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vacum lines

Getting the best performance from your Isuzu, the in's and out's

vacum lines

Postby gcisuzu » Tue Sep 15, 2015 2:51 pm

I have put a 3.1 into my 92 mu which had a 2.8 the 3.1 has few more vacum lines and extra solarniods are they important to the running of the engine or are there some I can do way with is there anyone with one on the gold coast I can referance with any help appreciated
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Re: vacum lines

Postby turnturn » Tue Sep 15, 2015 8:45 pm

From memory there are only two or three things that use vacuum in a 92.
1) Brake booster, big hose from vacuum pump to brake booster. This is a neccesity.
There is a vacuum supply line (smaller, about 6-8mm diameter) that runs from your vacuum pump over to a couple of actuators mounted on the passenger side inner guard. These actuators trigger -
2) Fast idle for air conditioning (part of your Injector Pump). Handy if you use the air conditioning a lot in city driving.
3) Exhaust Gas Reticulation (EGR) valves on your intake manifold. This can be removed/disabled.
4) Quick Warm-up System (QWS) is two vacuum operated butterfly valves. One in your intake system and one in your exhaust system. The actuators for these two may be on the drivers side inner guard. These can be removed/disabled. On the 2.8 the exhaust butterfly valve is part of the exhaust manifold. On your 3.1 donor motor it was probably about under the drivers seat.

Also be aware that there is another hose that looks very similar to a vacuum hose but is actually a boost hose. It goes from your intake system (post turbocharger) to the Boost Compensator that is part of your Injector Pump.
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Re: vacum lines

Postby gcisuzu » Wed Sep 16, 2015 5:31 am

Cheers for the advise
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Re: vacum lines

Postby Mukaniko » Fri Dec 18, 2015 2:56 am

Hello Everyone, I have an isuzu Mu which has all its vacuum hoses messed up and i would like to know which goes where regarding Fast idle for air conditioning.

im form PH which is hot and humid so i use AC alot but its hard to compensate for idle speeds on heavy traffic.

thanks in advance!
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Re: vacum lines

Postby geeves » Fri Dec 18, 2015 5:08 am

From diaphram on the injector pump vac line goes to a solinoid then joins the othere hoses and goes to the alternator
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: vacum lines

Postby Mukaniko » Sun Dec 20, 2015 3:08 am

Thanks alot mate, one more thing there 2 solenoids and both were disconnected. Any idea which of the 2 should i connect the vac line?
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Re: vacum lines

Postby geeves » Sun Dec 20, 2015 6:13 am

Only suggestion is to use a piece of tube to see which one operates with the air con.
Sanding your knuckles before starting work can help. That way you cant skin them
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