can anyone advise procedure on checking correct operation of boost solenoid. Car is only boosting to 0.5 bar. I am trying to fault find.

 

If you join the 2 green under dash connectors, all the underbonnet electronics will be cycled in turn. Solenoid is one of these. This will confirm operation (you should hear it clicking happily away during it's turn). This can also be used to clean it (just remove bolts and pipes, turn upside down and squirt in cleaner while it's cycling), which you maybe try if you haven't already - contaminated solenoid is a common cause of overboost, but can also cause no boost if the oil has set and seized the solenoid.

When did this problem occur? It's also worth inspecting all the pipework (draw a diagram before removing it, and note that the pipe coming off the turbo outlet has a restrictor in it before the t-piece....it *must* go back on the right way ).

Good luck , Richard

 

Hi Richard,
I tried to clean it last week. Thanks for the tip of using the diagnostics to hear the operation of the solenoid - I will try a clean out while it cycles.

The problem was on the car upon delivery from Japan. I think I found the restrictor - a metal ferrel within the pipe a cm long or so.

I also noted a "denso" plastic cylinder (it resembles a small fuel filter) on the pipe from inlet manifold going to the solenoid. What is this for? It has no mesh or filter properties and is basically an empty plastic can?

 

Who knows what happened to it before leaving Japan. I would just get it to an expert to diagnose, probably simpler/cheaper in the long run?

I'd suggest using the check connectors to make sure there is power to the solenoid, and taking it from there. The plastic filter thing is normal.

If you were brave, you could try removing the pipe from the wastegate actuator and confirm that boost then goes through the roof...but be careful

Richard

 

Hi Richard,
I did the brave thing first disconnected the feed from the solenoid to the wg actuator - and cautiously got it to 1 bar before backing off.

squirted a load of cleaner in the solenoid and reconnected - tiny improvement 0.6 bar

Im going to do the diagnostics tonight to see if it clicks.

 

You cannot clean the solenoid properly unless it is in the test mode and clicking You need to squirt the cleaner in while it's operating to properly flush any crap out. Also note: if it is this, then also remove all the hoses one at a time and clean them too.

Richard

 

ah right. i did the diagnostics it was clicking away quite fast - not that loud. I have cleaned all pipes - but I will do this again while squirting cleaner in.

This morning - a friend tried a few things. He noted that i did not have the ferral in the small diameter pipe going to the actuator. We tried his and still no joy.

We noted that the layout of my pipes are very different to his - how are they meant to connect?

Finally we connected a bleed valve from turbo to actuator to bypass the solenoid. We then set this at 16 psi/1.07 bar. The sluggishness has dissapeared at last.

However I wish to go back to the factory settings but im convinced -

1) Pipes may have been incorrectly fitted. i.e. I have a blanking plug fitted on the connection after the maff. all my pipes lead from the manifold.

2) The solenoid is not working correctly.

thanks
Mark

 

Just sat here reading throught this thread;

I'm almost 100% certain that the pipe that comes from the manifold with the 'fuel filter' device in it should actually go to the MAP sensor NOT to the top of you boost solenoid.

The correct connections should be;


2 Port solenoid;

Pipe should come from compressor outlet (with brass restrictor in it) to the T, this then continues to the wastegate actuator. The pipe from the T should connect to the bottom of the solenoid. The top of the solenoid connects back to the air intake AFTER the MAF but BEFORE the turbo. If this pipe is connected after the turbo (as it sounds) then it will see pressure and will not be able to bleed pressure away from the wastegate actuator.


3 Port Solenoid;

Similar to the above except that the compressor outlet connects to one of the bottom ports on the solenoid with the other returning back to the wastegate actuator. The top port then connects back to the intake track.


If you have a friend then the obvious answer is to make your's look the same as his. Check that your MAP sensor is connected also, I'm not totally sure on this (some of the mappers may/may not correct), but I believe the ECU uses boost in part of the calculations for ignition timing, without this connected your ecu will not know what boost you are running.

BTW, the map sensor is the solenoid and sensor that resides just below the boost solenoid.

 

Zsatph can you help me see my other thread entitled help!!

 

don't mean to hijack the thread bit i think i have the same problem as you gravel


i've got a p1, standard boost should be 1.1 bar but only getting 0.8 (only found this out after fitting a boost gauge today), cleaned the solenoid using the green connectors method and all pipework, there was some crud in there but now clear.

that said the car doesnt feel slow - maybe i've just got used to it being like it, I put it down to the hot weather but seems now that there's more to it?

i'm wondering pehaps whether a bigger restricter has been t in at soem pont to stop overboost?

any other thoughts appreciated. thanks

 

update on my boost prob, that might help you gravel, took it to local subaru dealer to check on select monitor, ecu had gone into limp mode probably due to prior fault solenoid, cleared ecu and car is now boosting to 1.2

if you havent aleady reset the ecu that's something you might consider to see if clears the problem, like it did mine

 

Thanks STi High,
I tried the ECU reset. The problem with my car is that the turbo pipes are not connected correctly -

http://bbs.scoobynet.co.uk/showthread.php?t=337578

The bleed valve brought mine up to 1.0 bar - but I am trying to get everythng back to factory set up.

 

i have a MY93 WRX and have the same problems but my engine looks different from the pictures because my Boost solenoid has three pipes. can anyone tell me how all my pipes should be fitted?

 

yes your engine bay is entirely diffrent to the facelift cars - sounds like you have the 3-port solenoid from Zhasaph posts.

 

does anyone have a picture of the intake track, not sure what this is
"The top port then connects back to the intake track"

 

Conclusion - Boost pipes reconfigured to correct configuration, brass restrictor replaced. Car is now boosting 1.2 to 1.5 peak. Solenoid was ok!