Boost or No Boost Help Needed

[FormulaSuby]

I posted this in a few places and am hoping those who browse only certain area see it.

I have an EJ20R from a 1996 Legacy GTB in a race car. I have run many events and have been working the bugs out of it. I got to an event where I could really open it up, and started having some bogging issues. I had no gages in it but a tach and CEL. I did some testing tonight and here is what I found.

I added a boost gage to the intake opening on the left intake runner where the power brake booster hooked up. When I start the car, I get a steady vacuum reading around 18". If I accelerate quickly in first or second, and hold it to redline while in gear with wheel raised, I never get below a 5" vacuum reading. It never goes to boost.

When I shift to third and try to load up the engine by feathering the brakes, again, I never see less than 5" of vacuum, and never any boost. It runs smooth to 4500 RPM, then it starts cutting out and dying.

I think I have all the lines hooked up OK. I see the secondary turbo exhaust actuator open up, and even disconnected the vacuum port going to valve that opens the turbo to the intake so it would stay open. All that did was cause a code 66 but no boost.

Is it possible that the boost gage is in a bad area in the intake? I can't see how it would matter as it still ties to the intake.

When the car cuts out, I thought it might be running out of fuel, but I am not so sure right now. I do not get any check engine light or no codes are displayed.

If I am not running off of boost, this car will be scary fast when it does boost.

Any thoughts on this?

Thanks,
Steve

[anothernord]

The best place to get the vacuum/boost signal is from the line that attaches to the bypass valve. You could have a vacuum leak somewhere else as well.

[Bookem]

Make sure your "t" for vac/boost line to the gauge is before anything in the brake boost vac line, some vehicles have a valve so during boos it is not putting pressure into the brake booster. I do believe you have either a boost leak or fuel problem though, having the boost gauge in correctly might help in tha. Get an air fuel gauge in there and get back with the readings.

[FormulaSuby]

Here is an update.

I checked the boost gage location, and it was for the vacuum booster, but there was no valve and it was open to the intake.

After further applying thottle and brake, I was able to get it to read as much as 8 lbs boost. Guess I wasn't loading it hard enough.

That still leaves my main problem. The engine is from a late 96 JDM Legacy GTB with EJ20R and twin turbos running off the factory ECU with no mods. It has yellow topped fuel injectors.

In first or second gear, even with the brakes nearly locked and boost at 7 lbs, it powers right up to redline and I can hold it there (7500), When I go to third or fourth gear and apply load, if I increase gradually, I can get it to redline. If I apply heavy load and try to squeeze throttle, the car just sputters and dies. When it is dying, it feels like it runs out of gas. It is usually at 4000 - 4500 RPM when the car shows boost. If I leave off completely, and car drops down significantly in RPM, I can go right back up. If I try to lift slightly, or mash it to the floor, it continues to die like if I have no fuel. If I keep on it, it will drop right ot 2000 RPM and start sputtering. Sometimes, I can go almost to the floor and it will pick up for a few seconds then die again. I do not have any codes or CEL while any of this is happening.

I am going to try to test fuel pressure under load next to see what happens. If I disconnect MAF or anything to put it in open loop with CEL on, it does not change.

Any other thoughts on this?

[FormulaSuby]

Just checked fuel pressure.

It sits at 46 PSI with engine off.

Starting up, it runs at 38 PSI at idle.
At High RPM, it runs up as high as 50 PSI.
Under mild boost, about 46 PSI.
When it is acting up, it never drops under 44 PSI.
Those numbers are right to what the liberty manual says they should be.

So I am guessing that it is not fuel related, but something driven by the computer that does not create a Code.

Is anyone using a datalog system with this typw and model ECU?

Thanks,
Steve

[subba]

Try this buddy.


the three hose plugs under the top mount should be like this.....
the first plug should be hose 21 and the other two should be 2 and 3.

hose #1 should be hooked up to the secondary actuator, NOT the intercooler.

I think because hoses #1,2,3 is tied together, my mechanic thought all three should be connected together on the topmount (intake air control solenoid valve) and # 21 was left dangling so he put it on the actuator. (differental pressure sensor - #22 In #21 is out to the actuator)

[FormulaSuby]

Try this buddy.


the three hose plugs under the top mount should be like this.....
the first plug should be hose 21 and the other two should be 2 and 3.

hose #1 should be hooked up to the secondary actuator, NOT the intercooler.

I think because hoses #1,2,3 is tied together, my mechanic thought all three should be connected together on the topmount (intake air control solenoid valve) and # 21 was left dangling so he put it on the actuator. (differental pressure sensor - #22 In #21 is out to the actuator)

Hi thanks for th try, but I am good there. I am tracking down some info now on these systems having as many as 4 pills in the lines to restrict signal volume.
Posts can be found here:
http://www.uklegacy.com/forums/index.ph ... ntry267490 (http://www.uklegacy.com/forums/index.php?showtopic=91427&st=20&p=267490&#entry267490)

And another one here:
http://www.ozliberty.com/home/index.php ... c&id=16475 (http://www.ozliberty.com/home/index.php?option=com_agora&Itemid=402&task=viewtopic&id=16475)

[subba]

so you got it sorted out?

[FormulaSuby]

so you got it sorted out?

Not yet but working on it daily.
I am 99% sure it is overboost due to having a no restriction exhaust.
Going to put in a fuel cut defender and boost controller.

[subba]

Before you spend big bucks, try why i told ya to do, it will only take 2 mins and its free :)

Put the boost gauge on hose #11 of the vacum solenoid block

[FormulaSuby]

Before you spend big bucks, try why i told ya to do, it will only take 2 mins and its free :)

Put the boost gauge on hose #11 of the vacum solenoid block

I did reply to your post that I know that I have those lines correct.
Did you post something about hose #11 somewhere, I must have missed it.
But based on what I know, you are asking to replace the MAP sensor with the gage to see what it reads I guess? I was actually planning on doing that tonight.
I'll post up here when I get the reading.

[subba]

Map sensor?

this guy has #12 Tapped but mine was 11 but you can look and see which one goes into the intake manifold.
http://img174.imageshack.us/img174/3701/p1000855.jpg

Here is the diagram i used( i was getting no boost, corrected a hose then i was getting secondary boost but no primary)
http://www.ozliberty.com/home/index.php ... 78#p163878 (http://www.ozliberty.com/home/index.php?option=com_agora&Itemid=402&task=viewtopic&pid=163878#p163878)
http://www.veloce.pwp.blueyonder.co.uk/Otherttdocs/TwinTurboSetup.bmp
^^^ Where it says Boost controller on the left, it should be 22 in and 21 out, if that's not hooked up correctly, either your over boosintg (open boost) or preventing it from boosting, the secondary turbo is ECU Controlled IIRC hopefully ruben see this and correct me if i am wrong but i know one is ECU controlled.

Are you feeling any boost at all?

[FormulaSuby]

OK,

Back at it last night. Re-checked many of the hoses, cleaned all solenoids and checked them for operation, traced all lines to components and they were where they should be. I think solenoid box is OK now.

Took off MAP sensor hose, replaced sensor with gage and only getting about 5 PSI with little load, but I can still shut it down, so now I am thinking it may not be over boost. I read on some boards, and the solenoid box schematic seems to show that map sensor is after a solenoid in this twin turbo system, and maybe on all.

Tonight I am going to try to rig a test light to the solenoid before the MAP, and pu a meter on the MAP sensor. What I am hoping it may show is sthat if it switches to MAP on secondaries, that I can see the solenoid open up and then watch the MAP readings. I have not checked MAP output up to this point, so it is possible that is bad sensor, wire, or ground.

After that I am going to add 5 gallons of 107 CAM 2 Race gas to take away any thoughts about octane causing this.

I did notice now when I snap throttle open, I get a pop in the intake manifold almost like a backfire. Does that give any new clues? I had not heard this before.

[subba]

sorry man, wish i could've help ya.

IS the motor in a subaru, Porshe, VW or dune buggy?

Do you have a aftermarket or Turbo Subaru Fuel Pump installed? Does the motor have a Orange sticker Maf Sensor and yellow top Injectors?


easiest thing to do is go single TBH lol