91 BC5 RS LEG Diagnostic

[THUNDA]

Hey all just ran a diagnostic on the RS

Car is fuel/boost cutting once boost spools up (spools to around 10psi then cut)

 

Got code 45 which I cross referenced to be 

 

: 

Pressure duty solenoid (turbo)/atmospheric pressure sensor circuit (non-turbo)

 

So Pressure Duty Solenoid

 

Tried to look it up to find out where it is / what it looks like and I cant get any information about it

 

Can anyone help me out or link?

 

Im guessing ive got a leak somewhere? does pressure duty solenoid read pressure before the turbo (i.e intake from afm to turbo inlet) or after the turbo (from turbo to ic to throttle body)

 

Cheers

[Zeus]

It's the mess that sits on the drivers strut tower. I have heard of this issue before, try bandaid it with a boost tap

[THUNDA]

Arg, it's all plugged in the standard way, do these solenoids poke out often?

 

keen as to have it set up standard , spent hours and hours on it over the last 2 weeks disconnecting all the years of gauges and shitty wiring , I'll plug it and see if that helps after work 

[slystiguy]

spray a bit of brake clean in it, make sure it's plugged in to power and the wires aren't damaged, check the plumbing is done right. I've heard of them failing but never happened to me. If you plug the testing plugs in and turn on the ignition it should make clicking noises 

[THUNDA]

Sooooooooooortttttteeeeeeeeeed

 

Just put a 2nd hand pressure solenoid in and everything back to normal

 

Weird though, spent hours putting this car back to standard (fixing vacuum leaks putting vacuum pipes back to standard and standard wiring) and car is running standard boost control setup but boost sits strongly at 14psi : /

 

chipped ecu maybe? 

 

Its just a standard ej20 from what i can see

engine mods are 

td05h

yellow top injectors

free flow exhaust from turbo back

wrx top mount

[slystiguy]

could be, pull ecu and have a look in the case. yellow injectors are not normal and HAVE to be tuned to run. If it's a speedlab chip I would advise you to remove it and go back to stock setup or at the least get it checked with a knock link/AFR , the yellows if untuned could be causing it to be very rich. Smokey out the exhaust? 

[THUNDA]

Whats a knock link/ afr ? ill google it

 

No smoke at all car runs really well considering how old it is, , it had a miss on idle when i first got it but after changing spark plugs and new h/t leads it purrs tight.

 

body has done 260,000 and im guessing the engine is the original one, no service history at all came with it

 

so going back to greys is better yeah? i used to see alot of guys running yellows when i last had a bc5, but i always kept my greys and never had any injection problems with any subaru ive owned

[slystiguy]

knock link to see if shes knocking 
Air Fuel Ratio to check it's not running rich

 

If it running well then it's likely tuned to the yellows. Yellows are a good upgrade if you are tuned. People will say you can run yellows on a stock ecu but it's really not ideal. 

[THUNDA]

would the knock sensor not pick up on a knock?

 

would having yellow injectors and it not bring tune make the engine knock ?

 

looked up knocklink but can only find a sensor that detects det that connects into a link ecu so bit pricey

[slystiguy]

Yes it will pickup knock but you won't have any idea it's actually doing it, when the ecu detects knock it pulls spark timing to compensate which results in sluggish power delivery and potential for an early engine failure if it's knocking badly. 

Heaps of things cause knock. I'm not sure if yellows would make it knock but they will be over fueling (hence need to check AFR). IF the ecu is expecting a 380cc injector and you're running a 440cc injector then it won't be able to inject the right amount of fuel and it will run rich. The o2 sensors adjust the fuel mixture but works on such a small voltage/scale range that it can't actually adjust or workout why it's over fueling, it will try to make the mixture leaner to an extent. 

 

Take it to a tuner to get them to chuck their knock link and afr on it. Shouldn't cost too much and will give you peace of mind. Or at the least pull ecu case and see what type of ecu it has. A guy in the states has rewritten the ecu code so people can run 550cc yellows so it's possible on a stock ecu to run upgraded injectors. Speedlabs reckons he has tunes to run yellows but a large amount of people have had failures very quickly after installing his chips(including myself and the guy i sold my speedlabs ecu to lol), so i suspect he hasn't changed the scaling/algorithms properly .

 

No point buying a knocklink for yourself but an AFR is a pretty handy tool to have around. Mighty car mods did an o2 sensor episode so go check it out for information