Seeking help on understanding weird vacuum gauge

[Gabrielfrancisteo]

OK guys, before you all start to flame me....i did use the search button and google to find out more but dun understand tons and din really find the answer.

 

Background.

 

Have one of those taiwan guages, "Auto garage", installed in this old mit lancer. The GLX model. Manual. 5 plus year old.

Car also have those open pod air filter.

 

When idle the needle states, slightly below 10, din fluctuate nor jump around or even wiggle. just stays there. Steps accelerator, the needle will move towards 0 and rather responsive to the pedal.

 

Search all over, seems that the needle should be showing 14-22, but mine is below 10. And i dunno if it is because open pod air filter is affecting it.

 

Dare not really bring to a mechanic as i dunno if there is any problem, dun have much money to pay for repairs and rather paranoid if mechanic use fear tactics on me.

 

Please help me with some advice as to what i can do to check if anything is wrong, or if anything is wrong at all.

 

BTW, car drives smoothly.

 

Thank you very much.

 

 

 

[Yc86]

You might be tapping from the wrong vacuum source, or your hose to the gauge (or sensor if electronic gauge) might have a leak somewhere.

 

Care to share where you are tapping the vacuum from? or if you're sure that it's correct, try another hose.

Edited March 5, 2012 by Yc86

[Ladykillerz]

OK guys, before you all start to flame me....i did use the search button and google to find out more but dun understand tons and din really find the answer.

 

Background.

 

Have one of those taiwan guages, "Auto garage", installed in this old mit lancer. The GLX model. Manual. 5 plus year old.

Car also have those open pod air filter.

 

When idle the needle states, slightly below 10, din fluctuate nor jump around or even wiggle. just stays there. Steps accelerator, the needle will move towards 0 and rather responsive to the pedal.

 

Search all over, seems that the needle should be showing 14-22, but mine is below 10. And i dunno if it is because open pod air filter is affecting it.

 

Dare not really bring to a mechanic as i dunno if there is any problem, dun have much money to pay for repairs and rather paranoid if mechanic use fear tactics on me.

 

Please help me with some advice as to what i can do to check if anything is wrong, or if anything is wrong at all.

 

BTW, car drives smoothly.

 

Thank you very much.

 

i used to drive GLX but with auto gb, installed with a big carbon charger (open pod filter) and my vacuum reading is about 23.

from what you had mentioned, the needle stated below 10 and when accelerate, the needle move towards 0. this means the connection is somehow correct.

open your car bonnet and check the rubber hose connecting the vacuum gauge, either your hose is leaking (hairline crack) or the hose is not fully insert properly.

 

just to add, maybe during the installation, the vacuum hose is forced into a small gap causing the hose to be either twisted or bend and thus, the reading is incorrect.

 

Edited March 5, 2012 by Ladykillerz

[Heelntoe]

Your gauge displays in PSI or inHg? If in PSI, then -10psi should be the normal range

[Ladykillerz]

Your gauge displays in PSI or inHg? If in PSI, then -10psi should be the normal range

 

yup, you are right.

-23inHg / 2.036254 = 11.295psi

[Gabrielfrancisteo]

Guys, thanks for the replies.

 

Reading is in inhg, at least that's what indicated on the gauge. Btw, analog gauge.

 

Did try to open up the bonnet but pure idiot, have no idea what I am looking for nor at. As this car is purchased recently, I guess my only choice is to visit some mechanic. Dun wish to trouble anyone here as I suspect this discussion will drag on quite a bit.

 

Nevertheless, I dunno if attaching a pic here will help but here it goes anyway.

 

Guys, really thanks for ur time.

Edited March 6, 2012 by Gabrielfrancisteo

[oomph]

this forum got a lot of gearheads, I'm sure they will help. just be patient, give it some time, and ask politely!

[Zhlow]

Low vaccum gauage reading common causes are the following :

 

1. choke/ kinked hose

2. leaking hose result in loose of pressure

 

for vaccum guage there are basically 2 source to tap from ur engine. look for your air intake pipe. from there there should be a T-joint with one small tube connected. trace the tube all the way to the rear of ur engine bay, where the pipe will enter a rubber "hole" together with other wires on the right rear wall of the engine bay on the drivers side. alternatively, u can trace from the right rear wall of the engine bay, there is a hole where wires are coming out, u should see a rubber tube ( those fish tank type ) that is the vaccum tube for ur gauge.

 

As many wires are coming from this hole, and due to the soft characteristic of the rubber hose, the hose can be pressed by other wires resulting in u getting low readings. try pressing n repositioning the tube ,press the tube move it left and right , to loosen it. ( i noe it sounds wrong. =P) . check if any changes to vaccum reading. this shuld solve the problem.

 

 

[Kwanheng]

Low vaccum gauage reading common causes are the following :

 

1. choke/ kinked hose

2. leaking hose result in loose of pressure

 

for vaccum guage there are basically 2 source to tap from ur engine. look for your air intake pipe. from there there should be a T-joint with one small tube connected. trace the tube all the way to the rear of ur engine bay, where the pipe will enter a rubber "hole" together with other wires on the right rear wall of the engine bay on the drivers side. alternatively, u can trace from the right rear wall of the engine bay, there is a hole where wires are coming out, u should see a rubber tube ( those fish tank type ) that is the vaccum tube for ur gauge.

 

As many wires are coming from this hole, and due to the soft characteristic of the rubber hose, the hose can be pressed by other wires resulting in u getting low readings. try pressing n repositioning the tube ,press the tube move it left and right , to loosen it. ( i noe it sounds wrong. =P) . check if any changes to vaccum reading. this shuld solve the problem.

0 means pistion leak, which also comes with alot of other stuffs, engine eat oil, rpm not stable, car losing power.

 

1.6 car for me i get 17 to 21 idle in N, 15 in D.

the other qns is how much oa the idle oil press?

[Gabrielfrancisteo]

Thank you everyone for your replies.

 

Read up even more and while reading keep referring to the car engine. Finally found the vacuum tube and does looks a little old. cant see that it is anywhere bent out of shape nor any knots. Straighten the tube a little, tighten the joints then start engine, still display the same.

 

Finally, decided to change the vacuum tube since it is the cheapest and tube does look a little old. (maybe my eyeballs old)

 

Went down to a workshop, paid about 20 dollars to change tube. Mechanic told me to change to a thicker tube and i changed. After almost 45 mins of wrangling, comes to showtime.

 

Start engine and display remains the same. At this point, i felt like a complete idiot and fool. Just wasted 20 dollars. Sigh...

 

Which of course, now begs the question. What is the problem then....

 

I am curious yet afraid to find out more.... Spent a good portion reading up again, common theme that keeps coming up, seems like some worn out rings. (I am really grasping for straws here, i have no idea.)

 

Am i falling into the classic case of penny wise pound foolish here???

 

If i may ask one more time, is there anyway for me to find out whats wrong?

 

Thank you once again for your time and replies.

 

Really lost.

[Kwanheng]

Thank you everyone for your replies.

 

Read up even more and while reading keep referring to the car engine. Finally found the vacuum tube and does looks a little old. cant see that it is anywhere bent out of shape nor any knots. Straighten the tube a little, tighten the joints then start engine, still display the same.

 

Finally, decided to change the vacuum tube since it is the cheapest and tube does look a little old. (maybe my eyeballs old)

 

Went down to a workshop, paid about 20 dollars to change tube. Mechanic told me to change to a thicker tube and i changed. After almost 45 mins of wrangling, comes to showtime.

 

Start engine and display remains the same. At this point, i felt like a complete idiot and fool. Just wasted 20 dollars. Sigh...

 

Which of course, now begs the question. What is the problem then....

 

I am curious yet afraid to find out more.... Spent a good portion reading up again, common theme that keeps coming up, seems like some worn out rings. (I am really grasping for straws here, i have no idea.)

 

Am i falling into the classic case of penny wise pound foolish here???

 

If i may ask one more time, is there anyway for me to find out whats wrong?

 

Thank you once again for your time and replies.

 

Really lost.

let me hint you, the gauge might be faulty. test with our gauge, before spent a bomb for new rings.

[Zhlow]

let me hint you, the gauge might be faulty. test with our gauge, before spent a bomb for new rings.

 

agree. try squueze hard on ur vaccum tube to cut off air flow. see if the reading drops. ( suppose to drop if air is cut off in the hose) If reading no change, highly likely vaccum gauage faulty. It is rather unlikely for piston rings to be worn out during the 10yrs lifecycle of a mitsubishi and given tht ur car is considered still nt very old...unless previous owner whacked the engine jia lat jia lat...

[Gabrielfrancisteo]

Wow this is a piece of advice i have never seen anywhere on the web. Thank you very much. Will be trying that later.

 

Errr...if this sounds like a stupid question, please forgive.

 

Does it matter which part of the tube is squeeze? The part in the engine bay or the part just before entering into the gauge.

 

Once again, thank you all for your replies.

[Gendut]

To help you further please show a pic of your gauge at idle and when throttle is opened. Better still if you have a video. Because you did not describe the readings in the proper convention.

 

And I find it puzzling you did not ask the shop that changed the hose, the problem.

[Ladykillerz]

Wow this is a piece of advice i have never seen anywhere on the web. Thank you very much. Will be trying that later.

 

Errr...if this sounds like a stupid question, please forgive.

 

Does it matter which part of the tube is squeeze? The part in the engine bay or the part just before entering into the gauge.

 

Once again, thank you all for your replies.

 

agree with some of the mcfers, the gauge might be faulty.

try going to WS and borrow a new gauge, just plug it in and see if the reading is still the same.

trouble shooting method, might work though. hope it helps. cheers!

[Kwanheng]

agree with some of the mcfers, the gauge might be faulty.

try going to WS and borrow a new gauge, just plug it in and see if the reading is still the same.

trouble shooting method, might work though. hope it helps. cheers!

well, it happen to me. so here i am sharing

[Zhlow]

Wow this is a piece of advice i have never seen anywhere on the web. Thank you very much. Will be trying that later.

 

Errr...if this sounds like a stupid question, please forgive.

 

Does it matter which part of the tube is squeeze? The part in the engine bay or the part just before entering into the gauge.

 

Once again, thank you all for your replies.

 

i would recommend u to check 2 points, squueze the tube just before the gauge, or rather, the stretch between the A-pillar where the tube comes out to the gauge. second part is check the stretch between the air intake towards the rear of the engine bay wall where the tube enters the passenger cabin.

 

this method will see if ur gauge is still sensitive to any change in pressure. if u see readings nt changing highly lykly its a mechanical problem in your gauge.