how to test vacuum?

[lorolia]

one of the procedures to test for rough idling in the symptoms manual says:

"check intake manifold vacuum at dynamic chamber while engine is idling.
Reference value for Vacuum: 18.9 inHg (480 mmHg) at idle.
is intake manifold vacuum within specification?"

So my question is: is this reference value correct? because I went to my local kia dealer asking for making this test and they told me the reference value is incorrect...is it true?

also how do you do to test vacuum? where do you connect the device for measure this value?

thanks

[TEXKIATECH]

you gat a vaccum gauge and hook it up to the vaccum pot you are trying to test. and usually the vaccum at idle is 30inhg

[ron1004]

480 mmHg (or more) vacuum at idle is correct.

Connect the vacuum gauge to the inlet manifold - basically anywhere after the throttle body - if you don't find a convenient point to connect , temporarily remove a vacuum hose and connect the gauge in its place.

[2004riotuner]

Originally Posted by TEXKIATECH

you gat a vaccum gauge and hook it up to the vaccum pot you are trying to test. and usually the vaccum at idle is 30inhg

Yeah um.. Once again.. Don't open your mouth.. 30 inhg is a perfect vacuum if your engine is running at that you have mastered something that can only be acheived in outer space. You engine should idle around 22-25 inhg.. I am assuming the use that like Ron said as a lowest amount of vaccum to meet the standard possibly any les vacuum then that and you have a vacuum leak. You can remove the connection to the pcv valve and use that for a vacuum source it may be the easiest one to get to so you can check.

[lorolia]

what if mine measures around 237 mm Hg at idle? this is according to the hi scan pro device (connected in the diagnosis connector in the engine bay)
is it bad if it measures that?

This car has no OBD-II connector just the "diagnosis connector" or maybe you know it with the "data link connector" name.

Something else I´ve noticed is it won´t give me as many info or codes showing something is wrong as in usa version model.
I now have the correct translation to english for the symptoms my car is showing...the word is "stall".

My car stalls driving in a normal hot and sunny day and when I demand power from it pushing the gas pedal...it makes this stalling for about 1 or 2 miliseconds
this has happened only when engine is fully warmed up and it will do it once or twice in a month period.
I´m also getting misfires and I have the sensation it has poor acceleration on demand.

what else should I check/change?
They alredy change the computer once and I´ve made this list of sensors I´d like to change:
1-TPS
2-ISC
3-CKP
4-Knock
5-CMP
6-ECT

What do you recommend?

I really want to fix my car...any idea?

I already changed the t-map sensor and noticed no improvements.

Every time they connect the kia scanner it doesn´t show any codes.Now I know why. Because this "siemens" computer is made to only show this codes: (maybe because emissions are not important at all here)

P0107
P0108
P0112
P0113
P0117
P0118
P0122
P0123
P0131
P0132
P0135
P0201
P0202
P0203
P0204
P0325
P0335
P0340
P0440
P0606
P1505
p1506
p1507
p1508

Maybe the program that carries the computer is different or maybe the brand beacause I´ve seen on ebay kia rio computers with the "bosch" brand but this one is siemens.
Also if you have the kia microcat EPC it will show you different part numbers of PCM or ECT for different regions all over the world

[TEXKIATECH]

Originally Posted by 2004riotuner

Yeah um.. Once again.. Don't open your mouth.. 30 inhg is a perfect vacuum if your engine is running at that you have mastered something that can only be acheived in outer space. You engine should idle around 22-25 inhg.. I am assuming the use that like Ron said as a lowest amount of vaccum to meet the standard possibly any les vacuum then that and you have a vacuum leak. You can remove the connection to the pcv valve and use that for a vacuum source it may be the easiest one to get to so you can check.

ok well i think you are not correctly informed becuse when you pull a vaccum on an a/c system with an a/c machine it goes to 30inhg which is only about -15psi so maybe you should shut your mouth. and why would vaccum gauges for cars gow as low as 30inhg. and thats whre it should stay at idle connected to the intake manifold after the throttle body i dotn know if that changes with different altitudes like up in canada but here in southern N.America thats were cars idle

[ron1004]

Originally Posted by TEXKIATECH

ok well i think you are not correctly informed becuse when you pull a vaccum on an a/c system with an a/c machine it goes to 30inhg which is only about -15psi so maybe you should shut your mouth. and why would vaccum gauges for cars gow as low as 30inhg. and thats whre it should stay at idle connected to the intake manifold after the throttle body i dotn know if that changes with different altitudes like up in canada but here in southern N.America thats were cars idle

You cannot expect the same vacuum on the cars inlet manifold as you can achieve with the A/C vacuum pump.

The range of a gauge is not confirmation that the system to which it is attached can attain that range - much the same idea as a cars speedometer.

The Effect of Atmospheric Pressure on Vacuum Level
Maximum Vacuum
Level Attainable at Sea Level
(inches Hg)
29.921

[TEXKIATECH]

Originally Posted by ron1004

You cannot expect the same vacuum on the cars inlet manifold as you can achieve with the A/C vacuum pump.

The range of a gauge is not confirmation that the system to which it is attached can attain that range - much the same idea as a cars speedometer.

The Effect of Atmospheric Pressure on Vacuum Level
Maximum Vacuum
Level Attainable at Sea Level
(inches Hg)
29.921

im going to send you a vaccum/booost gauge. thenyou can hook it up and show us the results it will be 30inhg at idle. and also 29.9 is close enough to 30 to call it thirty. but seriously i will send you a boost gauge made by stewart warner for free to test out your 22-25 inhg theory

[lorolia]

so what if mine measures 237 mm Hg? is it wrong?

I found 237 mm Hg = 9.33 in Hg

[TEXKIATECH]

if its at 9inhg at idle you sir have a vaccum leak