / turbo and camcover breather system - all ok. (this took bloody hours) I have pressurised the system again and again and sprayed soapy water everywhere and cannot see or hear any leaks. All small diameter hoses have been replaced with brand new silicon hose. All jubilee clips are new etc...

I have driven the car and although it is better and will boost to 6k rpm in second, as the load increases and you go up through the gears you can feel the boost bleeding away somewhere. The car has 75% of its true performance.

Any ideas as to what to try next?!

Thanks,

Steve

[newsh]

Hi mate
Stick with it, you’ll get there.

Firstly I would test with the PCV system completely disconnected.
The pipes from the crankcase vent to the cam cover and MAF hose only ever see vacuum so pull the 20mm pipe out of the MAF hose and plug the hole in the MAF hose.

You should be able to pump it up to 1Bar and it goes down slowly for 20-30 seconds.

Some air will escape past the rings into the sump.
Check around the injector seals. (Not sure if you fitted new ones)
Hoses to and from ISV.
WG diaphragm (air from top chamber).
WG valve guide (air escaping into exhaust).
To isolate WG disconnect it’s hose and plug it.
Air leaking at WGFV (I’ve seen a few of these)
To test the DV you have to disconnect its vac line from the nipple at the front of the manifold, then listen to the line and block the nipple with your finger. If the DV diaphragm is split then air will come out of the hose.

Just a thought, have you got a boost gauge on the car? If so what’s it actually boosting to when you drive it?? Full throttle at 3k5 in 3rd?

Is the vac/boost line to the MAP sensor in the ECU connected?

Oh yeah. There’s also a vac line under the rear seat for the diff lock which can split or come disconnected. Usually hear that when driving though!

If you want to discuss anything on the phone PM me your number and I’ll get back to you.

[Fat Audi 80]

Hi mate
Stick with it, you’ll get there.

Firstly I would test with the PCV system completely disconnected.
The pipes from the crankcase vent to the cam cover and MAF hose only ever see vacuum so pull the 20mm pipe out of the MAF hose and plug the hole in the MAF hose.

You should be able to pump it up to 1Bar and it goes down slowly for 20-30 seconds.

Some air will escape past the rings into the sump.
Check around the injector seals. (Not sure if you fitted new ones)
Hoses to and from ISV.
WG diaphragm (air from top chamber).
WG valve guide (air escaping into exhaust).
To isolate WG disconnect it’s hose and plug it.
Air leaking at WGFV (I’ve seen a few of these)
To test the DV you have to disconnect its vac line from the nipple at the front of the manifold, then listen to the line and block the nipple with your finger. If the DV diaphragm is split then air will come out of the hose.

Just a thought, have you got a boost gauge on the car? If so what’s it actually boosting to when you drive it?? Full throttle at 3k5 in 3rd?

Is the vac/boost line to the MAP sensor in the ECU connected?

Oh yeah. There’s also a vac line under the rear seat for the diff lock which can split or come disconnected. Usually hear that when driving though!

If you want to discuss anything on the phone PM me your number and I’ll get back to you.

Thanks John, great advice. Let me try and have another go at the weekend. I have started to try and understand the various Sub systems that can be isolated via the excellent sticky on this, As trying to diagnose leaks over the entire system seemed impossible...

I appreciate the offer of a voice on the end of the phone too and will let you know....

Thanks