keeweechris

1999 GTB BH5 running sluggish... new owner things to look for?

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Hi all,

I'm after a few tips on where to start diagnosing a ****ty performing stock gtb. It's done 170000km, NZ new, and it fairly good nick, but doesn't really perform. Never driven another BH5 GTB, but heard they should have a bit of hoof.

Big turbo lag from standstill, nothing really happens until about 3.5k. Nothing really happens there either, but you can hear an obvious induction sucking noise, which I don't think should be present on a stock gtb. Has to get to around 5k for the secondary to kick in, and get through the VOD.

For 280hp, it really has no seat-of-pants to it. Feels like a big old heavy granddad car.

Feels a bit like something's up with boost, or lack of boost. Fuel economy is ok though, about 9L/100km open road, so I figure the guts of the engine is ok. No smoke or anything.

What are common problems with a 17 year old gtb? Where do I start looking?

Thanks guys.

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how much boost is it running man?

Manual/Auto?

REV A,B,C or D?

The more info you give us the more we can help :D

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Thanks b01z.

It's manual, and I don't have a boost gauge. I'm figuring I need to buy one and hook it it up asap?

What's the Rev A/B/C/D? How can I find out?

Cheers

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 keeweechris said:
Thanks b01z.

What's the Rev A/B/C/D? How can I find out?

Cheers

They were different revisions that the BH/BE series Legacy's were brought out in.

Rev A/B/C were all quite similar from what I gather but Rev D came with a factory ECU that can be remapped

and some further detailed engine changes that I can't answer confidently.

Being a 1999 I would suspect yours is a Revision B but this can checked on the car info plate with the chassis number colour code etc.

It should read BH5A, B, C or D which will tell you what you've got.

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Cool, thanks GG, I'll check tonight. Yeah, prob not a RevD, but that would be nice. I remapped my 06 WRX with a romraider stage1 base map, and made world of difference. Would love to do that to the gtb, but too old I think.

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"It's manual, and I don't have a boost gauge. I'm figuring I need to buy one and hook it it up asap?"

With a boost gauge installed you will be able to diagnose weather or not you have a Vac or Boost leak, if neither of the two are apparent it could be something as easy and a solenoid that needs cleaning, sometimes the turbo inlet pipes crack/split which can cause a whole hell of a headache, again if you find something wrong replace it with a part that is new, the last thing you want to do is rip apart most of the motor to find that it all needs to come back off again at some stage because the 2nd hand part you installed failed.

Alot of the time the plastic piping under the intercooler crack/split, I suggest replacing these if you pull the intercooler of as they are restrictive standard and they are a prick to put back on.

I am fairly new to this forum but I believe there are quite a few people that have posts up about how to do most things related to these motors.

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Thanks b01z.

It's a RevB by the way, if it makes any difference.

I was kinda after any common probs with this car first, but yeah, will get the boost gauge sorted soon and get some readings.

Cheers

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should be very little lag. My RevB is on about 10psi by 2k, and 15psi by 2.5k. At 3k, its hard to keep off boost in 5th.

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Good to hear. Def something wrong with mine then. What are common problems which prevent boost on gtb's?

Saying all that, once it's finally climbed up to 5-6k, it goes pretty well. But takes ages to get up there. Does that point to the primary being poked? Or a leak in the primary plumbing?

Hope it's not that rubber turbo intake pipe wedged under the intake. That's a bastard to see, let alone replace.

What's the best way to check for intake air leaks? I had this random thought of pumping some sort of smokey gas into the intake, so you'd see where it was escaping, but not sure if that's possible?

Cheers for any idea's.

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Have you checked the primary down pipe for a blocked or collapsed cat converter? Or maybe check for to make sure I cracks in primary up pipe?

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 les666 said:
Have you checked the primary down pipe for a blocked or collapsed cat converter? Or maybe check for to make sure I cracks in primary up pipe?

Thanks. Nope, not yet, but I will!

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 keeweechris']Good to hear. Def something wrong with mine then. What are common problems which prevent boost on gtb's?

What's the best way to check for intake air leaks? I had this random thought of pumping some sort of smokey gas into the intake, so you'd see where it was escaping, but not sure if that's possible?

Cheers for any idea's.

A lot of workshops use a smoke test just as you've described. Another couple of options below:

[quote name='Rosssub said:

To check for boost leaks. Either spray ether (starter fluid) or anything highly flammable around any possible vac/boost leak spots. If any fluid gets sucked in the idle rpm will change straight away.

Or block the intake off at the AFM end:

img]https://s25.postimg.org/or4nozjqn/Fuel_pump_ECU_fix_014.jpg[/img]

Then use an air compressor to pump 10-15 psi into the intake manifold through a vac hose. The system should hold pressure, any air/boost leaks will hiss and be obvious.

Fuel_pump_ECU_fix_015.jpg

If nothing shows up, then as b01z mentioned it could be a dirty solenoid. Most often inside the BBOD, here's a write up on cleaning it out:

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

Then also clean out the primary boost solenoid inside the F/L guard, if it's blocked you'll get waste gate spring pressure at 7.5psi:

Primary_Boost_Control_TT_004.jpg

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Oh - don't forget to run it in test mode and see if obvious things like the IACV are opening and closing.

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Thanks Rosssub and Duncanm, legends. Got plenty to get on with now.

Yeah, BBOD was on my list.

Why the hell is the prim boost solenoid hidden under the front guard? Seriously!

Still miffed why I can hear induction sucking (or hissing) on boost on a stock car. But I bet I'll find something with the intake leak test. Off to get some ether...

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Posted (edited)

Bringing this thread back from the dead... thats ok, I'm the OP.

 

Finally got round to making a smoke tester (soldering iron in jar with babyoil, works brilliantly). Found a pretty obvious leak around the primary turbo intake, mostly from around the worm-clamp head, but also from somewhere on the other side of the fitting. I'm guessing it's time for a new intake pipe... that looks like a b!tch to change.

 

 

Cleaned out BBOD solenoids and boost solenoid too, and did hose 10 mod.

 

Also got a boost guage hooked up a while back... about 10psi on primary, 15psi when secondary comes in. So guessing the bits from turbo's onward are ok.

 

Saying that, after putting everything back after BBOD cleaning today, I'm only getting 9psi, and nothing later in rev range (5-6k). Almost like there's no secondary now. I think I missed something. Any idea's?

Edited by keeweechris
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Problem fixed, the primary boost solenoid was stuck closed. I opened it up, looked like the plunger/seal got stuck to the port inside, and solenoid couldn't pull it back (open).

 

This is interesting, because the Exhaust Gas Control Valve Duty Solenoid (in BBOD) is the same type, and I had exactly the same problem after cleaning out the BBOD the first time. A day after flushing it through with CRC Carb Cleaner it got jammed shut. Had to open it up (pry back the metal tabs) and clean it again from the inside. After reassembling it worked ok again. I'm guessing the carb cleaner reacted a bit with the rubber seal inside and made it stick to the port inside.

 

Anyway, back to 10/15psi boost. Now to replace that intake pipe with a new silicone one.

boost solenoid.jpg

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Four years haha jk it's cool to see the older subies being fixed, I'm sure principles will apply to single turbo cars too as stated in the thread i/c pipe and turbo intake do fail, it's happened to both on my 95 wrx and I need to replace them! 

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7 hours ago, swamp said:

Four years haha jk it's cool to see the older subies being fixed, I'm sure principles will apply to single turbo cars too as stated in the thread i/c pipe and turbo intake do fail, it's happened to both on my 95 wrx and I need to replace them! 

 

Haha, I know. Thought someone might benefit from hearing how I got on. Yeah, there's plenty of life left in the old girl yet. It's a challenge too, learning about how they all work. Over-complicated though... a single turbo system is so much simpler.

 

I inspected the pipe properly today, and it's rooted. All perished underneath the end rubber bit. Someone told me it's caused by oil (from crankcase breathing system) sitting inside the pipe, and the oil eats the rubber.

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I'll definitely refer to this thread, the soldering iron smoke device sounds good 👍 if it's the gasket you can get by with rtv, I made my pipe work by taking it to supercheap and fitting together all sorts of rad hose, slipped over smaller hose, hose clamped together. That's because I needed it to work ASAP and a new replacement is like 200 nzd (ej20g wrx v1 mind you) though I should do a proper fix ASAP! 

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Yeah, I'm seriously considering doing a similar thing. If I can get a good condition used pipe, I might be able to cut mine off at the red line without having to remove the whole intake manifold/etc. Cut in same place on the new part, then find a metal pipe to fit inside as a sleeve, then hose clamp both sides down.

(red arrow is where the damage is)

 

Annotation 2020-05-01 095914.png

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Posted (edited)
51 minutes ago, Technikhaus said:

Damn that is stuffed!

Yeah, it's almost like its dissolved or something, only on the under-side. The replacement pipe I got has fairly thick rubber there.

 

I guy I talked to thought blow-by oil collects there, and over time eats the rubber. Makes sense, as I had a fair bit of oil in my intake and IC, and all over the top of the engine.

 

The big ol hose clamps wouldn't help. I'm going to replace with T-Bolt hose clamps, which should be gentler on the rubber.

 

Clamp T-Bolt 140-150mm PT SS JBS HD

Edited by keeweechris

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