Failed Boost Controller + Throttle Body Annoyances

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thesameguy
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Failed Boost Controller + Throttle Body Annoyances

Post by thesameguy » Fri Sep 29, 2017 1:03 pm

After spending last weekend fighting a boost problem on my Saab Viggen, the XR4Ti decided to get into the act. On the way home yesterday the XR went ppooooooooooooooooft and then nowhere fast. Spent about two hours trying to find what was leaking with an intake pressure tester and got nowhere. I was just about to call it quits, when I heard a pooft from somewhere down low. It was close enough. Spent another hour replacing things with test pieces and disconnecting things and getting frustrated. As I was getting ready to pack it in for the night, lightning struck... the noise was from the damn Hallman boost controller! From the vent hole a sound like a choking owl.

This is one of those moments where I don't know how to feel. The boost controller is about 10 years old, but only has around 20,000 miles on it. I can't decide whether I should be happy about the time or angry about the mileage. It's not some random ebay garbage. I feel like it should generally last a lifetime, and shouldn't much be subject to straight age. But, it's dead anyway I guess.

So, two questions:

1. Anyone have any alternative recommendations before I just buy another Hallman? (I considered picking up a PIMP and using a solenoid, but I can't take on that work right now - got other projects)

2. Part of the difficult in troubleshooting was because the shaft sealed on my throttle body leak pretty badly. It used to be worse - I rebuilt it with new seals a while back, but it still a totally unacceptable amount of loss. I tried two other throttle bodies, both leak the same or slightly worse. This is a stupid problem and it annoys the crap out of me. Does anyone have any recommendations for a legitimate fix, or an alternatively throttle body that is visually close enough to not earn the ire of a California smog tester?

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Re: Failed Boost Controller + Throttle Body Annoyances

Post by John Brennan » Fri Sep 29, 2017 2:19 pm

Any reason why a simple manual boost controller wouldn't fill the bill?
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Re: Failed Boost Controller + Throttle Body Annoyances

Post by thesameguy » Fri Sep 29, 2017 2:42 pm

Nope, no reason - just curious if folks have opinions about better alternatives to the Hallman part.

I was really hoping that electronic ones had become affordable, but entry price is about $300 and goes up really fast. Not something I need to be doing right now. ;) It's crazy that a brain-dead technology like cycling a solenoid based on a pressure sensor is $300 worth of hardware, but I'm not that smart. :|

Edit: FWIW, the attraction of an electronic controller would be a boost limiting feature - per-gear, etc. With an 8psi wastegate (IIRC) and a 20psi Hallman, I get a nasty boost spike at around 5k rpm in 2nd, which makes for an awkward shift into 3rd. I tried messing around with difference balance between wastegate and boost controller and didn't really get satisfactory results - either totally slow boost build or gnarly boost creep in higher gears. End result is I short-shift 2nd and that's ok. It'd be nice to have a controller that would limit boost in 1st and 2nd and then open it up in 3rd. It's a pipe-dream - it's not a $600 problem for me, and if I was gonna spend that money I'd probably just do PIMP with one of the MS3 boost solenoids, etc.

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Re: Failed Boost Controller + Throttle Body Annoyances

Post by reddy2300 » Fri Sep 29, 2017 5:25 pm

http://www.boostvalve.com/

So cheap it seems like it'd never work. I've had them on about a half dozen different cars in the last 20 years. Works great.
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Re: Failed Boost Controller + Throttle Body Annoyances

Post by thesameguy » Fri Sep 29, 2017 6:07 pm

Good to know - I'd be very interested in saving a few bucks now with the intent on something more... intense... down the road! Thanks!

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Re: Failed Boost Controller + Throttle Body Annoyances

Post by Esteban » Sat Sep 30, 2017 3:54 am

The spike is the nature of a ball and spring type controller. You can try the Gillis, but these days an EBC with closed loop boost control, overboost limiter, and full tune-ability is the way to go. I have a MS2 based PiMP available if you want to give it a try. The Pierburg solenoids are only $40 or so.
Last edited by Esteban on Sat Sep 30, 2017 3:56 am, edited 1 time in total.

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Re: Failed Boost Controller + Throttle Body Annoyances

Post by Esteban » Sat Sep 30, 2017 3:56 am

BTW, what turbo are you running that you get a boost spike as high as 5k in 2nd gear? My buddy with a hallman had an issue a few months back and new internals, seals or springs, fixed that problem.

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Re: Failed Boost Controller + Throttle Body Annoyances

Post by Mike McCreight » Sat Sep 30, 2017 8:19 am

Any chance of finding an old HKS? Totally happy with my 2 stage EBC.
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Re: Failed Boost Controller + Throttle Body Annoyances

Post by thesameguy » Sat Sep 30, 2017 10:14 pm

It's a possibility, but I'm always hesitant about old tuner stuff... you know how people treat their stuff!

Today I removed the Hallman and connected the wastegate actuator directly to the manifold. Things are definitely weird. The fluttery sick sound is gone, but there is still a really loud woooooo when the turbo spools. If anyone's heard a really old turbo, you know the sound I mean. This turbo is pretty old - maybe 10 years - but has less than 5000 miles on it. It's a genuine Turbonetics T3/T4. It seriously sounds like old, failed turbo. I can't for the life of me explain such a sudden change in behavior. Real weird.

Car seems ok, other than oddly loud. I'm going to keep driving it hard, sans boost controller at about half boost and see what happens. I'd really rather not spend the money, I'd really rather not take the car apart, but meh... I guess it's not the end of the world if I have to. It'd literally be the first turbo I have ever replaced in my entire life due to failure!

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Re: Failed Boost Controller + Throttle Body Annoyances

Post by thesameguy » Tue Oct 03, 2017 2:13 pm

My loud turbo may be an exhaust leak... I drove it this morning, and about five minutes in the noise got much quieter. I'm thinking heat expansion in the exhaust sealed a leak. Maybe worth trying a new ATP flange or wastegate housing gasket, maybe with a little CopperSeal or something.

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Re: Failed Boost Controller + Throttle Body Annoyances

Post by thesameguy » Tue Oct 03, 2017 5:26 pm

Bah. Now I am getting frustrated.

Drove fine on the way to work today. Took it out at lunch and things started great. About 20 minutes in boost went from a wastegate limited 10psi to exactly 0. I looked around, replaced some unlikely but suspect vacuum hose, listened and felt with the engine running, found nothing.

Back on the road, no boost. Then boost. Then no boost. At around 0psi during a no boost moment there is a sound like someone capped off or opened up a whistle.... from nornal turbo spoiling sound to plbththth to nothing.

Upon arrival at my next destination I had a very high idle - 1500rpm or so. Initially I assumed the issue was pre throttle body since my idle was solid, but maybe things have changed. Or maybe not. Grr.

I can't tell whether there is a big intake leak preventing boost build or a wastegate issue or a preturbo exhaust issue. I have pressure tested to 20psi the intake from turbo to cylinders and shows no leaks other than the same throttle butterfly shaft leaks I have always had (and apparently all XRs do). I should be totally fine at 8psi.

Not sure of the approach here, so I am driving it around waiting for something to break severely enough to leave a trace.

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Re: Failed Boost Controller + Throttle Body Annoyances

Post by Esteban » Tue Oct 03, 2017 5:44 pm

Check clip on the WGA arm.

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Re: Failed Boost Controller + Throttle Body Annoyances

Post by thesameguy » Tue Oct 03, 2017 7:00 pm

Yep, did that, all good. Checked WGA with a Mityvac and it's behaving fully properly. No binding, good tension on the arm near as I can tell. I will double check when it's all cooled down though.

After my last post, after leaving my appointment, I hit the freeway again. First 10 minutes, no boost. Rest of the drive (about an hour), regular boost. I took some video which I'll throw up on youtube that I *hope* captures the "no boost noise." No further idle problems. This car has an extremely rare idle problem - about once every three months it does the 1500rpm idle thing - so today's event could be complete coincidence.

I went by the house and did some emergency vacuum hose re-routing. ;) I disconnected the hose to the vacuum tree and ran hose directly from the intake manifold to the brake booster. I tee'd into the FPR hose to run the WGA and BPV. I swear - I can't make this stuff up - I am getting a DIFFERENT noise than I have ever gotten before... a whooshing sound. It *could* be the air filter, it's just a data point. Boost for the next 30 minute leg. I don't know how much boost since I have no gauge now, but *some*, more than 0.

I could not quickly find my EVTM - can anyone tell me what the solenoid valve over by the vacuum "bomb" (and battery, etc.) is? I have no specific reason to think it has anything to do with anything, but I thought I should probably - 15 years later - learn what it is. LOL I assume something to do with HVAC? The *reason* why I am curious is that I am thinking about doing some vacuum system adjustments - *way* too early to know, but I can't help but wonder if my issue is a leak or similar problem in that area. It holds 20psi of Mityvac pressure, but since this problem is clearly intermittent, I don't consider that test conclusive.

I have had various boost & idle issues with this car for 10+ years, but they come and go. Mostly go. In '14 when I installed the RS500 intercooler and hybrid turbo, I assumed the problems would be cured since it was essentially a complete intake system rework. They ultimately did not change - and now have gotten worse - so I can't help but think the root cause is in something I did *not* change, like the vacuum system. I'm grasping at straws.

TL;DR: Can anyone tell me what the solenoid valve over by the vacuum "bomb" (and battery, etc.) is?

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Re: Failed Boost Controller + Throttle Body Annoyances

Post by Esteban » Tue Oct 03, 2017 7:04 pm

Fresh air door solenoid and BAP. not boost related unless they are leaking. You could temporarily cap off the port on the tree that feeds the vacuum ball to rule out that circuit

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Re: Failed Boost Controller + Throttle Body Annoyances

Post by thesameguy » Tue Oct 03, 2017 7:25 pm

The BAP is just atmosphere, though, is it not? It's not connected to the engine's vacuum system.... ?

I'm sure the solenoid I'm referring to is the fresh air vent. That's exactly what it looks like it'd be. ;)

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