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Old 11-01-2017, 07:43 PM   #691
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Removed that hose as per below which shows it's three termination points, the plenum, the brake booster and interestingly, directly over the air flow plate....



The hose was free flowing in both directions I blew down although I sensed some sort of click that didn't appear to restrict flow.

The engine wouldn't run properly with the inlet to the plenum blocked off completely or completely open.

There exists a status somewhere in between blocked and open that would allow it to run, but I wasn't able to find that compromise with my finger tip. Is that normal?
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Old 11-01-2017, 07:44 PM   #692
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I think I'd try and borrow a wide band gauge to see what it's doing on start up.
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Old 11-01-2017, 07:52 PM   #693
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Quote:
Originally Posted by type3 View Post
I think I'd try and borrow a wide band gauge to see what it's doing on start up.
I believe wide band needs welding into the down pipe to get sufficiently hot to be accurate. Not the sort of thing that can be borrowed?

Plus, nobody can tell me what warm up AFR numbers should be.

"A bit richer" is all I can find. 14.2:1? 13.7:1? 13.2:1? 12.7:1? etc?

Without knowing what it should be, I can't tell if it's where it should be.

CO numbers say it's rich when cold. But becomes 'correct' after 3 mins when the WUR / AAV have reached their warm running state, yet the issue continues for much longer until properly warm. Suggesting it's not mixture related?

What we know for certain is that the issue persists until properly warm.
We also can see from the CO numbers and the fuel pressure tests, that correct fuel pressure and mixture is achieved within 3 mins.

Yet it got closest to running well when massively rich.

Driving me nuts.
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Old 11-01-2017, 07:55 PM   #694
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I think I'd just clamp the hose as close to the plenum as possible.. the hose that goes to the air box is obviously to account for the servo air usage, fuelling wise.. if the pipe is clamped shut it should rule the whole system out.. maybe yours doesn't have the valve to the airbox.. the click could have been the one way valve to the servo?
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Old 11-01-2017, 08:01 PM   #695
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Quote:
Originally Posted by Philsmatewhoknowsstuff View Post
I think I'd just clamp the hose as close to the plenum as possible.. the hose that goes to the air box is obviously to account for the servo air usage, fuelling wise.. if the pipe is clamped shut it should rule the whole system out.. maybe yours doesn't have the valve to the airbox.. the click could have been the one way valve to the servo?
What difference does clamping the hose as close to the plenum make compared to what I just did by blocking off the plenum intake inlet tube with the hose out the way?

Both blocked off at the plenum, right?

Either way, with it blocked off at the plenum it wouldn't run.

Ah, hang on.... I didn't block off the inlet duct end, bugger...

Back in 10....
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Old 11-01-2017, 08:35 PM   #696
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No, runs like absolute dog shit with the plenum end blocked off.
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Old 11-01-2017, 08:37 PM   #697
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I would try and apply air pressure into the inlet, hopefully if there are air leaks then it should show up.
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Old 11-01-2017, 08:45 PM   #698
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I concur.. fire up the leak down tester! Let's find an air leak
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Old 11-01-2017, 08:56 PM   #699
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Quote:
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I concur.. fire up the leak down tester! Let's find an air leak
For another night - it's blowing a crazy gale and its freezing cold.

However...

Can someone explain the venturi Y shaped plastic part in the brake booster vacuum hose section?

I understand that the venturi design is to maintain more even vacuum under closed throttle etc, but given it links into the intake ducting, downstream of the air flow plate, how does this not act like a partially open throttle, delivering air directly from the air flow plate to the intake manifold, after the throttle body flap?

i.e, the throttle might be closed, but there's still effectively a hose of metered air getting right into the plenum?
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Old 11-01-2017, 08:59 PM   #700
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I concur.. fire up the leak down tester! Let's find an air leak
Help me work out which cyl will have an open inlet valve first after #1 is at TDC....
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