What is a "REAL" boost leak test?
 

Been trying trace down a boat load of Boost leaks after I installed a new FMIC and a small 20G.

@ WOT the car sounds like a broken gas main, and gives off a gaint PSHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH, sound like I've never heard before?

Why now, does this thing sound like it's leaking so bad?

And the car actualy fells a bit SLOWER than before?.....:-<

I've found a leaks off the the IC pipe, and the PVC valve and corrected or blocked them off.

The car still won't hold Boost, it leaks out almost as fast as I can pump it in with the compressor?

Cause I'm now finding leaks on biss, injector and TB shaft seals?

I've talked to a local un-named "DSM Guru" and he said that I'm being "anal" by doing the boost leak tests, and that these smaller leaks, like on th TB shaft, biss and injector seals, are too small to even matter, and that the turbo should "make up" for these kind of leaks?

My questions is what is a "REAL" boost leak test?

I've read else where that it should be able to hold it at whatever the amount of LBS od boost, that you plan on Boosting at WOT, and it should hold there for about 30 seconds?

Is this "anal" or not? Are the "smaller leaks" imporatant or not?


Many Thanks in Advance................


Howie

Re: What is a "REAL" boost leak test?
 

The BISS and TB shaft are common leaks that often aren't worth fixing, since they are tiny and sometimes hard to fix. You should fix any leaks at the injectors, leaks there can be fixed and they can turn into large leaks quickly.

Are you using an air compressor? It should be able to maintain a decent boost level for a bit, unless it's a small tank.

Re: What is a "REAL" boost leak test?
 

Keep in mind with new hard pipes and a bigger turbo you will actually hear the air moving through the IC/pipes and actual spool up. I remember that when I got my car back from QPR last summer and I thought it was a big ass boost leak but was actually the sound of air moving through 2.5 stainless pipes. Later that season we did a boost leak test and only found one at where I blocked off the PCV fitting on the intake manifold.

Re: What is a "REAL" boost leak test?
 

Yep I'm using a compressor. So should the "boost system" HOLD the pressure I'm putting in with the compressor on the Turbo inlet for like 30 seconds or not?

The car does spool ~3600, and hold 20lbs on the gauge to redline?

But I does seem a like fair amout of air is leaking out of the TB Shaft and Biss seals?

Guess I can start with the Injectors first?

Do I need to release the fuel pressure some how before removing the fuel rail to replace the seals? Do I need to buy new insulators as well as the seals?

Any links to a good tech articles or walk throughs for this n00b, who has never installed a fuelrail or injector seals?



TIA......

Re: What is a "REAL" boost leak test?
 

Thanks for your input!

If there wasn't a big boost leak "somewhere" I probably shouldn't have a problem with DSMLINK reporting that I'm ok running at a ~18/1 A/F, but when I richen it up to where DSMLINK reports close to 11/1 the car bogs and back fires?

This leads me to believe that the Mas is measuring Air that never makes it to the motor, there by giving the symptom of running ok while that lean?

Does this make sense, or am I way off base?

I'm really trying to diagnose the weak power, strange loud noise and weird DSMLINK reading symtoms to get this car back on base?


TIA.....

Re: What is a "REAL" boost leak test?
 

I never tried the pump it up with a bicycle pump or whatever method for checking boost leaks. I can't imagine it works the best or gives you the best idea of how bad a boost leak exactly is without some actual CFM going through the system. Don't expect it to hold perfect pressure though, even with no boost leaks, it will all eventually get out in the motor anyways.

Insulators are the seals. Buy new ones from Mitsu, they get old and hard over time causing leaks. You can try to relieve the pressure one way or anything or just pull the fuel rail off and be ready for fuel. There will be fuel no matter what you do. Just don't drop the 3 black fuel rail spacers, they can get lost in the 2G intake manifold, you might want to tape them to the head before pulling the rail off.

Re: What is a "REAL" boost leak test?
 

Shane, I have a Big tank craftsman compressor, NOT a lame bike pump man!

Thanks again for the good tips!

Re: What is a "REAL" boost leak test?
 

try soap/water mix, should work at any psi, just watch for the bubbles. :P cheap too, also on ur tb, injectors spray the area with carb cleaner......idle goes up... leak

Re: What is a "REAL" boost leak test?
 

Soapy water is how I found the Injector and Biss leaks, carb cleaner on the injectors is a good idea too!

Thx!

Re: What is a "REAL" boost leak test?
 

Yea, I read that wrong the first few times.

Re: What is a "REAL" boost leak test?
 

btw, make sure to lube the inj. O-ring before reinstalling them... and check for cracks, breaks..etc.

Re: What is a "REAL" boost leak test?
 

Any comments on this???

If there wasn't a big boost leak "somewhere" I probably shouldn't have a problem with DSMLINK reporting that I'm ok running at a ~18/1 A/F, but when I richen it up to where DSMLINK reports close to 11/1 the car bogs and back fires?

This leads me to believe that the Mas is measuring Air that never makes it to the motor, there by giving the symptom of running ok while that lean?

Does this make sense, or am I way off base?

I'm really trying to diagnose the weak power, strange loud noise and weird DSMLINK reading symtoms to get this car back on base?


TIA.....
__________________

Re: What is a "REAL" boost leak test?
 

What kind of MAS are you using?

Re: What is a "REAL" boost leak test?
 

OEM 2G Mas, with the default 2G MAs setting on v2.5 of DSMLINK.

Re: What is a "REAL" boost leak test?
 

Ok, so if you were to have a boost leak, since your MAS is before your turbo and IC, you would be losing metered air. Therefore the ECU will add more fuel than is actually needed, which would create problems while under boost, bucking, backfiring, etc... I had a similar problem when my ECU was acting up last summer and I would go under 10:1 with any amount of boost than the car would hate me and buck real hard for a moment until all the unburnt gas got out of the cylinders. Now when you add fuel by richening the sliders on DSMLink, yes you would be adding even more fuel and not helping anything at all, and causing the symptoms you list. So yes, your thinking is correct in your situation. For those of us that have MAF-T's in blow through it doesn't matter because the air doesn't get metered until it going into the TB, so there would have to be a pretty big leak there to cause anything. Not that buying a GM MAS setup is the fix, as it only hides a problem, but just the other scenario, which obviously doesn't apply to you.

Get those leaks taken care of and go from there. Also, are you using a wideband O2? Or are you just going off of the claculation that DSMLink makes for you? If using DSMLink, do you have its individual settings set right? Then also you have to realize it is going off of data that also involves your MAS, which isn't telling the ECU the right info with all those boost leaks. Plus in the end the AF ratio function built into DSMLink is just an estimation, not something I would completely rely on. IE to get the backfiring and such you are now, you are probably going a lot lower than 11:1 like it said.

Hope this helps.

Re: What is a "REAL" boost leak test?
 

Thanks much for verifying my thought and troubleshooting process on this issue.

I'm going to fix all the leaks, <have a new 63 mm TB ordered to take care of the TB Shaft and Biss leeks, and then I'll need to buy and install new injector insulators and seals> THEN I can take this AWD A/T car to RS Racing PREPARED for some Dyno/Wideband time.

Re: What is a "REAL" boost leak test?
 

I wouldnt order a TB, if it is leaking it is very minor, like Ecoli mentioned. Most Boost controlers have a bleed hole that will leak out more than the TB will adn its not a big deal.

If you care that much just order the TB shaft seals and a new BISS screw.

Re: What is a "REAL" boost leak test?
 

Have you checked your intercooler for leaks? Just because its brand new doesn't mean that a a weld didn't break open.

Re: What is a "REAL" boost leak test?
 

I haven't heard any from that area, buy also haven't sprayed it with soapy water yet either? I'll try that as well, Thx.....

Re: What is a "REAL" boost leak test?
 

Is there a cheaper Wideband system that lets you use the wideband O2 sensor as the cars front O2 sensor, or do you have to put in another hole into your O2 housing?
Is there a system that can dump the wideband A/F data off to the DSMLINK as well? What's the best value in onboard Wideband systems right now?

TiA

Re: What is a "REAL" boost leak test?
 

The stock O2 location is too close to the turbo for a wideband. The best value for use with a laptop or system like the DSMLink is the Innovate LC-1.

Re: What is a "REAL" boost leak test?
 

Or you could get the PLX M-250, that doesn't have the display on it. You would then have the reading only through DSMLink or other logging software. I bought the M-300 and that is the same but has a seperate display so I can see my AFR just by looking down.


PS if you plan on running race fuel to dyno, don't, Ron won't let anyone dyno with race fuel and use their wideband. At least that is the way it was last year.

Re: What is a "REAL" boost leak test?
 

Thanks out again for the great info to you both!

Re: What is a "REAL" boost leak test?
 

Check this out!

The M-300 Controller come with two analog outputs, linear wideband and narrowband. Our linear wideband output gives you the freedom to interface with a number of tuning devices, such as data loggers, piggy back fuel systems and stand alone engine management systems. With the narrowband output you are able to completely replace your stock narrowband sensor and "feed" our analog signal directly into your ECU. This eliminates the hassle of welding a second sensor bung on your down pipe. Your ECU will "think" that your narrowband sensor is still there while you're measuring wideband information at the same time!

http://cgi.ebay.com/ebaymotors/PLX-D...spagenameZWD1V


Sounds like this is the shit for $300.00 including the display! And it REPLACES the regular O2 sensor??? Now all I need is the $300.00!....:->

Re: What is a "REAL" boost leak test?
 

Honestly, if you are able to hit 20 psi, you probly do not have that many holes in the system. I have had it where I couldn't build more than 10 or so on the turbo. I wouldn't mess with the TB. Just get a new BISS oring at your local hardware store. Check the core and pipes and call it a day. With how your tune sounds, it sounds as if you have a huge leak but I cannot see why you are able to hit 20 psi though...

Re: What is a "REAL" boost leak test?
 

That's the exact one I use. I just replaced the stock sensor with the WB and used the narrowband simulator to go back to the ECU and then used the wideband output to log to DSMLink. The nice thing about the PLX system is that it uses the VW style Bosch sensor which is right around 40-60 dollars to replace when it goes bad, as opposed to some of the other sensors that go into the hundreds to replace.

Re: What is a "REAL" boost leak test?
 

I have been able to make over 30psi and hold it with a large crack hole in my intercooler, it did make it much laggier and lose a 100 HP though.

Re: What is a "REAL" boost leak test?
 

The real issue here is not nessesarly the leaks at the TB, and Injectors, it's WHY all of a sudden is the car slower and DSMLINK shows that I'm running so lean , 18/1 and the car is even slower?

This changed with ONLY the swapout of new small 20G and a install of a FMIC?

It would make sense that I have a large boost leak, that is causing the "false estimations" from DSMLINK right?

Guess the smartest thing is to nail down as many of the leaks as possible, and get on a wideband?....Or???

Also can you buy the M-300 unit without the display, and just dump the signal off to your DSMLINK?

And do you need another seperate "module" to make that M-300 WB O2 sensor work in narrow band mode?

What would you guys think between spending the $200-300 for a wideband unit or $100-200 for some time at the RS's AWD dyno/WB?

I know I should be getting both but, my DSM budget and my wifes tolerance is running pretty lean as of late.......;->

Or does Elite have a portable WB unit so Shane could just help me street tune and diagnose this pig, for a price of coarse?

Agian a Thank you both for the solid information!

Someday I'd like to get this A/T slug into the 13's!

If I had all the $ I put into this damm 2G A/T car, put into a 1G M/T, bet I'd be close to the 11's by now!

Re: What is a "REAL" boost leak test?
 

As I mentioned above, the M-250 is the same thing as an M-300 but without the display, they run 249 from Mach V motorsports. And not nothing is required to make it seem like a narrowband O2 to your ECU, just got cut and tap into some wiring at the ECU and then you are done. Easier than installing an AFC.

If I remember RS Motors wideband for their dyno is one that only would go into an existing bung, unlike Elite's where it just goes into the tailpipe. Therefore you would either have to weld an additional bung in, or if you don't have your rear sensor anymore and still have an open bung you could do that.

Re: What is a "REAL" boost leak test?
 

Just replaced all the injector seals, man the old ones were totally crap! Took it her out for a run and it is much better than before! Still need to look at the DSMLIMK readings, but my alternator is toast so gotta find a good one somewhere before I can test any further. Please PM me if you know where I can get a descent one for a 2G auto?

Thx......

Re: What is a "REAL" boost leak test?
 

Anyone know just how does the PLX M250 interface with the DSMLINK?


TIA....

Re: What is a "REAL" boost leak test?
 

Well you would use one of your unused inputs to hook up to the output from the PLX. I don't know what the unused inputs are on a 2G, I think MAP, BARO(Only if you use lock BARO or a GM MAF), EGR Temp, or the Rear O2, I think those are the available ones. A quick search of the DSMlink forums would yield the answer you are looking for. It doesn't need to be specific for the 250, the 300 would work too, so if you find a thread that says 300 it hooks up the same, just because I have seen a few threads for the 300 on there recently.

Edit:
After looking, this thread has some good info for all the inputs that are available on a 2G:
http://www.dsmlink.com/forums/showth...ight=2G+Inputs

Re: What is a "REAL" boost leak test?
 

The PLX M-300 should be here Friday, hope to have it all setup and tuned up better for the cookout!

Thanks for your help!