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Discussion Starter · #1 ·
Hi all
Two separate questions really.
Firstly, I have got my self a replacement BPCV after Gordy was kind enough to lend me his for the day to confirm that this was the cause of some problems I was having. My replacment is now fitted and this has totally stopped the tubo boost pulsing that I was getting at WOT. I do have one query regarding this though.....I no longer boost into the red. The car is a 1993 9000 aero I was under the impression that it should boost slightly into the solid red at WOT, but instead it is only going into the red/yellow hatched bit. I have tried disconnecting the battery a couple of time (once for 2 mins and, when this had no effect, overnight). After reconnecting and taking it out for a run it still only goes onto the hatched red/yellow and not once did it go through the thumping fuel cutouts that it used to. I thought the fuel shut-offs were part of the normal adaptation after the battery had been disconnected??? Is this not alwasy the case? Any ideas?

Second question....when I pull away I can often hear a dull clonk from, I think, the front driver side wheel area. I had hoped that this might have been a result of flexing due to the old wishbone bushes, but I now have poly ones on there and the wheel alignment checked...but it still clonks. I can't feel any flex in the ball joint. Again, any ideas?

Cheers for any help/advice
Kev
 

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Over boost cut out isn't normal- you shouldn't get it during an adaptation run.

The gauges aren't that accurate and your car may be boosting to the corret levels. The only way to be sure though is to use a caibrated gauge- you could also check the base boost at the same time.

The clonking could possibly be the subframe needing to be tightened- it's a fairly common cause of that sort of noise.
 

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Discussion Starter · #3 ·
Cheers Mark
If the clonking is the subframe needing tightening should I be able to see some sign of scuffing around the responsible bolts?

For the adaptation I'll find myself a gauge then. I'd been wanting to check the base boost anyway.

Kev
 

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Discussion Starter · #4 ·
Hmmmm....I'm not convinced it is just a gauge inaccuracy now. When I drove home last night it would only boost half way through the yellow. This morning it is back to mid hatched red. The car is also soundiung a bit gruff. Made me wonder if there was an exhaust leak before the turbo, but I would have thought this would be like a million shotgun salute if there was enough gas leaking to slow the turbo

I may just replace the vacuum pipes to be on the safe side (BTW, how is the vacuum generated?) as I wanted some more colourful ones anyway, just in case it is a leak.

Is there anything else that might cause a combo of gruffness and low/variable boost?

Kev
 

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when my DI pack was on its way out, the car wouldn't give me full boost and would feel very 'gruff' but only when on boost. I would only get a boost into the yellow. New DI boosts well into red.
Mine had a real hesitation - felt like a bit of a misfire at full boost. Sounds like yours is generally 'not happy' through the revs. hmm
 

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Discussion Starter · #7 ·
Sorry Mark. Someone contacted me before your post appeared. I should have contacted you sooner I know, but I wanted to check that the one I have fitted was good before saying I didn't need another
 

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The engine can be thought of as an air pump in some ways. The vacuum is generated by the pistons drawing in air (and fuel) on the induction cycle. The more the throttle plate is closed, the greater the vacuum, as the engine is trying to pull air in but the plate is resisting the flow, causing a pressure drop on the engine side of the plate.

Just to confuse matters, on a turbo car, sometimes some of the "vacuum" pipes are under positive pressure, so they are badly named really.
 

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Discussion Starter · #9 ·
Cheers John

So more correctly they might be called 'pressure differential pipes', or some such?

It always helps me to understand what is going on (or wrong) if I understand the logic (or illogic
) begind something.
Kev
 

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Discussion Starter · #10 ·
Just have to say that I'm
and pleased as Punch to have full boost back and working properly for the first time since I got the car, now that I have the new BPCV installed AND the correct brake light bulb installed
. Put my foot down in third on a hill yesterday and nearly went off roadin'...crackin'
 
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