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Marcus3

loss of vacuum to brake boost, bad idle, no boost

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Hi folks

I have a question,

where does the vacuum line to the brake booster connect to the engine ?

on the way home from work tonight I almost rear ended the car in front of me when I had a complete loss of brake vacuum, the car also idles all over the place and no boost at all, i think the hose to the brake vacuum assist unit has come off or has split , at the engine and before I look I went through the V8 manual and I could not find where this hose connects to the engine, can someone please help me by letting me know where this hose goes ?

I have a 1997 V8

thanks

Marcus

California, USA

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ahhh no worries, I found it and that's not the problem, brake booster is ok too, so i am guessing something under the intake manifold has come loose :/

-Marcus

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Hi Marcus3,

Please have a look at the sticker inside of your rear hatch.

There you will see that the vacuum for the brake servo comes directly of the plenum (black 1/2" hose).

BTW, just next to it there is another smaller vacuum pipe that goes into a reservoir which is used for the climate control flaps.

If you (almost) completely lost your brake servo assistance and your engine is idling way too high then you should investigate:

- is the black vacuum hose properly attached (both ends)

- is the black hose fine (no holes, cuts, splits ...)

- maybe the diaphragma inside the brake servo itself is leaking

- or you have some other severe parasitic air supply (=leak) somewhere between the throttle butterflies and cylinder head

Cheers

Marcus

www.PUKesprit.de

Hi folks

I have a question,

where does the vacuum line to the brake booster connect to the engine ?

on the way home from work tonight I almost rear ended the car in front of me when I had a complete loss of brake vacuum, the car also idles all over the place and no boost at all, i think the hose to the brake vacuum assist unit has come off or has split , at the engine and before I look I went through the V8 manual and I could not find where this hose connects to the engine, can someone please help me by letting me know where this hose goes ?

I have a 1997 V8

thanks

Marcus

California, USA

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I think my problem is the Idle valve (blue) hose from the throttle body side has popped off so I am going to remove the intake plenum (again) :/ this weekend

I checked the vacuum hoses and tested the brake booster with a vacuum pump and it's fine

the one thing I would ask (because I cant find it in my service manual right now) is , what are the torque specs for the bolts when I bolt the intake plenum back on

thanks,

-Marcus

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I think my problem is the Idle valve (blue) hose from the throttle body side has popped off so I am going to remove the intake plenum (again) :/ this weekend

I checked the vacuum hoses and tested the brake booster with a vacuum pump and it's fine

the one thing I would ask (because I cant find it in my service manual right now) is , what are the torque specs for the bolts when I bolt the intake plenum back on

thanks,

-Marcus

From Lotus service notes Section ED page 18

"Using new gaskets (dry) if necessary, fit the plenum onto the housings and tighten the plenum fixing bolts to 20 Nm (15 Ibf.ft)."

JoeyO

2001 V8

Edited by joeyoesprit

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From Lotus service notes Section ED page 18

"Using new gaskets (dry) if necessary, fit the plenum onto the housings and tighten the plenum fixing bolts to 20 Nm (15 Ibf.ft)."

JoeyO

2001 V8

excellent.... thanks Joey

-Marcus

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