did a boost leak test and no boost?????

[drmotorsports]

earlier today me and a buddy of mine did a boost leak test and couldn't find or hear any so I thought only the best. but the last time I went to look at the boost gauge I noticed it wasn't moving at all. recently I did a 14b swap and installed a new boost gauge along with the dejon tool licp for a 2g with a 14b. I can't figure out what it could be.

any suggestions?

thanks

jason

 

[liquordrunk]

First off when you ride in the car. does it BUILD boost. if so then the guage is hooked up wrong or either a wire is come lose of something of hte sort.

 

[drmotorsports]

yea I build boost just fine (running 15 psi). vac sits right where its supposed to.

 

[liquordrunk]

yea I build boost just fine (running 15 psi). vac sits right where its supposed to.

But just your gauge doesnt work... have you opened the hood and checked ot see if the Vac line is still hooked up.

 

[drmotorsports]

yea everything is still hooked up fine I'd made sure before we stopped testing.

 

[liquordrunk]

okay so your gauge is STILL not working? then your gauge is bad.

 

[drmotorsports]

no the gauge is fine. driving it shows boost fine. just when I was doing the leak test it wasn't showing any boost at all when it should have.

 

[RamenPride]

no the gauge is fine. driving it shows boost fine. just when I was doing the leak test it wasn't showing any boost at all when it should have.

because you have a leak somewhere. spray soapy water on the pipes to find it/them.

 

[IMMORTALSPYDER]

Where's the gauge tapped in to?

 

[drmotorsports]

its tapped into the same place as my last one. which is the vac port on top of the intake mani on the drivers side. I just went for a drive and when I try and launch (auto) I can't leave with more than about 5 psi. and it feels very very weak.

 

[steve]

Does your guage need power to work?

If it's doesn't, like most mechanical boost gauges, then clearly your leak test didn't pressurize the intake.

Steve

 

[CyberEye]

Turn the motor over by hand to Top dead center, then try. The first time I did a boost leak test on my 2g I couldn't get the boost gage to move when pumping air into the system. Turned it to TDC and it built boost just fine.

 

[steve]

That's interesting since TDC is one of the worst places to do pressure testing since either 1 or 4 will be in overlap with both sets of valves open. I usually tell people to do 30 degrees before or after TDC when at most one set of valves of any cylinder is open.

Steve

 

[oldman]

Turn the motor over by hand to Top dead center, then try. The first time I did a boost leak test on my 2g I couldn't get the boost gage to move when pumping air into the system. Turned it to TDC and it built boost just fine.

I think I told you the same thing steve just said when you made the same claim three months ago.

earlier today me and a buddy of mine did a boost leak test and couldn't find or hear any so I thought only the best. but the last time I went to look at the boost gauge I noticed it wasn't moving at all.

1. Disconnect or turn the mbc all the way in during test.

2. Open the oil cap and listen for leaks.

3. Listen for hissing at your tail pipe.

4. Spray soapy water like mentioned above.

steve is right, the intake isn't being pressurized. Either the compressor is too weak or you have huge leaks.

 

[drmotorsports]

thanks guys I'm gonna bring the car to my friends who has a bigger compresser and re-test it. the one we used was pretty dinky.

 

[ColdAudio]

since oldman is transforming me into a boost leak testing expert, let me tell you this: use a good sized compressor that has a tank as well or else you aren't going to get anywhere, at first i used a small pump and built between 1-4 psi, so after i used a 2 gal like .5hp and it worked perfectly building 16 psi and actually showing the leaks, you can usually find someone whos got one or if not sears has em for about 100-150 bucks, good luck!

 

[Jiggalude]

What's the easiest way of telling your 30 degrees before or after TDC?

 

[steve]

The 30* isn't critical, it's just easy to find. It's twice the distance on the crank pulley as the space between TDC and 15* BTDC on the front cover.

 

[4gfun]

All I see is 10 degrees BDTC on the marker. I guess it would be 3 times as far in that case? I am just wondering why mine is different.

Also, what mark am I looking for on the pulley. Is it a little notch?

I am in the middle of a boost leak check....not to hijack but the thread looks relatively dead and I found this one in a seach.

Thanks!

 

[Absit]

Does your guage need power to work?

If it's doesn't, like most mechanical boost gauges, then clearly your leak test didn't pressurize the intake.

Steve

I'm gonna re-ask this question because it's the simplest answer. Which boost gauge do you have?

 

[steve]

I'm gonna re-ask this question because it's the simplest answer. Which boost gauge do you have?

I have several, not that it matters. Lets say Autometer.

Mechanical gauges only use power for the lighting. The actual pressure measurement is via a Bourbon tube and gears to move the pointer. If you don't know what that is Google it.

Electronic gauges usually have a MAP sensor connected up to the pressure source and they need power for both the sensor and to drive the pointer.

 

[steve]

All I see is 10 degrees BDTC on the marker. I guess it would be 3 times as far in that case? I am just wondering why mine is different.

Also, what mark am I looking for on the pulley. Is it a little notch?

There is a notch in the pulley edge, that's the timing mark,

On the front cover there are marks for TDC, 5* BTDC, 10*, and 15. Only TDC and 10* are labeled.

 

[Absit]

I have several, not that it matters. Lets say Autometer.

Mechanical gauges only use power for the lighting. The actual pressure measurement is via a Bourbon tube and gears to move the pointer. If you don't know what that is Google it.

Electronic gauges usually have a MAP sensor connected up to the pressure source and they need power for both the sensor and to drive the pointer.

Yes, that's all true, which is why I re-asked the question you asked that wasn't answered by drmotorsports. It wasn't directed to you, I just quoted you for reference.

 

[4gfun]

There is a notch in the pulley edge, that's the timing mark,

On the front cover there are marks for TDC, 5* BTDC, 10*, and 15. Only TDC and 10* are labeled.

Thanks again!

 

[Thomas91169]

probably a gaping leak somewhere that your turbo is able to pressurize but your dinky compressor isnt.