Boost dropped to exactly half...WTF happened

[Redeyeblueeye]

Ok this happened.

Boost went to half the normal pressure jus so. was intermittent for a while then back down never to return.
Same fuel, no additives

Stock 03 WRX

What to do?

[STi-N]

get the car tuned for the sh!t gas we have here

[Redeyeblueeye]

Thought the WRXs ECU automatically tunes for this 95RON...and STis require tuning?

Any chance of something like a leak in the vacuum lines ... u suppose?

[Alpha_2nr]

^^The WRX and STi's both try to COMPENSATE for the local low RON gas. But in both cases, you'll lose power.

The STi runs a more aggressive ign map and boost curve (together with a bigger turbo), making it difficult to operate without some degree of knock on pump 95 RON (which equates to a USDM 93 RON).

The WRX doesn't run "as" aggressive as the STi, and also runs a smaller turbo (less air flow), so it's better able to "compensate" for knock. IT retards timing normally, so it will try to combat knock, but you'll lose power.

In extreme cases, your ECU will start to cut back on boost if the engine is knocking heavily, as your car may have done.

If you have a boost leak, you'd hear a loud screeching/whooshing noise in some (but not all) cases. Also, with a boost leak, your boost regulation may be irregular.

[sr18 Primera]

The ecu disabled your boost control. You're stuck at wastegate boost ~7psi.
It did that because it was detecting lots of knock... get your car tuned!!!

[Polydor]

The ecu disabled your boost control. You're stuck at wastegate boost ~7psi.
It did that because it was detecting lots of knock... get your car tuned!!!

^^^What

[Redeyeblueeye]

The ecu disabled your boost control. You're stuck at wastegate boost ~7psi.
It did that because it was detecting lots of knock... get your car tuned!!!

^^^What

But isn't 'tuning' reflashing? Will my car have permanently retarded IT (timing) afterwards?

Would it be better to leave the current tuning and use an octane boost additive to the fuel...? Would the ECU re-compensate and bring back up the boost?

Whats the difference if any with these two options? , what tuning really will do? ... anyone?

[STi-N]

its not permanent
u could go bak to the stock map if u dont like the tune
but i assure u
if u go ECUTEK.. you would have no complaints and be very impressed

get it tuned

[Redeyeblueeye]

its not permanent
u could go bak to the stock map if u dont like the tune
but i assure u
if u go ECUTEK.. you would have no complaints and be very impressed

get it tuned

U sound quite convincing and logical.

I think I will take ur advice...but any views on the fuel additives? Are u running additives and is ECUTEK tuned for premium (95RON)?


Who can do this for me?

[Alpha_2nr]

The ecu disabled your boost control. You're stuck at wastegate boost ~7psi.
It did that because it was detecting lots of knock... get your car tuned!!!

Maybe. But for him to be knocking that bad on a WRX, maybe there's another problem?

What??

Polydor, he's referring to the Wastegate Actuator setting/pressure (basically a baseline boost level).

U sound quite convincing and logical.

I think I will take ur advice...but any views on the fuel additives? Are u running additives and is ECUTEK tuned for premium (95RON)?


Who can do this for me?

Reflashing is what is done to help cars like ours cope with lower quality gas.

Of course, as another, CHEAPER option to EcuTEK, there is now OpenECU/Enginuity software...which is FREE to download, and tune (if you can yourself). You can also pay a tuner to do it for you. If you have a laptop, and a subaru reflash cable, you can solve your problems in about 5 mins.

Don't discount it's abilities 'cuz it's free. It's the most popular appraoch for tuning out there in the USDM market to date.....You can have a tuner tune your car with the free software, OR you can also go to www.osecuroms.org to purchase a custom made/ready made map for your car (which should be EASY and CHEAP to procure since your car is stock). Reflash the map in....and drive.

Of course, running a "premade" map has it's risk....as it's better to have your car custom tuned.

The OpenECU software is used to adjust fuelling and ign, and pretty much any setting in your ECU, for it to run better on local gas, and more powerful if you want it to be.

Would it be better to leave the current tuning and use an octane boost additive to the fuel...? Would the ECU re-compensate and bring back up the boost?

This is also an option, but most "off the shelf" octane boosters will grenade your O2 sensors over time. So......you could buy some VP racing fuel .

This is the ideal option (higher RON gas)...but cost is a factor I guess.


You can look into this if you want, but IMHO, get your car checked out first by a proper/experienced mechanic, before tuning. It's pretty strange that a WRX should knock that badly on 95 RON.

See if the problem persists, then decide your next move.

[Polydor]

EcuTek locks your ECU into their software.

[Redeyeblueeye]

All very informative, I have so much to learn, thank goodness for u guys.

Who can I go to to check out the problem...?

[Alpha_2nr]

^6Get your car checked by a mechanic first.

or in my view, get your hands on some racing fuel (just this once).

Run it in your car, and see if the problem goes away. If the problem DOES go away, and only returns when you fill up with normal pump gas.....you have your problem.

That should be your first step.

[DavetoExtreme]

^6Get your car checked by a mechanic first.

or in my view, get your hands on some racing fuel (just this once).

Run it in your car, and see if the problem goes away. If the problem DOES go away, and only returns when you fill up with normal pump gas.....you have your problem.

That should be your first step.

^^What about if he does an ECU reset

[Alpha_2nr]

^^^An ECU reset doesn't change engine parameters...so I can't see why it would help.

In fact, if his car his knocking that badly that boost is dropping, resetting the ECU may make it even worse, as the ECU will lose the "learned" data of having gone into "high detonation mode/map".

All a reset will do is force the ignition advance multiplier (IAM) back down to 8....after which the ECU will try to learn/adapt to gas conditions again...attempting to reach 16.

You'll have two scenarios at this point to consider:

1) If the problem is that he got a "bad spot" of gas...then by the time the old gas is used up, and a fresh "better" gas (I use that term loosely) is put in, the ECU will correct itself in a few hours of driving, with boost returning to normal.

This could be the scenario depending on where you buy gas from. I bought Premium from Valpark gas station once..and my boost refused to cross 14.6 psi afterwards. Once that tank was done, and I continued buying near my workplace....boost levels returned to normal

So in short, an ECU reset is not really needed.

2) If the problem is a mechanical one (say faulty ignition etc), then an ECU reset will not help either.

[InDeForest]

Ok fellas, besides all of this reflashing and retuning talk

Check to see if any of the vacuum hoses on the intake manifold have split or severed, this could cause loss of boost pressure while stipp operating normally in vacuum, idling etc.

[DavetoExtreme]

^^^An ECU reset doesn't change engine parameters...so I can't see why it would help.

In fact, if his car his knocking that badly that boost is dropping, resetting the ECU may make it even worse, as the ECU will lose the "learned" data of having gone into "high detonation mode/map".

All a reset will do is force the ignition advance multiplier (IAM) back down to 8....after which the ECU will try to learn/adapt to gas conditions again...attempting to reach 16.

You'll have two scenarios at this point to consider:

1) If the problem is that he got a "bad spot" of gas...then by the time the old gas is used up, and a fresh "better" gas (I use that term loosely) is put in, the ECU will correct itself in a few hours of driving, with boost returning to normal.

This could be the scenario depending on where you buy gas from. I bought Premium from Valpark gas station once..and my boost refused to cross 14.6 psi afterwards. Once that tank was done, and I continued buying near my workplace....boost levels returned to normal

So in short, an ECU reset is not really needed.

2) If the problem is a mechanical one (say faulty ignition etc), then an ECU reset will not help either.

^^ Bess you come and tune my car boy

[Alpha_2nr]

Ok fellas, besides all of this reflashing and retuning talk

Check to see if any of the vacuum hoses on the intake manifold have split or severed, this could cause loss of boost pressure while stipp operating normally in vacuum, idling etc.

Hey InDeForest....what about his BC Solenoid (OEM one). If there're no leaking vacuum lines, then....could an issue with the BCS cause that?

[Redeyeblueeye]

Knight 1 BSC OEM one ....embarrassed but al lil confused with the terminology, care to explain.

Also, is there any chance dirty injectors and old plugs have anything to do with my boost dropping intermittently to half?

(Oh, I tried the C16 and the boost seemed intermittent as well)

[Alpha_2nr]

^^Was referring to the Boost Control Solenoid (BCS). But I doubt that's your problem. That solenoid controls your boost levels through wastegate control etc (in a nutshell).

Did you try a significant amt of C16 in your tank? If you tried just a wee bit of booster, it won't help much....

If your boost is still intermittent....then you may have a boost leak. Did you install any boost gauges recently? Cracked vacuum hoses say?

Is the boost climbing to 14 then dropping for no reason?

Is it possible that maybe you have leaky lines on your boost gauge setup, so it's registering the wrong boost maybe??

[riderz]

I agree with knight1 in this regard. Get your car checked by a mechanic but find one who is familiar with the ECU not only the engine.

Some mechanics would look at your problem as a mechanical one (eg boost leak, failing turbo etc). One mechanic even had a customer change his clutch on a STi for a IAM pull. So best bet get it checked.

Dont spend a cent until you see what your ecu is doing.

[Redeyeblueeye]

Ok did not interfere withe the BSC

Used abt a gallon of C16 to 3/4 tank ... boost intermittent towards the end of the tank

Stock without mods yet I getting abt 225 km per tank on premium. (injectors perhaps....?)

The boost pressure guage shows the boost to half but I know there is less boost when I accelerate. (so I don't think its the boost gauge set up)

It when its working its working ...no problem full boost but then when it drops to half it stays there...doesn't get up to 14 (full) just half no matter how much I rev until it suddenly like it i 'breaks free' to 14 again...(hence intermittent)

Who is ur mechanic?

[riderz]

Thats definitely the IAM. Thats easy to fix. Find someone with the cable.

[Redeyeblueeye]

Well IAM....???????

I spoke with the mechanic I paid to check the car out for my RORO purchase and explained to him the problem as I did here without telling him what u guys said.

He said immediately without checking vacuum lines or ECU or nothing that it was the BCS and that thats a common problem with all subbies and suggests I put in a boost controller.

Suppose he's wrong and I spend money for nothing...
How do you suggest I deal or address this... what to do now?