Date: Thu, 22 Aug 2002 07:54:05 -0400
From: KeithG <>
Subject: Re: My dealer hasn't got a clue, can you help? ('97 9000 Aero, Manual)

the pressure transducer or MAP sensor. It is on the RHS firewall. It is a small rectangular piece bolted to the false bulkhead and has a small silicone tube connecting it to the intake manifold. As I understand it, the BPCV on these cars is a dual acting solenoid valve. It probably fails mostly in a mechanical mode and does not seal in one direction or the other. Electrically, it would be pretty much work or not work. and I would think it would show some sort of odd behavior at acceleration less than WOT as well (wavering boost, lagging accel, delayed boost, etc.) I am just musing here, keep that in mind. I have the trionic engine control manual for a 96-98 NG900 which is similar but not exactly like the 9k. I do not think that this manual is much more than U$20.00 and is available from the dealer. Basic system operation is all controlled by the ECU (spark timing, boost, fuel injection). It does not have an Air mass meter, but uses a Manifold Absolute Pressure transducer, air temp sensor, throttle position and a lot of math to determine fuel delivery and boost limitation. You say that the the ECU and BPCV have been replaced... The wiring is 3 simple wires from the ECU to the BPCV. I think it is also 3 wires to the MAP sensor as well. You could always pin them out to check for continuity and ground. good luck and keep us posted. KeithG Lee Marshall wrote: > The problem is not intermittent, it always happens when the engine is under > load i.e. full throttle in 3rd, 4th and 5th, pulling from low revs, it > happens more if the car is carrying extra weight. Thankfully I never have to > tow anything. It is not affected by heat, road conditions or anything. > > I've never heard of the pressure transducer, where is it situated? It could > have already been replaced, so much has! BTW all the hoses have been checked > or replaced. > > My personal thought is that it is some kind of electronic connection > (probably to the BPCV) that can only be tested when the car is at full > boost, making it almost impossible to test in the workshop. > > Does anyone know where I could get hold of a wiring diagram for the turbo > system? > > > "KeithG" <> wrote in message > > >>Lee, >> >>They replaced the part I would suspect 3 times. It shows you how much I >>know... I think I would have to get to know Trionic a bit more to hazard >>another guess. I would disagree, though, with some of the previous logic >>used, but what do I know. Have they looked at the pressure transducer >>its hose, fitting or its wiring? Is it possible that the pressure >>transducer hose could be a problem or the transducer itself? From my >>limited understanding, I would guess that the system, somehow, does not >>know that the pressure has exceeded normal values. I could imagine a >>pressure transducer which is nonlinear and reports decent values back at >>idle and vacuum and becomes nonlinear and under reports pressure at >>higher pressures. A wastegate would stand an outside chance of causing >>this, a BPCV could do this, too. If the system is operating properly >>(still an IF, but mostly confirmed) and still overboosts, it HAS to be >>that the pressure signal is not reported correctly to the system. Does >>it do this all the time? Does it do it cold and hot? Over bumps and >>smooth pavement? >> >>Just some ideas YMMV! >> >>KeithG >> > > > > > --- > Outgoing mail is certified Virus Free. > Checked by AVG anti-virus system ( > Version: 6.0.380 / Virus Database: 213 - Release Date: 24/07/2002 > >

Return to Main Index

The content on this site may not be republished without permission. Copyright © 1988-2019 - The Saab Network -
For usage guidelines, see the Mission and Purpose Page.
[Contact | Site Map | on Facebook | on Twitter | Shop Amazon via TSN | Site Donations]