low vaccuum at idle

sneakypete

Regular Member
Jul 18, 2007
1,129
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0
Central NJ
after installing my maftpro ive noticed that my vaccuum at idle is only around -9.8 the car actually runs very well, but something is not right with the vaccuum.
ive check over and over again for vaccuum leaks and changed all the original fittings, hoses and tees but its still the same.

anyone have any idea why it would be so low?

the only thing i can think of is that the hose that goes from the turbo to the boost solenoid, then to the wastegate is a smaller diameter than the fitting but i squeezed it on there anyway (ran out of the larger hose).

i removed the egr and vsv and all that. the only vaccuum lines that i have go from the back of the intake manifold to the cruise control and heater. and the front of the intake manifold to: bov, afpr, and map sensor.

any help would be appreciated
thanks
-pete
 

sneakypete

Regular Member
Jul 18, 2007
1,129
0
0
Central NJ
thanks
my idle is at around 850 rpm at idle. too high i assume. guess i need to work on lowering that.
thanks for the link
-pete
 

sneakypete

Regular Member
Jul 18, 2007
1,129
0
0
Central NJ
could have anything to do with the screw on the tb? a year or so back i had a wierd problem with what i thought was my tps and i gave up and brought my car to a toyota "specialist"... ill never do it again. he turned that screw to make the idle right and it turned out after i got the car back that it was the afm. anyway when i swapped the afm the car ran fine but my idle was way too high... so i turned the screw to lower the idle a little bit. been running fine since but the idle has been around 850-900 rpm since. if i turn this screw could i correct the idle?
 

johnathan1

Supra =
Aug 19, 2005
5,056
1
36
35
Downey, California, United States
The idle speed is computer controlled by the ISC, so it shouldn't need adjustment.

However, I also had a high idle problem for a long time, I checked every possible source for the problem (including ISC) and everything checked out OK...so I ended up adjusting the screw, and set the idle to 650RPM warm idle, and it has been perfect ever since...