Boost and Hesitation Problem 2000 BE5B RSK

Hey, so I've had my Legacy for about 2 and a half months now, imported from Japan. About a month and a half after owning it I started experiencing a boost issue, every now and then it would slightly hesitate if I got on boost in primary and shifted into the next gear before VoD. After the shift boost would hover at about 4psi for about 2-4 seconds (feels like forever) if I applied a fair amount of throttle or full throttle. After about 2700rpm it would start boosting properly and jump to 13 pretty quickly until either VoD or I shifted.

This problem now happens all the time if I'm applying enough throttle to get on boost in first gear (or 2...3) but only after I shift into the next gear is when I experience that slight lag.

I have also noticed that the exhaust note changes and becomes a little bit deeper and less of a burble after the shift. Leading me to believe it could be something to do with the waste gate or exhaust control. Not familiar enough with these cars to go any further than that.

If I boost into secondary it behaves just fine with no extra lag. Also if I boost in first gear, shift and then gradually apply throttle in the next gear or apply full then back off a bit it boosts fine. This issue is only present if I apply full throttle after a shift.

For mods I have done the hose 10, placing a 0.8mm restrictor pill into hose 1 to slow IACV opening speed although I didn't notice such a difference as stated here http://clubsub.org.nz/forum/showthread.php?40911-Inside-the-BBOD&p=526939&viewfull=1#post526939

Is there anyone that would know what could be causing this issue? Thanks!

Exactly what rpm do you shift?

If it's anywhere near 4000-4500 rpm on load then it is just stuck in secondary mode and needs a couple of seconds to return to primary mode once you change gear.

If I shift while still in primary, usually at 2800-3500

It didn’t start when you did the hose 1 mod did it? Could have a play around with that and see if it’s related. I doubt its causing anything but still if you didn’t think it had an effect then remove the pill.

Honestly it just sounds like your getting tangled up in the VOD/change over.

Rome1017 can you upload a few pic's, showing your hose 10 mod. BOV hose and hose #10 bleeding back to the intake.

I would think it's a bov problem but the issue happens much sooner than vod. The hose 1 does shorten vod tho. But yes the issue was there before the mod, I had hoped adding the pill would help with the hesitation.

Ok I can upload pictures of that tomorrow.

Sweet, keen to see a pic of your hose setup. Will save asking a lot of questions. Thinking either BOV or ECV misbehaving.

Here is the BOV hose

http://postimg.org/image/d0z3vo41f/

And the capped hose from inlet/hose 10

http://postimg.org/image/8p391rk6r/

http://postimg.org/image/x7uwllzg1/

I really think its something to do with either as well, just not sure what

There's another hose #10, coming from the primary boost solenoid inside the F/L guard and running behind the battery. Is this hose connected, venting or T'd in somewhere?

Pull the BOV hose off at the manifold and suck on the hose, you should hear the BOV open. Then cover the end of the hose with your tongue and make sure it holds vac. If it wont hold pressure there's a hole in the BOV diaphragm.

Put the car into test mode (green & black plugs), so fans cycle on/off and all solenoids start clicking. While in test mode the ECV and IACV (intake air control valve under TMIC) should both be moving open/closed.

Wasn't able to do this today but I will find out how everything is tomorrow.

So i checked the BOV, all good. Put it in test mode and it looks like the IACV is not moving at all, ECV sounds like it is though.

I removed the restrictor pill to see if this was causing it and even without it it still doesn't move. With the pill removed it still drives the same and it still boosts properly to ~16psi in secondary. what do you think could be the issue?

You should be able to see the ECV actuator rod moving in test mode:

The IACV is held closed with vacuum during single turbo mode:

With the IACV not working in test mode, it's not getting vacuum. So it's open during primary boost causing problems.

During test mode both the IACV and ECV are running off stored vacuum from the TT vacuum tank. Could be:

-Leaking/spilt hose between the manifold and BBOD, (hose 12 from manifold-BBOD feeds vacuum).

-Faulty one way valve inside the BBOD.

-Gunked up IACV solenoid in the BBOD.

-Could test the IACV diaphragm same as BOV diaphragm.

-Also check the hose at the base of the BBOD that runs into the F/R guard, this hose runs to the vacuum tank. Most likely if you've had the BBOD out recently.

The blue valve in the middle of the BBOD is the one way valve:

Here's a BBOD clean out how to, for dirty/sticky solenoids:

http://www.uklegacy.com/forums/index.php/topic/11043-code-66-and-boost-issueshow-to-clean-them-out/

Here's a pic of hose 12 from the BBOD into the F/R guard, running to the vacuum tank:

Thanks for the link. So when cleaning the solenoids the car should be on (not running)? I'm looking to do this tomorrow as well as test the IACV.

The one way valve (hose 12?)only allows air to flow from the bbod to the mani correct? And is hose 12s only function to feed air away from vacuum tank?

From which way should I clean the solenoids? or does it not matter?

And at idle do all the hoses that go to the bbod feed air away from it or are there any that go the opposite?

Thanks for all the help.

For cleaning, have the car in test mode (ignition on/engine off). So the solenoids are opening-closing as you spray carby cleaner through them.

Doesn't matter which way the spray goes through. Some of the solenoids have a small air filter on top. You can carefully rotate the filter and slide it off, then clean out the filters too.

Correct on the one way valve flow, only from BBOD to manifold. So it wont let manifold boost through, only vacuum. It doesn't flow much at all, but definitely only one way.

Hose 12 gives manifold vacuum to the BBOD. Inside the BBOD (after the one way valve), hose 12 splits to give vacuum to the IACV solenoid, the ECV negative solenoid and the secondary relief valve negative solenoid. Then connects to the vacuum tank, which stores vacuum for the solenoids to use when the manifold is in boost.

So a complete loss of vac tank vacuum can effect 3 solenoids. IACV/ECV/Secondary relief valve.

So being that my ECV is working properly its unlikely that hose 12 or the check valve are the problem here correct? Also what does the secondary relief do exactly? And the Positive and negative ECV pressure solenoids? Would love to know each solenoid's function.

Also does it matter the pressure I spray the carb cleaner at?

Sweet, with the ECV working in test mode. Then it's either the IACV diaphragm, IACV solenoid or a split in hose #1 between the IACV actuator and BBOD. If the IACV solenoid was dead, you should get CEL-61.

All the info your after should be in here:

http://clubsub.org.nz/forum/showthread.php?40911-Inside-the-BBOD/page2

Could it be a clogged IACV? I put my finger over the hose 1 nipple at the BBOD while in test mode and couldn't feel any air flow or vacuum. there is also what looks like some oil residue on the IACV. I haven't seen a CEL come on at all.

Pull hose 1 off at the BBOD, then suck on the hose. You should see the IACV actuator move as you suck. Then it should hold vacuum if you block the end of the hose.

IACV holds vacuum. Tomorrow I will be cleaning the solenoids. hopefully this solves my issue.

Could unbolt the BBOD from the guard and pull it forward slightly. In test mode, put the tip of a flat head screwdriver on the IACV solenoid. With the screwdriver handle on your ear you should hear the solenoid clicking open/closed.

If it's not clicking, then unplug the BBOD loom plug and use an external 12v to test the solenoid (speaker wire/car battery).

The IACV solenoid is the 2 white wires/pins at the BBOD loom plug:

 Rosssub said:

BBOD Wiring:

Solenoid: +/- Colour Code

ECV Duty Solenoid + Pink P

- Black B

Map Sensor + Pink P

- Green G

ecu signal White W

ECV Negative Pressure + Brown Br

- Brown Br

ECV Positive Pressure + Blue L

- Blue L

IACV Solenoid + White W

- White W

Supercharged Relief #1 + Pink P

- Pink P

Supercharged Relief #2 + Green G

- Green G

Map Vac Solenoid + Yellow Y

- Yellow Y

So I cleaned all the solenoids in the BBOD, they were all clean except for the ECV solenoid, a whole bunch of dirt popped out of that one.

They were all clicking as well while cleaning.

After the cleaning I went for a little drive, CEL 45 came on and there was no boost. The CEL soon went away but still no boost. decided to disconnect the battery for about half an hour and there still wasn't boost. Now there was a whooshing sound coming from the BBOD, thought it was just a loose hose but everything was connected fine. Pulled each out one at a time while checking with a stethoscope to see which was the problem one.

Turned out to be that I had not cleaned the filter of the Negative ECV solenoid well. That solved the boost issue.

Went for a drive and I still had the minor lag after the shift at full throttle. I made a video to show this. https://www.youtube.com/watch?v=l4KcCrGKOBo

First gear to 3rd. Shifts are at 4k rpm falling to roughly 3k in the next gear. Throttle is applied when boost rises to 0psi.

Also notice the change in exhaust note until it starts boosting again.

The only solenoid I didn't clean today was the Boost control. Could this be my issue? I will be cleaning it tomorrow.

Are both the IACV and ECV working in test mode? The IACV should also close on startup/at idle.

CEL 45 is the pressure change solenoid/atmospheric pressure change solenoid. Hose 11 goes from the manifold to the BBOD, to the pressure change solenoid and then to the MAP sensor.

During deceleration the pressure change solenoid blocks manifold pressure to the MAP sensor. So that the MAP sensor can read atmospheric pressure.

This pic shows the location of the MAP and pressure change solenoid (labelled as MAP feed control).

Primary boost solenoid in the F/L guard:

Yes they are both working in test mode.

Sorry I completely forgot to post the video! https://www.youtube.com/watch?v=l4KcCrGKOBo

Sweet, yeah now that the IACV is working give the primary boost solenoid a cleanout. Also back to an earlier question on your hose 10 mod:

 Rosssub said:

There's another hose #10, coming from the primary boost solenoid inside the F/L guard and running behind the battery. Is this hose connected, venting or T'd in somewhere?