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5psi Boost - what BHP?

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Old Jun 11, 2002 | 02:04 PM
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Tried both forms of ECU reset (under-dash plugs and battery disconnect) No luck. Also cleaned the thingys on driverside suspension turret (MAP, Boost Solenoid and the other one! ). No luck.

It's at the Subaru garage at the mo and they've just called to say that they haven't got a clue. They've found out that the boost solenoid fitted is a MY97 one and my car is a UK MY95 (should this make any difference?) and they are ordering a new MY95 one to see it this is the problem.

My thoughts are: is there anyway to check if the solenoid is working properly?

If the solenoid is working properly, then it must be the control system. In which case, will it be one of the other sensors, the ECU or some other wiring issue.

Anyone got any ideas?

Andy

[Edited by andyp - 11/6/2002 2:05:19 PM]
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Old Jul 11, 2002 | 11:37 AM
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Toerag - feels like it, although it still goes round corners alright.

Paul - it's a MY95, so it's a 3 port one I think. Well, it had 3 pipes coming out of it when I cleaned it - is this what 3 port means?

Garage has still got the car and they've not got in touch yet. I'm hoping it's something obvious that they broke during the clutch change/service. So if it's one of the hoses then I'll be happy.

Cheers,

Andy


[Edited by scrappydog - 11/7/2002 12:22:52 PM]
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Old Aug 11, 2002 | 01:44 PM
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Well, I've finally got a fully boosting car . And the diagnosis was a blockage in the brass restrictor thing in the boost solenoid pipe - I should have spotted that!

Garage is gonna charge me for time - but do you think this could have happened due to overfilling at the service?

They've replaced the pipe & restrictor - but aren't there different size restrictors. How do I know they've fitted the correct one?

Andy

[Edited by scrappydog - 11/8/2002 1:52:01 PM]
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Old Nov 6, 2002 | 10:03 AM
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Car is currently at the garage trying to sort out why it's only making 5psi boost. I've been driving it the last few days and wondered what sort of BHP will it be making at it's reduced boost level? Seems really slow, but how slow?

(UK car, MY95 with PPP)

Cheers,

Andy
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Old Nov 6, 2002 | 10:24 AM
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About 160 BHP if it holds 5 BHP to the top.
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Old Nov 6, 2002 | 10:39 AM
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Cheers John

So that's what a 160bhp car feels like - can't wait to get 13psi boost back!!! Although I hope it doesn't cost too much to fix

Andy
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Old Nov 6, 2002 | 01:46 PM
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did you try a ECU re-set???
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Old Nov 6, 2002 | 03:05 PM
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Is the 5Psi constant boost ?
So you never go above 5PSi ?
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Old Nov 6, 2002 | 03:25 PM
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Scrappy,

yup, that's right. Boost gauge reads the following:-
a) 0 with engine off.
b) around -8/-9 psi on idle
c) rises to 5 psi on full boost.

So I don't get any overboost, just seems to rise up to around 5 psi. i.e. WOT, 3rd gear, 5000rpm.

Not very impressive and not that much fun with only around 160bhp on tap!

Car is UK model with PPP ECU. Pulled "very strongly" before going to garage for clutch change and intermediate service, but I didn't have the boost gauge fitted. But I'd got 5.4 sec 0-60 from a Race Technologies performance monitor so I'm guessing I had more than 5psi boost!

I'm desparate to get this sorted...please help me!

Andy
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Old Nov 6, 2002 | 03:47 PM
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Does it feel as the power is coming in and out or just feels the same ?
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Old Nov 6, 2002 | 04:00 PM
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Andy, 5 psi will be about the pressure needed to crack the wastegate open.

This means that there's a big chance it's the solenoid not doing any work. Shouldn't be too expensive to fix.

If they connect the turbo nipple out directly to the wastegate they should get the same boost (boost controlled completely by wastegate). Or disconnect the power to the solenoid should do the same again.



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Old Nov 6, 2002 | 04:05 PM
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<<Does it feel as the power is coming in and out or just feels the same ?>>

Not too sure if I understood the question, but the car drives like normal - power comes on smoothly, but just when you expect to get the mid range surge of power the boost seems to just level off at 5psi. Power feels smooth, actually smoother than normal because I'm not getting the "kick in the back" that I normally get. Much more boring to drive!

Are there any characteristics I should be looking for? Got any ideas what could be wrong?

Andy

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Old Nov 6, 2002 | 04:14 PM
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Evil - I tried the "test cycle" using the green under-dash connecters and it seemed to do the clicking-thang, so I assumed it was still functioning. Anyone got a better way to test if the solenoid is functioning?
What you say it's not too costly to fix - I'm assuming a new solenoid will sort it. Any ideas on price for a new one?

Andy
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Old Nov 6, 2002 | 04:15 PM
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Right....it could be a blocked intercooler or slightly cracked plastic "Y" shaped pipe. That would cause underboosting such as what you are experiencing.
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Old Nov 6, 2002 | 05:40 PM
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Scrappy - sounds plausable. I wounder if a cracked Y pipe or blocked intercooler be caused during the clutch change? I know a clutch change is usually an "engine out" job - but what does this mean? Would they have to disconnect all the hosing etc when doing the change - I'm guessing yes because they broke the radiator expansion tank while changing the clutch.

However, the garage did say they "disabled" the wastegate (not too sure how) and ran it up to see how much boost it got and they said it boosted okay until the fuel-cut came in.

Andy
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Old Nov 7, 2002 | 01:15 AM
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Get a pair of mole-grips round the wastegate, that'll sort it
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Old Nov 7, 2002 | 09:31 AM
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if it's the later boost solenoid, it's only a 2 port design. SO it's feesable that the plumbing in place just doesn't allow it to work properly, the whole setup is matched, including the boost maps in the ECU, any restrictors etc.

Paul
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Old Nov 7, 2002 | 09:34 AM
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Are you sure you didn't take home a forester S-Turbo by mistake?
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