Saabscene Saab Forum - Saab Technical Information Resource banner
1 - 3 of 3 Posts

·
Registered
Joined
·
95 Posts
Discussion Starter · #1 ·
As a result of the helpful responses to another question on Boost and Throttle response, I checked the impedance across the three pins on my APC solenoid (Anniversary 2.3T) and found that while the resistance across the centre pin and the left-hand pin was 3 ohms, across the centre and right and across the left and right were open circuit. This suggests that one of the coils in the solenoid has failed. The odd thing is that regardless of whether the solenoid is connected or disconnected I am getting full boost and can easily get the car to boost into the red - something which has rarely been the case in the recent past. It would appear that the wastegate path is stuck closed. I was under the impression that the failsafe mode is that the car should revert to base boost but this is clearly not the case. Can anyone else with (or without)experience of solenoid failure cast any light on this?

Many thanks
Martin
 

·
Registered
Joined
·
2,277 Posts
Hi Martin,

It could be that someone has wound the wastegate rod adjustment up so that it mimicks the amount of boost normally availible, but without the safety of the APC being able to control the boost limit if the engine management detects the onset of detonation.
Perhaps the first thing to do before worrying too much is to attach a graduated boost gauge temporarily to the spare nipple on the intake manifold and see exactly what pressure you are getting. I had a similar problem with my car and found that, although the needle was just into the red sector, I had only got 11 psi boost instead of around 14 psi and just three psi makes quite a differance.

Nick.
 

·
Registered
Joined
·
95 Posts
Discussion Starter · #3 ·
I thought I'd post a follow-up to my APC solenoid problems. I ended up ordering a used solenoid from Hannants (thanks to Scaero for the recommendation) for just £35 including postage and fitted it on Saturday. This has cured the problem and after a couple of adaptation runs the car feels pretty swift again, if not the bonkers quick I was experiencing with the failed solenoid in place. So, to summarise, when your solenoid fails, it can result either in base boost, or, as in my case, with the wastegate port stuck closed and associated overboost. The latter is much more enjoyable but of course potentially hazardous to the health of the engine.

Many thanks for all the helpful responses
Martin
 
1 - 3 of 3 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top