480 turbo boost loss

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m616tls
480 Newbie
Posts: 33
Joined: Mon Oct 12, 2015 3:08 pm

480 turbo boost loss

Post by m616tls » Sun Aug 26, 2018 7:02 pm

Hi all
Suddenly, after driving really well, I can hear a massive boost leak from the right hand side of the dashboard, just above the dash vent for the driver's window. I suspect that a hose or pipe has let go. Has anyone had this symptom before? I do not know the routing of the pressure pipes. The turbo gauge appears to be working fine but because of the leak, isn't showing the true boost.
Is there a confluence of pipes behind the dashboard from where the noise appears to be coming? I don't really want to remove the dash and speedo cluster if there are no pipes to be seen there. I am also aware that noises can travel and appear to come from X and it is really from Y. I have looked under the bonnet for obvious pipe damage but to no avail. If not a pipe, could it be the turbo leaking out of the system or would that be a raucous noise. The car drives smoothly but with obvious power loss.
Does the ECU on the right hand side of the driver's foot well have any pressure pipes leading to it.
Any info from your brilliant minds will be gratefully received.
I need EVA to be mended soon, as Sylvia has organised the Hampshire trip......annoyed of Norfolk
480 GT Green Aug 1994 "Sven"
480 Turbo Robou Paris Blue Aug 1992 "Eva"
SAAB 9-5 HOT Aero estate 2008 Black "Kemosaaby".........weasel xxxx comes to mind.
Previous cars.
940 2.3 SE Turbo May 1995 Burgundy "The Spy"
850 SE 2.5 1996 Burgundy. "Mew"
940 2.0 White "Dexy"

Robou
Knows an Aerodeck isn't a 480
Posts: 270
Joined: Sun Jul 08, 2007 11:34 pm

Re: 480 turbo boost loss

Post by Robou » Sun Aug 26, 2018 8:00 pm

A pipe runs from the inlet manifold under the right fender through the plating under the dash, splits there and feeds the turbo gauge as well the the ECU you mentioned.
Too old to bother
480 Turbo midst '91

m616tls
480 Newbie
Posts: 33
Joined: Mon Oct 12, 2015 3:08 pm

Re: 480 turbo boost loss

Post by m616tls » Mon Aug 27, 2018 7:26 pm

Thanks Robou.

I have investigated and there is a place where it splits, one line, from the plating grommet, splitting to the turbo gauge and one pipe to the Robou ECU. I have replaced some old braided rubber pipes for new rubber ones. Hopefully this will slow down the boost drop. I have seen a pipe with a braided connection, near to the Jetronic ECU, that appears to come from the inlet manifold. I mention this only because the noise distinctly came from the right hand side of the dashboard. I did hear the pressure loss coming from the right hand side of the dashboard.

Thank you for your help, it was gratefully received.

Alastair
Last edited by m616tls on Mon Aug 27, 2018 7:53 pm, edited 1 time in total.
480 GT Green Aug 1994 "Sven"
480 Turbo Robou Paris Blue Aug 1992 "Eva"
SAAB 9-5 HOT Aero estate 2008 Black "Kemosaaby".........weasel xxxx comes to mind.
Previous cars.
940 2.3 SE Turbo May 1995 Burgundy "The Spy"
850 SE 2.5 1996 Burgundy. "Mew"
940 2.0 White "Dexy"

Gmac34
480 Newbie
Posts: 47
Joined: Fri Mar 11, 2016 3:01 pm

Re: 480 turbo boost loss

Post by Gmac34 » Mon Aug 27, 2018 7:48 pm

If you cannot reach it just leave the old one in and run a new one. That should be doable without removing much else.

m616tls
480 Newbie
Posts: 33
Joined: Mon Oct 12, 2015 3:08 pm

Re: 480 turbo boost loss

Post by m616tls » Mon Aug 27, 2018 8:21 pm

Thanks, I was thinking of that but not sure where to go through the bulkhead.
480 GT Green Aug 1994 "Sven"
480 Turbo Robou Paris Blue Aug 1992 "Eva"
SAAB 9-5 HOT Aero estate 2008 Black "Kemosaaby".........weasel xxxx comes to mind.
Previous cars.
940 2.3 SE Turbo May 1995 Burgundy "The Spy"
850 SE 2.5 1996 Burgundy. "Mew"
940 2.0 White "Dexy"

Robou
Knows an Aerodeck isn't a 480
Posts: 270
Joined: Sun Jul 08, 2007 11:34 pm

Re: 480 turbo boost loss

Post by Robou » Tue Aug 28, 2018 2:49 pm

As the Jetronic has no connection to the manifold the tube there is redundant. You do better to investigate this matter. Maybe someone already replaced the old tube and you are looking at the relics.
It isn't hard to find a leak, blow into the manifold side and it should hold the pressure. If not the leak manifests itself by a hissing sound that a partner could locate.
Too old to bother
480 Turbo midst '91

gsa60
Started learning about 480
Posts: 96
Joined: Tue May 21, 2013 10:18 pm

Re: 480 turbo boost loss

Post by gsa60 » Wed Aug 29, 2018 12:10 pm

Hi guys,
What about the vacuum pipes that control the heater.
On the turbo, the heater has vacum pipes to control the direction of the blower.

jifflemon
480 Is my middle name
Posts: 2464
Joined: Sat Dec 17, 2016 11:03 am

Re: 480 turbo boost loss

Post by jifflemon » Thu Aug 30, 2018 7:00 am

that's not a bad shout - The control is right above the drivers clutch pedal too.

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